Putting a distortion pedal in front of a tube amp

[progrmr]

I've got an Epi Valve Jr en route (trade) - given that it doesn't break up until the volume gets high, there's really no option to get distortion from such an amp other than putting a pedal between the guitar and the amp.

My question is this: What's the difference between a tube amp with a pedal in front of it or a solid state amp?

A tube amp's sweet sound comes from driving the power tube - feeding it a signal that when the power tube amplifies it, starts to degrade/breakup. So if you've got a pedal in front of the amp with the volume low - are you getting any impact from the power tube? Doesn't seem like it would because the signal coming to it, while already broken up from the pedal, would be amplified but not exceed the power tubes ability to amplify that signal w/o it breaking up further.

Of course when the tube amp can be turned up and the power tube can amplify the signal but causes the signal to degrade - well that's where the tube sweet sounds come into play. I'm just not seeing any sweet tube tones from a tube amp with a pedal in front of it at low volumes.

Am I right in my thinking here?

[jeffhorrigan]

generally correct I would say. But tube based pre-amp distortion is generally "rounder" and more ear pleasing than solid state and an overdrive or slight distortion in front of a tube amp will push the pre-amp tube(s) harder than just the guitar pickup to yield a nice sound. So even without the power tube distortion you will still get a nice sound out of a tube preamp. A small amp like the Valve Jr can be run at max volume to push its power tube hard without being so loud that you can't be in the same room but it will still be pretty loud and you may want some kind of attenuation. I have a Valve Jr combo which I've modified with a power reducing circuit that allows me to turn it up all the way to get power tube distortion at a lower volume (don't wake the baby kind of levels.)

[tunghaichuan]

I've got an Epi Valve Jr en route (trade) - given that it doesn't break up until the volume gets high, there's really no option to get distortion from such an amp other than putting a pedal between the guitar and the amp.


Not true, Hall Amps VVR (http://www.hallamplification.com/main.html#2,2) and Skipzcircuits VariWatt (http://www.skipzcircuits.com/VariWatt.html) are both power scaling circuits that allow you to crank the amp to distortion but get whisper-level output levels out of the amp. These types of circuits dial down the high voltge (B+) in an amp and allow it to distort at lower volume levels.

You also can use some type of attenutator, but I haven't had good luck with them and the VJ. YMMV.



My question is this: What's the difference between a tube amp with a pedal in front of it or a solid state amp?

A tube amp's sweet sound comes from driving the power tube - feeding it a signal that when the power tube amplifies it, starts to degrade/breakup. So if you've got a pedal in front of the amp with the volume low - are you getting any impact from the power tube? Doesn't seem like it would because the signal coming to it, while already broken up from the pedal, would be amplified but not exceed the power tubes ability to amplify that signal w/o it breaking up further.


From Wikipedia (http://en.wikipedia.org/wiki/Tube_sound):


Musical instrument amplification

Some musicians[4] also prefer the distortion characteristics of tubes over transistors for electric guitar, bass, and other instrument amplifiers. In this case, generating deliberate (and sometimes considerable, in the case of electric guitars) audible distortion or overdrive is usually the goal. The term can also be used to describe the sound created by specially-designed transistor amplifiers or digital modeling devices that try to closely emulate the characteristics of the tube sound.

The tube sound is often subjectively described as having a "warmth" and "richness", but the source of this is by no means agreed on. It may be due to the non-linear clipping that occurs with tube amps, or due to the higher levels of second-order harmonic distortion, common in single-ended designs resulting from the characteristics of the tube interacting with the inductance of the output transformer.

Tubes impart "warmth" to a signal, which means even though the amp may not be distorting to the human ear, it may in fact have lots of distortion. It is a gradual thing with tubes. With SS devices it is either/or. Clean or lots of audible distortion.



Of course when the tube amp can be turned up and the power tube can amplify the signal but causes the signal to degrade - well that's where the tube sweet sounds come into play. I'm just not seeing any sweet tube tones from a tube amp with a pedal in front of it at low volumes.

Am I right in my thinking here?

Not necessarily. A tube amp can be used to warm up a pedal with good results. The VJ is not a hifi amp in that it does not accurately reproduce the incoming signal. There is interaction between the guitar/pickups, preamp, power amp, output transformer and any dirt pedals plugged in.

Personally, I don't like the sound of a cranked, stock VJ. It doesn't have gobs of OD, which is a limitation of the circuit. It does have gobs of distortion, it is just that the distortion that the stock circuit produces is not pleasing, to me at least.

One common use for a dirt pedal is to use it as a clean boost, that is, gain down, volume up and tone to taste. This produces a strong, clean signal that overloads the preamp, which in turn overloads the power amp. This does, however, produce lots of volume, which is the down side.

Personally, I use dirt pedals into a stock VJ as my main amp. The VJ is set relatively clean and I use the dirt pedals to generate distortion/OD. It works well for me.

[Eric]

My experience has been that with tube amps, there's a roundness to the clean tones that is not always there with solid-state amps. So it's not just the power-tube distortion that is noticeable with a tube amp IMO.

My impression is that this is due to the low-level distortion that Tung mentioned, where mild tube distortion still sounds like a clean tone in a tube amp.

