Bass control behavior...normal?

[greiswig]

Duplicate deleted because of "debug mode" issues...

[greiswig]

You must have the input and wiper connected. That is the correct way. The relay breaks that connection in PAB mode.

Bass mod, shmase mod. Dumble connected the lugs and he designed the stack

Thanks, Dogears...I was submitting my last post before I read yours. I think what you said indicates that I'm barking up the right tree with the bass mod. I've been fiddling, and with the jumper back in a number of things are starting to line up that I've been struggling with for a bit.

Question: you said that the correct format is to break that jumper in PAB mode, but the D'Lite doesn't do that. Did I read you right? The only connection the PAB breaks in the D'Lite is between the bass wiper and the treble outer lug.

[dogears]

Dumble broke the wiper from bass pot input since then you have the full 500K to ground when PAB is on. PAB breaks the bass pot input from treble pot and the input and wiper lugs of the bass pot.

You must have the input and wiper connected. That is the correct way. The relay breaks that connection in PAB mode.

Bass mod, shmase mod. Dumble connected the lugs and he designed the stack

Thanks, Dogears...I was submitting my last post before I read yours. I think what you said indicates that I'm barking up the right tree with the bass mod. I've been fiddling, and with the jumper back in a number of things are starting to line up that I've been struggling with for a bit.

Question: you said that the correct format is to break that jumper in PAB mode, but the D'Lite doesn't do that. Did I read you right? The only connection the PAB breaks in the D'Lite is between the bass wiper and the treble outer lug.

[Structo]

That jumper is known as the bass mod.
It increases the bass.
I originally had that but removed it because the bass was too heavy.

This is how I have mine wired now.

[dogears]

Not using the jumper is the mod. Dumble always had those lugs connected. If the amp is bass heavy, I'd look elsewhere to fix. Altering the tonestack makes it not a Dumble.

Try a smaller PI cap, smaller Cl2 cap, lower bypass caps on V1, etc. There are many ways to skin a cat without ruining the tonestack operation.

Of course, you may prefer it with the bass mod in place (that is without the lugs connected). I'd still explore doing the things the correct way as a baseline.

That jumper is known as the bass mod.
It increases the bass.
I originally had that but removed it because the bass was too heavy.

This is how I have mine wired now.

[Structo]

Thanks for the clarification Scott.
I guess I was just going by what the D'Lite stuff said.
Everything I had read said the jumper was the bass mod. lol
But I like the range of adjustment without the jumper currently.
I have most of your suggested mods or tweaks in place and am quite happy with the results.
Although I do have a high freq hash or sizzle I can't quite pin down.
I may try Gil's OD bleeder.

[greiswig]

After fiddling with the amp a bit more, I'm definitely with Scott: I prefer it with the wiper jumpered at least somewhat...I have a switch with values of 0, 56k, and 110k ohms. Previously the switch was either at 110k, 220k, or open. But...

As soon as I did this change, I remembered why I did it in the first place. The amp was pretty boomy. Fiddling with the cathode bypass caps kept the ballsy quality, but culled the boom. Me like.

I had also changed V1 to have 100k/120k values before, to try to get some grind at higher volumes from the clean channel. I hadn't been able to get that before. As soon as I jumpered the wiper, that came on in spades. Part of fiddling with those cathode bypass caps was to even that out a little: distorted subharmonics around 30Hz just don't sound that great.

[Bob-I]

Not using the jumper is the mod. Dumble always had those lugs connected.

That's not what I've seen. All the Dumble pics I've seen do not have the jumper on the bass pot. It's connected through the PAB relay and disconnected in PAB mode. I think what this mod is designed to do is add bass in PAB mode.

[dogears]

Bob, I know. I mentioned this in my earlier posts on this thread. The issue is that they disconnect the lugs in normal stack mode. They also did not use the second half of the relay to disconnect them in PAB mode. Their bass mode essentially totally alters tonestack operation (unless PAB is on)

Not using the jumper is the mod. Dumble always had those lugs connected.

That's not what I've seen. All the Dumble pics I've seen do not have the jumper on the bass pot. It's connected through the PAB relay and disconnected in PAB mode. I think what this mod is designed to do is add bass in PAB mode.

