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DIY Purifi Amp builds

shawnbd

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Nov 28, 2020
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Hello!
I guess this is not for Eval2 but for the other boards?

My understanding is that SMPS1200A400 is a 4 quadrant PS, thus not subjected to power supply pumping

This is already included in the 1ET400A

This is already included in the 1ET400A

Maybe simplifying your design by suppressing redundant functions a bit will allow a cleaner layout :).

1. SMPS1200A400 Output Voltage Vaux are +20.5V -20.5V , I use the TPS7A4700 TPS7A43300 regulated to +15V, -15V, Eval2 asking the 15V input .

2. this idea come from ergo at #87
http://www.htguide.com/forum/showthread.php?44316-Purifi-class-D-amplifiers/page3.

3,4 Thx,Good advice, I didn't notice before
 

boXem

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1. SMPS1200A400 Output Voltage Vaux are +20.5V -20.5V , I use the TPS7A4700 TPS7A43300 regulated to +15V, -15V, Eval2 asking the 15V input .
+/- 15V Typical, but maximum is +/- 25V, you do not need external regulators.
I could find why he did this, except the cool factor, which is a good reason when DIYing
3,4 Thx,Good advice, I didn't notice before
[/QUOTE]
You welcome :)
 

beren777

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1. SMPS1200A400 Output Voltage Vaux are +20.5V -20.5V , I use the TPS7A4700 TPS7A43300 regulated to +15V, -15V, Eval2 asking the 15V input .

2. this idea come from ergo at #87
http://www.htguide.com/forum/showthread.php?44316-Purifi-class-D-amplifiers/page3.

3,4 Thx,Good advice, I didn't notice before

Hopefully someone else will correct me if I'm wrong, but I believe the EVAL2 is expecting three different power inputs: power stage, gate drive, and unreg for the op amps. The A400 will output ~63V for power stage, 15.6 Vdc for gate drive, and 17Vdc-25Vdc for aux. This should all be in the ranges the EVAL2 is expecting for the matching inputs. Please take a look at the user guides for the EVAL2 (table 10) and 1200A400 to confirm, it should show the acceptable ranges.

I experienced poor results when I accidentally regulated Vaux feeding an EVAL1.
 

shawnbd

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Nov 28, 2020
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Update from Purifi Kim
Eval2 have a transistor-zener preregulator before the LT30xx devices, so don‘t need to add an extra regulator, I can use the SMPS1200A400 with unregulated Vaux :).

in my case, I can sell my TPS7A4700 TPS7A43300 on ebay,
 
OP
J

JimB

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Hopefully someone else will correct me if I'm wrong, but I believe the EVAL2 is expecting three different power inputs: power stage, gate drive, and unreg for the op amps. The A400 will output ~63V for power stage, 15.6 Vdc for gate drive, and 17Vdc-25Vdc for aux. This should all be in the ranges the EVAL2 is expecting for the matching inputs. Please take a look at the user guides for the EVAL2 (table 10) and 1200A400 to confirm, it should show the acceptable ranges.

I experienced poor results when I accidentally regulated Vaux feeding an EVAL1.
Right. The EVAL2 interface board is 'just' a single channel version of the EVAL1. I don't know if they degraded anything in the on-board regulator since it has to support only a single 1ET400A.
 
OP
J

JimB

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Update from Purifi Kim
Eval2 have a transistor-zener preregulator before the LT30xx devices, so don‘t need to add an extra regulator, I can use the SMPS1200A400 with unregulated Vaux :).

in my case, I can sell my TPS7A4700 TPS7A43300 on ebay,
Once it is done, let us now what your trigger solution is.
 

JaapDeventer

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Oct 29, 2018
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Try a star-quad cable for analog mic applications, such as Canare L-4E6S. Many places offer good star-quad cables, including Ghent and Benchmark.

Not necessarily "a more audiophile choice ", it's more to do with its noise rejection and interference immunity properties. Wikepidia can explain it better than I can: https://en.wikipedia.org/wiki/Star_quad_cable :)

Thank you both very much. Today I have assembled the Canare star quad cables. The amp is dead silent now. It's unbelievable. The other cable was also a shielded Canare. Much thicker wires. But only two of them. Star quad really removes the mains hum. Now I can finally enjoy the amp. Thanks again .
 

Hogh

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Jun 19, 2020
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I got all the main parts for my build; 2x1ET400A with Neurochrome input and a smps1200a400 and is now looking for a case to put it all in.

