freestompboxes.org

Hello all.

I have an old no-name (actually a MultiVox Big Jam) EQ pedal that I'm going to rehouse with some other stuff(a boss CE-2).

To keep the CE-2 'always on' I was told to remove one of the 2 bypassing transistors (Q6/Q5). I did that and it worked. The LED stays on now (haven't tested audio throughput yet).

The EQ pedal has a similar switching system (from looking at it), and it also has a pair of trannies bunched together facing opposite ways (like the boss pedal). It also bypasses like a boss pedal (a small spst momentary).

I tried removing one of the trannies but the LED still switched around (I didn't test audio though).

Is that 'pair of switching trannies' system common among alot of pedals,with the solution being to remove one of them?

The traces on the PCB like coming up so I'm hesitant to just keep trying random things, hence why I'm asking here.


Is there a chance that removing one of the trannys did in fact keep the pedal 'on' even though the LED would still change status?

If I can't find a way to just keep the pedal on, where should I look for a 'wet' signal to tap from for the output?

It's a 6band graphic eq, with with 3 4558 dual op-amps (I'm guessing 1 per channel). There's also 2 larger ICs, a MC14007UB(dual inverter) and a MC14011B(CMOS gate). The LED is being fed by the 4011 it seems.
There are also only 2 trannys on the board.

Thanks

If you have the schematic, you can locate the input and output of the circuit, and remove the electronic switching.

I don't have a schematic, and haven't been able to find one online either.

Not a very popular pedal.

Can you post good sharp pictures of the track and component sides?

This is the best I can do with my digital cam:



I tried removing the FETs (like for a boss pedal) and it didn't work. Removing either one kills the 'wet' signal.

Normally the switching in the bigjam pedals is done with the 4007.
Have a look at the Pearl schematics to get an impression how it is done.

analogguru

Found it on the 4007. There were 2 pins with a trace jumper running underneath.

Thanks for all the help, I'll post photos of the rehouse/mod once it's done.

I'm going to power both pedals off one 'channel' from my PedalPower2.

Should I bother isolating them?

I read a simple mod (I think on here) to use a 100omh resistor + a 220uf cap to isolate the power going to each.