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What is on your workbench right now?
Another guitar amp that someone else tried to repair and failed miserably at. This time, it might not even be economically feasible. It's a cheap amp and some traces got absolutely mangled. May or may not be repairable, I don't know. Running wires would be doable, if the connected passives weren't surface mount.
Anyway, what's going on is U6, a 7812 linear regulator IC, had problems with overheating and failing, so Peavey replaced the part. The problem is, somebody did it in this amp and really managed to screw things up. Pads on the bottom side of the PCB? gone. Traces on the top? Heat damaged and separating from the PCB. Ugh.
Anyway, what's going on is U6, a 7812 linear regulator IC, had problems with overheating and failing, so Peavey replaced the part. The problem is, somebody did it in this amp and really managed to screw things up. Pads on the bottom side of the PCB? gone. Traces on the top? Heat damaged and separating from the PCB. Ugh.
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Rubbersoul2
Member
- Joined
- Oct 11, 2021
- Messages
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hi not sure this is correct section to post ,,,, AMP electrical advice needed .
circuitry design n testing beyond my volt meter on caps n stuff is not my area of experteise a meer novice for 40 years
.
keen to learn Again ..like the look of pma s test equip. espensive no doubt like everthing these days .my MBP 16 inch 2020 replacment screen £800 sterilng. wtf i have old G4S like tanks you cant break them if you try tft screen good enough ,one gets to a certain age joins fourms like these gets even less sleep and cant see sod all anyway , all this HD stuff its for kids to make supermen films with .
i mean my £1200 iphone is made of glass yes the back to .
i know im over the apple barrel ive said no more before have you ??
In the picture my DAD Flying mole M100-pro HT mono .switching.amp 120vac.
ive had these years and fairly enjoyable not the RCA though.
1x each to ditton 44s. not the best match would prefer some anolog monos on those beauts ,even x2 small a slight bright tube or purifi e EVAL1 maybe way to go been looking at nord to
Back to subject is there anything that i should double check in the Flying mole board that i could ? the one that i did not mis power i cant see any faults (burns swellings n checked all i can all seems ok untill i get to the last stage at output ( checking again today .
can provide detailed pics .
The other
long short,,, i mistakenly on a dimmly lit ,fiddling with cables feeds n runs systems tables plugged the 240V into,The mole 120vac.
well the fuse in the amps went but that dident save somthing ? question is what im testing best i can today ( diLogic multi on caps.resitors
whatever i can with bit of guidence perhaps or just an opinion on best path of action
look forward to response
dan
circuitry design n testing beyond my volt meter on caps n stuff is not my area of experteise a meer novice for 40 years
.keen to learn Again ..like the look of pma s test equip. espensive no doubt like everthing these days .my MBP 16 inch 2020 replacment screen £800 sterilng. wtf i have old G4S like tanks you cant break them if you try tft screen good enough ,one gets to a certain age joins fourms like these gets even less sleep and cant see sod all anyway , all this HD stuff its for kids to make supermen films with .
i mean my £1200 iphone is made of glass yes the back to .
i know im over the apple barrel ive said no more before have you ??In the picture my DAD Flying mole M100-pro HT mono .switching.amp 120vac.
ive had these years and fairly enjoyable not the RCA though.
1x each to ditton 44s. not the best match would prefer some anolog monos on those beauts ,even x2 small a slight bright tube or purifi e EVAL1 maybe way to go been looking at nord to
Back to subject is there anything that i should double check in the Flying mole board that i could ? the one that i did not mis power i cant see any faults (burns swellings n checked all i can all seems ok untill i get to the last stage at output ( checking again today .
can provide detailed pics .
The other
long short,,, i mistakenly on a dimmly lit ,fiddling with cables feeds n runs systems tables plugged the 240V into,The mole 120vac.
well the fuse in the amps went but that dident save somthing ? question is what im testing best i can today ( diLogic multi on caps.resitors
whatever i can with bit of guidence perhaps or just an opinion on best path of action
look forward to response
dan
Attachments
GaN Systems eval board with a SCAMP8 dongle, running AudioCanvas for tuning and signal flow control. The features and options of this system are amazing- they seem to have been entirely overlooked in the review here. I intend to correct that in a soon-to-appear article. Not shown: the superbly performing Orchard Starkrimson Ultra, which is sharing bench time.
