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Definitive Technology (Def Tech) BP7006/BP7004/BP7002 - BP8954MOD

datrumole

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Mar 26, 2020
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BLOWN/BUSTED Definitive Technology (Def Tech) BP7006/BP7004/BP7002 Amp Module? - Read On (BP8954MOD)

so i stumbled into some bp7006s in a nice package deal

i tested them in person only to find that the output on one of them was limited, and the other appeared fine

upon further inspection when i got them home, i realized they were both having some output issues. one was like '50%' output, the other, barely made any noise

called def tech after numerous reports on how good their support was, i was deflated to find out how poor their support now is. despite numerous folks reporting they have been replacing failed BP amps at no cost, and even polls taken from owners showing almost a 50% failure rate, they refused to take ownership of the issue. quoted me at 200/ea to replace, and after fighting tooth and nail only offered a 25% discount. and this is to replace the busted modules with the SAME design, not even a new and improved design offering more reliability. f that, sucks when a company falls from doing the right thing in the name of profit

rant over, anyway, i searched the interwebs only to find someone who suggested replacing a bank of caps that are a frequent issue. i performed that fix, and to no avail, the output was still limited. i suspect the main caps, but the continued guessing game will get costly

so i searched for a different solution. after inspecting the toroidal transformers, i learned we had dual 24v and 49.5v AC leads to work with

the 49.5v leads would have been great, but ultimately as the voltage goes up, so does the cost. the ~66-68VDC that would have produced would have required some beefy rectifier boards, added cost, and space. and as the power went up on the amp modules, the cost did as well

i figured i didnt need that of power to push these 4ohm woofers in the BP7006s, plus i really didnt know the VA rating of the transformer

enter, the TDA8954 (picked up this one (x2), a whopping < $20/module): https://www.ebay.com/itm/US-TDA8954...o-Amplifier-Board-Core-BTL-Class/303086477878

while most of the ebay posts indicate this is 4ohm BTL stable, the spec sheet says otherwise. however since we are only bring ~32VDC to the table and they are rated to 41VDC, 80% capacity should be enough to ensure they dont overload/overheat.

the only spec i could find on input sensitivity indicated 1.4v, most AVRs should be able to supply enough voltage to run the board without needing a pre-amp/pot stage. maybe as this MOD evolves, someone can work something more exotic into the picture

it already has the power supply baked into the board, so all you needed to bring to the table was the 24VAC leads, awesome. plug and play

the entire MOD should run $30-$40/ea speaker depending on how many parts you have lying around

and the obvious downside, you'll lose the ability to power it with speaker line inputs. honestly, while the manual suggests hooking them up this way, most professionals frown against it. there is greater control to be had using them in an LFE capacity and letting the AVR control the bass management. i suspect when the manual was written, bass management may not have been as mature? who knows. if you really needed that, we could build a small circuit to handle, but that goes beyond my skillset

you'll need:

(2) RCA female inputs (ebay, 7bucks for like 5 pairs, make sure they come with nylon/plastic spacers)
(2) Bread board/ .25"/.125" wood/peg board....whatever
(2) TDA8954 amp modules
(8) Standoffs of some kind for the amp board

Spade/Quick Connect connectors/crimp connectors (assorted depending on how you wire it up)
Soldering iron
Wire
RTV/Silicon
Sockets/Wrenches (metric)
Screw drivers

REMOVE THE PLATE

first we need to remove the plate from the speaker. disconnect the 11 outer perimeter screws from the plate. take a flat head and pry the edges, work your way around the plate prying little by little while also pulling up on the power cord (it's fine, it can take some pulling). eventually it will separate from the box and pull out

disconnect the speaker leads from the plate. you'll have two leads that connect to the speaker inputs (these are the upper speaker arrays), and two leads that connect directly to the amp module (goes to the woofer)

REMOVE THE AMP MODULE

the speaker input leads have a wire running from them, to the amp module. using a socket, remove the nut, washer, spade terminal/tab, and then the ring connector that the wire is connected to. put the spade terminal, washer, and nut back on. do this one at a time, one of the spade connectors is fatter than the other, so just make sure you're paying attention if you do them both at the same time before you put it back together

remove the input sensitivity knob (potentiometer, pot). place two flat heads under each side of the knob, pry up, it will pop off with some force. take a socket and remove the nut under the knob

find the power connector from the transformer to the amp board. it likely has some glue crap to hold it in place, just hack away at that glue with a flat head, push the tab, and pull up to disconnect

remove the screw that is right next to the RCA input

remove the two screws that hold the head sink to the plate (not the triangular brace between the transformer and amp module)

remove the two screws under the amp board that hold it to the triangular brace

optionally, you can remove the two screws that hold the triangular brace to the plate as you can always replace it later. we use this to mount our new board to

NOW the fun part, disconnecting the amp from the f'in glue. honestly, there really isn't an easy way to do this other than just prying and rocking. get a flat head under any spot you can, and start prying up, little by little. apply some force to the board in all directions, up down left right, pull side to side...etc. just keep working your flat head around until you can get it under the board and apply more and more leverage. the two troubled areas will be the RCA input, and the LED. if the LED breaks off, thats fine, one less hole to seal later. the glue should be very rigid, so it will crack and break eventually, just be patient. it will separate

i think thats it, you should now be left with just the speaker terminal inputs, the triangular brace, the transformer, and possibly an LED the ripped from the board :) (like me, ha)

