DIY Purifi Amp builds

[JimB]

It's still under warranty, and I'm sending it back to Hypex. Thanks for your help. It came back from one such warranty repair and didnt work just like the first time. My concern is that something else is causing the SMPS to fail. I have Ghent's wiring kit, so it will no longer be my wiring. I've requested and they've agreed to look at my wiring harnesses to see if they were (are) the root cause of this difficulty.

If' that's not the cause, then perhaps something went wrong with the Purifi. I will be reaching out to them in the next day or so. That's why I am concerned by the switch removal, though it involved nothing more than the process I described and not touching anything soldered.

My final concern is that the board practically touches the back plate, so I worry that could cause a short, though I've been assured there's nothing electrical near the board's back edges to come into contact with the back plate.

Sorry to hear your problems here continue. It must be very frustrating. Just removing the face of S1 is no problem - mine ran fine after that, as did the one where I unsoldered it altogether. But there does need to be a working /AMPON signal on J3p1 of the EVAL1. And it must be in hardware control mode. The absence of VDR seems to be the top culprit at the moment. Why?

I suppose an active /FATAL from J3p3 of the EVAL1 to the SMPS could be an issue, as well.

 

[JimB]

It's still under warranty, and I'm sending it back to Hypex. Thanks for your help. It came back from one such warranty repair and didnt work just like the first time. My concern is that something else is causing the SMPS to fail. I have Ghent's wiring kit, so it will no longer be my wiring. I've requested and they've agreed to look at my wiring harnesses to see if they were (are) the root cause of this difficulty.

If' that's not the cause, then perhaps something went wrong with the Purifi. I will be reaching out to them in the next day or so. That's why I am concerned by the switch removal, though it involved nothing more than the process I described and not touching anything soldered.

My final concern is that the board practically touches the back plate, so I worry that could cause a short, though I've been assured there's nothing electrical near the board's back edges to come into contact with the back plate.

You can space the back panel away from the EVAL to confirm that it is not causing the problem.

 

[JimB]

Today the brand new Ghent Audio case for the Eval1 arrived in the mail and also the Hype SMPS1200A400 so that I was able to finally assemble my new amp. I am very happy with the Ghent case, the fit was excellent and assembly took probably less than an hour and a half.
I am very familiar with Bruno Putzey's work given that I have been listening to a DIY Hypex Ncore 400 kit for years before it broke down this summer, probably due to heat issues.
It is always difficult to make comparisons by memory, but here are my first listening impressions: There is definitely a family resemblance between Bruno's Ncore amps and the new Purifi module. Both are very transparent and revealing. To my ears the Purifi is a tad more revealing and transparent. And there is more micro information in the recorded material. There also seems to be a little more bass. The Ncore had tremendous control in the lower regions, just like the Purifi. But the Ncore was a little shy with the bass, it had a lack of emphasis there and the Purifi does away with that shyness having a more developed bass region, which is not emphasized, just more balanced in my opinion. All in all I am very happy with the sound of the Eval1 and consider it an upgrade from the Ncore 400.
My hifi chain is geared toward leanness and transparency. My music is stored on a Roon Nucleus, streaming is via Sonore's ultraRendu to the Metrum Hex Dac. My preamp is a buffered passive Wyred4Sound STP, the whole digital chain including the Purifi amp is balanced. Probably the weaker link when it comes to micro information and transparency are my wall mounted Sehring loudspeakers, but they are good enough to hear the difference the Purifi makes.

I'm jealous! I've been waiting for mine for a year (not that they were even thinking of making them back then). But, I am glad several of you are now getting good, complete cases for your builds.

 

[JimB]

I too received a Ghent case and wiring kit this afternoon. Assembly was easy even with no instructions whatsoever. Took about two hours, mostly searching for tiny screws I had just dropped and tools I just put down over here. Issues are:

- what are you supposed to do with the thoughtfully supplied SpeakOn connectors? No illustration, no instructions, no extra wires for them. How Am I missing something?

- the nice thick magnet mounted front panel isn’t working for me. The recessed bits on the back are not fitting into the supplied metal bars. Am I missing something again?