The lab might be tidy but the bedroom bench certainly isn't.
We must have completely different definitions of "bedroom workbench..."
- Thread Starter
- #347
I will use one of my older prototype cases to test this amplifier. The Hypex UcD180HG HxR module is already on the way. It should have the frequency response almost independent on speaker complex impedance and also distortion almost independent on frequency. This should be a major improvement compared to TPA3255 based amplifiers. The price of the UcD is higher, however still acceptable and much lower compared to NCore.
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- Thread Starter
- #348
This is on my "PC workbench" - I believe that circuit simulation is necessary for proper understanding of the real thing behaviour.
Below is my attempt of UcD classD amp simulation:
1) block circuit diagram
2) estimation of self-oscillation frequency
3) output waveform behind the LC filter (10kHz) and switching output
Below is my attempt of UcD classD amp simulation:
1) block circuit diagram
2) estimation of self-oscillation frequency
3) output waveform behind the LC filter (10kHz) and switching output
- Thread Starter
- #350
class D filter for noise and distortion measurements
Though I do not have special problems with soundcard saturation from class D amplifiers during measurements, I have decided to make a simpler version of something like AP AUX-0025 filter. I made an RLC filter that is possible to use with both single ended and BTL output class D power amplifiers, in 20Hz - 20kHz band.
It looks like this, and it has air-core inductors and MKP capacitors:
and this is the frequency response:
Not ideal, but usable.
Though I do not have special problems with soundcard saturation from class D amplifiers during measurements, I have decided to make a simpler version of something like AP AUX-0025 filter. I made an RLC filter that is possible to use with both single ended and BTL output class D power amplifiers, in 20Hz - 20kHz band.
It looks like this, and it has air-core inductors and MKP capacitors:
and this is the frequency response:
Not ideal, but usable.
KSTR
Major Contributor
Excellent, as always.
I'm cheap here and mostly use a simple RCRC filter and normalize the mag/phase response which is very easy to do in REW.
I'm cheap here and mostly use a simple RCRC filter and normalize the mag/phase response which is very easy to do in REW.
- Thread Starter
- #353
A new amplifier based on Hypex NC252MP OEM module is being prepared. It will be built in a full-size aluminium case with side heatsinks, to allow for maximum continuous sine power without time and temperature limitations. It will have large ELECAUDIO BP-206 binding posts to allow for insertion of Nakamichi lock-in N0575 banana plugs. Input connectors Neutrik NC3FDM3-L-B-1. The goal is to get the most from the Hypex module, its full potential. Not to be cost/size/weight limited. Below is the casework preview.
MakeMineVinyl
Major Contributor
What is the part number of that 16 pin DIP IC on the soft start PCB?Prototype is working and playing music, time to make measurements
View attachment 173802
Below is the THD vs. output power plot. So we have 300W/4ohm/1kHz at 1% distortion.
View attachment 173835
JayGilb
Major Contributor
Just came from the garage workbench where it was recapped and a left channel high voltage dc offset (+27 vdc) fixed.
Carver PM-1201 rated at 450 watts RMS, .5% THD at 8 ohms. It's a class G triple rail switching topography (+-36.5 vdc/+-76.5 vdc/+-124.0 vdc).
New 24 vdc muffin fans were used to replace the older dc motor fans. Brought to spec; idle current was adjusted as well as rail voltages.
Slated to drive some DIY sub enclosures as soon as they're made.
Brought into my music room for testing over the holidays.
Got it off of Mercari for $100 was sold for parts. Put $75 into replacement caps, transistors and diodes.
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- Thread Starter
- #358
It is CD4020BE.
Digital Mastering System
Active Member
This work too: https://tinyurl.com/2p8jsp9n
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