[Migroo]

Hi guys. I've built a PIMETA with Tangent's v1.1D board.

OPAL/R is a BB OPA2132PA
OPAG is a BB OPA134PA

The amp sounds pretty good, and has potential, but it does sound quite 'dull' and bass heavy.

Someone said a while ago to swap in an AD opamp in place of the main OPAL/R. I've got an AD8620AR on it's way to me. Can I use this for OPAL/R while still using the BB OPA134PA in the OPAG position?

Thanks

 

[d-cee]

yes

 

[Migroo]

Thanks d-cee

 

[NelsonVandal]

Yes, it's all about blending opamps when you use active ground, since no opamp is perfect. You're description of the sound is spot on the sound of OPA134/2132/2134. What buffers do you use? There are alternatives for buffers as well - discretes, LMH6321, BUF634, different opamps etc.

AD8620 is very expensive, but since you've already ordered it, go ahead and try it. To my ears the most neutral combination of opamps is AD8599/AD825. AD744/AD829 like used in LISAIII is also very good. LM4562(LME49720) goes well with OPA134. OPA627/637 is classic, but I haven't heard them. Buy a bunch of opamps and find your favourite combination.

You can find many review of opamps here on Head-Fi, but unfortunately not so much about blending them, do some searching. I'm thinking of posting a thread like "the best blend of opamps".

 

[Migroo]

Thanks Nelson.

At the moment its the opamps as stated above, plus BUF634 buffers (paralelled).

I'm slowly getting a collection together

 

[Pars]

I've had good luck in my son's Pimeta with an OPA2107 and an LM6171 for ground. I changed the 2107 for a pair of AD744s (comp pin out) and my son didn't like them as well, so back went the 2107. I did quickly try an LM4562 in here and it sounded good as well. I haven't tried the AD8599s yet (don't have any). Nor have I really played around with the ground opamp much. This one is running discrete buffers (Mono's design), as we liked these much better than BUF634s.

 

[Migroo]

Thanks for your suggestions guys

I'll see what I can do about getting the chips together