Perhaps not so uber tech op amp IC question:p

[TSE]

So I borrowed my YJM308 od to my friend and when it was returned to me I noticed something a little bit different, it no longer works! So I thought this would be a great time to fix it and mod the Yngwieness out of it. I plan to change the diodes to LEDs, add an LED indicator, true bypass mod, put a DPDT switch at the input cap to toggle between .01 and .001, acts like a fat/tight switch, and(the part that I'm confused about) I want to be able to toggle switch between OPA2134 and TL082 OP AMPS.

I found some info on how to stack op amps for Tube Screamers and use pin 1 and 7 to switch between ICs, what confuses me is that the site has differing info on the pinout of the ICs to the datasheet specification. I got the info from http://www.beavisaudio.com/projects/ScreamerLab/ Also, I'm not sure if this would work for the 308/250 circut because I guess it uses only half of the IC and the TS may use both sides of the IC. Any advice? I don't want to screw this up:/

[TSE]

Re: Perhaps not so uber tech op amp IC question

Are none worthy? Lol bump it!

[Chris of Arabia]

Re: Perhaps not so uber tech op amp IC question

Perhaps you could try on a drummer's forum?

[ErikH]

Re: Perhaps not so uber tech op amp IC question

Pinout sometimes depends on the manufacturer of the IC but in pretty much all cases, they are the same. There may be one or two out there that are different. What you need to do is look at the IC that is in there now, look up the info on it, and if you want to swap, you need to match the pin out exactly.

IIRC, the 308 uses a single-stage IC rather than an dual like the Tube Screamer and variants. If that is the case, then you can only use IC's that match what is in t here.

If there's nothing wrong with it, leave that part alone. Changing the clipping diodes and input cap will have a more drastic effect on it than swapping the IC anyway.

[MojoMonster]

Re: Perhaps not so uber tech op amp IC question

I remember Dano's site from a few years back when I did my first BYOC OD build.
Most awesome.
That said, I don't recall him ever getting that stacked opamp thing to work, so I'd be leery of trying to duplicate that.

After a quick googling, it looks like the typical mod is to "Gray 250 Specs".
Have you seen those?

This guy had a nice diagram.

Analogman talks about it here.

I've always liked the idea of socketing switches so you've always got the stock configuration available.
Beavis did a Clipping Mod diagram that is really useful.
(It's a PDF. You might want to do "right click, save as".)

[TSE]

Re: Perhaps not so uber tech op amp IC question

Perhaps i will abandon my plan since the tone change is not that noticeable. I bought two switches though, and I want to use them! I can just have a switch toggle between the diodes and LEDs in the clipping section instead. Also, the YJM comes with an RC4558 which has the same pinout as the TL082 and OPA2134 that I bought so they are interchangeable. The old Grey 250 used the 741 and has a slightly different board.