How can I make a power amp from Sonic Impact?

[hsu]

Hi, I am new to forum so I don't know if this was discussed earlier.I tried to eliminate the volume pot but I encountered some problems as follows:
1.Gain is too high.
2.Sound is thin but detailed.
3.Dynamics overly increased.

I guess I should be adding some resistors somewhere.
Can anybody help me?

[Kensai]

I'll second that. A good, unified how-to would be nice.

Also, can the t-amp handle a 2ohm load? And if so, what sort of performance characteristics does it have driving such a load?

Kensai

[pepolman]

Search is your friend

Try this as a starting point

Sonic Impact 5066 Parts List & Modifications

and this is a good site for diy beginners and SI mods

http://www.tnt-audio.com/clinica/t-amp_tweaks_e.html

There's also Tripath's website for info (check out Application Notes and Data Sheets)

http://www.tripath.com/support.htm

[Pano]

And there is my site. See below in sig.

Please read the forum and the FAQ - Wiki. The info you want is all over this site.

[hsu]

So I have to replace 36K resistors 4 and 5 with 20K ones and connect the pot wires together,is that all?

[Lostcause]

Originally posted by hsu
So I have to replace 36K resistors 4 and 5 with 20K ones and connect the pot wires together,is that all?

It's the input caps that are affecting the base. You need to replace them.....can't help on the gain question but I'm sure someone out there could advise.
I actually removed the 20K and replaced with 36K...not the other way around.

Pano, that's a good question actually...the wording and first diagram on your site show a 22K resistor but the schematic shows 36K?

Lee

[hsu]

You are right Lostcause, after checking with Tripath's data sheet,the original value is 20K actually...By the way why did you replace that resistor?Was that a modification,or did you change it into a dedicated amp?If so,I would like to hear your comments.

[Lostcause]

Originally posted by hsu
You are right Lostcause, after checking with Tripath's data sheet,the original value is 20K actually...By the way why did you replace that resistor?Was that a modification,or did you change it into a dedicated amp?If so,I would like to hear your comments.

I modified a sonic T with the 'classic' input mod on Michael's site. I jumped in just before the feedback resistor (36K) with a matching value to set the gain. This bypassed the entire input section and filters. This is soon to be directly wired to a PS1's DAC chip (as per the thread on the digital forum) via a pot. Then put it all in a single box! That's as pure a signal path as you can get I think?...unless someone knows a better way of altering the volume?

Lee