[mewrei]

I kind of fell into the business of building myself a B22 (not that I didn't want to that is), and as this is a huge project, I'm wanting to put a lot of effort into it.

As such I do have a few questions. I notice Ti lists Silmic II caps on both the B22 and o22 BOM, but I find it uncharacteristic of Ti to put any capacitors (much less electrolytics) in the signal path. A quick look over the schematics seems to confirm this assertion, but I could very well be wrong.

And obviously there's no signal traveling through the o22 (yes yes, I know the whole "everything is signal path" argument).

So bearing this in mind, is there any rationale to using the Silmic II's anywhere here? Its not like cost is an issue with Digikey selling them for such reasonable prices, but I'm wondering if the ripple currents and ESR of other capacitors like the Nichicon HE and Panasonic FM series would be better fits. Or if there's some particular benefit to using Silmic II's.

I'm also wondering if its worth stepping "up" to silver mica caps instead of MLCC caps in a few areas. Is their reliability and "sound" better?

I also assume this is a very low inductance amp like Ti's other products so "don't use any longer leads than absolutely necessary" applies here as well.

And finally, are there any caps in the signal path on the B22? I know my assertions could be wrong so I'd like to clarify it.

 

[amb]

My standard recommendation is to use either Nichicon PW or HE, or Panasonic FC or FM for the power supply. The fact that the Silmic is in the list is for those who must put something with a bit of "bling" into their builds (for bragging rights, perhaps).

As for silver mica in place of the MLCC, there is no demonstrable advantage in this application. But again, some people have a bias against any kind of capacitor with the word "ceramic" in it, so for them, silver mica would work just fine.

There are no caps in the signal path. It is a true DC amplifier.

 

[mewrei]

Now it sounds a bit more like one of your amps

I assume, if possible, organic polymer caps would work best if I can find them in the specified sizes? (unlikely, but at least worth looking)

Otherwise I guess I'll go for the HE's and FM's.

Thanks Ti!

 

[FallenAngel]

Ah, but what about C1 in the feedback loop?

 

[amb]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Ah, but what about C1 in the feedback loop?

lol. No audio signal goes through it... it's effect is up in the MHz region.

 

[FallenAngel]

Well, I certainly hope you aren't discriminating against bats!

I've always been curious about that, and also wondering about the "balancing" caps such as C6-C8. Also, about C2-C5, what exactly do they do? I know the over-simplified "compensation" to keep the transistors from oscillating, but is there a less simple answer?