how to use Dumble's OD?

[skippymchaggis]

(I apologize if this is the wrong place to ask this, as this is my first post.)

I recently got a secondhand Ceriatone OTS 50 (after chickening out from building one...I decided to start with something simpler first.). It needed new power tubes, so I got that taken care of and biased it a bit on the cold side as I saw recommended here. And I've really been enjoying getting to know it. The clean channel makes sense to me, although I haven't played with the FET input.

I'm still trying to figure out how to use/dial in the OD section and was wondering if anyone has some guideline settings on using the OD "channel"? I understand it's not really a "channel" as it uses the same tone stack as the clean channel, but it's at least switchable. I also understand there are multiple gain stages in play, but it's all just a bit over my head right now how they interact, and would appreciate any pointers.

If it helps, my amp has a PPIMV on the back, and I have a Kleinulator that's not hooked up yet because I needed to get a power supply, which i know will also add another gain stage (although I think it's generally just used for volume control?).

Thanks for any info!

[pompeiisneaks]

The basics of a non HRM ODS is that you have two settings for OD on the panel, and one on the circuit board itself. (if it was included?). The one on the board sets the maximum gain of the drive, by having a voltage divider like a small volume pot that limits the current going into the OD stage. That shouldn't usually need much tweaking, unless the front panels don't help you at all.

The front panel has two controls, the drive amount and drive volume. The volume is used to try and match the overall volume that is added by the drive, letting you either intentionally have it boost the signal a lot or a little, depending on what you're going for. (or just have it the same volume as the clean channel). The second is how much drive there is, you can dial it down pretty low so the drive is more bluesy, or push it into pretty heavy gain at the far right rotation.

The HRM mod allowed dumble to have a 'tone section' for the od channel, but it was on board and was designed to be a set and forget kind of thing per the specific desire of the player. Dialing in the 'sweet spot' for their playing style. I have no idea if the ceriatone's allowed the HRM mod by default but you could definitely add one if you wanted to.

Hope that helps.

~Phil

[MakerDP]

iMHO, setting a Dumble is about compromises. You really need to find a happy medium between your clean tone and your OD tone, focusing on which one is most important to you and then set up the other to be as good as you possibly can get it. Fortunately, it's still going to be pretty good.

My experience has been that it takes a LONG time to dial-in the channels to get where you want to be. I really like the fact that my normally internal OD Trim control is on the back of my amp and that gives me a LOT more flexibility when dialing-in the OD channel.

[Rollylama]

I have a zingaro and am a total noob to the dumble thing but you can use the input (clean) gain to influence the lead channel. If you set it lower your lead gain probably goes up to compensate and is smoother in general. If you wind up the input gain then the lead channel is getting a hotter signal and can get way more aggressive or you can dial down the lead channel gain to compensate for the hotter input.

FWIW I aim to get the sound I’m looking for out of the lead channel and then the clean is what it is. As mentioned above, it’s a compromise. Add a “lator” and you get even more confusing options with the send/return levels.

[JD0x0]

Signal flow typically goes:

FET (When being used) > V1a is your input stage, the first half of the V1 tube. > Tonestack > ('clean') Volume > V1b (second half of first tube) > Overdrive trimmer > V2a (first half of 'overdrive' stage) > Drive/Level gain control > V2b (second half of OD stage) > Ratio/OD volume > Pre-PI MV > FX Loop > Phase inverter > Powertubes

Essentially, each stage has an attenuator after it, so you can control how hard each stage hits the following stages.

[norburybrook]

you can also set your amp up so that you're in permanent OD and use your guitar volume control. Joe Bonamassa uses his Dumbles this way.

https://youtu.be/rNvOUmwPiUQ?t=2111

I've been using mine like this for a while and it works well if you like that kind of sound/ feel and are running alongside another non master volume amp.

Also Jazz mode can be useful in this scenario as well.

They're complex amps, the tone controls and /jazz/rock modes are very flexible and as said above there's many ways to set your clean/OD tones.

Main thing is to play the thing as much as possible in all situations and eventually you'll work out what 'works' for you.



M

[martin manning]

The wonderful flexibility and clean/OD interaction is exactly the reason that some people don't like these amps... too many knobs! To each his own, I guess. I look at the internal OD entrance trimmer as setting the minimum distortion level in OD.

[skippymchaggis]

thank you all for your replies! it's starting to make more sense.