MOUNT THE NEW MODULE

solder up your RCA jack, and mount it to the chassis

RTV/Silicon the following: LED hole, screw hold next to the RCA input, potentiometer/pot hole (i luckily found a plastic plug that i jammed in there, but then sealed with some RTV), and the two screw holes that held the heat sink

well, this is where you all can get creative. however the hell you plan to mount the board is entirely up to you. i personally used the existing triangular brace to mount a 3"x5" bread board. i had to drill one hole that didnt line up to accept a M3 screw (use a 1/8" or #31/220 bit)

i then used the same bit to drill out the stand off holes as mine were also M3 sized. mounted the amp to the board

i ran two little wire leads from the speaker output from the board and crimped two male spade connectors for quick connecting the sub

hook in your RCA leads into the amp module

POWER DELIVERY

you have two options here, depending on how much wire you leave and where you cut to get to your amp module

if your amp module is going to be super close to where the old wire leads went, you can actually remove the wire from the plastic connector to maximize the wire lead. take a small flat head, and put down on the metal tabs holding the wire into the connector. then you can cut, strip, and wire directly into the power input of the amp

if not, just cut em whereever and crimp some new leads to it and bring it to your amp module

we are looking for the WHITE lead (GND) and the two RED leads (24v). connect those to the respective inputs on the amp board. the BLUE lines are the 49.5V and we will not be using, properly end cap them

HOOK IT UP

before you do this, do a quick test if possible. use your cell phone or whatever and a random speaker to ensure everything is working before sealing it back into the box

when ready,

take the wire pair that has the red wire, and hook that onto the speaker inputs

the black and white pair is the one that goes to the new amp module, white is pos(+), black is neg(-)

screw it back together, enjoy

honestly, this is a quick, inexpensive, and fairly easy MOD most people can do without shelling out the hundreds of getting more modules that have the same likelihood of dying again

i'm sure there is tons of room for improvement, so maybe someone will come up with an alternative or V2. perhaps a tone control board/pot, or some other module that takes advantage of the 49.5V leads

for now, this module can literally bottom out the radiators (whoops) in my testing. while my AVR set it to +3.5dB on the sub, i had to lower it to -4dB to keep it under control, so plenty of power is available
 

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Pursuer

Member
Joined
Nov 3, 2020
Messages
6
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0
Location
Wisconsin
BLOWN/BUSTED Definitive Technology (Def Tech) BP7006/BP7004/BP7002 Amp Module? - Read On (BP8954MOD)

so i stumbled into some bp7006s in a nice package deal

i tested them in person only to find that the output on one of them was limited, and the other appeared fine

upon further inspection when i got them home, i realized they were both having some output issues. one was like '50%' output, the other, barely made any noise

called def tech after numerous reports on how good their support was, i was deflated to find out how poor their support now is. despite numerous folks reporting they have been replacing failed BP amps at no cost, and even polls taken from owners showing almost a 50% failure rate, they refused to take ownership of the issue. quoted me at 200/ea to replace, and after fighting tooth and nail only offered a 25% discount. and this is to replace the busted modules with the SAME design, not even a new and improved design offering more reliability. f that, sucks when a company falls from doing the right thing in the name of profit

rant over, anyway, i searched the interwebs only to find someone who suggested replacing a bank of caps that are a frequent issue. i performed that fix, and to no avail, the output was still limited. i suspect the main caps, but the continued guessing game will get costly

so i searched for a different solution. after inspecting the toroidal transformers, i learned we had dual 24v and 49.5v AC leads to work with

the 49.5v leads would have been great, but ultimately as the voltage goes up, so does the cost. the ~66-68VDC that would have produced would have required some beefy rectifier boards, added cost, and space. and as the power went up on the amp modules, the cost did as well

i figured i didnt need that of power to push these 4ohm woofers in the BP7006s, plus i really didnt know the VA rating of the transformer

enter, the TDA8954 (picked up this one (x2), a whopping < $20/module): https://www.ebay.com/itm/US-TDA8954...o-Amplifier-Board-Core-BTL-Class/303086477878

while most of the ebay posts indicate this is 4ohm BTL stable, the spec sheet says otherwise. however since we are only bring ~32VDC to the table and they are rated to 41VDC, 80% capacity should be enough to ensure they dont overload/overheat.

the only spec i could find on input sensitivity indicated 1.4v, most AVRs should be able to supply enough voltage to run the board without needing a pre-amp/pot stage. maybe as this MOD evolves, someone can work something more exotic into the picture

it already has the power supply baked into the board, so all you needed to bring to the table was the 24VAC leads, awesome. plug and play

the entire MOD should run $30-$40/ea speaker depending on how many parts you have lying around

and the obvious downside, you'll lose the ability to power it with speaker line inputs. honestly, while the manual suggests hooking them up this way, most professionals frown against it. there is greater control to be had using them in an LFE capacity and letting the AVR control the bass management. i suspect when the manual was written, bass management may not have been as mature? who knows. if you really needed that, we could build a small circuit to handle, but that goes beyond my skillset

you'll need:

(2) RCA female inputs (ebay, 7bucks for like 5 pairs, make sure they come with nylon/plastic spacers)
(2) Bread board/ .25"/.125" wood/peg board....whatever
(2) TDA8954 amp modules
(8) Standoffs of some kind for the amp board

Spade/Quick Connect connectors/crimp connectors (assorted depending on how you wire it up)
Soldering iron
Wire
RTV/Silicon
Sockets/Wrenches (metric)
Screw drivers

REMOVE THE PLATE

first we need to remove the plate from the speaker. disconnect the 11 outer perimeter screws from the plate. take a flat head and pry the edges, work your way around the plate prying little by little while also pulling up on the power cord (it's fine, it can take some pulling). eventually it will separate from the box and pull out

disconnect the speaker leads from the plate. you'll have two leads that connect to the speaker inputs (these are the upper speaker arrays), and two leads that connect directly to the amp module (goes to the woofer)

