Getting more tube power amp overdrive

aja

I looooove tube power amp distortion/overdrive. With almost every amp I own/play on, I always crank the master volume to full and keep the preamp gain just high enough to get some breakup going. Guess that is why I like vintage amps so much because of the lack of master volume.

Can't get enough of that fat creamy sound as opposed to the thin industrial modern preamp overdrive sound people seem to go gaga for these days! With poweramp overdrive, cutting the bass control to almost zero still leaves you with awesome tone - it never seems to fizzle out. Perhaps it is a compression thing going on... That and the playing dynamics are awesome - don't even need to change the guitar volume all the time, just adjust your playing style to get more or less overdrive.

How can I increase power amp overdrive? Can I use a boost pedal in the effects loop somehow? Would swapping preamp tubes from say 12AX7's to 12AT7's or even 12AU7's help at all in taming preamp overdrive? Looking for smooth gentle overdrive that increases slowly as you increase the gain...

AlanRatcliffe

I'm with you on this. There's nothing wrong with some preamp drive, but it's best used in moderation and in combination with power amp drive.

The best valves I've found for taming a 12AX7 preamp are 5751s - same gain as a 12AT7 (60 - v. 100 for an AX7) but unlike an AT7 has a similar transconductance to an AX7, so it responds in the circuit the same way. Magic in V1 - brings the pre gain down but keeps the response and feel.

In Fender style circuits, some like changing the PI (Phase inverter) from a 12AT7 to an AX7 to drive the power section harder. Didn't work for me, but some swear by it.

Nicholas-L

Ditto to the 5751 statement ?

I want to try them in my SLO just to see what happens

AlanRatcliffe

Nicholas L wrote: I want to try them in my SLO just to see what happens

I suspect you might find the same thing I did with my ADA MP-1 - it's just so high gain that nothing will really tame it without neutering it.

Nicholas-L

Hahaha oh no in that case :roflmao: ? I'll leave it be then for now

ezietsman

aja wrote: How can I increase power amp overdrive? Can I use a boost pedal in the effects loop somehow? Would swapping preamp tubes from say 12AX7's to 12AT7's or even 12AU7's help at all in taming preamp overdrive? Looking for smooth gentle overdrive that increases slowly as you increase the gain...

VVR, How many times must I say this ?

aja

ez wrote:
aja wrote: How can I increase power amp overdrive? Can I use a boost pedal in the effects loop somehow? Would swapping preamp tubes from say 12AX7's to 12AT7's or even 12AU7's help at all in taming preamp overdrive? Looking for smooth gentle overdrive that increases slowly as you increase the gain...
VVR, How many times must I say this ?

How would that help? I am running at max volume already. I thought VVR is to get the same overdrive at lower volume, not more overdrive at the same volume? I have not used a VVR before, so maybe I do not understand.

aja

Alan Ratcliffe wrote: I'm with you on this. There's nothing wrong with some preamp drive, but it's best used in moderation and in combination with power amp drive.

The best valves I've found for taming a 12AX7 preamp are 5751s - same gain as a 12AT7 (60 - v. 100 for an AX7) but unlike an AT7 has a similar transconductance to an AX7, so it responds in the circuit the same way. Magic in V1 - brings the pre gain down but keeps the response and feel.

In Fender style circuits, some like changing the PI (Phase inverter) from a 12AT7 to an AX7 to drive the power section harder. Didn't work for me, but some swear by it.

Thanks! That's great advice. I will have to get some of those goodies!

ezietsman

aja wrote:
ez wrote:
aja wrote: How can I increase power amp overdrive? Can I use a boost pedal in the effects loop somehow? Would swapping preamp tubes from say 12AX7's to 12AT7's or even 12AU7's help at all in taming preamp overdrive? Looking for smooth gentle overdrive that increases slowly as you increase the gain...
VVR, How many times must I say this ?
How would that help? I am running at max volume already. I thought VVR is to get the same overdrive at lower volume, not more overdrive at the same volume? I have not used a VVR before, so maybe I do not understand.

Oh, I assumed you couldn't get more because it got too loud, which is the standard problem. If there's not enough for you then you must boost the amp somehow, a clean boost pedal into the front usually does the trick (using a higher gain PI tube like Alan says can also work) The amount of drive obviously depends on the amp itself.

aja

I am using class A in this case (laney lionheart L20T-112), so no PI but still some good ideas to try... ?

ezietsman

Oh those, You could try different power tubes too. I put some new production Mullards in my 18 watt, they break up a bit sooner than JJs, also sound a slight amount less harsh than JJs. This is subtle though. Besides that, adding a bit of extra gain from the front or clean boost pedal is the only thing I can think of. (It must be loud with that G12H30 in there ne?)

arjunmenon

I don't how effective or safe this is, but i've seen a friend of mine (forumite who moved to Canada) use an EP Booster in his effects loop.
Seems to work well for him.

