DIY Purifi Amp builds

[Synergy4]

I have mains with only a 120VAC input, but when I sensed the signal using a small laminated core inter-stage XFMR and a scope, I noticed inpulses from the SMPS1200A700, so a added a thin Mu Metal shield to the Copper shield which snuffed the added SMPS noise near the Purifi amplifier module. Using shields, extra distance and keeping the electric fields at right angles helps with noise.

https://www.audiosciencereview.com/...-purifi-amp-builds.10478/page-125#post-983258

 

[mocenigo]

View attachment 172568

Finally I am satisfied with my build. My first ever.

I am personally not very fond of vu meters (hey, it's taste), but I admire the cleanliness and sophistication of your build. Congratulations!

 

[NTSOS]

I was hoping y'all would answer a basic question about power supplies that has me confused.

The EE that built a CNC controller told me to wire a NC limit switch like this:

Positive wire to common, NC wire to the - V terminal of the power supply, not chassis ground.

I couldn't get the limit switch to work.......I checked the voltage between the breakout board terminal that NC went to and the -V1 terminal.......there was zero volts once triggered.

I changed the NC terminal to ground and once the limit switch was triggered, it enabled the needed 5 volts high to stop the motor.

Why didn't NC to -V1 work and why do you think the EE told me to do that?

Thanks.

John

 

[somebodyelse]

Limit switch connection depends on the controller and the software configuration, at least for the ones I've seen. Do you have any more details? Probably deserves its own thread too.

 

[AdamG]

I was hoping y'all would answer a basic question about power supplies that has me confused.

The EE that built a CNC controller told me to wire a NC limit switch like this:

Positive wire to common, NC wire to the - V terminal of the power supply, not chassis ground.

I couldn't get the limit switch to work.......I checked the voltage between the breakout board terminal that NC went to and the -V1 terminal.......there was zero volts once triggered.

I changed the NC terminal to ground and once the limit switch was triggered, it enabled the needed 5 volts high to stop the motor.

Why didn't NC to -V1 work and why do you think the EE told me to do that?

Thanks.

John

Create a new thread to ask for help with this. Do not start discussing this problem in this thread. Please and thank you.

 

[NTSOS]

Create a new thread to ask for help with this. Do not start discussing this problem in this thread. Please and thank you.

Well, ok....this is where I used to hang out and I liked the people here, but delete it if you must....it doesn't matter!

 

[AdamG]

Well, ok....this is where I used to hang out and I liked the people here, but delete it if you must....it doesn't matter!

You can start a new thread asking for help with your problem. Then come back here and drop a post with a link to your separate thread and ask folks from here to come and help you. Not difficult. This thread is about “DIY Purifi Amp builds”.

 

[Vavilen]

Hey guys!
Did anybody add a volume control to the Purifi-based amps?
Is it a good idea? I'm afraid to pass full power to my speakers if something goes wrong with my source.

 

[mocenigo]

Hey guys!
Did anybody add a volume control to the Purifi-based amps?
Is it a good idea? I'm afraid to pass full power to my speakers if something goes wrong with my source.

Just add an external one.

 

[Vavilen]

Just add an external one.

I would like to put it into the same case with amp modules.

 

[mocenigo]

I would like to put it into the same case with amp modules.

You can always put something like this
https://a.aliexpress.com/_vrM1Ph (there are balanced variants somewhere)

 

[fraa]

I am personally not very fond of vu meters (hey, it's taste), but I admire the cleanliness and sophistication of your build. Congratulations!

Thanks. At first I just wanted a silver roundish case. But the one I found was rather large so I added the meter.

 

[Keened]

Am I missing anything big from this DIY parts list:

(3) Purifi 1et400a amplifiers
(3) Neurochrome input boards
(1) Hypex SMPS3KA400 powersupply
(1) Soft start board (Neurochrome can't handle the SMPS3KA400 I think, should I use the Hypex or are there other suggestions?)
(3) Cable harnesses, either directly from Hypex or equivalents
(3) Neurochrome Guardian-86 speaker protection boards
(3) Neutrik combo XLR/TRS panel for balanced in
(6) Gold plated RCA panel for single end in
(6) 5-way binding posts
(1) IEC C14 socket with powerswitch and EMI filtering
A fuse for the AC in or is the softstart board enough?
12ga wires and standard electronics solder
Mu-metal strip to place in-between the powersupply and the amplifiers
Heat sinks? Or should I just attach everything to a solid plate of aluminum underneath? I'm not even sure where you should attach a heat sink on these things.

This is getting to be a rather long list...I haven't priced it all out but I feel like I'm creeping up on the cost of Nord or Apollon amps here.

 

[goryu]

Am I missing anything big from this DIY parts list:

(3) Purifi 1et400a amplifiers
(3) Neurochrome input boards
(1) Hypex SMPS3KA400 powersupply
(1) Soft start board (Neurochrome can't handle the SMPS3KA400 I think, should I use the Hypex or are there other suggestions?)
(3) Cable harnesses, either directly from Hypex or equivalents
(3) Neurochrome Guardian-86 speaker protection boards
(3) Neutrik combo XLR/TRS panel for balanced in
(6) Gold plated RCA panel for single end in
(6) 5-way binding posts
(1) IEC C14 socket with powerswitch and EMI filtering
A fuse for the AC in or is the softstart board enough?
12ga wires and standard electronics solder
Mu-metal strip to place in-between the powersupply and the amplifiers
Heat sinks? Or should I just attach everything to a solid plate of aluminum underneath? I'm not even sure where you should attach a heat sink on these things.

