DIY Purifi Amp builds

[JimB]

Ah! Yes! All right! I understand better what you are trying to explain to me now thanks to the graph! (I didn't know how to read/interpret the graph before.) (I'm an amateur as a reminder)

Actually 3.2vrms I couldn't compare with 4.2vrms or 2vrms but I think the feeling/listening will be closer to 4.2vrms than what I appreciate less in listening at 2vrms.

So what would be the value to replace of resistance R17 on EVAL1 or R22 on EVAL2 to get 3.2Vrms?

Thanks again!
Vincenzo.

Sorry, but the performance difference between a 3.2V and 4.0V rating is not enough to make me want to do the calculation for you. I recommend doing the 4.0V mod if you must - that gives you a somewhat "standard" unit. But you can do the calculation for 3.2V using the manufacturer's gain equation, just as I did.

 

[tomchr]

I now offer a custom machined chassis for a stereo Purifi 1ET400A or Hypex NC500 powered by a Hypex SMPS1200A400 power supply: https://neurochrome.com/collections/connectors-parts/products/purifi-chassis

The chassis is made by Takachi in Japan and is of incredible quality – better than that of many commercially available Purifi/Hypex amps – and that's reflected in the price tag. Sorry... Custom machined aluminum is expensive to start. Custom machined aluminum at this quality level is even more expensive.

I expect to have them in stock towards the end of February. I won't have too many made as I hate having money tied up in aluminum. Also I'm approaching this as a bit of an experiment to see if I should offer a full Purifi/Hypex kit. Given that the DIY kit will be more expensive than a completed amp by [INSERT CHEAP BRAND NAME HERE] I see it as a bit of an uphill battle and will limit my risk until I see where it goes.

The chassis comes with all the mounting hardware; including the two custom made mounting plates for the amp modules and buffers. All the connectors, switches, circuit boards, etc. are available separately.

Anyway. You can watch a previous iteration of the chassis in the video below. That version of the chassis did not support the Guardian-86 optional speaker protection. The current version of the chassis does.

Tom

 

[HarmonicTHD]

And what do you think of Neurochrome's buffer?

@tomchr does very solid engineering and provides detailed AP measurements here.

Purifi 1ET400A / Hypex NC500 Input Buffer

This Purifi/Hypex input buffer provides a fully differential output. It is an excellent upgrade on the Purifi EVAL1 and features extremely low distortion.

neurochrome.com

So it should be beyond a doubt and transparent. Any additional questions he usually answers quickly.

At @tomchr : Do you also have measurements with your buffer (at 13dB gain) and the ET400? Sorry if I missed them.

 

[tomchr]

The Performance Graphs tab on the Purifi/Hypex Input Buffer product page has measurements at 13.2 dB and 0 dB gain for the buffer. I have yet to measure the completed amp. I should probably do that ... especially if I end up offering a kit.

Tom

 

[HarmonicTHD]

The Performance Graphs tab on the Purifi/Hypex Input Buffer product page has measurements at 13.2 dB and 0 dB gain for the buffer. I have yet to measure the completed amp. I should probably do that ... especially if I end up offering a kit.

Tom

Yes I saw them. I meant a completed amp. Let us know once you have them. Thx

 

[radeon]

I'm looking to build a DIY 8-channel amp in one single large chassis and I'm wondering if anyone can give some advice for what is the best way to power it?

Since one SMPS1200A400 can handle at most 3 purifi channels, I would need 3 units of the SMPS1200A400 in order to do 8.

But, is there any bennefit to using 8x seperate SMPS1200A400 with one power supply for each channel? This would be the equivelent of 8 monoblock amps in a box? Or is there no point in this?

Or conversely, could I instead use a single SMPS3kA700 to power the whole box? Purifi mentioned that if I use the SMPS3kA700, then I would have to flip half the channels to be in opposite phase? Just trying to understand what is invovled in that. Thanks

 

[starfly]

I'm looking to build a DIY 8-channel amp in one single large chassis and I'm wondering if anyone can give some advice for what is the best way to power it?