Pretty minor stuff all in all, especially after weeks of effort to get everything into a Modushop2000 Galaxy case, albeit most of my issue was with getting a front panel button to work. I finally gave up on that little dream.

speakONs of no use to you? Ignore them. Otherwise, you can either solder wires up from the open pads on the EVAL1 to the corresponding tabs of the speakONs, OR make jumper cables from the inside ends of the on-board DELTRON-style speaker sockets to the tabs on the speakONs. I believe Ghent provided these sockets at the request of a major first customer, who knows what to do with them.

 

[JimB]

Received my Ghent case today and assembled. EVAL1+ Hypex SMPS.

Biggest issue is a high-pitched static/whistling/squeal sound from one output. It's clearly audible with source or nothing connected, annoying but not so loud I worry about speaker damage. Is audible with music. If I swap speakers, the static noise follows the output, not the speaker. It's the channel closest to the power inlet. I did make sure to twist the wires for the wire connecting outlet to SMPS. Are there additional troubleshooting steps to follow? No such noise when using the same audio source, wires, power with my VTV 252.

Two other minor issues which I haven't communicated to Ghent yet:

1. Couldn't find a screw for connecting the ground lead. I scavanged something elsewhere to use temporarily.
2. It looks like 4-pole Speakon connectors were included instead of 2-pole.
   1. Edited to add, it looks like 4-pole is what is advertised on the website, so I got what was advertised - but why two 4-pole connectors? If you're using two Speakon, one for each speaker, don't you just need two 2-pole connectors?

Whistling output does not sound good. Are you using the EVAL input buffer, or is it configured to 'by-pass'?

Did the others who have received cases get a dedicated grounding screw?

I don't think the speakONs were Ghent's idea (customer specification). They are a case/cable maker, not an amp maker, just trying to satisfy demand. You can certainly use 4-pole plugs for 2-pole duty. And you can wire them fully so that either socket does both left and right speakers (or high and low drivers, etc..). You have more options. If you intend to use speakONs, just decide how you want them to work and wire accordingly. If they bother you, you can also replace them with ones that suit you better.

 

[beren777]

Whistling output does not sound good. Are you using the EVAL input buffer, or is it configured to 'by-pass'?

Did the others who have received cases get a dedicated grounding screw?

I don't think the speakONs were Ghent's idea (customer specification). They are a case/cable maker, not an amp maker, just trying to satisfy demand. You can certainly use 4-pole plugs for 2-pole duty. And you can wire them fully so that either socket does both left and right speakers (or high and low drivers, etc..). You have more options. If you intend to use speakONs, just decide how you want them to work and wire accordingly. If they bother you, you can also replace them with ones that suit you better.

1. Oh, yeah, no real problem getting 4-poles. Just confused. I have a set of 2-poles I can throw in if I really care.
2. I didn't change anything on the EVAL1. It looks like B1 and B2 are both set to enable pre-gain. I can change that to see if it helps. Or hurts.
3. I don't think screws were included for the XLR connectors either, to secure them to the back plate. Can anyone recommend some?

 

[beren777]

Whistling output does not sound good. Are you using the EVAL input buffer, or is it configured to 'by-pass'?

Same trouble with bypass enabled.

 

[phoenixdogfan]

You can space the back panel away from the EVAL to confirm that it is not causing the problem.

When I get the Hypex back I will first test with no back plate. Also plan to take it out and see if there's any traces that look like they could be contacting the back plate, though I don't think my case with the fabricated back plate fits together any differently from the new Ghent Purifi case.

 

[JimB]

1. Oh, yeah, no real problem getting 4-poles. Just confused. I have a set of 2-poles I can throw in if I really care.
2. I didn't change anything on the EVAL1. It looks like B1 and B2 are both set to enable pre-gain. I can change that to see if it helps. Or hurts.
3. I don't think screws were included for the XLR connectors either, to secure them to the back plate. Can anyone recommend some?

Their website page says screws are included, but not exactly which ones. My cases for Hypex amps from them in the past included all required screws.

 

[beren777]

Mystery solved re: squeal, the Hypex SMPS is shipped set to regulated Vaux by default, and the EVAL1 wants unreg. Changed the jumpers, and it's happy now. More testing tomorrow.

 

[JimB]

I too received a Ghent case and wiring kit this afternoon. Assembly was easy even with no instructions whatsoever. Took about two hours, mostly searching for tiny screws I had just dropped and tools I just put down over here. Issues are:

- what are you supposed to do with the thoughtfully supplied SpeakOn connectors? No illustration, no instructions, no extra wires for them. How Am I missing something?

