A bit too much bass on OD - 2nd Gen Hybrid

[rogb]

I managed to playout at some decent volume last weekend.
I noticed it was bass heavy when cranking the OD.
I've done a search and as usual come up with a bunch of different possible cures. Is there one surefire way of cutting the bass in OD? Clean sounds fine!
I am using a SwampThang in TL806 style cab.
I've got an EV12 off Jestaudio here, needs a recone so maybe I should go ahead with that if folks think it will hold up better.
I have seen some ideas for changing V2a/b caps - I want to stay close to the circuit if I can.
ISTR changing the bass pot for 1M to get a better sweep.
Right now I can't go above 2.5 -3
Thanks

[wjdunham]

I managed to playout at some decent volume last weekend.
I noticed it was bass heavy when cranking the OD.
I've done a search and as usual come up with a bunch of different possible cures. Is there one surefire way of cutting the bass in OD? Clean sounds fine!
I am using a SwampThang in TL806 style cab.
I've got an EV12 off Jestaudio here, needs a recone so maybe I should go ahead with that if folks think it will hold up better.
I have seen some ideas for changing V2a/b caps - I want to stay close to the circuit if I can.
ISTR changing the bass pot for 1M to get a better sweep.
Right now I can't go above 2.5 -3
Thanks

Lower your V2 cathode bypass caps, I've gone down as far as 1uF and it definitely will balance out the low end without altering the character of the amp. It affects the low E string up to about B or C notes on the scale. Some times I only change V2B cathode cap, but most times wind up lowering both if the customer is having any issues with boomy low end.

Hope that helps.

Bill

www.sebagosound.com

[rogb]

I managed to playout at some decent volume last weekend.
I noticed it was bass heavy when cranking the OD.
I've done a search and as usual come up with a bunch of different possible cures. Is there one surefire way of cutting the bass in OD? Clean sounds fine!
I am using a SwampThang in TL806 style cab.
I've got an EV12 off Jestaudio here, needs a recone so maybe I should go ahead with that if folks think it will hold up better.
I have seen some ideas for changing V2a/b caps - I want to stay close to the circuit if I can.
ISTR changing the bass pot for 1M to get a better sweep.
Right now I can't go above 2.5 -3
Thanks

Lower your V2 cathode bypass caps, I've gone down as far as 1uF and it definitely will balance out the low end without altering the character of the amp. It affects the low E string up to about B or C notes on the scale. Some times I only change V2B cathode cap, but most times wind up lowering both if the customer is having any issues with boomy low end.

Hope that helps.

Bill

www.sebagosound.com

Hey Bill, thanks for that. I will try it.
I forgot to mention I was tuned down a whole tone to D at the time.
In fact I liked it so much that guitar is staying 11s and D now.
Thanks again, I will hit them both down to 1uF and see where we are.
I also sent the EV12 off for a recone so that will be going in when it gets back too.

[wjdunham]

Hey Bill, thanks for that. I will try it.
I forgot to mention I was tuned down a whole tone to D at the time.
In fact I liked it so much that guitar is staying 11s and D now.
Thanks again, I will hit them both down to 1uF and see where we are.
I also sent the EV12 off for a recone so that will be going in when it gets back too.

Great, let us know how it goes. What value do you have in there now? If you're having issues with a drop D tuning, then I'd guess 10uF?

Bill

www.sebagosound.com

[rogb]

Hey Bill, thanks for that. I will try it.
I forgot to mention I was tuned down a whole tone to D at the time.
In fact I liked it so much that guitar is staying 11s and D now.
Thanks again, I will hit them both down to 1uF and see where we are.
I also sent the EV12 off for a recone so that will be going in when it gets back too.

Great, let us know how it goes. What value do you have in there now? If you're having issues with a drop D tuning, then I'd guess 10uF?

Bill

www.sebagosound.com

4.7 or 5 - not sure what I put in there now.
Thanks Bill, it's full D tuning, ie DGCFAD. I also had FuzzFace and Univibe clones running, as well as a 50w 2204, both amps running behind a perspex screen, so I was wondering if the bass getting fired out of the TL806 was getting involved in this phenomenon.
Man it was getting to be like Band Of Gypsies in there
I've ordered some 1 and 2.2uF caps so I will give it a try, and get the screen out the way of the bass port.

[rogb]

I ended up with 2.2 in a and b. 1uF in b seemed to lose the character, so this seemed the best compromise.
The EV is on its way back so I will see how that goes.
Still only got my bass pot barely open, maybe just under 2. It would be great to get some more useable range. It's 1MA with no caps. Maybe I will try Low Plate classic 250KA with 1k8 to ground?