Since one SMPS1200A400 can handle at most 3 purifi channels, I would need 3 units of the SMPS1200A400 in order to do 8.

But, is there any bennefit to using 8x seperate SMPS1200A400 with one power supply for each channel? This would be the equivelent of 8 monoblock amps in a box? Or is there no point in this?

Or conversely, could I instead use a single SMPS3kA700 to power the whole box? Purifi mentioned that if I use the SMPS3kA700, then I would have to flip half the channels to be in opposite phase? Just trying to understand what is invovled in that. Thanks

8x SMPS1200A400 would be extreme overkill. If you want to go 8x mono, get 8x SMPS600. But again, probably extreme overkill as surround channels don't need as much power.

 

[3ll3d00d]

Just trying to understand what is invovled in that.

Described in section 2.1 of the datasheet, reverse the wiring on half of the channels basically (both input and output). It's only really an issue for low frequency use though so it depends how you use the channels.

 

[JimB]

8x SMPS1200A400 would be extreme overkill. If you want to go 8x mono, get 8x SMPS600. But again, probably extreme overkill as surround channels don't need as much power.

Better might be four SMPS1200A400, with two modules fed by each.

 

[Matias]

I now offer a custom machined chassis for a stereo Purifi 1ET400A or Hypex NC500 powered by a Hypex SMPS1200A400 power supply: https://neurochrome.com/collections/connectors-parts/products/purifi-chassis

The chassis is made by Takachi in Japan and is of incredible quality – better than that of many commercially available Purifi/Hypex amps – and that's reflected in the price tag. Sorry... Custom machined aluminum is expensive to start. Custom machined aluminum at this quality level is even more expensive.

I expect to have them in stock towards the end of February. I won't have too many made as I hate having money tied up in aluminum. Also I'm approaching this as a bit of an experiment to see if I should offer a full Purifi/Hypex kit. Given that the DIY kit will be more expensive than a completed amp by [INSERT CHEAP BRAND NAME HERE] I see it as a bit of an uphill battle and will limit my risk until I see where it goes.

The chassis comes with all the mounting hardware; including the two custom made mounting plates for the amp modules and buffers. All the connectors, switches, circuit boards, etc. are available separately.

Anyway. You can watch a previous iteration of the chassis in the video below. That version of the chassis did not support the Guardian-86 optional speaker protection. The current version of the chassis does.

Tom

Could you please create a thread on the Desperate Dealers section and post updates there so that we can watch the thread and keep updated? Thanks!

 

[radeon]

8x SMPS1200A400 would be extreme overkill. If you want to go 8x mono, get 8x SMPS600. But again, probably extreme overkill as surround channels don't need as much power.

I'm using them for super high end avantgarde horn speakers. They are pretty efficient, so wattage is not a huge concern, but I just want the best possible performance. Each driver(highs, mids, lows) is powered individually with seperate amps and custom software crossovers.

What exactly is the bennefit in running them in 8x mono instead of running all the channels together with a single SMPS3kA700? If there is zero bennefit, then I might as well not do 8x PSUs.

The are currently running on a Lexion RX-7. I hope this purifi amp is much better than what I have now, but I'm really not sure.

 

[radeon]

Better might be four SMPS1200A400, with two modules fed by each.

If I am planning to feed multiple amps off a single power supply anyways, why dont I do three modules per SMPS1200A400? Why limit it to two?

 

[mumford]

I think it makes more sense to make 2 separate 4-channels amp. 4 Purifi modules and 1 PSU each. Your compression horns require maybe a couple watts at most. 1200w is more than enough. Building 2 separate amps provides you a bit of accident proofing. If one amp fails, only 1/2 the system fails.

 

[radeon]

I think it makes more sense to make 2 separate 4-channels amp. 4 Purifi modules and 1 PSU each. Your compression horns require maybe a couple watts at most. 1200w is more than enough. Building 2 separate amps provides you a bit of accident proofing. If one amp fails, only 1/2 the system fails.

