Incredible Guitar Tube Drives

[finnbio]

Power amps are not meant to distort, that's just plain fact. Any audiophile or tech will tell you that. 6l6's and El84's are power tubes, their primary function is clean power, nothing else. That's why power amps in 99% of preamp/power amp combos (imo opinion the two need to be seperate) have absolutely no controls on them. All your tone is created in the pre-amp and the power amp only has one purpose, to amplify that tone.

Hink,

Unfortunately, I think you are confusing HiFi Tube amps with guitar tube amps. Completely different story.... HiFi power amps are not meant to distort, but guitar power amps are supposed to saturate. Initially, of course, this was a fluke - an imperfection of design, that is now exploited in rock music. Boutique amp manufacturers like THD have had great success with amps like the univalve, which alloes you to switch power amp tubes to get different saturation characteristics. That would not make any sense AT ALL if the power amp tubes didn't color the sound as you claim. Also the current 18W amp craze is based on the principle that the best sound is achieved when the power amp stage is driven hard.

Also, all the better amp sim plugins (Amplitube, Revalver, Trash) allow you to adjust for power amp saturation to emulate the interplay between pre amp and power amp distortion

What you are writing goes againstn anything you can read in guitar magazines - who knows, maybe it's all just a ploy to make us fry our 6L6s...

These stomp boxes have got to be the ugliest pieces of equipment I've seen in a long time. And the placement of the tubes is like begging for somebody to wrench them off with a hearty kick.

Jeez, who are these designed for? Retro Glam rockers and Kiss cover bands???

Alex

[dimitar]

But chips, unlike tubes, act differently in the overdrive phase and even the famous tube-emulating schemes on chips does not produce the same effect in the overdrive phase as does a simple tube limiter. The difference can be easily noticed not only aurally. The signal obtained can be broken down to its constituent parts and the difference between a tube limiter and the transistor or the chip can be visually observed. Tube limiting amplifiers produce both even and odd harmonics depending on the degree of overdrive, enriching the guitar sound at the low level of limiting.

full story here
http://www.udaloff.com/english_avtorhistory.php
Very interesting...

[rogerperrin]

Okay, okay, okay, Guys. Let me, a real pro, sort all of this tube stuff out for you once and for all. Enough of this bickering. Actually I'd just like to throw in my 2 cents, which may or may not be of value. First, I can see some validity in all arguments presented here, vis-a-vis the fact that there are many "tube sounds," created by various means. Secondly, there seems to be some confusion between a "power amp" and the "power stage" of a guitar amp. Power Amps are disigned to amplify with transparency, and minimal compressive-distortion. Guitar amps are not simple. Originally, back a half century or so ago, guitar amps had only one stage. The notion of a preamp didn't exist. The amps only put out 5 to 10 watts, and to be heard, guitarists would crank higher, and as they did, they noticed that the tonal characteristics changed. Partly the power tubes did the MAGIC and also the audio output transformer did some magic, as well as the older speakers styles. Some folks claim that the rectifier tubes of the power supply had an effect, also.
One year I was injured and out of work, and I bought and sold tube guitar amps as a sideline business. Man, you could find a lot of really old, cool amps back then, just sitting around the pawnshops. So I got to play, repair, and sell about 20 different amps: Gibson, Supro, Marshall, Alamo, Fender Bassman, etc. For great guitar tone the Supro ruled. The Bassman came in last place. Great for bass, just too freakin clean for any tone at all. The small Supro, single power tube (no double push-pull tube setup) was the sweetest and the most versatile. From warm clean to compressed to Clapton, you could do a lot with that tiny little amp.
IMHO, for tone it is the small single stage amps that rule - no channel volume, just the one main volume control. The power tubes are capable of the best magic, to my ear - veeery sweet, gentle compression overdrive. The 12A... whatever tubes will give lots of distortion, depending on the circuitry, but more of a clipped style of disto, than the power tubes.
By the way there are 12AX7, 12AT7, and 12AU7 tubes. They are interchangeable in any circuit without harming the device. 12AX7 has the highest gain/distortion. 12AT7 is the middle, and 12AU7 has the least gain/disto. The volume decreases also. So turn down your 12AX7's and you will find the 12AU7 sound.
I got broke and sold all of my amps. Now I play through a Marshall bluesbreaker, into a Zoom503, into my home stereo, and I do almost anything.
Pods are awesome also.

[herodotus]

My God!!!

Guitarists and THEIR FREAKING "TONE".

