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DIY Purifi Amp builds

Naturlig

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Yes Tom, it is exactly what I do but I pretty sure the bump occur also without any source connected


This guardian-86 seem interesting, unfortunately I am using EVAL1 build-in soldered speaker connectors, use this Guardian-86 will require som work (I see these board need power supply.. do you know where to find some instruction?)

Thank you for all TOM!
I have built two Purify amps, one EVAL1 and one with the Neurochrome buffers, both with the Hypex SMPS1200A400 psu. In the amp with Neurochrome buffers I mounted the psu with the aluminium "wall" towards the 1ET400A components. Before the installation of Guardian-86 I turned the psu with the alu "wall" against the front plate (shorter power cables). The bump sound almost disappeared, still a small tick from the psu. Measured lower voltage values on the speaker terminals and a cleaner graph with the Picoscope. Why? For me it looks like that the psu rectifiers are mounted on the alu "wall"?
 

tomchr

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I doubt the orientation of the SMPS1200 plays into the magnitude of any thump. I could see how it could impact the mains hum, though. Rectifiers should generally be kept at a comfortable distance away from amplifier inputs and other sensitive circuitry.

I'm obviously not denying your data or experience, but I wonder if the difference is actually from better electrical connections to the SMPS. Maybe there's lower strain on the connectors (especially on the 6-pin power connectors) with the new orientation. Just a thought.

Tom
 

Naturlig

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I doubt the orientation of the SMPS1200 plays into the magnitude of any thump. I could see how it could impact the mains hum, though. Rectifiers should generally be kept at a comfortable distance away from amplifier inputs and other sensitive circuitry.

I'm obviously not denying your data or experience, but I wonder if the difference is actually from better electrical connections to the SMPS. Maybe there's lower strain on the connectors (especially on the 6-pin power connectors) with the new orientation. Just a thought.

Tom
Could be the case if you have a chassis design with short distance (a few mm) between the components.
But I have seen that it is the rectifiers on the SMPS and the "230V side" that make the most noise.
 

tomchr

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But I have seen that it is the rectifiers on the SMPS and the "230V side" that make the most noise.
That's been my experience as well.

Tom
 

Synergy4

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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

Top.jpg
 

NTSOS

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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

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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.
 

AdamG247

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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

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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!
 

AdamG247

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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

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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

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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.
 

fraa

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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

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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

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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 | audio

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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

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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:

1642802065357.png


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:

1642802833950.png


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.
 
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