Yup, probobly will never come close to drawing the full 1200w anyways. So I guess this means one single SMPS1200A400 feeding into four modules is doable?

The reason I want to put it into a single chassis is more because of space concerns. I already have two full rackmount shelves of gear, trying to avoid adding a third.

I also already have a dead Lexicon MC-12 which has a giant chassis. I was thinking of building the entire 8 channels kit inside that box, maybe add a slient fan and a bunch of heatsinks.

Thanks alot for your advice, and to everyone else who gave feedback.

 

[Doodski]

I also already have a dead Lexicon MC-12 which has a giant chassis. I was thinking of building the entire 8 channels kit inside that box, maybe add a slient fan and a bunch of heatsinks.

It makes more sense to have Buckey Amps build it custom for you and have it properly milled and machined.

 

[radeon]

It makes more sense to have Buckey Amps build it custom for you and have it properly milled and machined.

The buckeye and boxem amps look absolutely incredible and I would love to have them, but it would be double the cost, if not more.

I have priced it out to be around 3840CAD for 8 purifi modules, 8 input stages from @tomchr and two SMPS1200A400.

This is about 2880USD. I have a hard time beleiving that an 8-channel system from buckeye wont be 3x this number. Plus the cost of shipping and import taxes into canada.

Also glad to support local businesses by purchasing both the purifi modules and Tom's input buffers from Canada.

I have a mill and will be redoing the front and back panels on the lexicon. I'm sure it won't be as pretty as a boxem/buckeye amp, but I can use those savings to upgrade the pre-pro or other parts.

 

[Doodski]

The buckeye and boxem amps look absolutely incredible and I would love to have them, but it would be double the cost, if not more.

I have priced it out to be around 3840CAD for 8 purifi modules, 8 input stages from @tomchr and two SMPS1200A400.

This is about 2880USD. I have a hard time beleiving that an 8-channel system from buckeye wont be 3x this number. Plus the cost of shipping and import taxes into canada.

Also glad to support local businesses by purchasing both the purifi modules and Tom's input buffers from Canada.

I have a mill and will be redoing the front and back panels on the lexicon. I'm sure it won't be as pretty as a boxem/buckeye amp, but I can use those savings to upgrade the pre-pro or other parts.

WoW! A enthusiast's system... Far Out!

 

[mumford]

Yup, probobly will never come close to drawing the full 1200w anyways. So I guess this means one single SMPS1200A400 feeding into four modules is doable?

yes. You probably need a splitter board for the PSU. You may also want to check price of the amp modules at Purifi web store, as you get quantity discount.

 

[radeon]

yes. You probably need a splitter board for the PSU. You may also want to check price of the amp modules at Purifi web store, as you get quantity discount.

@tomchr sells the splitter boards, but his only splits into 3 channels. Do you know of any other manufacturer that can split into 4 or more? Otherwise I would just have to build my own cables.

I have looked at the purifi web store, if I buy just 1ET400A modules, it comes out to 3,560CAD with the discount, and this does not include any input buffers or any power supply. So it's still cheaper to get them from canada.

The second cheapest way to do this is to buy the EVAL2 boards directly from purifi, this comes out to $3690CAD including factory input buffers, but no power supply.

So the cheapest way to do this is to buy the modules from Canada and the input stage from tom/neurochrome

 

[mumford]

I do not know who makes 4 way Hypex splitters. Also, if your DAC/crossover has enough output, you may consider this buffer instead. Depending on parts cost, you may save another $70 - 80 USD per channel.

Universal PCB for Purifi 1ET400A amps

I have correct the faulty track. Give some components more space. And changed the holesize of the connectors to get a better fit. Updated the schematic as-build.And publish the gerber files. Hello Kofarm, I allow myself to contact you because I came across your BUFFER for Purifi Audio. I...

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