"Be quiet, something is wrong with MY TONE"

"MY TONE! MY TONE! MY PRECIOUS TONE!"






Just kidding.

Great post RogerPerrin.

We used a Supro when I was recording a demo a few years ago. The most amazing 15 watts I have ever met.

Is it not strange that this thread about tube amplification should pop up on a plugin site?

[Hink]

Power amps are not meant to distort, that's just plain fact. Any audiophile or tech will tell you that. 6l6's and El84's are power tubes, their primary function is clean power, nothing else. That's why power amps in 99% of preamp/power amp combos (imo opinion the two need to be seperate) have absolutely no controls on them. All your tone is created in the pre-amp and the power amp only has one purpose, to amplify that tone.

Hink,

Unfortunately, I think you are confusing HiFi Tube amps with guitar tube amps. Completely different story.... HiFi power amps are not meant to distort, but guitar power amps are supposed to saturate. Initially, of course, this was a fluke - an imperfection of design, that is now exploited in rock music. Boutique amp manufacturers like THD have had great success with amps like the univalve, which alloes you to switch power amp tubes to get different saturation characteristics. That would not make any sense AT ALL if the power amp tubes didn't color the sound as you claim. Also the current 18W amp craze is based on the principle that the best sound is achieved when the power amp stage is driven hard.

Also, all the better amp sim plugins (Amplitube, Revalver, Trash) allow you to adjust for power amp saturation to emulate the interplay between pre amp and power amp distortion

What you are writing goes againstn anything you can read in guitar magazines - who knows, maybe it's all just a ploy to make us fry our 6L6s...

These stomp boxes have got to be the ugliest pieces of equipment I've seen in a long time. And the placement of the tubes is like begging for somebody to wrench them off with a hearty kick.

Jeez, who are these designed for? Retro Glam rockers and Kiss cover bands???

Alex

saturation and distortion are two different things. A power amp in any system is not imo suppose to color, distort. The concept of of a master volume was to cure that problem...that is precisely why you have master volume knobs. I assume many of you have never owned a plexi without a master. There is gonna be distortion with any stage to an extent. But many guitarits myself included bailed out on tube poweramps because they are inconsistant ( my boogie needed it's own circut) Power tubes take an amazing amount of power to run as opposed to pre-amp tubes. As a result of being high voltage they are by nature microphonic. Like backlash in machine heads it's a physical law. Any variation in power even the one volt drops will cause highend signals to get muddy ( the transformer mutiplies the voltage to run the power tubes one volt mutiplied can get probmatic)...again a fact of power tubes which are nothing like pre-amp tubes in any way. The pre-amp tubes are meant to deliver and shape the signal and the power amp is meant to boost it...common sense.

That's why on the back of my pre-amp is a switch for three output levels SO YOU DO NOT OVERDRIVE THE POWER AMP..those three choices are +4,-10 and -20 db. Do you want to take a guess why there is only a slight boost of of 4 db but two negatives of 10 amd 20 (which the difference between them if you understand the scale is friggan huge)? The answer is simple and common sense, IT IS VERY BAD TO OVERDRIVE POWER TUBES.( you hinted what I was aying was bad for your tubes and what you are saying truly is) Power amps are just a stage in an amp that boosts, on most pre/power combos you have absolutely no control over the power amp because a tube pwoer amp is a basic circut and yes they saturate from microphonic tubes. To clear that up cause I picture someone talking to their tubes, that does not mean it's a microphone it means it picks up some of the sound and reprsocesses it, that's what gives tube power amps their good sound...

Comparing a real amp to software and generic terms they use is not very accurate...

Now remember I started this saying the good sound of tube distortion is derived in the pre-amp and by that I mean the majority...go find any credable link, article or what have that says different please....and if you're ever in this area please stop by and plug in to my hybrid, in you want to feel some kick. Hybrid amps are very common though there are not as many hybrids that are solidstate pres and tube power amps...that's because the vast majority of the tube sound is in the pre-amp

[Hink]

But chips, unlike tubes, act differently in the overdrive phase and even the famous tube-emulating schemes on chips does not produce the same effect in the overdrive phase as does a simple tube limiter. The difference can be easily noticed not only aurally. The signal obtained can be broken down to its constituent parts and the difference between a tube limiter and the transistor or the chip can be visually observed. Tube limiting amplifiers produce both even and odd harmonics depending on the degree of overdrive, enriching the guitar sound at the low level of limiting.

full story here
http://www.udaloff.com/english_avtorhistory.php
Very interesting...

again you are mixing up what I am saying, a power tube and a 12ax7 in a compressor is not an equal comparison. They are two totally different things, I'm talking strictly power tubes...high voltage, not low votage like 12ax7's...other then that you're completely right and actually saying exactly what I have been saying...