Im leaning towards the Mini Dissipante 2U 300mm placing the smtp against the heatsink on one side. The 300mm internal length
should just be enough for mounting both set sets of 1ET400A+buffer vertical on the other heatsink. Im thinking to put the two input buffers next to each other in the middel of the heatsink to keep them "away" from the high switching currents. This means one 1ET400A will have the little daughter board to toward the button and the other toward the top of the case.
Im thinking this should provide a good thermal solution and leave plenty of room for cabeling :)

Have anyone tried this approach or forsee any issues? Thanks

https://modushop.biz/site/index.php?route=product/product&path=284&product_id=725
 
D

Deleted member 65

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I got all the main parts for my build; 2x1ET400A with Neurochrome input and a smps1200a400 and is now looking for a case to put it all in.

Im leaning towards the Mini Dissipante 2U 300mm placing the smtp against the heatsink on one side. The 300mm internal length
should just be enough for mounting both set sets of 1ET400A+buffer vertical on the other heatsink. Im thinking to put the two input buffers next to each other in the middel of the heatsink to keep them "away" from the high switching currents. This means one 1ET400A will have the little daughter board to toward the button and the other toward the top of the case.
Im thinking this should provide a good thermal solution and leave plenty of room for cabeling :)

Have anyone tried this approach or forsee any issues? Thanks

https://modushop.biz/site/index.php?route=product/product&path=284&product_id=725

Great idea, just go for it. You’ll solve challenges as you go, that’s what I did with my build ...
https://www.audiosciencereview.com/forum/index.php?threads/diy-purifi-amp-builds.10478/post-579018
 

beren777

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Feb 25, 2020
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I got all the main parts for my build; 2x1ET400A with Neurochrome input and a smps1200a400 and is now looking for a case to put it all in.

Im leaning towards the Mini Dissipante 2U 300mm placing the smtp against the heatsink on one side. The 300mm internal length
should just be enough for mounting both set sets of 1ET400A+buffer vertical on the other heatsink. Im thinking to put the two input buffers next to each other in the middel of the heatsink to keep them "away" from the high switching currents. This means one 1ET400A will have the little daughter board to toward the button and the other toward the top of the case.
Im thinking this should provide a good thermal solution and leave plenty of room for cabeling :)

Have anyone tried this approach or forsee any issues? Thanks

https://modushop.biz/site/index.php?route=product/product&path=284&product_id=725

If this is a stereo build, why not use an EVAL1? Not that there's anything wrong with doing it differently, just wondering if you considered using the EVAL1 to make life easier. Results should be equal or superior and I think you can get the EVAL1 separately if you already own the amp modules.
 

Hogh

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If this is a stereo build, why not use an EVAL1? Not that there's anything wrong with doing it differently, just wondering if you considered using the EVAL1 to make life easier. Results should be equal or superior and I think you can get the EVAL1 separately if you already own the amp modules.

All the parts except the case are sitting on my desk so no going back on this approach. I did consider the Eval1 and even Eval2. I want SpeakOn and XLR and I wanted them proper mounted on the back panel without any way of stressing the PCB. Yes, I could desolder the Eval1 plugs and run a wire between the pcb and the plugs.. but the neurochrome buffer ticks all the boxes.

Less important; I also like that the neurochrome buffer can drive the 1ET400A to clipping with a single-ended signal (RCA). It looks like the EVAL2 copied the trick but then the price is about the same as neurochrome and I still would have to solder.
 
D

Deleted member 65

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All the parts except the case are sitting on my desk so no going back on this approach. I did consider the Eval1 and even Eval2. I want SpeakOn and XLR and I wanted them proper mounted on the back panel without any way of stressing the PCB. Yes, I could desolder the Eval1 plugs and run a wire between the pcb and the plugs.. but the neurochrome buffer ticks all the boxes.

Less important; I also like that the neurochrome buffer can drive the 1ET400A to clipping with a single-ended signal (RCA). It looks like the EVAL2 copied the trick but then the price is about the same as neurochrome and I still would have to solder.

I’m very happy with my Neurochromes and you’ll get great support from @tomchr.
 

Valhalla

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Jan 16, 2021
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has anybody done any side by side comparison between Hypex nc1200 and Purifi 1ET400A ?
 

NTSOS

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Oct 19, 2020
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Location
TN
Hi,

Ok, finished my amp, everything checks out, no hum or line noise and sounds pretty nifty (scientific terminology).

Next step, move everything up to the loft and setup up a listening room. Yay!

Next amp build, four EVAL 2 mono blocks in individual cases with their own power supply's to bi-amp my speakers.


John

Complicated solutions for non-existent problems
 
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