REMOVE THE AMP MODULE

the speaker input leads have a wire running from them, to the amp module. using a socket, remove the nut, washer, spade terminal/tab, and then the ring connector that the wire is connected to. put the spade terminal, washer, and nut back on. do this one at a time, one of the spade connectors is fatter than the other, so just make sure you're paying attention if you do them both at the same time before you put it back together

remove the input sensitivity knob (potentiometer, pot). place two flat heads under each side of the knob, pry up, it will pop off with some force. take a socket and remove the nut under the knob

find the power connector from the transformer to the amp board. it likely has some glue crap to hold it in place, just hack away at that glue with a flat head, push the tab, and pull up to disconnect

remove the screw that is right next to the RCA input

remove the two screws that hold the head sink to the plate (not the triangular brace between the transformer and amp module)

remove the two screws under the amp board that hold it to the triangular brace

optionally, you can remove the two screws that hold the triangular brace to the plate as you can always replace it later. we use this to mount our new board to

NOW the fun part, disconnecting the amp from the f'in glue. honestly, there really isn't an easy way to do this other than just prying and rocking. get a flat head under any spot you can, and start prying up, little by little. apply some force to the board in all directions, up down left right, pull side to side...etc. just keep working your flat head around until you can get it under the board and apply more and more leverage. the two troubled areas will be the RCA input, and the LED. if the LED breaks off, thats fine, one less hole to seal later. the glue should be very rigid, so it will crack and break eventually, just be patient. it will separate

i think thats it, you should now be left with just the speaker terminal inputs, the triangular brace, the transformer, and possibly an LED the ripped from the board :) (like me, ha)

MOUNT THE NEW MODULE

solder up your RCA jack, and mount it to the chassis

RTV/Silicon the following: LED hole, screw hold next to the RCA input, potentiometer/pot hole (i luckily found a plastic plug that i jammed in there, but then sealed with some RTV), and the two screw holes that held the heat sink

well, this is where you all can get creative. however the hell you plan to mount the board is entirely up to you. i personally used the existing triangular brace to mount a 3"x5" bread board. i had to drill one hole that didnt line up to accept a M3 screw (use a 1/8" or #31/220 bit)

i then used the same bit to drill out the stand off holes as mine were also M3 sized. mounted the amp to the board

i ran two little wire leads from the speaker output from the board and crimped two male spade connectors for quick connecting the sub

hook in your RCA leads into the amp module

POWER DELIVERY

you have two options here, depending on how much wire you leave and where you cut to get to your amp module

if your amp module is going to be super close to where the old wire leads went, you can actually remove the wire from the plastic connector to maximize the wire lead. take a small flat head, and put down on the metal tabs holding the wire into the connector. then you can cut, strip, and wire directly into the power input of the amp

if not, just cut em whereever and crimp some new leads to it and bring it to your amp module

we are looking for the WHITE lead (GND) and the two RED leads (24v). connect those to the respective inputs on the amp board. the BLUE lines are the 49.5V and we will not be using, properly end cap them

HOOK IT UP

before you do this, do a quick test if possible. use your cell phone or whatever and a random speaker to ensure everything is working before sealing it back into the box

when ready,

take the wire pair that has the red wire, and hook that onto the speaker inputs

the black and white pair is the one that goes to the new amp module, white is pos(+), black is neg(-)

screw it back together, enjoy

honestly, this is a quick, inexpensive, and fairly easy MOD most people can do without shelling out the hundreds of getting more modules that have the same likelihood of dying again

i'm sure there is tons of room for improvement, so maybe someone will come up with an alternative or V2. perhaps a tone control board/pot, or some other module that takes advantage of the 49.5V leads

for now, this module can literally bottom out the radiators (whoops) in my testing. while my AVR set it to +3.5dB on the sub, i had to lower it to -4dB to keep it under control, so plenty of power is available

Hello, Excellent Article. I have a set of Def Tech. BP7002 speakers with blown amplifiers. With your direction I am going to try the amplifier mod. you described. Will the TDA8954 have enough power to push my single 12" woofer. I am not looking for high volume just enough to make it work properly. I am not an electrician but have some experience soldering.
Please let me know of any tips that might help me during this mod.
I will let you know how my amp. Mod. Works out.
I plan on adding an on off switch where the potentiometer was located. Thank you for the help...
 
OP
D

datrumole

Active Member
Joined
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Messages
151
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EDIT: for those that want to throw a pot on it to adjust the input level, you are looking for a single gang through hole potentiometer, 5/10/15/20k ohm (doesnt much matter, 10k probably the easiest to find), knurled/slotted shaft, 6mm shaft diameter, 15-17mm shaft length, with an audio taper (not linear)
 
OP
D

datrumole

Active Member
Joined
Mar 26, 2020
Messages
151
Likes
62
Hello, Excellent Article. I have a set of Def Tech. BP7002 speakers with blown amplifiers. With your direction I am going to try the amplifier mod. you described. Will the TDA8954 have enough power to push my single 12" woofer. I am not looking for high volume just enough to make it work properly. I am not an electrician but have some experience soldering.
Please let me know of any tips that might help me during this mod.
I will let you know how my amp. Mod. Works out.
I plan on adding an on off switch where the potentiometer was located. Thank you for the help...

yes, plenty! i can't say for certain, but it should have just as much if not more output power as the stock module

i put in as many tips as i could in teh write up, so if anything isnt clear (which i'm sure there is plenty) feel free ask here and i'll give a hand

yeah, you can even put a pot on it as well, noted in my EDIT post (not sure why i couldnt edit the OP)
 
OP
D

datrumole

Active Member
Joined
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Messages
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Curious, why did you decide to buy them when you found an issue with one of them?