[Hink]

Boutique amp manufacturers like THD have had great success with amps like the univalve, which alloes you to switch power amp tubes to get different saturation characteristics.

Boutique amps are known for class A tubes...that is the same thing with hi-fi amps...

[IIRs]

A power amp in any system is not imo suppose to color, distort.

In a PA system, or a hi-fi I would agree. not in my guitar amp though! Just like the speakers.. I wouldn't try to mix a track through a pair of greenbacks, but my guitar doesn't dound right without them!

I'm still on the original valves in my Boogie btw: I've had it over 8 yrs and played literally hundreds of gigs.. the only time the power consumption was a problem was at the Northern Green Gathering when our tent's PA was powered by the sun and a pair of exercise bycicles.

[Sascha Franck]

hink, sorry, but you're just talking utter nonsense.

IF power tubes (in guitar amps, mind you) WEREN'T there to color the sound in *whatever* way, why would almost every guitarist in the world still lust for full tube heads instead of going the drastically more affordable way of using solid state amps?

Some kind of "glowing tube magic"? All based on hallucinations?
Sorry, NO f**king WAY!

Tube power amps in guitar amplifiers ARE coloring the tone, and that's what you buy them for.
Just run the same setup (preamps and speakers) through different PAs (been there, done that). If you don't experience a more or less drastic difference, go check your ears (fwiw, I am by no means a Mr. Golden Ear at all).

Regarding the master volume stuff: That was made for convenience reasons. With a master volume you could drive the preamp stage harder while keeping the level moderate.
Still, why would people still use amps without master volumes in a recording situation? Yeah, right on, because they WANT that straight path including a hard driven PA (just as Roger described).

Also, why do almost all better tube powered amp have various switches to change the power amp behaviour (low power, tweed power, whatever it's called).
Right again - because you WANT the PA color at "affordable" levels.

Of course, the "main" part of the sound usually is shaped in the preamp section. Nobody would argue about that.

But whatever you may say, there's a (sometimes drastic) difference between running something through a solid state or tube PA.

Power amps are just a stage in an amp that boosts, on most pre/power combos you have absolutely no control over the power amp because a tube pwoer amp is a basic circut and yes they saturate from microphonic tubes.

That pretty much would be a nice runner up in a "greatest technical bullshit ever post contest".

As said above, most tube power amps these days have additional controls to determine their basic behaviour (ever heard of "presence"?).
Also, the volume control IMO is quite a mighty thing... and while you may start laughing, it's nothing else but the gain control in your preamp. Turn it up and the sound starts to distort/overdrive - just that there's no further control to tame the output level, this being the VERY reason people are using "load boxes" or "dead boxes" (acoustically isolated speaker enclosures).

Now, on to the "and yes they saturate from microphonic tubes" bullshit.

In a studio situation, you often have your amp in the control room with the speaker enclosure left alone in the recording booth.
Now, one would often listen/track at very low levels, but the amp would still be cranked up.
Why in the world would there happen to be ANY saturation in such a setup, following your funny assumption? There defenitely IS some saturation going on - magic again, uh?

Why in the world would almost everybody have their PA tubes exchanged once they are getting too microphonic? I mean, following your brilliant theory, that would just be what people want.
Still, I'm spending a fortune on new tubes each year whenever they are burning out, thus getting microphonic.

More on microphonic tubes: I can pretty much stomp around on the same stage element my Boogie or Fender is sitting on, tons of vibration - still, there's no stomping sound coming outta my rig though (unless the tubes are worn out).
How would that suit your theory?

Apart from all that, in a power amp scenario saturation and distortion are pretty much the same - or let's say, distortion is a result of the tubes being saturated.
Same goes for tape saturation. Turn up the level too much and you'll get distortion.


Seriously hink, I don't have anything against you, more like the opposite, as I liked some of your posts in the past, but you should stop spreading such an immense bullshit nevertheless.

[Hink]

when you show me your degree in electronics than you can attack my position. To clairify the vast majority of the desired tube distortion is derived from the pre-amp stage. Yes any power amp of any type will add it's own color. However it is not advised to push power tubes (but go ahead if you want) to the point of overdrive. It is much better (imo) to run a consistant power amp and tubes are extremely inconsistant. That is why Marshall came out with hybrids But remember the one that was a solid state pre and a tube power amp (I forget the model, it was a head 30-35 watts)..it was to date probably the biggest flop in the history of Marshall...why do you suppose that is?

