[Vul Kuolun]

Hi,

i've build this cute little amp:

http://www.audioattic.de/projects/small_eaton.html

I tried to put the bass boost from the ppa:

http://tangentsoft.net/audio/ppa/amp...tml#bass-boost

(0,22µF/ 5K, worked fine with my Cmoy) in the feedback loop of the "smEaton" (right behind the 10k feedbackresistor). It sucked considerably by frying my OPA.

Now i'm not sure, if this was something to be expected (as the feedback loop with the "smEaton" involves the buffer stage)?
Is there a way of putting a bass boost ala ppa into this?

Otherwise i'm thinking about building a Cmoy with a railsplitter and Sijosae's discrete buffering stage made out of BC 337 an BC327, and include the boost in the Cmoy "core".
almost like Sijosae's A/B-Amp:

http://69.36.189.159/usr_1034/audio/...4_discrete.gif
http://www.headphoneamp.co.kr/bbs/zb...esc=asc&no=225

The feedback loop in "my" design would be closing right behind the OPA, and the buffering stage would be behind it.

Good idea?

 

[tangent]

Which direction is "behind"? If it's toward the output stage, then you put it in the right place.

If you used an OPA2132 as shown in the schematic, I would say that it isn't actually dead, or it died some other way. A passive circuit can't kill a chip by itself.

 

[Vul Kuolun]

Quote:

Originally Posted by tangent /img/forum/go_quote.gif Which direction is "behind"? If it's toward the output stage, then you put it in the right place. If you used an OPA2132 as shown in the schematic, I would say that it isn't actually dead, or it died some other way. A passive circuit can't kill a chip by itself.

WOW, the master himself! First let me thank you for your great Website. Almost everything i know about electronics (which is not really much anyway as you can see), i know from your site! Thanks dude.

As for the direction, im not realy sure anymore. It could also have been a combination of errors, as i had some probs with the connections in the beginning.
The OPA just became veeery hot, and after a last desperate smoke signal remained suspiciously quiet ever since.

So you're saying, if everything is working correctly, and i put the R/C between the R and the bufferstage, there's basically no oportunity to really mess it up again?

Maybe i'll try again then.

 

[Vul Kuolun]

Works great, thanks a lot.