so, only one of the modules appeared bad when i tested them in the garage of some guy with multiple people looking over me. the price was absurdly low for what he was selling. so i knew i could either attempt a replacement from DefTech, or if i had to, use some other amp to power them. so i wansnt overly concerned if i had to throw a few more bucks at them just based on price

it wasnt until def tech failed to stand by their shit design at the beginning of the year after numerous reports of them just giving replacements for free that this even really became the next thing. i then attempted the 'cap fix' but that didnt work either (and it was a massive PITA)

i contemplated even pulling the torodials out and making a standalone amp because i was going to need some potential extra room for a power supply, but the self contained really became a reality when i found these
 

Pursuer

Member
Joined
Nov 3, 2020
Messages
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Location
Wisconsin
EDIT: for those that want to throw a pot on it to adjust the input level, you are looking for a single gang through hole potentiometer, 5/10/15/20k ohm (doesnt much matter, 10k probably the easiest to find), knurled/slotted shaft, 6mm shaft diameter, 15-17mm shaft length, with an audio taper (not linear)

Thanks for the suggestion. Maybe I can find a POT. with an on/off on it.
Can you please describe how the POT. should be wired correctly?
Thank you for your assistance.
 

Pursuer

Member
Joined
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Location
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yes, plenty! i can't say for certain, but it should have just as much if not more output power as the stock module

i put in as many tips as i could in teh write up, so if anything isnt clear (which i'm sure there is plenty) feel free ask here and i'll give a hand

yeah, you can even put a pot on it as well, noted in my EDIT post (not sure why i couldnt edit the OP)

I was looking at some other Amps.
This one has the same chip. It has 2 extra caps. And a cooling Fan.
https://www.amazon.com/dp/B07W4ZSPDW/ref=cm_sw_r_u_apa_i_EuEOFb2R4GV2Q
Do you think is much better than our original amp.?
I really appreciate your help with this. Thank you, Mark
 
OP
D

datrumole

Active Member
Joined
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Messages
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Thanks for the suggestion. Maybe I can find a POT. with an on/off on it.
Can you please describe how the POT. should be wired correctly?
Thank you for your assistance.

pots have 3 pins, 1 is input, one is ground, one is output. you may need a multimeter or something to test which pin is which, but they should all be standard, outers are your input (from the RCA), middle to the amp

1604459373671.png


I was looking at some other Amps.
This one has the same chip. It has 2 extra caps. And a cooling Fan.
https://www.amazon.com/dp/B07W4ZSPDW/ref=cm_sw_r_u_apa_i_EuEOFb2R4GV2Q
Do you think is much better than our original amp.?
I really appreciate your help with this. Thank you, Mark

your call, i went the discount route :) class D usually operates very cool
 

Pursuer

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Messages
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Location
Wisconsin
pots have 3 pins, 1 is input, one is ground, one is output. you may need a multimeter or something to test which pin is which, but they should all be standard, outers are your input (from the RCA), middle to the amp

View attachment 91395



your call, i went the discount route :) class D usually operates very cool

Quick question, the Pot. Is connected from the rca plug to the Pot and then to the amplifier circuit board? Waiting for parts. Going to attempt install soon.
Thank you....
 

Pursuer

Member
Joined
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Messages
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Location
Wisconsin
Quick question, the Pot. Is connected from the rca plug to the Pot and then to the amplifier circuit board? Waiting for parts. Going to attempt install soon.
Thank you....

I have been looking for Pots and think I found one that will work.

uxcell WH138 Potentiometer with Switch B10K Ohm Variable Resistors Single Turn Rotary Carbon Film Taper 2pcs https://www.amazon.com/dp/B07SJ7LT44/ref=cm_sw_r_em_apa_fabc_fYdPFbCFMR4DR?_encoding=UTF8&psc=1
Will this Pot.work for my amp. board. This Pot. Has an on off switch. Can you please describe how to wire this with the on off switch properly.
Thanks for all your help. I really appreciate your assistance.
 
OP
D

datrumole

Active Member
Joined
Mar 26, 2020
Messages
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Likes
62
I have been looking for Pots and think I found one that will work.

uxcell WH138 Potentiometer with Switch B10K Ohm Variable Resistors Single Turn Rotary Carbon Film Taper 2pcs https://www.amazon.com/dp/B07SJ7LT44/ref=cm_sw_r_em_apa_fabc_fYdPFbCFMR4DR?_encoding=UTF8&psc=1
Will this Pot.work for my amp. board. This Pot. Has an on off switch. Can you please describe how to wire this with the on off switch properly.
Thanks for all your help. I really appreciate your assistance.

it should work fine, however the shaft may come out the other end a little short compared to the stock one

i'd also verify that its not a linear pot but a logarithmic pot

i put the specs of the pot above, i'd hit up mouser/newark/digikey for finding one

rca --> pot --> amp, using the diagram above (element = amp, jack = rca input)
 

corbano

New Member
Joined
Nov 24, 2020
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BLOWN/BUSTED Definitive Technology (Def Tech) BP7006/BP7004/BP7002 Amp Module? - Read On (BP8954MOD)

so i stumbled into some bp7006s in a nice package deal

i tested them in person only to find that the output on one of them was limited, and the other appeared fine

upon further inspection when i got them home, i realized they were both having some output issues. one was like '50%' output, the other, barely made any noise

called def tech after numerous reports on how good their support was, i was deflated to find out how poor their support now is. despite numerous folks reporting they have been replacing failed BP amps at no cost, and even polls taken from owners showing almost a 50% failure rate, they refused to take ownership of the issue. quoted me at 200/ea to replace, and after fighting tooth and nail only offered a 25% discount. and this is to replace the busted modules with the SAME design, not even a new and improved design offering more reliability. f that, sucks when a company falls from doing the right thing in the name of profit