I will say that when you said your power tubes were not microphonic I kinda dismissed everything you said after that because that's not true. It may not be noticable but it is there. I don't think you really understand tubes and their attributes.

I was raised with shoved in my face as my father was an eltro-mechanical engineer (he was one of the first engineers for Raytheon) and a ham radio buff. As I said we refurbished an old ham radio amp (it was about 35 watts) for my first amp when I was twelve. Not a single thing I said was bull, sorry pure facts a power amp in say a marshall head has absolutely no control on it...you're at it's mercy.

For me I want the same control over my sound at 1000 watts (if I ever needed it) that I have at 10 watts.

BTW Sascha I think you're a good guy too,(you're the only other person I know who wires a five way like me) I certainly do not want any hard feelings. I would never presume to tell you to change your sound, I like my sound and it does work for me as I'm sure yours does for you. But I will say that I spent 25 years plus as a diehard tube fan, never anything else. When I got my Marshall tube pre I got that monster Marshall tube power amp (it cost a fortune) and I didn't like it, in fact plugged into my CS400 it was much better when cranked. Against all my nature (I am known to hate Peavy with the exception of pa gear) I chose a Peavy solid state over a marshall tube power amp. It really was against all I believed and now I am not sorry (except for the damn hernia ). The funny thing is there was a guy just like me when I was a stead fast tube fanatic and he said trust me you'll go solid state oneday...I guess if I ever see him I'll be eating some crow...

[Hink]

Also, why do almost all better tube powered amp have various switches to change the power amp behaviour (low power, tweed power, whatever it's called).

and why do you suppose your Boogie has slave outs? Face it hybrids are popular for a reason (I know they it's for recording too but,,,)

FWIW my Marshall pre sucks for recording, it has a cab simulation switch but the Sansamp GT2 is better.

[C00kie]

Here, my fellow observers, you can see a perfect example of the two different "schools" in guitar amplification.

Hink ( ) uses a super neutral power amp. For him it would not matter weather the final stage were valve or solid state. His pre-amp (and accompanying devices) does all the real work, and could as well be plugged directly into the mixing console (or soundcard.)

Platinumears ( ) on the other hand allows the final stage of his valve amp and speaker cabinet to contribute to the sound.

Both of them are very happy with "their" sound.

If you ask me, I've done it both ways. Now I'm only happy if I can crank up the final stage of my Orange OD-120. When it goes above a certain level the EL34 power stage adds something that can't be done using only gain on the pe-amp valves.

So the stomp box Dimitar found could be nice, but just like my Tech-21 Tri-OD it is no replacement for the real thing. (but comes rather close nevertheless)

[Hink]

If you ask me, I've done it both ways. Now I'm only happy if I can crank up the final stage of my Orange OD-120. When it goes above a certain level the EL34 power stage adds something that can't be done using only gain on the pe-amp valves.

the only problem with that is that you have no absolute way of being assured it's the power tubes creating the desired tone, it's likely it is. But that was not my original arguement, that refers to tone. It did get sidetracked, my original arguement is that the desired tube like like distortion is produced by the 12ax7's not the EL34's. Of course they have their own character and that is a very subjective thing. But the end result is that you overdrive pre-amp tubes for distortion, not power tubes....

[C00kie]

Overdriven 12AX7's are nice, we agree on that.
Overdriven EL34's are even nicer. Its like magic indeed. You have to hear it I think...

I know it comes from the power stage, but to be honoust I really could not care less if it turned out it came from the 1A fuse instead. As long as it does that job. And I know I have to turn up the volume to get that, I accept that.

Just remember, we don't have to agree on everything. Both ways work, both can be very pleasing.

[Hink]

Overdriven 12AX7's are nice, we agree on that.
Overdriven EL34's are even nicer. Its like magic indeed. You have to hear it I think...

trust me between the amps I have had and being in retail I have played through just about any tube amp made (even an Oliver) I don't disagree with you on sound but I do on terms. On your orange you have no way to overdrive the power section anyhow. Afterall the pre-amp out to power amp in is usually buffered (same reason for the three out choices on my pre-amp)

I think overdriving power tubes is overstating what you are doimg...but I define overdrive as running a hotter signal before the tubes to excite them and push them "over" their maximum specifications. Where as what you are describing I suppose could be called overdrive but not by me. When you push your amp to 10 you're driving the tubes at their maximum, too me there's no "over" to it...