Gearhead

aja wrote: I looooove tube power amp distortion/overdrive

aja wrote: I am using class A in this case (laney lionheart L20T-112), so no PI

So if your power distortion is class A from penthodes and your typical preamp distortion is class A distortion from triodes, how would you describe the difference?

psyx

ez wrote: Oh those, You could try different power tubes too. I put some new production Mullards in my 18 watt, they break up a bit sooner than JJs, also sound a slight amount less harsh than JJs. This is subtle though. Besides that, adding a bit of extra gain from the front or clean boost pedal is the only thing I can think of. (It must be loud with that G12H30 in there ne?)

Slightly off topic, but the mentioning of new mullard tubes set me on a voyage through the internet to find the origin of these new tubes. I found this link http://thetubestore.com/mullardel84.html which says that these mullard tubes are made in the same factory as EH and Sovtek tubes... And I also discovered the "winged C" tubes which were also manufactured in the same factory but are now only manufactured in St. Petersburg.
So are these mullards made to a different spec than the normal EH and sovtek tubes? ?

ezietsman

psyx wrote:
ez wrote: Oh those, You could try different power tubes too. I put some new production Mullards in my 18 watt, they break up a bit sooner than JJs, also sound a slight amount less harsh than JJs. This is subtle though. Besides that, adding a bit of extra gain from the front or clean boost pedal is the only thing I can think of. (It must be loud with that G12H30 in there ne?)
Slightly off topic, but the mentioning of new mullard tubes set me on a voyage through the internet to find the origin of these new tubes. I found this link http://thetubestore.com/mullardel84.html which says that these mullard tubes are made in the same factory as EH and Sovtek tubes... And I also discovered the "winged C" tubes which were also manufactured in the same factory but are now only manufactured in St. Petersburg.
So are these mullards made to a different spec than the normal EH and sovtek tubes? ?

No idea. They physically look different than the JJs I also have. That's as far as I researched. I got them to see if different tubes will indeed sound different. I believe they do, but its not a massive difference. I should prob do a proper test one of these days with a Mic and a looper pedal.

AlanRatcliffe

psyx wrote: Slightly off topic, but the mentioning of new mullard tubes set me on a voyage through the internet to find the origin of these new tubes. I found this link http://thetubestore.com/mullardel84.html which says that these mullard tubes are made in the same factory as EH and Sovtek tubes... And I also discovered the "winged C" tubes which were also manufactured in the same factory but are now only manufactured in St. Petersburg.
So are these mullards made to a different spec than the normal EH and sovtek tubes? ?

Different spec, same factory. Another subtle variation, but same kind of quality of sound. Still far off the original Mullards...

New Sensor have made quite a business of buying up other, well respected names and then producing variations of their valves under those names.

"Winged C" is an interesting one - JSC Svetlana used the brand name "Svetlana" in the US, with New Sensor being the distributors. These valves had a long history, a good reputation and made arguably the best new production 6L6s. I'm not sure exactly how they did it, but when the two parted ways, New Sensor got the rights to the Svetlana brand name in the US. Now New Sensor now make the Svetlana branded valves in their own factories (that's right - the same ones that make Sovtek and EH), while JSC Svetlana sell theirs (still made in the Svetlana factory) under the Winged C brand name.

psyx

Alan Ratcliffe wrote:
psyx wrote: Slightly off topic, but the mentioning of new mullard tubes set me on a voyage through the internet to find the origin of these new tubes. I found this link http://thetubestore.com/mullardel84.html which says that these mullard tubes are made in the same factory as EH and Sovtek tubes... And I also discovered the "winged C" tubes which were also manufactured in the same factory but are now only manufactured in St. Petersburg.
So are these mullards made to a different spec than the normal EH and sovtek tubes? ?
Different spec, same factory. Another subtle variation, but same kind of quality of sound. Still far off the original Mullards...

New Sensor have made quite a business of buying up other, well respected names and then producing variations of their valves under those names.

"Winged C" is an interesting one - JSC Svetlana used the brand name "Svetlana" in the US, with New Sensor being the distributors. These valves had a long history, a good reputation and made arguably the best new production 6L6s. I'm not sure exactly how they did it, but when the two parted ways, New Sensor got the rights to the Svetlana brand name in the US. Now New Sensor now make the Svetlana branded valves in their own factories (that's right - the same ones that make Sovtek and EH), while JSC Svetlana sell theirs (still made in the Svetlana factory) under the Winged C brand name.

Are the winged c's still as good as they used to be when they were svetlana?

AlanRatcliffe

Yup, still the best new production 6L6s...