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DIY Purifi Amp builds

phoenixdogfan

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It sort of depends on the application, the AES paper showed that op-amps can be audible, and also that people tend to prefer the ones that add distortion. Don't really know or care about the relative pricing of them, since that has nothing to do with their performance necessarily... Sort of similar to the cable debate in that sense; it shouldn't be a question of 'are expensive cables' but rather 'do any cables make any difference' - which some do, but usually only through some severely flawed construction, that makes them not 'transparent'... Which sounds like lunacy when we're talking about something as rudimentary as a cable or an op-amp.

But I digress... different can of worms. I think the only 'problematic' thing about amplifier matching with the Eval if if you bypass the buffer to get maximum performance, that would put some unusual demands on the pre-amp.
One way to achieve that is to buy an Octo Research and have it set to output 10v RMS. There is also another preamp Amir reviewed which is capable of that output, that's the Topping Pre 90.

https://www.tpdz.net/productinfo/551297.html
 
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I've been looking closer at the Nord Acoustic buffers, but they almost don't seem to be intended for DIY, but rather only for upgrading their own stuff? Has anyone used them for DIY and know how accessible it is? Because from what I can tell there are several cables/connectors you'd need along with some info on those connections to make it work...?
 
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JimB

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So, it appears Ghent has done a monobloc case for the EVAL2. As I understand it, internal cables are included, and it supports either an SMPS1200, or an SMPS600, though the cables are not yet available for the 600.
https://www.ghentaudio.com/kit/purifi-eval2-mono.html

It looks like they have a little discount on a pair.
 

kukocz

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So, it appears Ghent has done a monobloc case for the EVAL2. As I understand it, internal cables are included, and it supports either an SMPS1200, or an SMPS600, though the cables are not yet available for the 600.
https://www.ghentaudio.com/kit/purifi-eval2-mono.html

It looks like they have a little discount on a pair.
It's a pity they don't make holes for speakON connectors anymore...
 
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JimB

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They still have the EVAL1 case:
http://www.ghentaudio.com/kit/purifi-eval1-se.html

I was alerting people to the availability of a new case for the EVAL2. There are different versions of EVAL2. Once it is clear people are buying the set with speakOns, I suspect Ghent will offer a matching back panel for it. You'll have to email them to ask about that possibility.

Or did you mean Purifi is not offering speakOns for the EVAL2?
 

kukocz

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They still have the EVAL1 case:
http://www.ghentaudio.com/kit/purifi-eval1-se.html

I was alerting people to the availability of a new case for the EVAL2. There are different versions of EVAL2. Once it is clear people are buying the set with speakOns, I suspect Ghent will offer a matching back panel for it. You'll have to email them to ask about that possibility.

Or did you mean Purifi is not offering speakOns for the EVAL2?
What do you mean by different versions of eval2? I can see only one version on purifi’s site.

Case for EVAL1 has holes for speakon connectors but it was always up to the owner to solder them to the PCB. Nether eval1 nor eval2 has “built in” speakons.
Most probably not many users use them and Ghent decided to abandon this idea (just guessing)
 
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JimB

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What do you mean by different versions of eval2? I can see only one version on purifi’s site.

Case for EVAL1 has holes for speakon connectors but it was always up to the owner to solder them to the PCB. Nether eval1 nor eval2 has “built in” speakons.
Most probably not many users use them and Ghent decided to abandon this idea (just guessing)
The standard Ghent EVAL1 case has holes for both speakOns and the on-board banana plug sockets, and they provide the speakOns. The Purifi documentation for the EVAL2 showed three variants: banana plug sockets; speakOns; and nothing, though I don't know how you would order them. You should contact Purifi to find out any options you want.

1625533842865.png
 

kukocz

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You've surprised me. I haven't gone through Purifi documentation yet but I remember it wasn't present for EVAL1.
I assume that the default version has banana sockets and you have to de-solder them to enable other options. But maybe custom request can be made with order.
 
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JimB

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You've surprised me. I haven't gone through Purifi documentation yet but I remember it wasn't present for EVAL1.
I assume that the default version has banana sockets and you have to de-solder them to enable other options. But maybe custom request can be made with order.
I think they are offering at least the version without output connectors. If true, you would then need to get the indicated connector (Neutrik NL 4MDH3) and solder it on yourself. Of course, you can also just use wires up to a panel mounted socket. If you do go with a board mounted speakON socket, then you'll need a back panel made for it.