rant over, anyway, i searched the interwebs only to find someone who suggested replacing a bank of caps that are a frequent issue. i performed that fix, and to no avail, the output was still limited. i suspect the main caps, but the continued guessing game will get costly

so i searched for a different solution. after inspecting the toroidal transformers, i learned we had dual 24v and 49.5v AC leads to work with

the 49.5v leads would have been great, but ultimately as the voltage goes up, so does the cost. the ~66-68VDC that would have produced would have required some beefy rectifier boards, added cost, and space. and as the power went up on the amp modules, the cost did as well

i figured i didnt need that of power to push these 4ohm woofers in the BP7006s, plus i really didnt know the VA rating of the transformer

enter, the TDA8954 (picked up this one (x2), a whopping < $20/module): https://www.ebay.com/itm/US-TDA8954...o-Amplifier-Board-Core-BTL-Class/303086477878

while most of the ebay posts indicate this is 4ohm BTL stable, the spec sheet says otherwise. however since we are only bring ~32VDC to the table and they are rated to 41VDC, 80% capacity should be enough to ensure they dont overload/overheat.

the only spec i could find on input sensitivity indicated 1.4v, most AVRs should be able to supply enough voltage to run the board without needing a pre-amp/pot stage. maybe as this MOD evolves, someone can work something more exotic into the picture

it already has the power supply baked into the board, so all you needed to bring to the table was the 24VAC leads, awesome. plug and play

the entire MOD should run $30-$40/ea speaker depending on how many parts you have lying around

and the obvious downside, you'll lose the ability to power it with speaker line inputs. honestly, while the manual suggests hooking them up this way, most professionals frown against it. there is greater control to be had using them in an LFE capacity and letting the AVR control the bass management. i suspect when the manual was written, bass management may not have been as mature? who knows. if you really needed that, we could build a small circuit to handle, but that goes beyond my skillset

you'll need:

(2) RCA female inputs (ebay, 7bucks for like 5 pairs, make sure they come with nylon/plastic spacers)
(2) Bread board/ .25"/.125" wood/peg board....whatever
(2) TDA8954 amp modules
(8) Standoffs of some kind for the amp board

Spade/Quick Connect connectors/crimp connectors (assorted depending on how you wire it up)
Soldering iron
Wire
RTV/Silicon
Sockets/Wrenches (metric)
Screw drivers

REMOVE THE PLATE

first we need to remove the plate from the speaker. disconnect the 11 outer perimeter screws from the plate. take a flat head and pry the edges, work your way around the plate prying little by little while also pulling up on the power cord (it's fine, it can take some pulling). eventually it will separate from the box and pull out

disconnect the speaker leads from the plate. you'll have two leads that connect to the speaker inputs (these are the upper speaker arrays), and two leads that connect directly to the amp module (goes to the woofer)

REMOVE THE AMP MODULE

the speaker input leads have a wire running from them, to the amp module. using a socket, remove the nut, washer, spade terminal/tab, and then the ring connector that the wire is connected to. put the spade terminal, washer, and nut back on. do this one at a time, one of the spade connectors is fatter than the other, so just make sure you're paying attention if you do them both at the same time before you put it back together

remove the input sensitivity knob (potentiometer, pot). place two flat heads under each side of the knob, pry up, it will pop off with some force. take a socket and remove the nut under the knob

find the power connector from the transformer to the amp board. it likely has some glue crap to hold it in place, just hack away at that glue with a flat head, push the tab, and pull up to disconnect

remove the screw that is right next to the RCA input

remove the two screws that hold the head sink to the plate (not the triangular brace between the transformer and amp module)

remove the two screws under the amp board that hold it to the triangular brace

optionally, you can remove the two screws that hold the triangular brace to the plate as you can always replace it later. we use this to mount our new board to

NOW the fun part, disconnecting the amp from the f'in glue. honestly, there really isn't an easy way to do this other than just prying and rocking. get a flat head under any spot you can, and start prying up, little by little. apply some force to the board in all directions, up down left right, pull side to side...etc. just keep working your flat head around until you can get it under the board and apply more and more leverage. the two troubled areas will be the RCA input, and the LED. if the LED breaks off, thats fine, one less hole to seal later. the glue should be very rigid, so it will crack and break eventually, just be patient. it will separate

i think thats it, you should now be left with just the speaker terminal inputs, the triangular brace, the transformer, and possibly an LED the ripped from the board :) (like me, ha)

MOUNT THE NEW MODULE

solder up your RCA jack, and mount it to the chassis

RTV/Silicon the following: LED hole, screw hold next to the RCA input, potentiometer/pot hole (i luckily found a plastic plug that i jammed in there, but then sealed with some RTV), and the two screw holes that held the heat sink

well, this is where you all can get creative. however the hell you plan to mount the board is entirely up to you. i personally used the existing triangular brace to mount a 3"x5" bread board. i had to drill one hole that didnt line up to accept a M3 screw (use a 1/8" or #31/220 bit)

i then used the same bit to drill out the stand off holes as mine were also M3 sized. mounted the amp to the board

i ran two little wire leads from the speaker output from the board and crimped two male spade connectors for quick connecting the sub

hook in your RCA leads into the amp module

POWER DELIVERY

you have two options here, depending on how much wire you leave and where you cut to get to your amp module

if your amp module is going to be super close to where the old wire leads went, you can actually remove the wire from the plastic connector to maximize the wire lead. take a small flat head, and put down on the metal tabs holding the wire into the connector. then you can cut, strip, and wire directly into the power input of the amp

if not, just cut em whereever and crimp some new leads to it and bring it to your amp module

we are looking for the WHITE lead (GND) and the two RED leads (24v). connect those to the respective inputs on the amp board. the BLUE lines are the 49.5V and we will not be using, properly end cap them

