John East MMSR into a G&L L2000... very low output ***SORTED***

[mcnach]

I'm sure I must have done something wrong, especially considering I wrote down the wiring a few days ago while I was very ill...

Anyway, I finally went ahead to install the John East Stingray 3-band preamp into my Tribute G&L L2000...
I gutted it, removing everything except the pickup switch and the series/parallel switch, and stacked the MMSR on top of that.

As the pickups were already wired to a couple of switches all I had to deal with were:

the hot output from the pickup switch, which I fed into the + terminal of the preamp (the pickup hot wires go to the series/parallel swith, and the output into the pickup selector switch).

there was a ground cable from the series/parallel switch. Connected to a common ground ring.

the - wires from each pickup were joined together and connected to the - terminal of the preamp.

Each pickup has an additional shielding wire. I connected them to the common ground ring.

Then I rewired the jack socket as per the MMSR's (the L2000 uses a side mounted barrel type), and joining there the common ring grounds and the ground cable from the bridge.

When I tried it... I got no sound

Actually, I did... but it was so low it took me a while to realise it. I turned up fully my practice amp, and what should have been really loud for the house turned to be just about as loud as a whisper. Enough to verify everything worked... the switches, the EQ, everything... just at extremely low volume.

So, what did I do wrong?

Any hints before I disassemble the whole thing and I start a systematic aproach building it up one bit at a time? (very slow)


To summarise:
negative from each pickup joined together and fed to preamp -

positive(s) from each pickup fed into series/parallel switch and then into a pickup selector switch. Output fed to preamp +

grounds directly to jack socket: pickup shields, bridge, and wire from series/parallel switch (originally wired to the back of a pot)

Edited November 11, 2012 by mcnach

[LukeFRC]

has the preamp got a gain mini knob on it?

[mcnach]

No, and this is not the usual "it's a bit quiet compared to other basses". It's almost silent.

[mcnach]

I cannot test it right now but... I have an idea: the cable I took to ground from the parallel/series switch... should probably go to the negative terminal in the preamp, not to the common ground. I suspect I have a "simulation of a broken pickup" with my present wiring. I hope this is it, as it'd be easy to fix!

Tomorrow...

[mcnach]

[quote name='mcnach' timestamp='1352168216' post='1859693']
I cannot test it right now but... I have an idea: the cable I took to ground from the parallel/series switch... should probably go to the negative terminal in the preamp, not to the common ground. I suspect I have a "simulation of a broken pickup" with my present wiring. I hope this is it, as it'd be easy to fix!

Tomorrow...
[/quote]


No, it wasn't that

I must have made a silly mistake somewhere... but I can't see it. So, time to remove the whole thing and start again, carefully.

[ezbass]

Are you getting power to the pre amp?

Is the output jack wired correctly?

Just a couple of ideas.

[mcnach]

Aha! It lives!!!!!!!!!!!!

I wrongly wired the - wires of the coils at the - terminal of the preamp, when they should be grounded directly and instead take a wire from the parallel/series switch to the - of the preamp (which I had grounded by mistake).

It now works... and it's mighty

The only question left is... what to fill the hole left by the preamp off/on/boost switch with. I'll probably just put a dummy switch there.

[apa]

[quote name='mcnach' timestamp='1352317562' post='1861633']
Aha! It lives!!!!!!!!!!!!

I wrongly wired the - wires of the coils at the - terminal of the preamp, when they should be grounded directly and instead take a wire from the parallel/series switch to the - of the preamp (which I had grounded by mistake).

It now works... and it's mighty

The only question left is... what to fill the hole left by the preamp off/on/boost switch with. I'll probably just put a dummy switch there.
[/quote]

An LED

A

[mcnach]

[quote name='apa' timestamp='1352317945' post='1861644']
An LED

A
[/quote]


no kidding, I thought about it for a minute!