DIY Purifi Amp builds

[JimB]

Getting started, but more in an "assemble it yourself" context. ... Eventually I want to swap out the banana connectors for speakON but I'm dragging my heels to see what case Ghent releases later this summer. Until then I'll probably throw it into a temporary box. ...

I (and likely others) have asked that Ghent consider offering a case kit for these with SpeakONs, like they do for the Hypex. We'll see...

 

[Matias]

Sooo..... Anyone done any DIY with Purifi modules,lately?

I heard from Ghent that they are making slow progress due to the impact of COVID on efficiency, but also because they are creating a new case form for these amps (250mm wide, instead of 200 or 300). A new extrusion die is needed and they are still optimizing it (as I understand). It will likely be about 2 more months before we see any completed cases.

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.

 

[boXem]

Sooo..... Anyone done any DIY with Purifi modules,lately?

SMPS600A400, NC400 cables and 1ET400A are waiting for my prototype buffer to be built.

 

[boXem]

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

I have asked the CAD drawing of the Modu shop GX288 case and sent 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 on their demo unit, which is of very similar size to GX288 (photo by @Doug Schneider 's SoundStage! Network, they are going to release the Purifi review June 1st).

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

Stay tuned.

View attachment 65911

That's a really neat build.
Did they tell you who was supplying their case?

 

[Matias]

That's a really neat build.
Did they tell you who was supplying their case?

I did not ask, but honestly, the Modu shop GX288 looks very similar and costs 50 euros based in Italy. It is already an excellent option.

 

[Thomas Savage]

Sooo..... Anyone done any DIY with Purifi modules,lately?

I heard from Ghent that they are making slow progress due to the impact of COVID on efficiency, but also because they are creating a new case form for these amps (250mm wide, instead of 200 or 300). A new extrusion die is needed and they are still optimizing it (as I understand). It will likely be about 2 more months before we see any completed cases.

This is too on topic lol

 

[JimB]

... Attached is the original CAD file that the Purifi team used on their demo unit, which is of very similar size to GX288 (photo by @Doug Schneider 's SoundStage! Network, ... Notice that the demo unit has also speakon holes on the chassis. Purifi said they would send both files, with and without speakon holes, so the customer can ask Modu shop with or without the holes.

WHAT? No hole for S1???

But I do see that they used both fixing holes for each XLR socket.

 

[pos]

Any word about a purifi power supply yet?
That is the one thing that stops me from selling my nc400: without a dedicated low idle power supply there is very little to gain in going for a low idle 1ET400A.

 

[boXem]

I did not ask, but honestly, the Modu shop GX288 looks very similar and costs 50 euros based in Italy. It is already an excellent option.

I know it quite well. Not a huge fan of the form factor. But even after machining, will be far cheaper than a Ghent case.

 

[beren777]

WHAT? No hole for S1???

But I do see that they used both fixing holes for each XLR socket.

I'd be happy even with no hole for S1. At least it's one hole I need to punch instead of several. Plus I think the intended use will be for a front switch and S1 removed.

 

[Matias]

WHAT? No hole for S1???

But I do see that they used both fixing holes for each XLR socket.

Interesting, but the demo unit they sent to Soundstage looks different from the demo unit that was sent to Audiophile Style's review by @mitchco linked below.
https://audiophilestyle.com/ca/revi...and-1et400a-amplifier-technology-review-r866/

Notice how this one uses regular spade+banana binding posts. And both demo amps have no standby S1 switch.

 

[JimB]

Any word about a purifi power supply yet?
That is the one thing that stops me from selling my nc400: without a dedicated low idle power supply there is very little to gain in going for a low idle 1ET400A.

The OUTPUT STAGE idle losses for two 1ET400As are ~3.4W (rest of circuitry unspecified! 3W each?). An FE02A board, about 2-3W? Total maybe ~12W? The SMPS1200A400 idle spec is ~9W (230V, 50Hz). What would make you happy, 5W? 3?

 

[JimB]

I'd be happy even with no hole for S1. At least it's one hole I need to punch instead of several. Plus I think the intended use will be for a front switch and S1 removed.

You know I found a couple ways to remove S1!

 

[pos]

The OUTPUT STAGE idle losses for two 1ET400As are ~3.4W (rest of circuitry unspecified! 3W each?). An FE02A board, about 2-3W? Total maybe ~12W? The SMPS1200A400 idle spec is ~9W (230V, 50Hz). What would make you happy, 5W? 3?

I hope the buffer can be made less than that.
A single nc400 with proper VDR is supposed to be 4.5W, with integrated discrete buffer, and the 1ET400A is supposed to be the result of specific efforts to reduce idle.
Regarding power supply, I want to do a mono build, preferably class 2, so some sort of SMPS600 with a lower idle.
Something like 3W would be good I guess, no idea if this can be done...

 

[boXem]

I hope the buffer can be made less than that.
A single nc400 with proper VDR is supposed to be 4.5W, with integrated discrete buffer, and the 1ET400A is supposed to be the result of specific efforts to reduce idle.
Regarding power supply, I want to do a mono build, preferably class 2, so some sort of SMPS600 with a lower idle.
Something like 3W would be good I guess, no idea if this can be done...

Such an improvement would really be spectacular.
SMPS600 has 8 W idle losses, SMPS1200 9 W.
Using a single SMPS1200 would allow 4,5 W idle losses per channel, but it's no more dual mono.

 

[beren777]

If there are concerns about idle power loss, wouldn't it be easier to wire in a relay between line and power supply that is controlled by remote trigger or music sense? Then your idle power loss is limited to relay + sense circuit. Novice AIYer here, asking because I don't know any better.

 

[starfly]

Question for you experienced builders. If you were to add two 12V trigger inputs, would you just splice the cables together to where the signal needs to go to take the amp/psu out of standby?

 

[TimoJ]

Question for you experienced builders. If you were to add two 12V trigger inputs, would you just splice the cables together to where the signal needs to go to take the amp/psu out of standby?

Why two? I would put diodes to isolate the inputs.

 

[starfly]

Why two? I would put diodes to isolate the inputs.

This amp will be used with an AVR and a separate 2 channel dac (eventually), so I want the amp to be able to be triggered from two different sources.

I'll look into the diodes solution.

 

[JimB]

I hope the buffer can be made less than that.
A single nc400 with proper VDR is supposed to be 4.5W, with integrated discrete buffer, and the 1ET400A is supposed to be the result of specific efforts to reduce idle.
Regarding power supply, I want to do a mono build, preferably class 2, so some sort of SMPS600 with a lower idle.
Something like 3W would be good I guess, no idea if this can be done...

I understand less waste power is generally better than more, but, you seem to be very interested in saving just a few watts, in idle. Will you be leaving it "on" 24/7?