Need Help Extracting the Overdrive Circuit from Old Amp.

[nguitar12]

http://i1359.photobucket.com/albums/q783/nguitar12/1_zps8kn7moqw.jpg~original



http://i1359.photobucket.com/albums/q783/nguitar12/2_zpsgcquo93h.jpg~original



http://i1359.photobucket.com/albums/q783/nguitar12/3_zpssk4zavxf.jpg~original

After building many overdrive circuit I found that the best one is inside my guitar amp. Just wonder if anyone can help extracting the overdrive circuit? Or at least identify the circuit type. Sorry for very big pic I thought it can let you guys see more clearly. Also where should I add the effect loop to this amp?

For thr pic of the circuit. You may click on the link below the pic to view the original super large pics.

Many thanks.

[Groovenut]

Here's the parts list

http://www.ibanez.com/parts/2003_PARTS/electronics/amps/Guitar/TB15-TB15R/TB15-TB15R-PHL.pdf

[mth5044]

They sure don't make it easy to find a schematic for that thing. Your best bet it to start at the input and begin tracing. I don't think it would be long until you get to the clean/OD switch. Pick a direction - if you get to the clean volume, you went the wrong way.

[PRR]

I would start from the Clean/Overdrive switch. It makes two paths. One Clean. One Overdrive. Figure which poles connect in Overdrive. Following the traces should lead through the overdrive distorter and back to the switch. Now you have maybe one stage to trace-out.

However the stages before and after that may be critical to "the sound". The amount of gain in front (which may be common to both modes) sure will be important.

If you can cannibalize the amp, mount the whole preamp board in a box, find a place to tap-out to go to your main amp. (I fear that cannibalizing an Ibanez may be sacrilegious.)

[R.G.]

Start with D101/D102 and work your way outwards both directions.

[J0K3RX]

I had it somewhere..  but I can't seem to find it at the moment?

I did find the schem for the ibanez tone blaster xtreme 65R preamp which should be pretty close... Actually I really like the tone blasters and the TBX are killer sounding high gainers!
https://dl.dropboxusercontent.com/u/11178619/Ibanez/TBX65R_pre%20ver100.pdf

[Ice-9]

D101-102 pair go to ground, and to IC102, the gain pot is a dual gang so most likely controls the feedback path in two op amp sections. With this in mind and checking the schematic of a similar amp that Jok3rx posted it may be very similar to that.

[Groovenut]

I was able to throw this roughly together while I was mobile. There are a few comps I couldn't see the numbers for but I think all the labels are there. You should be able to use this with the parts list to trace the circuit. I hope it helps.