DIY Purifi Amp builds

[Naturlig]

Modu shop received back from Purifi the GX288 case CAD files with the necessary holes to be compatible with the EVAL1 kit. It costs some $ extra.
Have fun!

Super!
The extra cost is 25 euro (back panel) + 20 extra for drilling more that 20 holes = approx 93 euros
And this includes SpeakOn terminals.

 

[phoenixdogfan]

Super!
The extra cost is 25 euro (back panel) + 20 extra for drilling more that 20 holes = approx 93 euros
And this includes SpeakOn terminals.

So 93 euros for a complete case all pre-drilled. Will it include holes for the bannana plug receptacles if I don't want to use SpeakOn terminals?

 

[beren777]

Please ask Modu shop for quotes.
As for the Ghent case, maybe if you ask Ghent for the CAD drawings of the case and send to Purifi they can probably do the same.

Are you planning to use the inner removable base (Base Galaxy) for mounting your EVAL1 or do you plan to drill the base yourself?

If you're having them drill the base, do you have a plan you can share assuming an EVAL1 + Hypex SMPS?

 

[Matias]

Are you planning to use the inner removable base (Base Galaxy) for mounting your EVAL1 or do you plan to drill the base yourself?

If you're having them drill the base, do you have a plan you can share assuming an EVAL1 + Hypex SMPS?

I decided not to do the DIY Purifi EVAL1 project because of costs, so please ask Modu shop directly now.
I went with an NC502MP based custom Apollon amp instead.

 

[beren777]

@Naturlig what about you, do you have a drawing for holes to mount the EVAL1 and SMPS?

 

[Deleted member 65]

So Hypex confirmed that J4 on the SMPS1200 is the only way to get regulated voltage.

About to build an identical Purifi/Neurochrome/Hypex amp as yours except case. Waiting for Hypex & Neurochrome deliveries.

I’d appreciate if you’d share how you wire/connect everything from Hypex to the Neurochromes.

Thx & Good Luck with your build!

 

[kaka89]

About to build an identical Purifi/Neurochrome/Hypex amp as yours except case. Waiting for Hypex & Neurochrome deliveries.

I’d appreciate if you’d share how you wire/connect everything from Hypex to the Neurochromes.

Thx & Good Luck with your build!

I am interested in Purifi with Neurochrome buffer, but not certain how to do wiring without picture guide to verify.

Please share your process if you don't mind, really appreciate it!

 

[Deleted member 65]

I am interested in Purifi with Neurochrome buffer, but not certain how to do wiring without picture guide to verify.

Please share your process if you don't mind, really appreciate it!

I will, hope that @starfly who’s ahead of us will do the same.

Edit: Will receive Hypex SMPS next week, not sure when Neurochrome will apppear. Hopefully within the next couple of weeks, then I’m all set. Note I’ll be using a PC silent case, a bit of work with the back plate.

 

[starfly]

I haven't placed an order for my case yet. Was waiting on receiving the binding posts I had ordered so I could measure them with my caliper so I would know the right size cutout to use in the CAD drawing. I did receive them today, so after re-checking all measurements I'll probably place that order on Mon/Tue. Otherwise I have all other parts.

 

[kukocz]

I do have some exciting news about cases for Purifi DIY build.

I have asked for the CAD drawing of the Modu shop GX288 case and sent it to Purifi. They are helping me adapt the necessary holes of the EVAL1 into the CAD drawing. When I get it I will send it back to Modu shop. After that, anyone can order a GX288 case from Modu shop and ask for it and it will be EVAL1 ready!
https://modushop.biz/site/index.php?route=product/product&path=25_291_293&product_id=444

Attached is the original CAD file that the Purifi team used for their demo unit, which is of very similar size to GX288 (photo by @Doug Schneider 's SoundStage! Network, they are going to release their Purifi review was released on June 1st).

Notice that the demo unit also has speakon holes on the chassis. Purifi said they would send both files, with and without speakon holes, so that the Modu shop customer can choose.

Stay tuned.

View attachment 65911

Don't you think it would be better to move AC socket from right to the left, rotate SMPS by 180 degrees (to use heatsink as RF isolation) and route wires near left side? Not sure if this could have any significant influence but many applications are implemented that way.

 

[boXem]

Don't you think it would be better to move AC socket from right to the left, rotate SMPS by 180 degrees (to use heatsink as RF isolation) and route wires near left side? Not sure if this could have any significant influence but many applications are implemented that way.