HOOK IT UP

before you do this, do a quick test if possible. use your cell phone or whatever and a random speaker to ensure everything is working before sealing it back into the box

when ready,

take the wire pair that has the red wire, and hook that onto the speaker inputs

the black and white pair is the one that goes to the new amp module, white is pos(+), black is neg(-)

screw it back together, enjoy

honestly, this is a quick, inexpensive, and fairly easy MOD most people can do without shelling out the hundreds of getting more modules that have the same likelihood of dying again

i'm sure there is tons of room for improvement, so maybe someone will come up with an alternative or V2. perhaps a tone control board/pot, or some other module that takes advantage of the 49.5V leads

for now, this module can literally bottom out the radiators (whoops) in my testing. while my AVR set it to +3.5dB on the sub, i had to lower it to -4dB to keep it under control, so plenty of power is available
Hello, first of all, thank you for taking the time to write this article. I also have a pair of Def Tech BP7004 speakers that are currently outputting normal levels but one speaker has developed a noticeable hum which happens even though no sound is being pushed through. This seems to be a common problem along with amps that are faulty as you've experienced. I have a few questions for you if you don't mind. First, full transparency - I am a complete noob when it comes to the type of repair you've described so I apologize in advance for what will likely be "dumb" questions. It's taken me some time online looking at possible solutions to this problem and it seems that Def Tech will be of no use. Plus the fact that the problem is like to occur again even if they sent me a replacement. My main question is - would you recommend your mod as described above or attempting to replace the capacitors as described in this YouTube video:
- I'm assuming this was the video you referenced above when you mentioned replacing the bank of capacitors? Second, is this mod something that someone with no experience would be able to handle? I'm overall pretty handy and your instructions, as well as the photos, seem to be very thorough. Either way, I need to do something to fix this issue. These are great speakers and I'd like to get many more years of use out of them. I just need to know what your advice would be. I would also welcome advice from other members as well. Whichever way is best, I'm planning on doing the same repair for the other speaker in anticipation of its inevitable failure. Again, apologies for the newb questions. Thank you in advance.
 
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datrumole

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Hello, first of all, thank you for taking the time to write this article. I also have a pair of Def Tech BP7004 speakers that are currently outputting normal levels but one speaker has developed a noticeable hum which happens even though no sound is being pushed through. This seems to be a common problem along with amps that are faulty as you've experienced. I have a few questions for you if you don't mind. First, full transparency - I am a complete noob when it comes to the type of repair you've described so I apologize in advance for what will likely be "dumb" questions. It's taken me some time online looking at possible solutions to this problem and it seems that Def Tech will be of no use. Plus the fact that the problem is like to occur again even if they sent me a replacement. My main question is - would you recommend your mod as described above or attempting to replace the capacitors as described in this YouTube video:
- I'm assuming this was the video you referenced above when you mentioned replacing the bank of capacitors? Second, is this mod something that someone with no experience would be able to handle? I'm overall pretty handy and your instructions, as well as the photos, seem to be very thorough. Either way, I need to do something to fix this issue. These are great speakers and I'd like to get many more years of use out of them. I just need to know what your advice would be. I would also welcome advice from other members as well. Whichever way is best, I'm planning on doing the same repair for the other speaker in anticipation of its inevitable failure. Again, apologies for the newb questions. Thank you in advance.


we all start somewhere!

yes, the symptoms your describing seem to be more in line with what the video describes. i had hoped that that would have fixed mine, but apparently mine was a different issue

not gonna lie, that shit was a hard ass repair. i'm a fairly seasoned solder-er, but never had i done any surface mount soldering, just through hole. managed to overhead the SMD caps and the pads pulled off (stuff i didnt even know existed when i went into it). it was a nightmare and frustrating, ended up having to find the nearest through hole that corresponded to the pad i knocked out. i'm more surprised it turned on after i was done more so than anything

anyway, this mod honestly is a lot easier, and you walk out on the other end with IMO a better amp, and with no risk of this crap happening again. obvious the downside is that you no longer can use the speaker level inputs, but a small bank of resistors i'm sure could enable that route if you really needed it, but the RCA input is fine

the only thing i think i would change would be two/four small capacitors in series on the power input of the new board. if i'm super close to the speakers i can hear a faint hum from the amp modules, that may help clean up the power from the toroidal pending its the issue. i'm actually hoping for a little handheld oscilliscope and can better diagnose the noise when i have it, but for now, unless your up close, or in a dead silent room, you can't hear it

let me know how i can help if you do end up trying it!
 

Doodski

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managed to overhead the SMD caps and the pads pulled off (stuff i didnt even know existed when i went into it). it was a nightmare and frustrating, ended up having to find the nearest through hole that corresponded to the pad i knocked out. i'm more surprised it turned on after i was done more so than anything
Are you using liquid rosin flux? It makes the heat travel much easier from the iron, is much more delicate working with the SMD PCB and the end result after cleaning with alcohol is much better. :D It's worth getting a no-clean flux pen or even a small bottle of the stuff.
 