[brewdude]

Bob, I know. I mentioned this in my earlier posts on this thread. The issue is that they disconnect the lugs in normal stack mode. They also did not use the second half of the relay to disconnect them in PAB mode. Their bass mode essentially totally alters tonestack operation (unless PAB is on)

Not using the jumper is the mod. Dumble always had those lugs connected.

That's not what I've seen. All the Dumble pics I've seen do not have the jumper on the bass pot. It's connected through the PAB relay and disconnected in PAB mode. I think what this mod is designed to do is add bass in PAB mode.

Doesn't the PAB work by removing the tone stack from the signal path?
If so, why is it necessary to remove the jumper to the bass wiper in PAB mode.

[heisthl]

Say you have the bass control at noon - the resistance to ground for the bass frequencies becomes 250k (+10k), by separating the lugs the bass frequencies have a bigger path to ground (500k pot + 10k tail) and the path through the treble cap becomes more attractive, resulting in a little fuller sound in PAB mode.

[brewdude]

I just completed a D'Lite 22, following the "No Bass Mod" (no jumper on the bass pot). My initial reaction was that the PAB and OD modes were great, but the clean was somewhat thin and way too bright.

Today I had a chance to play a little while with some jumper clips. Connecting the wiper to the Right lug with the jumper was much fuller and dynamic. It sounded great.

I tried it both jumped and not in PAB. Now I'm trying to decide whether to wire the jumper such that it is disconnected in PAB, or always jumped. It sounded pretty fat with the jumper, yet without could probably cut through the mix better.

It sound as if a real Dumble would remove the jumper in PAB. Regardless of authenticity, does anyone else have a preference, one way or the other?

[dogears]

In PAB, the tone is better (IMHO) without the jumper. This is also the authentic way. With the tonestack in, the jumper must be there or the tone will be much thinner. I prefer it the Dumble way. Hands down.

Dumble used half of the PAB relay to connect/disconnect the jumper.

I just completed a D'Lite 22, following the "No Bass Mod" (no jumper on the bass pot). My initial reaction was that the PAB and OD modes were great, but the clean was somewhat thin and way too bright.

Today I had a chance to play a little while with some jumper clips. Connecting the wiper to the Right lug with the jumper was much fuller and dynamic. It sounded great.

I tried it both jumped and not in PAB. Now I'm trying to decide whether to wire the jumper such that it is disconnected in PAB, or always jumped. It sounded pretty fat with the jumper, yet without could probably cut through the mix better.

It sound as if a real Dumble would remove the jumper in PAB. Regardless of authenticity, does anyone else have a preference, one way or the other?

[Deric]

After fiddling with the amp a bit more, I'm definitely with Scott: I prefer it with the wiper jumpered at least somewhat...I have a switch with values of 0, 56k, and 110k ohms. Previously the switch was either at 110k, 220k, or open. But...

As soon as I did this change, I remembered why I did it in the first place. The amp was pretty boomy. Fiddling with the cathode bypass caps kept the ballsy quality, but culled the boom. Me like.

Are you swapping the resistors in place of the jumper via the switch? I recently re-wired the tone-stack in my D Lite the "correct" way (PAB breaks the jumper on the Bass pot). While I like the overall tone better with the jumper in, it's too boomy - too woofy on the clean and mushy on the OD. Before I started swapping parts I decided to clip-lead a pot in place of the jumper. So far, adding a resistor seems like a workable solution.

Can I ask what size bypass caps you are using on V1A and V1B?

Thanks!

[greiswig]

Are you swapping the resistors in place of the jumper via the switch? I recently re-wired the tone-stack in my D Lite the "correct" way (PAB breaks the jumper on the Bass pot). While I like the overall tone better with the jumper in, it's too boomy - too woofy on the clean and mushy on the OD. Before I started swapping parts I decided to clip-lead a pot in place of the jumper. So far, adding a resistor seems like a workable solution.

Can I ask what size bypass caps you are using on V1A and V1B?

Thanks!

Yes, the resistors are in place of a jumper. The cathode bypass caps on both sides of V1 are 1uF currently, and there's plenty of bass available, especially with single coils. Part of this may be my choice of speakers: I'm using a Celestion 12-65, but it's paired with an Eminence S2010, which is a bass speaker. Crazy, I know...