Universal PCB for Purifi 1ET400A amps

[DonVincenzo]

I have correct the faulty track. Give some components more space. And changed the holesize of the connectors to get a better fit. Updated the schematic as-build.And publish the gerber files.

Hello Kofarm,

I allow myself to contact you because I came across your BUFFER for Purifi Audio.

I would like to know what was the Voltage of the XLR output gain of your Buffer?

I have an ANTHEM MRX 540 / 740 and the RCA voltage in PreOut is 5.2Vrms.

Would it be possible to adapt your Buffer to make the most of the RCA Voltage of my Home-Cinema Amplifier (if I don't have an XLR in Pre-Out)

Thanks in advance,
Vincenzo.

 

[Koifarm]

Hallo Vincenzo,

With a 5Vrms signal you almost do not need a buffer. You can adjust the buffers in this thread too get the gain(about 2 times) you need in combination with your preamp. Which buffer you like to build, the one with the tubes or the opamp Version?

 

[DonVincenzo]

Hallo Vincenzo,

With a 5Vrms signal you almost do not need a buffer. You can adjust the buffers in this thread too get the gain(about 2 times) you need in combination with your preamp. Which buffer you like to build, the one with the tubes or the opamp Version?

Hi ! Thank for reply,

• Realy ? No Buffer ? 😵 (With XLR->RCA Cable)
• But have receipt in December OPAMP by SPARKOS LABS "SS2590 PRO Dual" (Dip8 Socket adapter)... : https://sparkoslabs.com/pro-discrete-op-amp/pro-to-dual-op-amp-adapter/
• It's for Your OPAMP Version 🙂 : (https://www.diyaudio.com/community/...-for-purifi-1et400a-amps.379211/#post-6855612)

Thank you,
Vincenzo.

 

[Koifarm]

Vincenzo, when use rca to xlr cable together with your preamp output voltage the opamp buffer works fine as is.

 

[DonVincenzo]

Hallo Vincenzo,

With a 5Vrms signal you almost do not need a buffer. You can adjust the buffers in this thread too get the gain(about 2 times) you need in combination with your preamp. Which buffer you like to build, the one with the tubes or the opamp Version?

Hello, I would have liked to make Your Buffer OP AMP.
After research, and some questions to people, they told me that according to the Measurement Chart of my MRX540 / 740 Pre-Amplifier (posted above) the 3.2Vrms voltage is the best sound reproduction obtained in RCA-> XLR.

Do you still have Buffers available already assembled? If so, would it be possible for you to adapt your OPAMP buffers @ 3.2Vrms for me? I would be interested in buying them from you according to your offer.

Thanks,
Vincent.

 

[Koifarm]

I have no pre build board. Just order your PCB with the supplied gerber files. If gain is to high you can adjust this by only changing R6.

 

[agent.5]

Just wondering if you can post the gerber of the unbuffered, naked board? My DAC has +24dBu out, so a naked board is adequte.

 

[Koifarm]

I also still using the unbuffered board.
See files below.

 

[agent.5]

Thanks

 

[bisouxxx]

Today completed the new design. Shall order PCB this week.

Good DAY Ronny.

Thank you for sharing your knowledge and project .
This thread is quite old but I'm really interested in builind a purifi amp using your tube buffer design.
I have some questions :
As this board doesn't have op amp(like vtv tube buffer for example), is it suitable to get full power of the 1et400a with a balanced 4v dacs?
Is the feedback loop of the 1et400a used ? (not connected to the speaker binding)
Which quality of pcb is needed? (layers thicknesses , gold plated or not etc etc)
Do you recommend special components quality/models (tubes relay caps etc etc)
I saw you sold yours. Did you designed a new version?

Thanks in advance for your answer.

Emmanuel

 

[Koifarm]

Below some answers:

The tube preamp version can drive the 1et400a to the max power output.
Feedback loop is used to the PCB connector.
Just use standaard pcb specs.( 1.6mm thick pcb, 1oz copper).
Just use MKP capacitors for audio in and output.
I use the unbuffered version (also in this thread), because i have already 10Vrms out from my tube(6n6p) preamp.

 

[bisouxxx]

Thank you for your prompt and nice reply 👍👍👍 actually I was hesitating between using tube preamp + original purifi buffer , or my actual dac with 2 9038chips + 1et400a and your tube buffers , or simply a minidsp SHD to improve everything 🤷🏻‍♂️
Also, which 6n6p tub es do you recommend ? Apparently there is various , from bad to nice , or the ecc99? I have focal 1028be speakers , and 936 as well

Thank you

 

[Koifarm]

If you can get them use 6n6p-dr or 6n6p with gold grid. Not use the 6n6p-i type.
See also link
https://www.diyaudio.com/community/threads/6n6p-vs-6n6p-i.138426/

 

[bisouxxx]

Thanks a lot for your answer 👍

 

[endless_tweaker]

I'm using Ronny's Purifi tube Input buffer everyday and it's just magic ! You really get the power and control of class D with the gold touch of tubes. It's clean and absolutely silent. I wouldn't hesitate if you don't run a tube preamp.

 

[Koifarm]

A nice thing with tube rolling is the little differences between the brands/types. I like also the JJ ECC99.

 

[bisouxxx]

Did you try your buffer with hyper board like ncx500 ? I was looking at the new diy nilai 500 as well. Not sure there is much differences between them now

 

[Koifarm]

No, i did not try the ncx500. The sound differences with unbufferred class D products are very small. The inputbuffer/ preamp has more influence on the sound signature.

 

[bisouxxx]

I'm starting shopping the parts needed to assemble your buffer.
I have some doubts regarding the various connectors, tubes supports etc,
where to find the smps 6pins white plugs, the 1et400a 36 pins barrettes and smps black connector (refer picture)

Are those OK?
XLR Jack https://a.aliexpress.com/_ExaBehL

Tube supports :
https://a.aliexpress.com/_Ewcd5Tj
or surface mount like you
https://a.aliexpress.com/_EGwKlf3
https://a.aliexpress.com/_EIbPiO5

Connectors https://a.aliexpress.com/_ExZu8N3

jst-xh2.5 https://a.aliexpress.com/_EGbkgJJ

Thanks again

 

[Koifarm]

See also post 92. And google the part numbers. You find them at shops like tme.eu or rs online. Use the pcb tube socket. The jst connectors you mention are wrong, please look at the pictures in this thread.