It could just be that it's reverb, EQ, compression, sustain, or something else that's imparting the different tone and feel to cleans in a tube amp, but my point is that it does sound different to me. So a clean tube amp + pedal(s) is still different than clean SS amp + pedal(s).

Of course, this is all contingent on how you use the pedal. If you're going to eliminate all trace of guitar characteristics and inherent amp tone via something like a Boss Metal Zone, then I would say it doesn't matter which amp you use.

[progrmr]

I've been checking out some youtube videos of some different types of pedals that might work well - I've read that the Ibanez Tube Screamer is good for basically boosting the signal, rather than distorting it.

This looks pretty cool:

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I do have a Boss Blues Driver - I will try taking the gain all the way down and the level all the way up and see how that works.

I'm starting to love tinkering with amps more than guitars :)

[tunghaichuan]

I do have a Boss Blues Driver - I will try taking the gain all the way down and the level all the way up and see how that works.

FWIW, I think the BD works best this way. I never liked the BD as an overdrive pedal. It sounds kinda fizzy with the gain up.

[deeaa]

A Tubescreamer and similar pedals is NOT a good booster pedal - they have a very distinct, midrangey 'hairy' tone that is unique to them and you either like it or not.

I used to like it lots, used one for a decade (original Ibanez) but I grew tired of that tone to the bone, and have gone for much less buzzy OD tones since. I dunno, I kind of developed an allergy to that typical TS type underlying buzz drive I just can't dig it no more.

As for the OT...well, I've always liked a combination of SS and tubes. 100% tube seldom sounds good to me, it's just too flabby, organic, messy or generally too 'tubey' but I do love an all-tube amp driven with active pickups and/or boosters and some crunchy drive (not TS type).

It's all about finding the best balance to me. I don't go for much OD at all, but still I sound quite driven anyway...and when I play some real high-gain amps, it's just buzz to me. The more tubey amp you have the more SS pedals/stuff you want in front to keep it tight, and conversely with all-SS amps you'll want passive pickups and organic-sounding pedals etc...but, this whole subject is insanely personal/matter of taste and such a delicate balance in each case, there really are no rules. Some of the best drive tones I've gotten from strictly SS gear or even computer plugins, so anything goes by me as long as it sounds good.

But, gimme a nice british-voiced tube amp, preferably EL84 so it's not insanely loud, and a nice, flexible OD pedal and/or active pickup guitar and I know I can get it to sound just as I like.

I wonder how much did I digress here...

[FrankenFretter]

If you're looking for a good clean boost, I'd try a Boosta Grande. Made by BBE, it's a great pedal and I found mine new on Ebay for about half of what they retail for.

[progrmr]

FWIW, I think the BD works best this way. I never liked the BD as an overdrive pedal. It sounds kinda fizzy with the gain up.

Well I just gave this a try - not very impressed. I think I should've never cranked the volume on a tube amp...it has ruined all other tones for me!

[progrmr]

I got the Valve Jr. today - only had a few minutes to try it out but it really sounds great. It doesn't start to break up good until about 12 o'clock on the volume knob though which is pretty loud. I ran the boss blues driver in front of it at a lower volume and strangely it sounded very good! It was warmer than I'd figured it would be.

Need to spend some more time w/ it but so far I'm very impressed with this little amp. Needs a 2X12 to bump up the headroom - at max volume it sounds pretty boxy.

[Brian Krashpad]

I got the Valve Jr. today - only had a few minutes to try it out but it really sounds great. It doesn't start to break up good until about 12 o'clock on the volume knob though which is pretty loud. I ran the boss blues driver in front of it at a lower volume and strangely it sounded very good! It was warmer than I'd figured it would be.

Need to spend some more time w/ it but so far I'm very impressed with this little amp. Needs a 2X12 to bump up the headroom - at max volume it sounds pretty boxy.

Congrats!

Fwiw, I used to use various OD/distortion pedals all the time with my '66 Super Reverb. Would've gone deaf otherwise. The sound of a pedal in front of a tube amp isn't exactly like a master-volume tube amp with the gain dimed and no pedal, but can still be a great sound with some tweaking to the amp and pedal controls. Or at least the Super sounded great with pedals anyhow.

Plus, if you carefully dial in the sound, a pedal in front of a tube amph (see Super on the right below) can make you magically levitate:

http://img.photobucket.com/albums/v26/BrianKrashpad/redcrossSDBKair.jpg

Who says white men can't jump?

[deeaa]

I quite liked my Valve Jr. with the Marshall JMP-1 in front of it as a preamp.

Here I'm playing it with an my mod-strat, but it's still quite bluesy enough if need be. The VJr breakup is pretty nice; I did however do a few mods to it, the most important the one that brightened up the input some, and also boosted it a little.

kgxN-NbouuA

[deeaa]

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Then I swapped to an active (EMG85) Jackson and the sound only improves greatly, and I needed much less effects to make it sound good. On this I also explain the mods I made.

But this vid also BTW maybe explains why I like them active EMG's so much with tube amps - the strat with a Seymour JB sounds way flabbier and less coherent but still less warm than the floyd-equipped super-thin necked Jackson does even without much anything in front. Since the VJr tests and that Jackson I've pretty much only used EMG85s.