lerxst88

how can i get some more bass out of this amp? its good now but its also maxxed out and id like to have some wiggle room. should i try re-capping the whole amp or just buy an EQ pedal/rack

JohnH

One of my favourite subjects:

There are things you could do inside the amp circuitry, but I think its better not to.

To get more bass without hacking the circuit, you can:

1. Add a closed back extension speaker
2. Change stock speaker to a Vintage 30
3. Use the FX loop – here’s three alternatives:

3a. Add an EQ pedal in the loop – set just to the low bass frequencies with everything else cut, since this is a parallel loop – the front panel FX knob then becomes a low bass control
3b Build a purpose made bass booster – I have a design that works pretty well, if you are into soldering together homebrew electronics (two transistors required)
3c Do a trick by patching the FX loop, with a lead that includes a resistor and a capacitor, forming a low pass filter. In OD mode, the FX loop has some gain built in, so this uses this available gain to add more low frequencies. It’s not as effective as the two options above, but it does work, approximately doubling the range of the current OD bass control.

If you or anyone would like to know more about the last two options, I’d be very happy to explain further.

John

__________________
DSL401
8412 cab
'76 Shergold Masquerader
'93 Les Paul Studio
'83 Roadstar

lerxst88

explain further!

those options sound very interesting. i might actually try the second one and i found a guy selling a dod 31 band eq for $10.

also say i wanted to scoop out the mids a bit. i couldnt do that if its in the effects loop correct?

lerxst88

also i should mention i have a delay in my effects loop. any concerns with the two tones clashing?

JohnH

lerxst88 - my bass booster cable is described on this thread, see the 9th post:
The Marshall Amp Forum: :: View topic - Play with caps ; DSL401

The active bass booster is here:
GuitarNutz 2 - Bass Booster - for FX loop

However, if you are using delay in the loop, you'll need all frequencies available, so the multiband EQ would be the way to go. I'm not sure what will happen, but if you can get one for $10 it won't cost much to find out!

John

__________________
DSL401
8412 cab
'76 Shergold Masquerader
'93 Les Paul Studio
'83 Roadstar

lerxst88

hey i just tried the first option and WOW. ive retubed this amp, bought a 4x12, and am about to buy an EQ to try and squeeze more bass out of this amp and this cable did the trick!

i didnt have a 10nF cap so i used a .1nF cap. what effect would changing the cap do?

JohnH

The idea of that cap and resistor is so that only bass frequencies are fed back through the loop, so they end up boosted compared to the direct signal in the amp. The cap across the hot and ground, on the return side is what cuts out those higher frequencies, so a smaller cap raises the frequencies that are boosted. I would think that 0.1nF is too small for this, almost all frequecies will be getting back through the loop.

But good luck

John

__________________
DSL401
8412 cab
'76 Shergold Masquerader
'93 Les Paul Studio
'83 Roadstar

lerxst88

so if i use a 10 nF cap itll be even bassier?

JohnH

It should be, because, combined with the resistor, youll be feeding only extra bass through the loop instead of extra of all frequencies. But if you have somethiug that is sounding good - then thats great, YMMV.

You could try different values, say 4.7nF, 10nF and 15nF. Or, with a 10nF cap you can vary the resistor, say 33k, 47k and 82k.

I used a cap at both ends of the patch wire, so it didnt matter which way round it went. But only the one at the return end is really effective. You can try a different one at each end to give you two options.

Or, some people patch the loop with a simple patch cord, which adds overall gain on OD.

John

__________________
DSL401
8412 cab
'76 Shergold Masquerader
'93 Les Paul Studio
'83 Roadstar

lerxst88

sounds cool. finally i just want to ask if its possible to screw up my amp by adding too large or too small of a cap. i shouldnt right because its only filtering frequencies right?

JohnH

you cant hurt it when you are only adding these passive components externally in the loop - zero risk.

__________________
DSL401
8412 cab
'76 Shergold Masquerader
'93 Les Paul Studio
'83 Roadstar

lerxst88

SWEET!!!

*fires up the soldering iron*