Marshall 3540 Running It Full Range

[Masher88]

I recently got one of these for pretty cheap ($300 used). I'm a big NoMeansNo fan, so that's where I heard of it. I've never had an amp like this. It's great sounding and ridiculously loud. I've been using it with no patch cables in back and it seems like the Bass Volume and Treble Volume knobs both add to the overall "volume" by being "biamped" into one output...weird. And the "Boost" knob does something that I can't quite figure out. It's supposed to be a foot-switchable volume boost for "solos", but makes some kind of difference when I turn it up and down. Kinda strange.
I'd like to patch the back jacks to run this "full range" into one cabinet and control the volume for "all" the frequencies at once with one knob (like a normal amp!). Is this possible? I am using a Barefaced Big Twin 2 (2x12" at 4 ohms). I found the manual online, but it's still pretty confusing with how patching should work.

https://www.marshallamps.de/fileadm...s/all-manuals/IBS-35xx-60xx-55xx-Handbuch.pdf

I believe I should patch it as shown in Example D...but still...I'm not too sure. Anyone have experience with this?

 

[Wasnex]

I recently got one of these for pretty cheap ($300 used). I'm a big NoMeansNo fan, so that's where I heard of it. I've never had an amp like this. It's great sounding and ridiculously loud. I've been using it with no patch cables in back and it seems like the Bass Volume and Treble Volume knobs both add to the overall "volume" by being "biamped" into one output...weird. And the "Boost" knob does something that I can't quite figure out. It's supposed to be a foot-switchable volume boost for "solos", but makes some kind of difference when I turn it up and down. Kinda strange.
I'd like to patch the back jacks to run this "full range" into one cabinet and control the volume for "all" the frequencies at once with one knob (like a normal amp!). Is this possible? I am using a Barefaced Big Twin 2 (2x12" at 4 ohms). I found the manual online, but it's still pretty confusing with how patching should work.

https://www.marshallamps.de/fileadm...s/all-manuals/IBS-35xx-60xx-55xx-Handbuch.pdf

I believe I should patch it as shown in Example D...but still...I'm not too sure. Anyone have experience with this?

Per manual, pages 1,3. When no patching is done the amp runs full range and the boost control is operative for extra gain. If your amp is not behaving this way, it needs to be serviced.

I ran one of these for a short time in the 90s and thought it sounded great. Unfortunately it was not reliable, and I abandoned it after the 2nd or 3rd repair.

It's been too long for me to remember, but the Treble and Bass volume controls working in an unexpected way sounds normal. See page 1 of the manual.

Good chance patching per diagram D will bypass the Treble and Bass controls.

Diagram D does the following. A jumper is connected between jacks 5, 9 and a jumper is connected between jacks 8, 12.

Jack 5 (PreMaster Preamp Out)->Jack 9 (A Amp In)
Jack 8 (A Link Out)->Jack 12 (B Amp In)

So this appears to connect the PreMaster Preamp to the A power amp; then link the A power amp to the B power amp. One of the jacks must be switching so it turns off some of the internal circuitry.

IMHO try it. I think I did, but found I preferred the sound and operation without the patching, so I put up with the quirky controls until the amp self-destructed.

Good luck.