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datrumole

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Are you using liquid rosin flux? It makes the heat travel much easier from the iron, is much more delicate working with the SMD PCB and the end result after cleaning with alcohol is much better. :D It's worth getting a no-clean flux pen or even a small bottle of the stuff.

yes, i do use flux. the issue is, the amps are on the older side, and the adhesive that holds the pads on the actual PCB failed with the heat. so they lift up and do not stay attached

compounded when you are trying to use through-hole caps in the place where SMD go, then you have an issue with them staying in place
 

corbano

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we all start somewhere!

yes, the symptoms your describing seem to be more in line with what the video describes. i had hoped that that would have fixed mine, but apparently mine was a different issue

not gonna lie, that shit was a hard ass repair. i'm a fairly seasoned solder-er, but never had i done any surface mount soldering, just through hole. managed to overhead the SMD caps and the pads pulled off (stuff i didnt even know existed when i went into it). it was a nightmare and frustrating, ended up having to find the nearest through hole that corresponded to the pad i knocked out. i'm more surprised it turned on after i was done more so than anything

anyway, this mod honestly is a lot easier, and you walk out on the other end with IMO a better amp, and with no risk of this crap happening again. obvious the downside is that you no longer can use the speaker level inputs, but a small bank of resistors i'm sure could enable that route if you really needed it, but the RCA input is fine

the only thing i think i would change would be two/four small capacitors in series on the power input of the new board. if i'm super close to the speakers i can hear a faint hum from the amp modules, that may help clean up the power from the toroidal pending its the issue. i'm actually hoping for a little handheld oscilliscope and can better diagnose the noise when i have it, but for now, unless your up close, or in a dead silent room, you can't hear it

let me know how i can help if you do end up trying it!
Thank you for the quick reply - I definitely have more homework to do on this. Had to look up some of the items you mentioned - didn't know that there were different types of capacitors - I thought they were all radial and thought it would be relatively easy to remove the old ones and solder in new ones in the holes. Watched a video on SMD - looks way difficult - and I appreciate your honesty about what a pain in the ass it was for an experienced solder-er. I might have to rethink attempting that fix but will have to practice accordingly. I'll reach out and let you know if I have questions which I'm sure I will. Thanks again for your time and offer of help - really appreciate it. Cheers and enjoy the holiday!
 

niras

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BLOWN/BUSTED Definitive Technology (Def Tech) BP7006/BP7004/BP7002 Amp Module? - Read On (BP8954MOD)

so i stumbled into some bp7006s in a nice package deal

i tested them in person only to find that the output on one of them was limited, and the other appeared fine

upon further inspection when i got them home, i realized they were both having some output issues. one was like '50%' output, the other, barely made any noise

called def tech after numerous reports on how good their support was, i was deflated to find out how poor their support now is. despite numerous folks reporting they have been replacing failed BP amps at no cost, and even polls taken from owners showing almost a 50% failure rate, they refused to take ownership of the issue. quoted me at 200/ea to replace, and after fighting tooth and nail only offered a 25% discount. and this is to replace the busted modules with the SAME design, not even a new and improved design offering more reliability. f that, sucks when a company falls from doing the right thing in the name of profit

rant over, anyway, i searched the interwebs only to find someone who suggested replacing a bank of caps that are a frequent issue. i performed that fix, and to no avail, the output was still limited. i suspect the main caps, but the continued guessing game will get costly

so i searched for a different solution. after inspecting the toroidal transformers, i learned we had dual 24v and 49.5v AC leads to work with

the 49.5v leads would have been great, but ultimately as the voltage goes up, so does the cost. the ~66-68VDC that would have produced would have required some beefy rectifier boards, added cost, and space. and as the power went up on the amp modules, the cost did as well

i figured i didnt need that of power to push these 4ohm woofers in the BP7006s, plus i really didnt know the VA rating of the transformer

enter, the TDA8954 (picked up this one (x2), a whopping < $20/module): https://www.ebay.com/itm/US-TDA8954...o-Amplifier-Board-Core-BTL-Class/303086477878

while most of the ebay posts indicate this is 4ohm BTL stable, the spec sheet says otherwise. however since we are only bring ~32VDC to the table and they are rated to 41VDC, 80% capacity should be enough to ensure they dont overload/overheat.

the only spec i could find on input sensitivity indicated 1.4v, most AVRs should be able to supply enough voltage to run the board without needing a pre-amp/pot stage. maybe as this MOD evolves, someone can work something more exotic into the picture

it already has the power supply baked into the board, so all you needed to bring to the table was the 24VAC leads, awesome. plug and play

the entire MOD should run $30-$40/ea speaker depending on how many parts you have lying around

and the obvious downside, you'll lose the ability to power it with speaker line inputs. honestly, while the manual suggests hooking them up this way, most professionals frown against it. there is greater control to be had using them in an LFE capacity and letting the AVR control the bass management. i suspect when the manual was written, bass management may not have been as mature? who knows. if you really needed that, we could build a small circuit to handle, but that goes beyond my skillset

you'll need:

(2) RCA female inputs (ebay, 7bucks for like 5 pairs, make sure they come with nylon/plastic spacers)
(2) Bread board/ .25"/.125" wood/peg board....whatever
(2) TDA8954 amp modules
(8) Standoffs of some kind for the amp board

Spade/Quick Connect connectors/crimp connectors (assorted depending on how you wire it up)
Soldering iron
Wire
RTV/Silicon
Sockets/Wrenches (metric)
Screw drivers

REMOVE THE PLATE

first we need to remove the plate from the speaker. disconnect the 11 outer perimeter screws from the plate. take a flat head and pry the edges, work your way around the plate prying little by little while also pulling up on the power cord (it's fine, it can take some pulling). eventually it will separate from the box and pull out

disconnect the speaker leads from the plate. you'll have two leads that connect to the speaker inputs (these are the upper speaker arrays), and two leads that connect directly to the amp module (goes to the woofer)