- the nice thick magnet mounted front panel isn’t working for me. The recessed bits on the back are not fitting into the supplied metal bars. Am I missing something again?

Pretty minor stuff all in all, especially after weeks of effort to get everything into a Modushop2000 Galaxy case, albeit most of my issue was with getting a front panel button to work. I finally gave up on that little dream.

In my experience, Ghent cases do not have magnets. They have bars with beveled ends that attach onto the front of the case. The front panel then angles onto them. Once flush in place, two tiny set screws from the bottom panel edge hold it in place. DO NOT OVERTIGHTEN THESE!

 

[sgoldwin]

I too got an email today saying they would be working on these soon. I will have three coming! I expect them to have no holes for the S1 or on-board DELRON sockets, much like the Purifi demo amps. Clean. But, it is not necessary to remove those parts to use this new back panel. One can just remove the face of S1 and the plastic 'lips' from the DELRONs and be good to go.

For example: https://www.audiosciencereview.com/...y-purifi-amp-builds.10478/page-25#post-344897

@JimB you

1. Oh, yeah, no real problem getting 4-poles. Just confused. I have a set of 2-poles I can throw in if I really care.
2. I didn't change anything on the EVAL1. It looks like B1 and B2 are both set to enable pre-gain. I can change that to see if it helps. Or hurts.
3. I don't think screws were included for the XLR connectors either, to secure them to the back plate. Can anyone recommend some?

re point 3. You are supposed to use Neutrik Type A screws but any self tapping 3mm screw will work. Try to get a countersink head. My kit also did not include them but I used some Type E screws I had from another project.

 

[zappa]

I guess Hypex are building power supplies for the world. The on board soldered 12A fuse is intended as a last ditch fail safe which should never blow if an additional lower rated fuse is fitted to the build.

I am for the fuse question again.
You recommend the Fast blow ones while HYPEX use the Slow blow ones, why ? it will not be a problem (fuses blows all the time ?)

 

[beren777]

I am for the fuse question again.
You recommend the Fast blow ones while HYPEX use the Slow blow ones, why ? it will not be a problem (fuses blows all the time ?)

My guess is that you want the fast blow fuse upstream of the Hypex to protect the Hypex fuse. If that one blows, it's more of a pain to replace. If the upstream, inline fuse blows, that's a quick swap.

 

[JimB]

I am for the fuse question again.
You recommend the Fast blow ones while HYPEX use the Slow blow ones, why ? it will not be a problem (fuses blows all the time ?)

I would recommend an appropriately sized slow blow. That is, one that is slightly larger than the maximum continuous power you expect to draw.

 

[wineds]

My guess is that you want the fast blow fuse upstream of the Hypex to protect the Hypex fuse. If that one blows, it's more of a pain to replace. If the upstream, inline fuse blows, that's a quick swap.

I am for the fuse question again.
You recommend the Fast blow ones while HYPEX use the Slow blow ones, why ? it will not be a problem (fuses blows all the time ?)

In the event of a fault I like my fuses to blow as quickly as possible.

 

[zappa]

Thanks to all,
I will start with a Fast blow fuse and see later if it burns to often.
Audiophonics offers the semi-slow fuses, I guess it's something in between ?

 

[sloth_kwj]

Input buffer sum for discrete OP-amp lovers

all prices in pair

ATM audio
https://atm-audio.com/product/buffer-hypex-nc500/
€335 w/o OP, VR

VTV amplifier
https://vtvamplifier.com/product/vtv-amplifier-custom-input-buffer-hypex-nc500-nc1200-nc2k-purifi/
$280 w/o OP, Sparkos SS78,SS79 VR

Nord Acoustic
https://www.nordacoustics.co.uk/product-page/nord-one-rev-d-input-buffer-board
Price w/o OP in inquiry, Sparkos SS78,SS79 VR

 

[sloth_kwj]

View attachment 71118

Who made this? I want to know more specific components and CAD drawing... It is same that I'm planning to build..

 

[kukocz]

Who made this? I want to know more specific components and CAD drawing... It is same that I'm planning to build..

This is Purifi's evaluation amplifier shared with reviewers. By the way, does anyone know what model of enclosure they used? It's quite interesting one.