Extremely low ouptup from Seymour Duncan active/active setup

brentonbassist · #1 11-23-2011, 02:03 PM

I guys,

I just swapped out my active MEC pickups and preamp in my 99 Warwick Streamer LX 5 for active Seymour Duncan pickups (AJB-5) and preamp (STC-3a). I wired this setup as 18V (wired a second 9V battery in series with the first one) and the only other thing that I did that differed from the SD wiring schematic is that I grounded the grounds from the pickups onto the back of one of the pots (this wasn't shown on the schematic, but I couldn't imagine leaving pickups ungrounded!).

The output is so low that I have to dig in very hard for my tuner to pick up any notes at all. On my TC RH450, I've gone from my gain sitting on about 10:00 to being fully maxed out, and I still think it's probably less than half the volume that it was before with the master set the same.

Any ideas as to some things to try? The majority of the preamp came prewired from Seymour Duncan (other than having to attach the pickup wires, jack, and battery). I inspected the quality of the solder job before I installed it all and it looked pretty clean, but I have to admit that I didn't check that they had soldered everything in the right place (but I imagine they would have). I'm lost as to where to even start.

Thanks heaps in advance!

MuzikMan · #2 11-23-2011, 02:08 PM

Are the batteries good?

brentonbassist · #3 11-23-2011, 02:14 PM

Oh I should also probably mention that the tone sounds very muted. No treble whatsoever, despite what I do with the EQ.

davens · #4 11-23-2011, 02:58 PM

Is the shell of the pot grounded? Did you use a stereo jack? If so are you sure the tip / ring / sleeve are connected properly?

brentonbassist · #5 11-23-2011, 03:16 PM

Batteries are fine. It's only a mono jack, which is what was previously in there. The SD pickups and preamp also came with only a mono jack. I've checked my wiring of TRS using a multimeter and it's all good there. Maybe one of the new battery clips is bung? Would that make sense?

davens · #6 11-23-2011, 03:25 PM

I'd recommend using a stereo jack so that the preamp / pickup don't use power when the patch is unplugged, unless you have a switch or something. To be sure, you have the reds from both the preamp and the pickup hooked up to two 9V batteries in series? (jack -> black, red -> black, red -> pickup/pre). You could try removing the preamp and hook the white from the pickup directly to the output jack to make sure the pickup is good.

elgecko · #7 11-23-2011, 03:27 PM

Pickup height maybe?

brentonbassist · #8 11-23-2011, 08:42 PM

Quote:

Originally Posted by davens

I'd recommend using a stereo jack so that the preamp / pickup don't use power when the patch is unplugged, unless you have a switch or something. To be sure, you have the reds from both the preamp and the pickup hooked up to two 9V batteries in series? (jack -> black, red -> black, red -> pickup/pre). You could try removing the preamp and hook the white from the pickup directly to the output jack to make sure the pickup is good.

I do have a stereo jack on it's way which I'll be swapping in once I get it for that very reason.

All wired as you described, unfortunately

.

brentonbassist · #9 11-23-2011, 08:43 PM

Quote:

Originally Posted by davens

I'd recommend using a stereo jack so that the preamp / pickup don't use power when the patch is unplugged, unless you have a switch or something. To be sure, you have the reds from both the preamp and the pickup hooked up to two 9V batteries in series? (jack -> black, red -> black, red -> pickup/pre). You could try removing the preamp and hook the white from the pickup directly to the output jack to make sure the pickup is good.

Oh & I think bypassing the pre is a great idea.

brentonbassist · #10 11-23-2011, 08:45 PM

Quote:

Originally Posted by elgecko

Pickup height maybe?

Set the same as my MECs were: 2.5-3mm. Could this possibly be too close for the SDs and not be set in the electro-magnetic sweet spot?

brentonbassist · #11 11-24-2011, 03:52 AM

Problem solved! It ended up being something very easy to troubleshoot. The pre-wired hot output wire coming off the preamp was faulty. Swapped her over and BAM! - wall of sound. Shame I started tracing the signal path from the input stage, as that was the absolute last wire in the chain hahaha.

Thanks all for your advice and suggestions! I really appreciate it.