DIY Purifi Amp builds

[pos]

@Science is fun, I am referring to this board: https://www.hypex.nl/product/nc500-evaluation-board/51
The datasheet specifies the different gain options page 4:

 

[Science is fun]

Yes but when you solder the bypass jumper that circuit is completely bypassed. Bypassing that circuit makes an audible and measurable improvement.

 

[pos]

Would you happen to know the price of this OEM nc500 buffer board?
What do you think of Neurochrome universal buffer solution here?
Might be interesting to combine the two here...

 

[Science is fun]

 

[pos]

Thanks, that is cheap enough to not justify building a dedicated PCB!

 

[Science is fun]

A pair of these Ghent kits:

https://www.ghentaudio.com/kit/ncore-mx4.html

or these:


https://www.ghentaudio.com/kit/ncore-mx.html

2 NC-500 evm boards, 2 SMPS1200A400's and 2 Purifi modules you have a pair of Purifi mono blocks today for around $1400

 

[Science is fun]

An industrious individual could offer an assembly service and a 3 year warranty for $800 of the above kits, and still undercut March's monoblocks by $300. And have the option of buffer bypass! Not bad for an hours work!

 

[pos]

https://www.ghentaudio.com/kit/ncore-mx4.html

That is the one I have for my nc400 modules: XLR in and speakon out.
Pretty nice and a perfect fit, although I had to drill the front panel to attach them because the original fixing system was way to flimsy.
And as a bonus this gives it a definite Benchmark look

So, what is your take on the neurochrome board? You seem to have some experience with these hypex buffers...

 

[Science is fun]

That is the one I have for my nc400 modules: XLR in and speakon out.
Pretty nice and a perfect fit, although I had to drill the front panel to attach them because the original fixing system was way to flimsy.
And as a bonus this gives it a definite Benchmark look

So, what is your take on the neurochrome board? You seem to have some experience with these hypex buffers...

I don't see the point of the buffer. Unless you have a weak source. The best sounding and measuring buffer is no buffer.

 

[restorer-john]

I don't see the point of the buffer. Unless you have a weak source. The best sounding and measuring buffer is no buffer.

Maybe for people with a simple little system comprised of one ultra low impedance, low noise, ruler flat, large amplitude swing source, at close range to the amplifiers, it might be OK.

But for people with multiple sources, of all types and abilities, possibly driving several amplifiers or amplifiers at a distance, source buffers/line drivers and amplifiers with reasonable input impedances are required and always have been.

 

[Science is fun]

Maybe for people with a simple little system comprised of one ultra low impedance, low noise, ruler flat, large amplitude swing source, at close range to the amplifiers, it might be OK.

But for people with multiple sources, of all types and abilities, possibly driving several amplifiers or amplifiers at a distance, source buffers/line drivers and amplifiers with reasonable input impedances are required and always have been.

Just buy a decent preamp then. Any preamp that can't drive 4.4k is a POS. It's not 1954 anymore. If you feel you have no choice but to buy a POS preamp, don't solder the buffer bypass jumper then.

 

[restorer-john]

Just buy a decent preamp then. Any preamp that can't drive 4.4k is a POS. It's not 1954 anymore. If you feel you have no choice but to buy a POS preamp, don't solder the buffer bypass jumper then.

What do think a preamplifier is? It's a multi-input buffer with a low output impedance designed specifically to drive power amplifiers. And low can mean 1R or it can mean >500R. One deals with long cables, high capacitance and stupidly low input impedances better than the other. Tell me, when did you last see a line output (RCA or XLR) output impedance actually measured?

 

[Science is fun]

What do think a preamplifier is? It's a multi-input buffer with a low output impedance designed specifically to drive power amplifiers. And low can mean 1R or it can mean >500R. One deals with long cables, high capacitance and stupidly low input impedances better than the other. Tell me, when did you last see a line output (RCA or XLR) output impedance actually measured?

Yes and most people who have multiple sources to connect to an amplifier use one. And any preamp worth its salt can easily drive a 600R load. Let alone a 4400R load. Maybe if you have 1000m long interconnects it could be a problem.

 

[Massimo]

Yes and most people who have multiple sources to connect to an amplifier use one. And any preamp worth its salt can easily drive a 600R load. Let alone a 4400R load. Maybe if you have 1000m long interconnects it could be a problem.

4400R ... where did you get this figure?

 

[Science is fun]

4400R ... where did you get this figure?

From the Purifi datasheet

 

[Massimo]

From the Purifi datasheet

Excellent. Thanks.

 

[Science is fun]

For those who think the Ghent cases are too expensive, and like the unibody look, these guys can make you cases for just over $40 a piece. Much cheaper with larger orders. ASR group buy???

https://www.alibaba.com/product-detail/Wholesale-pc-case-Supplier-Factory-pc_60174799773.html

 

[maxxevv]

For those who think the Ghent cases are too expensive, and like the unibody look, these guys can make you cases for just over $40 a piece. Much cheaper with larger orders. ASR group buy???

https://www.alibaba.com/product-detail/Wholesale-pc-case-Supplier-Factory-pc_60174799773.html

What's the overall size of your amp's internal layout with all the boards/modules populated ? The one in your link is only 200x200mm on the exterior. Will probably have to look at their other options from my guestimate by eye though ??

 

[Science is fun]

What's the overall size of your amp's internal layout with all the boards/modules populated ? The one in your link is only 200x200mm on the exterior. Will probably have to look at their other options from my guestimate by eye though ??

These guys will make custom cases of any size, and any cutouts. Look at the March amp cases for reference.

 

[Science is fun]

So let's see. A group buy of mono block cases, with shipping under $100 a pair. SMPS1200A400 with the NC-500 evaluation boards and cable set around $170 per set on a group buy. Purifi amp modules $232 each plus shipping for 6+. So with a group buy we could have mono block unibody kits, with the flexibility to bypass the buffer for just over $1000 per pair. Who wants to run the assembly service for $100 per pair? You'll make $100 for a half hours work maximum.