hiwattnick

I own a Marshall JCM 900 50 watt (w/EL34s). Is there some kind of a mod that I can do to get more bass response (espescially from the clean channel)?
I've tried an EQ pedal, but it seems to take away from the tone. Do I need a higher capacitor in the bass circuit, and if so-what, how, where?
Endless thanks and my first born to anyone that can help.

Brett Blackmore

hmm... never had a problem with my JCM 900, but the DSL 2000 admittedly has much more bottom.

The JCM 900 has not got a really fat meaty sound - but, it was neither thin or lacking in punch either - so either you are doing something wrong or there is a fault. Review your tone settings on pedals and tell us which guitars you have too. It might be worn out valves or even a faulty component. I personally would guess that you have a cheap shitty box/speaker.

Yes, a mod could be cheap and easy - a simple capacitor would reduce the treble. However, it will not add bass and add more bottom end push.

What guitars do you have and which box?

Cheers Brett

Brett Blackmore

hmm... never had a problem with my JCM 900, but the DSL 2000 admittedly has much more bottom.

The JCM 900 has not got a really fat meaty sound - but, it was neither thin or lacking in punch either - so either you are doing something wrong or there is an fault. You should really review your tone settings and guitars too. It might be worn out valves or even a faulty component. I personally would guess that you have a cheap shitty box/speaker.

Yes, a mod could be cheap and easy - a simple capacitor would reduce the treble. However, it will not add bass and add more bottom end push.

Which guitars do you have and which box?

Cheers Brett

Adwex

I also have a 50 watt JCM 900, and it has the same problem. An EQ in the effects loop is absolutely necessary. I don't think anything else will work.

AndyHighTides

Try a few different brands of preamp tubes. I've found Ruby's and GT's to have a little more bottom than Mesa or Sovtec.

DragonSarc

gots a 900 4100 and used GTs, Sovtek and JJs power and preamp, the only way to get more bottom end is to put an EQ on the loop just like coldsteal said, i even tried switching cabs vintage and still nope - it has nice and crisp cleans thou

coldsteal2

This is a well known problem thats why most
900 owners put an EQ in the Loop, you put one
in you WONT BELIEVE the improvement, you just
simply boost the subs and lows and Boom your
amp sounds as good as any
Dont listen to any nay sayers that they arent as
good as other marshalls its a simple fix

__________________
http://www.myspace.com/coldstealii


http://www.youtube.com/user/kroftkarl

PaoloJM

You could also try using a set of KT77 in place of the EL34s, they give a more pronounced bottom end as opposed to the accentuated mids from the EL34. There is no circuit modification required to do this, they're a "drop in" replacement.
Make sure to re-bias though, as they do bias hotter than EL34s.
They've gotten some bad rap as some people have claimed they have a high failure rate but I personally think that people just don't take the time to bias them properly.
Check out utube for KT77s for sound clips, I'll have one up myself next week of my JCM800 with KT77s and a few top secret modifications!!

radiomatts

also try a BBE Sonic Stomp pedal. That seems to work for me.

MKB

If you are up for amp modifications, there is a fairly simple one that might help. Some amps have what is called a "resonance" control, which is basically like a presence control but for the bass frequencies. This involves adding a pot and a capacitor in series with the feedback wire, but this can boost the bass of the amp quite a bit. Here's a schematic, this one is described for Fender amps but would work with a Marshall or most any power amp with a feedback circuit:

Resonance Control for Fender Amps

hiwattnick

Thanks to everyone that repield to "I need more bass". Anyway....my set up is as follows: 1- JCM 900 50 watt head, 1- Marshall 4x12 w/25 watt greenbacks 1- Les Paul standard w/a '57 plus in the bridge & a regular '57 in the neck. I use all Mogami cables. The only pedal I use is a MXR dyna comp that is always on. The amp has a NOS mullard 12ax7 for the first preamp tube and NOS GE's for the rest. The power amp tubes are GT E34Ls (5 rating). I'll probably try the KT77 route. If that fails I'll try the mod that MKB sent me. If all else fails I guess that I'll go the EQ pedal way.
Thank you everyone.