REMOVE THE AMP MODULE

the speaker input leads have a wire running from them, to the amp module. using a socket, remove the nut, washer, spade terminal/tab, and then the ring connector that the wire is connected to. put the spade terminal, washer, and nut back on. do this one at a time, one of the spade connectors is fatter than the other, so just make sure you're paying attention if you do them both at the same time before you put it back together

remove the input sensitivity knob (potentiometer, pot). place two flat heads under each side of the knob, pry up, it will pop off with some force. take a socket and remove the nut under the knob

find the power connector from the transformer to the amp board. it likely has some glue crap to hold it in place, just hack away at that glue with a flat head, push the tab, and pull up to disconnect

remove the screw that is right next to the RCA input

remove the two screws that hold the head sink to the plate (not the triangular brace between the transformer and amp module)

remove the two screws under the amp board that hold it to the triangular brace

optionally, you can remove the two screws that hold the triangular brace to the plate as you can always replace it later. we use this to mount our new board to

NOW the fun part, disconnecting the amp from the f'in glue. honestly, there really isn't an easy way to do this other than just prying and rocking. get a flat head under any spot you can, and start prying up, little by little. apply some force to the board in all directions, up down left right, pull side to side...etc. just keep working your flat head around until you can get it under the board and apply more and more leverage. the two troubled areas will be the RCA input, and the LED. if the LED breaks off, thats fine, one less hole to seal later. the glue should be very rigid, so it will crack and break eventually, just be patient. it will separate

i think thats it, you should now be left with just the speaker terminal inputs, the triangular brace, the transformer, and possibly an LED the ripped from the board :) (like me, ha)

MOUNT THE NEW MODULE

solder up your RCA jack, and mount it to the chassis

RTV/Silicon the following: LED hole, screw hold next to the RCA input, potentiometer/pot hole (i luckily found a plastic plug that i jammed in there, but then sealed with some RTV), and the two screw holes that held the heat sink

well, this is where you all can get creative. however the hell you plan to mount the board is entirely up to you. i personally used the existing triangular brace to mount a 3"x5" bread board. i had to drill one hole that didnt line up to accept a M3 screw (use a 1/8" or #31/220 bit)

i then used the same bit to drill out the stand off holes as mine were also M3 sized. mounted the amp to the board

i ran two little wire leads from the speaker output from the board and crimped two male spade connectors for quick connecting the sub

hook in your RCA leads into the amp module

POWER DELIVERY

you have two options here, depending on how much wire you leave and where you cut to get to your amp module

if your amp module is going to be super close to where the old wire leads went, you can actually remove the wire from the plastic connector to maximize the wire lead. take a small flat head, and put down on the metal tabs holding the wire into the connector. then you can cut, strip, and wire directly into the power input of the amp

if not, just cut em whereever and crimp some new leads to it and bring it to your amp module

we are looking for the WHITE lead (GND) and the two RED leads (24v). connect those to the respective inputs on the amp board. the BLUE lines are the 49.5V and we will not be using, properly end cap them

HOOK IT UP

before you do this, do a quick test if possible. use your cell phone or whatever and a random speaker to ensure everything is working before sealing it back into the box

when ready,

take the wire pair that has the red wire, and hook that onto the speaker inputs

the black and white pair is the one that goes to the new amp module, white is pos(+), black is neg(-)

screw it back together, enjoy

honestly, this is a quick, inexpensive, and fairly easy MOD most people can do without shelling out the hundreds of getting more modules that have the same likelihood of dying again

i'm sure there is tons of room for improvement, so maybe someone will come up with an alternative or V2. perhaps a tone control board/pot, or some other module that takes advantage of the 49.5V leads

for now, this module can literally bottom out the radiators (whoops) in my testing. while my AVR set it to +3.5dB on the sub, i had to lower it to -4dB to keep it under control, so plenty of power is available
hi mate , im new to this forum, me too have the same problem with bp7006,only the tweeter n mid is working , now its like two sattelites in a big box , i have zero knowlwdge in electronics , can u pls guide me in changing the new amp module pls
 
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datrumole

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hi mate , im new to this forum, me too have the same problem with bp7006,only the tweeter n mid is working , now its like two sattelites in a big box , i have zero knowlwdge in electronics , can u pls guide me in changing the new amp module pls

sure, i'd say read the above and see what questions you have from it and i'll do my best to help
 

youtubelover

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we all start somewhere!

yes, the symptoms your describing seem to be more in line with what the video describes. i had hoped that that would have fixed mine, but apparently mine was a different issue

not gonna lie, that shit was a hard ass repair. i'm a fairly seasoned solder-er, but never had i done any surface mount soldering, just through hole. managed to overhead the SMD caps and the pads pulled off (stuff i didnt even know existed when i went into it). it was a nightmare and frustrating, ended up having to find the nearest through hole that corresponded to the pad i knocked out. i'm more surprised it turned on after i was done more so than anything

anyway, this mod honestly is a lot easier, and you walk out on the other end with IMO a better amp, and with no risk of this crap happening again. obvious the downside is that you no longer can use the speaker level inputs, but a small bank of resistors i'm sure could enable that route if you really needed it, but the RCA input is fine

the only thing i think i would change would be two/four small capacitors in series on the power input of the new board. if i'm super close to the speakers i can hear a faint hum from the amp modules, that may help clean up the power from the toroidal pending its the issue. i'm actually hoping for a little handheld oscilliscope and can better diagnose the noise when i have it, but for now, unless your up close, or in a dead silent room, you can't hear it

let me know how i can help if you do end up trying it!

Hey man! Loved the write-up, went ahead and tried this myself with a BP7004. To my surprise I didn't break everything lol. However I am getting a ton of ground noise (i think) when the amp is on with nothing connected. If i connect to a source, the hum gets lower but is still quite noticeable. Any tips?

Thanks!
 
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