Is a KT66 amp inherently loose in the bottom end?

[HomespunEffects]

Throughout history, humans have been interacting with the universe via four-dimensional superstructures. We are at a crossroads of choice and suffering. Who are we? Where on the great journey will we be re-energized?

It is time to take power to the next level.

 

[Life Eats Life]

I thought those were the non money notes.

Nope, that’s Gilmourland.

 

[FuzzyAce]

Throughout history, humans have been interacting with the universe via four-dimensional superstructures. We are at a crossroads of choice and suffering. Who are we? Where on the great journey will we be re-energized?

 

[HomespunEffects]

It's funny, just reading the thread title I was going to comment about the VM 2466. I love that amp and it was my #1 for years, but yes the bottom end is pretty loose. I don't know if it's a characteristic of KT66s or just the design of that amp, though. I think Steve Dawson, the designer, was going for a hot-rodded JTM thing, inspired by his work on the Hendrix reissue stack. Maybe @santiall can comment?

You could try Gold Lion KT66s instead of the stock Shuguangs. I found they firmed up the bottom a bit, although I felt they took away some of the amp's character I liked (rich mids, mainly). Made it a bit more Fender-y.

At one time I had two 2466s. One had Gold Lions. The other has something else. I’m going to be honest that I’m not sure which one i kept. I’ll look today after gym.

I do know i sold the one that was modified with a choke as it made exactly zero difference to the tone and tightness.

Looks like I kept the ones with TAD originals.

 

[HomespunEffects]

OK, I didn't have a 25µF but I had a 20µF. Hmmm, it definitely went a little too far, I think. I'm going to try a different value in there. Maybe a 150µF or 47µF.

 

[HomespunEffects]

Hmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm, the 47µF seems nice. Is that really the only thing I had to change to make me happy? Seems way too simple.

I find that I have to set the tone controls way differently than before.

Is that really all I had to do? Like for real??

 

[HomespunEffects]

Two of the KT66s are loose from their base (the glass wiggles a bit with the base stationary). I've run tubes like that before but I was super poor back then. I'm just regular poor now.

 

[FuzzyAce]

Hmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm, the 47µF seems nice. Is that really the only thing I had to change to make me happy? Seems way too simple.

I find that I have to set the tone controls way differently than before.

Is that really all I had to do? Like for real??

Don't fight it, just accept it.

 

[HomespunEffects]

Don't fight it, just accept it.

I guess I'll accept it.

 

[HomespunEffects]

And thanks for the tips.

 

[FuzzyAce]

And thanks for the tips.

No prob. Glad a simple change did the trick!

 

[santiall]

It's funny, just reading the thread title I was going to comment about the VM 2466. I love that amp and it was my #1 for years, but yes the bottom end is pretty loose. I don't know if it's a characteristic of KT66s or just the design of that amp, though. I think Steve Dawson, the designer, was going for a hot-rodded JTM thing, inspired by his work on the Hendrix reissue stack. Maybe @santiall can comment?

You could try Gold Lion KT66s instead of the stock Shuguangs. I found they firmed up the bottom a bit, although I felt they took away some of the amp's character I liked (rich mids, mainly). Made it a bit more Fender-y.

hmmm, I think it will be a stretch to just 'blame' the looseness on the output tubes. I guess we could say that if we are comparing the same amp with different output tubes and one type is tighter than the other, but when talking about a different amp I'd say that the whole circuit will have something to say.
Usually, to make an amp tighter there is some sort of high pass filter by the front end of the amp, so you avoid "digetive problems" from the very beginning but I rather don't generalize, there are few ways of tightening an amp I guess.
I've pointed Steve to this thread, hopefully he'll join us!

 

[TubeStack]

hmmm, I think it will be a stretch to just 'blame' the looseness on the output tubes. I guess we could say that if we are comparing the same amp with different output tubes and one type is tighter than the other, but when talking about a different amp I'd say that the whole circuit will have something to say.
Usually, to make an amp tighter there is some sort of high pass filter by the front end of the amp, so you avoid "digetive problems" from the very beginning but I rather don't generalize, there are few ways of tightening an amp I guess.
I've pointed Steve to this thread, hopefully he'll join us!

Amazing, thank you! Also love hearing your input.

I remember Steve was a great help and super cool presence around the Vintage Modern forum, back in the day,

(Yes, there was a whole forum dedicated to this amp.)

 

[santiall]

Amazing, thank you! Also love hearing your input.

