[jerry1130]

First of all, I am planing to using Vishay Dale resistors, but I don't know what ohm to get, and if I should use the same ones on the whole board. The second question is what JEFT I should use in Q1,2,3 to bias the op-amps into a, I am using OPA627 for ground and OPA637 for left and right.

 

[jboehle]

Wow.

If you want to keep it simple, just use the resistor values specified on the schematic, here. If you want to customize the amp to your needs, read the Parts Selection Guide.

The Q3s are not used in the class A biasing. You can figure out which part numbers to use by reading the Parts Selection Guide.

-Jason

 

[jerry1130]

Thanks, didn't see thoes, but would they still applie if i use different value caps and different op-amp?

 

[jboehle]

Yes, the resistor values would still apply - but there are still some values you may want to tweak, for instance, to set the class A biasing current. PLEASE read Tangent's Parts Selection Guide as it will tell you pretty much everything you need to know about choosing and selecting the parts for your PPA. No offense meant, but it doesn't sound like you've read the guide. How did you even get a PPA board without knowing about Tangent's PPA website (as he is the only one selling boards)?

-Jason

 

[JohnFerrier]

Likely, the OPA627/637 doesn't "fall" out of class A without the FETs or resistor...


JF