This is getting to be a rather long list...I haven't priced it all out but I feel like I'm creeping up on the cost of Nord or Apollon amps here.

Much cheaper and quicker to get a VTV amp and upgrade the build.

 

[boXem]

Am I missing anything big from this DIY parts list:

(3) Purifi 1et400a amplifiers
(3) Neurochrome input boards
(1) Hypex SMPS3KA400 powersupply
(1) Soft start board (Neurochrome can't handle the SMPS3KA400 I think, should I use the Hypex or are there other suggestions?)
(3) Cable harnesses, either directly from Hypex or equivalents
(3) Neurochrome Guardian-86 speaker protection boards
(3) Neutrik combo XLR/TRS panel for balanced in
(6) Gold plated RCA panel for single end in
(6) 5-way binding posts
(1) IEC C14 socket with powerswitch and EMI filtering
A fuse for the AC in or is the softstart board enough?
12ga wires and standard electronics solder
Mu-metal strip to place in-between the powersupply and the amplifiers
Heat sinks? Or should I just attach everything to a solid plate of aluminum underneath? I'm not even sure where you should attach a heat sink on these things.

This is getting to be a rather long list...I haven't priced it all out but I feel like I'm creeping up on the cost of Nord or Apollon amps here.

Softstart board is not needed.
EMI filtering is a source of problems and not especially needed.
Using the SMPS3k is less trivial than the SMPS1200. Especially for a 3 channels setup.

 

[Count Arthur]

My thoughts:

(1) Soft start board (Neurochrome can't handle the SMPS3KA400 I think, should I use the Hypex or are there other suggestions?) - I'm not sure that a soft start is strictly necessary with a SMPS, they are more typically used with linear PSUs with large transformers and capacitor banks.

(3) Cable harnesses, either directly from Hypex or equivalents - Also available from Ghent Audio: https://www.ghentaudio.com/kit/purifi-eval1-harness.html

(3) Neurochrome Guardian-86 speaker protection boards - I didn't bother with speaker protection in my Hypex UCD amps.

(1) IEC C14 socket with powerswitch and EMI filtering - I don't think there's much point, there's one on the PSU, just get one with a fuse and a switch:

The bit in red is an EMI filter. Similar to the circuit you'll often see on indicated IEC filters, albeit there's no earth component on on the PSU filter:

Heat sinks? Or should I just attach everything to a solid plate of aluminum underneath? I'm not even sure where you should attach a heat sink on these things. - You don't mention what case you intend using. Attaching the PSU and amp modules to a aluminium case may be sufficient.

 

[Keened]

Softstart board is not needed.
EMI filtering is a source of problems and not especially needed.
Using the SMPS3k is less trivial than the SMPS1200. Especially for a 3 channels setup.

I was going to ask why softstart wasn't necessary but I think @Count Arthur covered it. I'm mostly trying to prevent issues on less-than-ideal wall circuits and prevent popping.

I'm confused by why EMI filtering would be a source of problems? But again @Count Arthur has pointed out it's already included on the board.

If I get the SMPS1200 then I just need a splitter like this right? I was reading how the Purifi amps essentially are PSU limited so I was going to stick in oversized one (that's also made for 3 amps) even though I'm pretty much never going to probably use all of that power. When you say less trivial do you mean about having to swap the polarity for one channel or are there other considerations that make the 1200 just better overall?

My thoughts:...

The speaker protection is just an insurance policy, especially if this does go well I might use it to lure some A/B people over to class-D and I absolutely do not want to accidentally blow up their speakers under any circumstances. Also I'd like not to blow up my own if something ever does go wrong.

Honestly, my use case will probably never even touch over 100W per channel, I have powered subs so this would be for the LCR in a fairly small area at the moment. But I'd like to build it out so it can handle anything the amp module can dish out so it is as future proofed as possible if I'm spending the extra money over a pre-built ncore.

@goryu
It's not the worst idea, but I'm not thrilled with the case (very large and blue LEDs) and if I'm going to modify it so heavily I might as well try my hand at building from scratch for the satisfaction. Actually if I am going to go this route I'm considering buying a custom from Buckeye but we'll see.

 

[Count Arthur]

If I get the SMPS1200 then I just need a splitter like this right?

Check the documentation, but it looks like the SMPS1200 already has 3 outputs:

 

[Keened]

Check the documentation, but it looks like the SMPS1200 already has 3 outputs:

View attachment 180867

I think that picture is mislabeled, I checked a couple sites and also saw this ASR sale post

 

[Synergy4]

Ghent Audio supplied a SMPS1200 Y splitter cable for my stereo Neurochrome/Purifi amplifier build.

Here is IEC inlet I used (no EMI filter): FILSHU DE-14-F6 IEC320 C14 inlet with switch & fuse holder (Amazon ), $9.00 a pair shipped.

The Ghent case is well made, fairly solid and looks nice.