The main influence is a psychological one . The heatsink is useless as RF shield since it's open on sides and top.
Staying on the EMI theme, one could argue that this solution shortens the mains wires a bit. Puts the SMPS FETs as far away as possible from the amps too.
Frankly I believe it's more a question of convenience than anything else.

 

[Matias]

I thought about the heatsink as a shield back from the Nord review, but truth is that aluminum is a terrible magnetic shield anyway, almost like air itself, so why bother? Better to leave the heat it generates away from the amplifier modules then.

 

[kukocz]

The main influence is a psychological one . The heatsink is useless as RF shield since it's open on sides and top.
Staying on the EMI theme, one could argue that this solution shortens the mains wires a bit. Puts the SMPS FETs as far away as possible from the amps too.
Frankly I believe it's more a question of convenience than anything else.

You're probably right. I was concerning about that because of the issue with Audiophonics HPA-S400ET where hiss was coming from Right channel. In this specific case input signal wire crossed AC power supply line (quoted below). AUDIOPHONICS LPA-S400ET seems to be nicer/smaller version and even cheaper.

Hello, we tried to detect this behavior
Yes, if no source is connected AND the RCA input selected, we can hear a noise on the right channel.

This is because the switch connect negative input with ground, and cancel the balanced design that remove any perturbation.
We found that this perturbation comes from SMPS1200 main capacitors.

One easy solution can be to route the right input wire under the IEC connector, along the back panel.

But this problem only occur when there is no source, because wires are on air and act as antenna with 47k impedance.
When a source is connected, no sound can be heard.

However, from today, we will take this parameter into account for our next assemblies.

 

[maxxevv]

I thought about the heatsink as a shield back from the Nord review, but truth is that aluminum is a terrible magnetic shield anyway, almost like air itself, so why bother? Better to leave the heat it generates away from the amplifier modules then.

Since its a DIY case, why not just add your own plates for shielding then ?


Magnetic steel plates or maybe exotic "mumetal"alloy plates are available for that purpose.

 

[Kemp]

Finished the simplified circuit, parts list is the same with the exception of the 4N35 optocouplers and sockets plus proto boards. This replaces the 4 channel relay board. Both methods work well so It’s just a matter of preference. I have not had any problems with either one but proceed at your own risk. Will show a picture of the new version which is a little less cluttered, I used two separate proto boards to split up the two functions SMPS standby and LED amp enable. So now need to set back and enjoy. Thanks again for all the help, at this time it is one of my favorite amps.
JimM

Thanks for this circuit. I have a stupid question.. can this be used to controls two SMPS in parallel without any additions. And also what diode should be used in series with R220 at J5.1 SMPS standby. Thanks

 

[wineds]

Thanks for this circuit. I have a stupid question.. can this be used to controls two SMPS in parallel without any additions. And also what diode should be used in series with R220 at J5.1 SMPS standby. Thanks

It will likely work driving two SMPS standby inputs in parallel without any additions. Possibly you may need to tweak the 750ohm resistor value a bit. No diode is needed. The parts on the RHS of the dotted line are internal to the SMPS.

 

[Kemp]

It will likely work driving two SMPS standby inputs in parallel without any additions. Possibly you may need to tweak the 750ohm resistor value a bit. No diode is needed. The parts on the RHS of the dotted line are internal to the SMPS.

Thanks. I may try your advice as I’m planning for multi channel amp.

 

[barrows]

It might be worthwhile to note the layout of the Mola Mola amps. They do orient the SMPS such as to allow the heat sink to act as a shield. also, I suspect the noisy aspect of the SMPS is the AC input and filter area, by using the heat sink as shield orientation, the AC input part of the SMPS is as far away form the amp modules as possible. Given that the Mola Mola is Mr. Putzeys’ work, I figure it is a good idea to note it’s layout.

 

[boXem]

It might be worthwhile to note the layout of the Mola Mola amps. They do orient the SMPS such as to allow the heat sink to act as a shield. also, I suspect the noisy aspect of the SMPS is the AC input and filter area, by using the heat sink as shield orientation, the AC input part of the SMPS is as far away form the amp modules as possible. Given that the Mola Mola is Mr. Putzeys’ work, I figure it is a good idea to note it’s layout.

If you forget this story of shield and only think convenience, you will have another explanation of the SMPS orientation in the Kaluga.
I personally think that Mr. Putzeys also had a look at the demonstrator for his latest amplifier. The orientation of the SMPS would have been inadequate, it would have been changed.

 

[boXem]

This is the dashboard of the demo amplifier. Can anybody show me a trace of mains leakage?