SOLVED LabRat not working

[Kilo95]

Just finished a Labrat build. Using a CioksDC7 at 12v. The bypass works as I can hear my bass guitar perfectly normal when the pedal is not engaged. When it is engaged, I have to turn the volume and the gain all the way up to barely be able to even hear my bass guitar. Suggestions?

 

[Erik S]

Suggestions?

Post some pictures

 

[Kilo95]

Photos

 

[GAStan]

How long did you have the pedal on when you tried it? I've read some posts where tube pedals could take several minutes for the tube to heat up enough to work.

 

[GAStan]

It also looks like your guitar cable plugs/jacks might be shorting out on the board.

 

[Kilo95]

It also looks like your guitar cable plugs/jacks might be shorting out on the board.

 

[Kilo95]

Probably 3-4 minutes. The jacks aren’t touching on the pcb

 

[GAStan]

Is the tube getting hot? It should be too hot to keep your finger on.

 

[GAStan]

Also try leaving it on at least 10 minutes then try it.

 

[jwin615]

Isn't one of the 555s 'posed to be a 308?

 

[jwin615]

Or did you get a fake 555 that's actually a 741

 

[Kilo95]

Or did you get a fake 555 that's actually a 741

There’s no telling. I clicked all the links on the c2c website. I’ll back and check that

 

[Kilo95]

Is the tube getting hot? It should be too hot to keep your finger on.

It’s warm after I unplugged and plugged on the cover off. I’ll double check that

 

[jwin615]

I was being a bit snarky. U2 should be a 308/OP07. Womp womp
Easy fix

 

[Kilo95]

Ok. So I wasn’t paying attention and plugged a 555 in the spot for the 308. Guess I missed ordering that one. Thank you for pointing that out. I will order a couple.

 

[jwin615]

It's not linked in the build doc because they're no longer made/stocked.
Jamco and I think amplified parts have some listed but they seem to be the same lots as some fake ones on eBay.
Not impossible to find, but also easy to get a fake. Just get a OP07 unless you need it to be super authentic.
741, 071, OP77, OP177, OP777, 071, 301, 201 101 will all work in the circuit as a means of testing.

 

[Audandash]

The op07 can be easily sourced from stompboxparts or tayda. Tariffs may be rough for tayda depending on where you live. If you want while you wait you can do some reading and search the web for the op07 vs the lm308. I will spoil it for you though, you can’t hear the difference.

 

[Kilo95]

I was being a bit snarky. U2 should be a 308/OP07. Womp womp
Easy fix
View attachment 121847

Got the LM308. Works. Distorts heavily very early (distorts a bit with the gain all the way down). Can I safely swap a 12au7 or 12ay7 to get a bit less gain? I don’t need heavy distortion. Thanks for the help figuring out my oops by the way. I appreciate it

 

[jwin615]

@vigilant3777
How's the current rating of the lab rat handle thirstier toobs?
Oops.
@vigilante398

 

[GAStan]

Got the LM308. Works. Distorts heavily very early (distorts a bit with the gain all the way down). Can I safely swap a 12au7 or 12ay7 to get a bit less gain? I don’t need heavy distortion. Thanks for the help figuring out my oops by the way. I appreciate it

You can use a 5751, its basically a 12AX7 with about 30% less gain.