[hywelg]

I have an Ev and Emi Red Fang in an oversize vertical 2x12 and I have to say its brilliant with bass heavy stuff. I use my Ceriatone a lot as a pedal platform on the clean channel and it handles the bass really well.

I think you find the EV to be difficult to fault when turned up loud.

[norburybrook]

Roger, was it on a hollow stage? Were the subs for the PA on/under the stage? I presume you we're mic'd up. All these things can contribute to too much bottom end. You'll find the bass will vary in every venue so I wouldn't start changing things until you've played the rig at a few different venues. Also a higher SPL will bring out the bottom end more than when it's quiet due to the old fletcher Munson curve scenario



Marcus

[rogb]

Thanks guys!
No Marcus nothing as glamorous as a stage, pub carpet "stage"
I did proper old skool, only vocals through the PA lol.
The EV is back and in the TL806, it's difficult to tell what is happening as it is very stiff sounding, typical after a recone, so it needs some long running in.
I hope I get to like it, but the bass seems more controlled, yes. I kinda like the swampy SwampThang, it certainly seemed to sustain better with that, but it's very early days yet.

[rogb]

Ran hours of 30Hz thru the EV, it sounds good when turned up high, but I prefer the Swamp Thang for lower volume practice and noodling. Need to get it in a separate cab for that, I guess.

Having said that, I had the whole rig fired up to try a Fulltone ABY with buffers, I did not like it and it has gone back, but with my usual BigShot and Cornish style buffer, the bass is definitely under control it seems, although I still am on just under 2 on the bass pot.

EDIT: Gave up with the EV, it's just too harsh unless you are giving a lot of level. Put the dear old Swamp Thang back and tried a 500K bass pot. The pot doesn't seem to give me a bit more adjustment range.
0 = bass off
1= almost enough
2= almost too much

[wjdunham]

Having said that, I had the whole rig fired up to try a Fulltone ABY with buffers, I did not like it and it has gone back, but with my usual BigShot and Cornish style buffer, the bass is definitely under control it seems, although I still am on just under 2 on the bass pot.

EDIT: Gave up with the EV, it's just too harsh unless you are giving a lot of level. Put the dear old Swamp Thang back and tried a 500K bass pot. The pot doesn't seem to give me a bit more adjustment range.
0 = bass off
1= almost enough
2= almost too much

Try changing the PI coupler to .01uF (assuming you have the typical Dumble .02uF in there now). This will affect both clean and OD, so you'll have to get that balance right. I often make this change if the customer is complaining about the low end not being tight enough at high volume levels. If you look at old Fender Twins, they have 25uF on the cathodes, and .005 ceramic PI coupler. I've always thought that the small value of the PI coupler was to compensate for the large cathode bypass caps. I feel the Dumble mods, smaller cathode caps with a larger PI coupler yield a more balanced amp, especially for overdriven tones.

Bill

www.sebagosound.com

[Guitarman18]

You could also try placing another cap straight after the switch on the OD input, so that it puts it in series with the cap just before the switch exiting the clean stage, which will reduce bass in OD only- I think!

Hope that helps/works!

Paul.

[rogb]

Thanks guys, your help is much appreciated! First I'm going to return the bass pot configuration as per the layout. I have made so many changes I have lost sight of the original concept, I think...

[Structo]

I had too much bass.
Dinked around with the cathode caps and did the single/ humbucker cap switch on V1A. (That helps a bit with a strat or LP)
That worked great for the input!
Schematic below.

I also have all the cathode bypass preamp caps at 5uF. (other than the switched cap on V1A)

I don't play out anymore so I tuned it for my place.
I have a large 2x12 EV 12L Classic (new generation) that sits close to a corner of the room. So more bass.
I don't play out anymore so I tuned it to my ears. (as bad as they may be)

I ended up borrowing from #183 and dropped the value of the coupling caps from the PI to the power tubes to .05uF.
That seemed to balance more things out than preamp changes.
Mind you I have a 4x 6L6GC 100w amp.

I also use a stand alone Dumbleator which I use extensively to control the amp.

Remember to try one change at a time or you will get lost.

I also built a ~50w amp.
Different animals and need to be tuned differently but along the same lines.

[bluesfendermanblues]

Remember to check your bass pot taper.

I you have a liniar, like an Alpha Bxx, the amount of bass will be hard to control. With a logaritmic's taper (I think the Alpha's are 15%) you get 50% resistance at something like 3 o'clock rotation, while it'll be noon with a lin.
A liniar bass pot will be like having bass on/off.

Make sure you have a logaritmic (Alpha Axx) in there, before trying out too many circuit mods.