pre-amp/power-amp overdrive versus pre-amp only overdrive

[rbc]

I'm curious about how many folks just use pre-amp overdrive and leave the power amp running with little or no overdrive? I know you lose some things, like the cascaded distortion and probably some of the dynamics in a transformer that's being pushed hard. I'm just curious how many overlook that.

Do any particular amps cascade the overdrive/distortion over multiple pre-amp tubes? I tend more toward classic rock sounds if that makes a difference.

 

[Aceman]

Re: pre-amp/power-amp overdrive versus pre-amp only overdrive

Said it before, I'll say it again: Power Tube distortion is a particularly and awesome thing.

That said - if you are doing that, your amp hates you, your transformers, your tubes, your speakers, all of it.

My opinion: Only for awesomely rich mega rawk stars. I am just fine with tasteful application of pre-amp gain. That's what it is there for.

 

[Sirion]

Re: pre-amp/power-amp overdrive versus pre-amp only overdrive

This is one of the reasons why I aim more for a late-80s than an early-80s sound: once the ADA and independent pre-amps came around, the sounds became much more easily to replicate at lower volumes. You will find luddites who claim that power amp distortion is the only way, and for some styles that might even be true, but it is so nice not having to worry about it.

 

[dystrust]

Re: pre-amp/power-amp overdrive versus pre-amp only overdrive

Do any particular amps cascade the overdrive/distortion over multiple pre-amp tubes? I tend more toward classic rock sounds if that makes a difference.

Most master volume amps cascade multiple tube gain stages together. A Marshall 2203/2204 cascades the two halves of V1 as gain stages, while my Jet City 22H cascades V1, V2, and the first half of V3 depending on which channel you're using.

This is one of the reasons why I aim more for a late-80s than an early-80s sound: once the ADA and independent pre-amps came around, the sounds became much more easily to replicate at lower volumes. You will find luddites who claim that power amp distortion is the only way, and for some styles that might even be true, but it is so nice not having to worry about it.

+1

Though I'd say it was the Mesa Boogie Mark II or maybe the Soldano SLO that started the preamp-gain-mostly trend. There were master volume amps before that, but anyone who's played a 2203/2204 knows that they need to be LOUD in order to give up the goods. Not so much the SLO or Mark II, III, IVs, etc.

I've been playing Marshall Jubilees since 2001, and IMO they don't sound all that great when over driving the poweramp. There's a point on the output master around 2.5 where the amp starts to sound really good, and it improves until about 4. Then from 4-6 it still sounds great but gets louder; beyond that it turns into mushy, over-compressed crap.

I picked up a Mini Jubilee last year because the 2555 is so loud that you'd be playing it on 1-1.5 in most rooms. At least with the 2525H I can get it into that 2.5-4 range without bandmates or sound persons wanting to kill me.

 

[Aceman]

Re: pre-amp/power-amp overdrive versus pre-amp only overdrive

I agree that a) it sounds different and that b) It isn't that different. It may even be more of a "feel" than anything.

Again - a Marshall on 11 is an awesome sound....for as long as you can stand it.


As said - there is no one way; Good sound is good sound. How many people cop perfect EVH tones all sorts of ways?

 

[rbc]

Re: pre-amp/power-amp overdrive versus pre-amp only overdrive

Most master volume amps cascade multiple tube gain stages together. A Marshall 2203/2204 cascades the two halves of V1 as gain stages, while my Jet City 22H cascades V1, V2, and the first half of V3 depending on which channel you're using.

Anyone know if the Peavey 6505/6505+ cascade the pre-amp distortion? It seems like they might.

 

[Mincer]

Re: pre-amp/power-amp overdrive versus pre-amp only overdrive

The 'Mesa' sound is essentially cascaded preamp stages. So is the 5150. Not many modern amps (unless they are replicating vintage designs) rely on power tube distortion, these days- and most people don't dig the loose thump that it provides...but I love it.

 

[jeremy]

Re: pre-amp/power-amp overdrive versus pre-amp only overdrive

almost everyone uses mostly preamp distortion. unless you have a nmv amp and run it most of the way up, you arent getting much power amp distortion. many people ignore pi distortion too.

 

[speed2dirt]

Re: pre-amp/power-amp overdrive versus pre-amp only overdrive

To me, speaker break-up makes a much more noticeable difference than power tube break-up. I run my amps loud, not because I need the tubes cooking, but because there's a point where the speaker opens up and heaven shines down. Honestly, I have low wattage amps and a bunch of attenuators, and all do well at giving good tone at lower volumes. But the thing that is missing in every equation is the speaker moving. When you hit the point where a V30 starts to sing, you'll know what I mean.

 

[rbc]

Re: pre-amp/power-amp overdrive versus pre-amp only overdrive

To me, speaker break-up makes a much more noticeable difference than power tube break-up. I run my amps loud, not because I need the tubes cooking, but because there's a point where the speaker opens up and heaven shines down. Honestly, I have low wattage amps and a bunch of attenuators, and all do well at giving good tone at lower volumes. But the thing that is missing in every equation is the speaker moving. When you hit the point where a V30 starts to sing, you'll know what I mean.

It seems like it would be pretty hard to simulate speaker breakup except in a computer with software to do it. Use a 1x12 and baffling to reduce the level? The 1x12 would lose the 4x12 phase cancellation that some like.

J Mascis from Dinosaur Jr. says he just likes the feel of a loud amp and turns it up with earplugs in to get the feeling without loosing his hearing. You can't really get that at low volumes either. The new amps that come with built in attenuators get you part way there, but it's hard to simulate what happens at the speaker and beyond.

 

[FuseG4]

Re: pre-amp/power-amp overdrive versus pre-amp only overdrive

My super sonic 22 had cascaded gain stages with a volume knob on each stage, but yeah with the second one dialed up I can go way low on the master volume and still get lots of warmth and sustain.
Not as liquid and alive as running the master high but that can get very loud