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DIY Purifi Amp builds

ABall

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Well I think Tom's board is the only one that can drive the amps to clipping using single ended inputs if that's worth the extra, amongst other things, other wise your not going to get better performance from anything else vs the Eval, now your talking about adding distortion to change the sound, that's nothing to do with better performance so you have to choose, colouration or performance, I dont think those 2 are mutual.
 
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Well I think Tom's board is the only one that can drive the amps to clipping using single ended inputs if that's worth the extra, amongst other things, other wise your not going to get better performance from anything else vs the Eval, now your talking about adding distortion to change the sound, that's nothing to do with better performance so you have to choose, colouration or performance, I dont think those 2 are mutual.
Thats fair - it might not be better performance, but if it is audibly more enjoyable, I can to an extent understand it. However I haven seen any mention of such. The Nord would seem the most likely culprit in that area though... Well again other than the NuTube ones, but at that point I'd rather just use an actual tube pre amp I think, based on what I've heard people say about those.

Also... who's Tom? xD
 

ABall

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Thats fair - it might not be better performance, but if it is audibly more enjoyable, I can to an extent understand it. However I haven seen any mention of such. The Nord would seem the most likely culprit in that area though... Well again other than the NuTube ones, but at that point I'd rather just use an actual tube pre amp I think, based on what I've heard people say about those.

Also... who's Tom? xD
That's why I bought a Schiit Freya plus.
Tom IS Neurochrome, probably should have used his full username, @tomchr
 
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JimB

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There were some discussions earlier in this thread, starting at about post 2262. Tom was explaining the differences between his buffer and EVAL1, but I assume it would be similar with EVAL2.
The front end of the EVAL2 set is essentially a single channel version of front end of the EVAL1 set.
 
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JimB

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In this case I'm trying to discern what the best performing one would be, regardless of price - and since I know someone who has the Eval1 based one, I'd like to try something different, just for the sake of curiosity...
I do also intend to make monoblocks... mainly just because I like it aesthetically. A shame purifi discourages bridging the amps even though its apparently possible. Would be interesting to know why/how it performs.

But yea, I'm sort of just trying to figure out how to add a different twist, for the fun of it, and hopefully get equal or better performance if possible.
Then the Neurochrome is a good option for you: it is "different", has some technically desirable features, is single channel, and performs extremely well (judging by the published data). But, I don't think it is going to 'sound' better than, or even different from, the EVALx units, unless you do something wrong.
 
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Rottmannash

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That's why I bought a Schiit Freya plus.
Tom IS Neurochrome, probably should have used his full username, @tomchr
ditto on the Freya+. Great combo.
 

JaapDeventer

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IMG_20210605_120745x.jpg

With Nelson Pass Korg NuTube preamp. With the two pots the plate voltage of the tubes can be adjusted. I like what it does. No added noises, just goose bumps
 
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Then the Neurochrome is a good option for you: it is "different", has some technically desirable features, is single channel, and performs extremely well (judging by the published data). But, I don't think it is gong to 'sound' better than, or even different from, the EVALx units, unless you do something wrong.
It I do something wrong, and it makes it sound better, I shall be amazed! But yea, I send to agree - plus it’s barely more expensive than the eval.
 
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View attachment 134059
With Nelson Pass Korg NuTube preamp. With the two pots the plate voltage of the tubes can be adjusted. I like what it does. No added noises, just goose bumps
Aren’t those quite tricky to come by, or make or something? I remember someone I spoke to mentioning that...

Edit: oh, I see it’s available to buy as a board. Have you compared its sound against anything else like the Freya with the Purifi? I’d be worried what it might do to the detail..
 
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JaapDeventer

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Aren’t those quite tricky to come by, or make or something? I remember someone I spoke to mentioning that...

Edit: oh, I see it’s available to buy as a board. Have you compared its sound against anything else like the Freya with the Purifi? I’d be worried what it might do to the detail..
In my test setup I used a double switch to compare between NuTube and NuTube bypassed. With a pot to match volumes. I did not hear a different sound signature. But with NuTube I find the music more engaging and more spacious. In the final build I left out volume pot and switch as not to clutter it up.
20210522_112028.jpg
 
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In my test setup I used a double switch to compare between NuTube and NuTube bypassed. With a pot to match volumes. I did not hear a different sound signature. But with NuTube I find the music more engaging and more spacious. In the final build I left out volume pot and switch as not to clutter it up.
View attachment 134090
Hmm, interesting. It’s a darn shame that the board doesn’t exist in a balanced/differential version, for this purpose.
 

mocenigo

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Hmm, interesting. It’s a darn shame that the board doesn’t exist in a balanced/differential version, for this purpose.

One could use two boards, one for each channel. Of course it would not convert unbalanced to balanced.
 
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Do we know of any more suited power supplies for mono builds and/or any possible benefits to mono builds?
I’m mainly considering it for aesthetic reasons, but also curious.
 

mocenigo

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Do we know of any more suited power supplies for mono builds and/or any possible benefits to mono builds?
I’m mainly considering it for aesthetic reasons, but also curious.

One of the Hypex SMPS600 power supplies has compatible voltages (one of the AUX is slightly high but still ok).
 

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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