I cannot confirm the socket details - I'm just noting the title of the box in the figure in their datasheet, but it looks right:
https://www.neutrik.com/en/product/nl4md-h-3

If you learn more, please let us know! :)
 

k525

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I think they are offering at least the version without output connectors. If true, you would then need to get the indicated connector (Neutrik NL 4MDH3) and solder it on yourself. Of course, you can also just use wires up to a panel mounted socket. If you do go with a board mounted speakON socket, then you'll need a back panel made for it.

I cannot confirm the socket details - I'm just noting the title of the box in the figure in their datasheet, but it looks right:
https://www.neutrik.com/en/product/nl4md-h-3

If you learn more, please let us know! :)
Hi

here it is what Soundimport is selling
https://www.soundimports.eu/en/purifi-eval2.html
 
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JimB

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I think they are offering at least the version without output connectors. If true, you would then need to get the indicated connector (Neutrik NL 4MDH3) and solder it on yourself. Of course, you can also just use wires up to a panel mounted socket. If you do go with a board mounted speakON socket, then you'll need a back panel made for it.

I cannot confirm the socket details - I'm just noting the title of the box in the figure in their datasheet, but it looks right:
https://www.neutrik.com/en/product/nl4md-h-3

If you learn more, please let us know! :)
It appears that there are the proper holes for that Neutrik socket on the board, but I don't have the parts to confirm it.
 
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JimB

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Is ghent going to have a dual mono eval2 chassis?
I heard they were thinking about it, but I'm not sure they know what the right options would be to make it worthwhile, commercially. (That is, power supplies and size/cost.)
 

jae

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What is the difference between the SMPS1200A400 and SMPS1200A700? Output voltage? Are both with non-removable fuses? The A400 is the correct one for Purifi modules, correct?
 

ironhorse128

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I purchased a Plexiglas front plate for my VTV EVAL1 amp (same case as ghentaudio case). Mainly because I wanted to have a front power button and I thought I might enjoy the look.

It costs about 25 € including all drillings at this place (https://www.plattenzuschnitt24.de/).

These are the dimensions of the Plexiglas piece: 25.7cm x 7.8cm x 0.7cm

These are the positions of the drillings for the four front screws (measured from the bottom left corner). I ordered 5mm drilling. But the screws are M4. It fits just fine with these positions:
0.95/0.75 cm
24.75/7.05 cm
0.95/7.05 cm
24.75/0.75 cm

Then the hole for the power button is 19mm at 21.5/3.9. If I were to do it again I would place the power button a bit higher or a bit more to the right as the button is a bit close to one of the screws of the power supply. But it is fine this way too.

PXL_20210729_182011972.jpg


PXL_20210729_182020188.jpg
 

ironhorse128

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I would like to connect a power button to my VTV EVAL 1 amp. I know that I have to connect the power button at J3 of the EVAL1 board between Pin 1 and 6. The problem is that there is this ribbon cable between J4 of the power supply to J3 of the EVAL1 board. It connects to pins 5 (positive rail voltage regulator input),6 (ground),7 (negative rail voltage regulator input).

I guess I cannot just remove the existing ribbon cable, right?

My question is: As somebody that is not really technical skilled in electronics, is there a safe and easy way to make this work (connect the power button to my VTV EVAL1 amp)?
I have some basic skills and tools. I could also buy adapters or tools. I would appreciate any help.

Here is J3 of the EVAL1 board.
PXL_20210729_181426537.jpg

And this is the other end of the ribbon cable at J4 of the power supply.

PXL_20210729_181433071.jpg
 

Billy Budapest

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I purchased a Plexiglas front plate for my VTV EVAL1 amp (same case as ghentaudio case). Mainly because I wanted to have a front power button and I thought I might enjoy the look.

It costs about 25 € including all drillings at this place (https://www.plattenzuschnitt24.de/).

These are the dimensions of the Plexiglas piece: 25.7cm x 7.8cm x 0.7cm

These are the positions of the drillings for the four front screws (measured from the bottom left corner). I ordered 5mm drilling. But the screws are M4. It fits just fine with these positions:
0.95/0.75 cm
24.75/7.05 cm
0.95/7.05 cm
24.75/0.75 cm

Then the hole for the power button is 19mm at 21.5/3.9. If I were to do it again I would place the power button a bit higher or a bit more to the right as the button is a bit close to one of the screws of the power supply. But it is fine this way too.

View attachment 144337

View attachment 144338
I do not like those power leads touching the top plate of the case. Maybe it would be Ok if they were double insulated or if there was a separate ground wire for the top plate.
 

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