I remember Steve was a great help and super cool presence around the Vintage Modern forum, back in the day,

(Yes, there was a whole forum dedicated to this amp.)

please ask him about the 'clean channel' of the Vintage Modern

 

[Life Eats Life]

JTM45’s are generally boomy/loose in the low end. Swapping poweramp valves won’t change the fact that the circuit allows more bass through than other Marshalls.

could swap the 0.022 coupling caps for 0.0022, I think the PI coupling caps also let more low end through. Or just use an EQ pedal and cut some lows before the preamp.

Yep, the Telos proves this.
You can’t remove it, it’s best to join it
like Clapton did in Cream.
When it comes to power tubes-EL-34’s are all that’s necessary when it comes to crunch.
I like everything, love 6L6’s and certainly would pummel down with 88’s, but my baseline power tube is the EL-34.
Many of my pre-amp tube & speaker recipes revolve around the threshold & break-up of the
EL-34.

 

[HomespunEffects]

hmmm, I think it will be a stretch to just 'blame' the looseness on the output tubes. I guess we could say that if we are comparing the same amp with different output tubes and one type is tighter than the other, but when talking about a different amp I'd say that the whole circuit will have something to say.
Usually, to make an amp tighter there is some sort of high pass filter by the front end of the amp, so you avoid "digetive problems" from the very beginning but I rather don't generalize, there are few ways of tightening an amp I guess.
I've pointed Steve to this thread, hopefully he'll join us!

Well, I’m sure you can see the reason for my wondering about it. I’ve got four EL34 amps (including a JTM clone) that don’t have that loose bottom and one KT66 amp that does. Up until this thread, I did blame it on the KT66s.

I’ve owned a handful of Marshalls and I’ve got to say the Vintage Modern 2466 is probably my favorite.

 

[HomespunEffects]

Amazing, thank you! Also love hearing your input.

I remember Steve was a great help and super cool presence around the Vintage Modern forum, back in the day,

(Yes, there was a whole forum dedicated to this amp.)

The forum is still up but it throws an HTTP error 500 when you try to go to a topic.

 

[santiall]

Amazing, thank you! Also love hearing your input.

I remember Steve was a great help and super cool presence around the Vintage Modern forum, back in the day,

(Yes, there was a whole forum dedicated to this amp.)

This is what he has to say:
On the Vintage Modern it's quite easy to overdo the Body when using humbuckers. KT66s always did get too flubby with excessive bass dialled in on the JTMs. The issue isn't as pronounced with single coils. This is why I put the Body control on. It enables precise control for different guitars and pickups.If some people are trying to get certain modern metal sounds, I don't think the KT66 is the best choice of valve to be honest.
also, he suggest to try different speakers and set the controls with your ears, not with the eyes!

 

[santiall]

Well, I’m sure you can see the reason for my wondering about it. I’ve got four EL34 amps (including a JTM clone) that don’t have that loose bottom and one KT66 amp that does. Up until this thread, I did blame it on the KT66s.

I’ve owned a handful of Marshalls and I’ve got to say the Vintage Modern 2466 is probably my favorite.

yeah, I can understand your conclussions but don't forget that between your pole pieces and the air moved by the speakers there are many variables, some have more effect that others of course. From my experience, I'd still not focus solely on the output tubes.

 

[HomespunEffects]

This is what he has to say:
On the Vintage Modern it's quite easy to overdo the Body when using humbuckers. KT66s always did get too flubby with excessive bass dialled in on the JTMs. The issue isn't as pronounced with single coils. This is why I put the Body control on. It enables precise control for different guitars and pickups.If some people are trying to get certain modern metal sounds, I don't think the KT66 is the best choice of valve to be honest.
also, he suggest to try different speakers and set the controls with your ears, not with the eyes!

So, he does say that the KT66s have an inherent property that gives them some potential looseness. That would also explain why my JTM clone with EL34s doesn’t seem to have the issue. I wasn’t entirely wrong in shaking my fist at the KT66s. Knowing this, I can work with it.

I generally don’t use humbuckers, the boomy bottom is less with single coils but it’s still there to the point that the neck pickup isn’t useful. The Body control does help a lot but not completely.

Oh, I wouldn’t say I’m trying to get a modern metal tone. That’s not my style.

I definitely have been experimenting with speakers. The only ones that didn’t do well so far have been the G12C, which were thin sounding. Perhaps they were designed that way to deal with the loose bottom in the amp. Vintage 30s is the answer to that question.

My permanent solution was to change C4 from 220μF to 47μF. Which may have gone a bit far maybe a 150μF would be better but I’m pleased with the change.

Thank you for all your advice.