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-   -   Best buffer for a chipamp? (http://www.diyaudio.com/forums/chip-amps/124446-best-buffer-chipamp.html)

Dxvideo 7th June 2008 07:10 AM

Best buffer for a chipamp?
 
Hi all,

I am planning to make an unity gain stage to use for my chipamps (LM3886, LM4780 and LM3875).
Whats the best sounding buffer design?
Should I use a discrete design (i.e. Pedja Rogics JFET buffer)?
Or may I use just an OPA134 in unity gain? (I dont know if it sounds good at unity gain)
Or do you advice a better alternative?

Thanks in advance for your replies.

sneih 7th June 2008 07:30 AM

waiting too

Nuuk 7th June 2008 08:25 AM

Don't wait - read ! ;)

AndrewT 7th June 2008 10:44 AM

go with Pedja Rogic's FET buffer.

ionomolo 7th June 2008 04:08 PM

I havn't tried the Pedja Rogic fet buffer, but i can tell that opamps at unity gain do sound bad.

juma 7th June 2008 05:43 PM

2 Attachment(s)
I can't decide between Pedja's buffer and AD797 in unity gain - they are both extremely good - and if you want to drive low Z headphones too, or very long cables - go for JISBOS.

Dxvideo 10th June 2008 06:29 AM

Finally I have decided to make Pedja's.. And finished in one weekend :D
http://img136.imageshack.us/img136/9...oto0010he7.jpg
http://img120.imageshack.us/img120/7858/pedjaap9.png
Now its ready for departured! But I have a problem with the power supply. Which is;
http://www.diyaudio.com/forums/showt...hreadid=124548
I havent got any replies from Power Supply Design guys until now. May you say something? Because I am growing impatient to try my JFET buffered gainclone...

AndrewT 10th June 2008 07:56 AM

get a 20-0, 20-0Vac transformer and you won't need a regulator/s

Nuuk 10th June 2008 08:02 AM

Or replace the 1083 regs with another pair of 317/337 to see if that cures the problem.

Dxvideo 10th June 2008 12:41 PM

Quote:

Originally posted by AndrewT
get a 20-0, 20-0Vac transformer and you won't need a regulator/s
But Pedja advices regulated supply in his web site...

Quote:

Originally posted by Nuuk
Or replace the 1083 regs with another pair of 317/337 to see if that cures the problem.
Hmm... With 30v supplies, one LM3875 sink more than 3.5A, in this case, do you think 317/337 will enough, especially if you take consider my speakers sensivity is just 86dB!


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