Dumble for bass; any known mods?

[Bernardduur]

Hey all!

Just wanted to know; I've build some amps and own a great Dumble like build that just really sings.... I also play bass and while I love the tone and the versatileness of the Dumble, it has too little bass response and clean power (only build a 50W version) to be usefull for bass.

Are there known mods to the ODS schematic that can be used to transform a ODS like preamp (no OD though) into a singing bass amp?

Tnx!

Edit;

on the schematicheaven website I noticed a couple of schematics that were called 'bass' schematics of the 60's Dumbles. Are these mods on bassamps (for example Bassmans???), are they used for bass amps or are they just typo's? ":)

[Structo]

Yeah, I'm not sure of the source for those schematics.
They are missing a lot of details and I'm not sure the era's are correct either.
HAD started out modifying Fender amps but not sure if they can be categorized into the 60's and 70's.

If I was interested in building a bass amp I would probably lean more towards an Ampeg design or one that is specifically designed with bass frequencies in mind.

Also, 50 watts may not allow you to keep up with guitar and drums in a band setting.

Typically with bass you strive for big clean tones and not much if any break up.

That is why you see bass amps with 300 watts of power such as the new Class D amps.
A lot of guys lean towards solid state for bass amps these days for the clean and big wattage factor.

[mojotom]

Well, Ampeg works great. SVT are more mid oriented than a V4 but still one of the best.

When you look further you'll notice the bass stack beside ampeg is a fender stack. Used in amps like acoustic, Alembic and even Aguilar (one of the best amp I've tried so far).

So if you use your old Fender tied to a real bass cab you got great sound for a nice vintage sound. Of course no Marcus miller slap or modern active bass tightness but if you like old fashioned soul vibe this is it.

From there plug a 100W non HRM into that nice bass cab (I like 12") and it's even better than the old Fender. Enough for practice maybe a bit underpower if you need to push it. Use a 4 Ohms cab then.

I really like it and will try soon with an EV without fear to blow it up. I think you can tweak even more if you just use it for bass but when I plug the fender back it was flat and less dynamic.

The cab is a key ingredient here, you already have good amount of bass and low mids (I like to switch the local feedback off).

[Structo]

I agree for a short term fill in or just messing around with tracks you can play a bass through just about anything as long as the speakers can handle the longer excursion that bass frequencies bring.
I use the EVM 12L's as well and I have played my five string bass through those although at lower volumes before just goofing around.

But for gig duty or any prolonged loud playing I wouldn't risk any speakers not made for bass.

[mojotom]

Didn't the EV12l suited for bass ?

I thought so when I read the datasheet both power and bandwith.

[jaysg]

Didn't the EV12l suited for bass ?

I thought so when I read the datasheet both power and bandwith.

They don't really have the Xmax you want, but I used to play with a guy who had a Road 4-12 full of them. Deafening and clean.

[RevD]

Obviously needs for Bass players have changed over the years in terms of I think response and probably filling a more distinct hole in the bands bandwidth. That said, look at about 1:24 to see what I think is one of the most tasteful arguable best bass players of all times rig. Oddly enough and I will admit I don't know all there is to know about silverface gear, but that almost appears to be a Dual Showman head (which were about 100 watts I believe) Jamerson is playing through? Or was there another large Fender bass head of that era which used a similar box? It appears much like the Dual Showman reverb I had (and lost in a divorce due to needing money grrrrrrrrrrrrrr.).
Anyway, I suspect although many bassist are using rigs from 300-1000+ watts in reality they use very little of that actual power unless they play somewhere VERY big. Then again I'm not a bassist. Times probably have changed too where a bassist sits in a mix too I donno, I know James Jamerson could almost be accused of playing Lead bass considering where he sat in the mix in early Motown stuff, but then again thats where they wanted it to sit in the mix too, perhaps that is what made "The Motown Sound".

http://www.youtube.com/watch?v=Y9KC7uhMY9s

Regards,

RD

Ps: Of course this rig he's using could have been a scramble to get whatever they had at the time for this particular shooting. *shrug* Although dual showmans are known as pretty decent bass heads I understand.

[marcos]

Hi Bernardduur,
I have an old Seymour Duncan tube preamp modded ODS style
that I use for recording both guitar and bass at home.
For use with bass I have a switch that increases the cathode bypass
caps on V1a and b, 22µF in parallel with the usual 4.7 µF.
This helps a lot with the bass response, after this the ODS should work fine with bass.I do agree,though, that 50 watts is not quite enough for bass.Hope this helps,
Marcos

[Darkbluemurder]

Hi Bernardduur,
.I do agree,though, that 50 watts is not quite enough for bass.

+1, unless you are playing in a bluegrass band.

[Structo]

Great Marvin Gaye tune, thanks for posting that.

Not sure what that amp is, huge head case though.

[M Fowler]

That was good, I wore out my 8-track tapes of Marvin Gaye and Otis Redding in high school while my class mates were listening to crap.

[dr. who]

Winterland

[JD0x0]

You can get alot of clean headroom with the new KT120 tubes that tungsol has put out. A pair is capable of 150 watts which isnt bad for a bass amp. Maybe use a hiwatt PI for maximum clean headroom, and a higher wattage OT for bigger bottom and more clean headroom.

[Bob-I]

That said, look at about 1:24 to see what I think is one of the most tasteful arguable best bass players of all times rig. Oddly enough and I will admit I don't know all there is to know about silverface gear, but that almost appears to be a Dual Showman head

Yes, that appears to be a Dual Showman. Before the SVT lots of bass players used a Dual Showman for bass.

One of the things that's changed over the years is the bandwidth of the speakers. When the SVT was designed they specifically rolled off bottom to prevent blowing speakers. The SVT doesn't actually reproduce the low E fundamentals, mush less the low B many bass players use today.

[Max]

Yes, that appears to be a Dual Showman. Before the SVT lots of bass players used a Dual Showman for bass.

As far as I know the Alembic preamps for bass are very similar to the Showman. So it seems, that perhaps you could simply connect the pre-out of your Dumble clone with a power amp and speaker cabinet of your choice - without any modification of the Dumble style preamp? Perhaps you could just try this and find out if this works for you?

Cheers,

Max