too much low end

[greg54]

I have a Dumble clone - late 80's, non-HRM, Skyliner.
It's not too dark. The high end is just fine. But the low end is too much. When I play the high E, B, G strings it sounds great. But on the A and low E strings the low end is way too much. I need to dial it back quite a bit.
Just wondering how to go about this.

[martin manning]

What value are the preamp cathode resistor bypass caps?

[greg54]

I don't know. I'm new at all of this. I'm asking to learn and understand.

Thanks.

[Zippy]

I have a Dumble clone - late 80's, non-HRM, Skyliner.
It's not too dark. The high end is just fine. But the low end is too much. When I play the high E, B, G strings it sounds great. But on the A and low E strings the low end is way too much. I need to dial it back quite a bit.
Just wondering how to go about this.

Is it a problem on all guitars? Might you just adjust the pickup pole pieces?

A check is to compare the A- and E- string outputs when fretted up the neck, and compare them to the D- and G-strings at similar pitches.

[greg54]

Zippy: Yes, I tried adjusting the pickups (as it's like this on all guitars). But the low end is pretty overwhelming.
I thought I would ask because I didn't know if it would be a simple fix within the amp or something more detailed.

[Zippy]

Zippy: Yes, I tried adjusting the pickups (as it's like this on all guitars). But the low end is pretty overwhelming.
I thought I would ask because I didn't know if it would be a simple fix within the amp or something more detailed.

OK, good to define the problem - so it's the frequency range rather than the strings.

[talbany]

The ODS was voiced for a semi open back cabinet.. ..So if you use a closed back cab it can get pretty bassy,especially on neck pickups..Also Bypass caps,coupling caps,pot and trimmer values,output tubes,speakers and the amount of GNFB all affect low end response!...Where should we start..

Tony

[jcsifu]

I have a Dumble clone - late 80's, non-HRM, Skyliner.
It's not too dark. The high end is just fine. But the low end is too much. When I play the high E, B, G strings it sounds great. But on the A and low E strings the low end is way too much. I need to dial it back quite a bit.
Just wondering how to go about this.

Greg,
Have you tried switching to jazz setting or without the deep switch or both?

[greg54]

zippy: it's definitely not the strings in regard to the pickups. In fact, I've lowed the pickups on the low end quite a bit to try and solve this.

talbany: I use a semi open back cab. I should mention that the issue is mainly with the OD. The clean isn't bad. But when I turn on the OD, that's when the low end is too much.

jcsifu: I have not switched to the jazz setting, as I never use it. But I'll do it to see if it makes a difference with the OD. By "deep" switch do you mean the Mid switch? I never use it.

Thanks!

[greg54]

jcsifu: I tried switching to the jazz setting (with OD on), and no issues at all with the low end. It's only with the Rock setting on OD. I'll keep working with it.

Thanks!
Greg

[aflynt]

I wound up taming the bass on my #102 clone by switching from an Alpha 500kA to a new CTS 500kA bass pot. The CTS is a 10% taper true-log pot and comes on much slower than the Alpha which is more like 15% and really just two linear elements stuck together. It's got a more usable range for that position. I also switched from a 716p .001uF bass cap to a 6PS .0012 and changed the 10k to ground off the bass pot to a 5.6k. The cap change had the effect of making the bass less boomy (I believe it was the switch in composition more than value). The resistor just gives less bass at minimum. The pot taper was the biggest part of the fix, oddly enough though.

-Aaron

[talbany]

Make sure your OD trimmer,OD drive,OD level's are all 100k..If so Make sure all your bypass caps are at least 5uf..If there is still too much bass lower the last gain stage in the OD V2b to a 1 uf bypass cap..If that still does not help chances are your 2 coupling caps .01 and .0047 could be out of spec and might need to be changed.. Check these off first..Also make sure your plate voltages on v2 a and B (pin 1 and 6) on the OD tube are all above 200v..This is all standard ODS tweaks and should work with most bridge pickups on your cabinet..If not you will have to modify it into something other than an ODS..
BTW..It also helps with bass response if you orient the coupling caps shield side to ground

Tony

[greg54]

Thanks, Aaron and Tony! I appreciate your suggestions.

Greg

[marcos]

Hi Greg,
just some thoughts. To some extent, this is just the way it it is,
the Skyliner eq has more bass and way more deep mid
content than ,say, a Fender style circuit. When I first modded an amp
this way, I thought it was way too boomy, but I found that by carefully dialing in you can get balanced sounds. Typically, you run the bass control below noon, I have mine at about 50k to ground or less (cannot be measured in circuit), which translates to about 12 o´clock with a 10
percent taper bass pot as Aflynt suggested, about 11 o´clock with the
Alpha pot. Bear in mind that anything that increases bass or gain will
tend to make the problem worse. So my advice is, spend
some trying to adjust the tone controls before soldering anything.
Also listen to everything Tony says, he´s the man.

my 2 Cents

Marcos

[tubedogsmith]

Greg, try Tony's suggestion, swapping out the OD 2nd stage cathode cap to a 1uf. You'll have to do some compensating with your tone controls afterwards as well.