Tubes Or Solid State, A Perspective

[BassmanPaul]

What I fail to understand is why this subject brings forth such virulence from both sides. If you enjoy what a tube amp does for you then no one has right to gainsay you. The same applies to SS amps. It's a personal choice.

As regards reliability, a properly designed tube amp will last as long as a properly designed SS one. I feel that tubes get an unfair reputation partly because many of them are designed to give the most power with the smallest tube count possible. Running anything at its limits does not help its longevity.

For the first part of my career I used tube amps. There were not other choices. Some of them were my own designs, the earlier ones commercial. When SS amps started appearing they were very unreliable and spotty at best. Like all things they improved as we learned more and better devices were developed. In todays world I use SS amps but I do like to have a tube in the signal chain somewhere. Not because it makes that much of a difference but I still like tubes. The amps I build are full tube, except for rectification, guitar amps.

Edit: I do own a "big" tube amp a Hiwatt 200W beast from 1973 but I would never dream of taking it on a gig. Just too darn heavy. I also have a B15N.

 

[BassmanAd]

At the risk of pouring fuel on the fire, please can someone explain to me in very simple terms what a diode is, the role it plays in the amp and what difference it makes to the sound?

Thanks peoples.

 

[aborgman]

Are we counting tubes aging and dying as the amp breaking? If people are answering that question differently that may be the cause of the disagreement.

If we're counting tube replacement as the regular cost of doing business then it could go either way.

If tube dying of old age = amp breaking, then the laws of physics are firmly behind the "SS amps are more reliable than equally well built tube amps" POV.

Yes, I'm counting necessary tube replacements as "repair" as I would do for replacing transistors.

 

[JimmyM]

You're talking right now to an electrical engineer, whose current job title is "Electronics Technician Senior" for a major research university Aerospace Engineering program... and I'm telling you that under normal, by the book, usage SS amps are GENERALLY more reliable.

well that's good anecdotal info

 

[seamonkey]

Fact is a diode does not make a tube amp any less tube. Almost
every tube bass amplifier ever made has diodes in the power supply. I can only think of one or two I have ever seen that had actual tube rectification going on. Horrors!
As far as the SVT and its diodes, big deal. A diode is a passive device. It serves one of two functions, either its used for it's directionality (allowing current to only flow in one direction) or for the break over characteristic.
It does not amplify the signal, it just modifies it, same as an inductor/capacitor circuit modifies the tone. Diodes date back to the tube era and predate the transistor by about 5 decades.
Preamp tubes are still preamping, Power amp tubes are still poweramping.
But hey, if it makes you feel good to try and rain on the tube-o-philes parade, more power to ya.
pun intended.

I don't care about power supply rectifiers.

So for this and BassmanAd
When a diode is in the signal path, and the signal voltage approaches the break-over voltage, then the diode will begin to conduct and cause soft clipping.

Link Removed

Marshall added them also.
Diode clipper in a tube amp, what do you think of it?

You can use tubes as diode clippers also. And some all Tube Path purist would think there's a differences between SS and Tube in this case.

 

[Phalex]

At the risk of pouring fuel on the fire, please can someone explain to me in very simple terms what a diode is, the role it plays in the amp and what difference it makes to the sound?

Thanks peoples.

It's a tiny wad of sand, melted down with a doping agent (Germanium is nice and boutiquey) with a wire coming out either end.

It only conducts in one direction, and it takes a bit better than a half a volt (in the proper polarity) to get one to conduct at all.

 

[BassmanAd]

OK, so the diode is there to push the amp into clipping (which we hear as overdrive I guess) to prevent too hot a signal from doing bad things further down the signal chain. I guess in that case if a tube can be used as a diode then to a real purist then it's not 100% tube. More like 99%. But given the number of tubes to be found in an SVT CL or VR, it almost seems like splitting hairs. Thanks for the links, they made it a bit clearer.

I think it goes back to using your ears and seeing what sounds good to you. I absolutely love the SVT sound and would take it over anything given the cash to buy one and the back to carry one but that's not an option right now. My 3pro is a nice compromise, as close to the sound as I've heard so I'll stick to that for now.

I have learned something today!

 

[metron]

I don't care about power supply rectifiers.

So for this and BassmanAd
When a diode is in the signal path, and the signal voltage approaches the break-over voltage, then the diode will begin to conduct and cause soft clipping.

Link Removed

Marshall added them also.
Diode clipper in a tube amp, what do you think of it?

You can use tubes as diode clippers also. And some all Tube Path purist would think there's a differences between SS and Tube in this case.

This is wacky. So you are trying to say that the use of diodes violates the idea of an all tube amp? There is no question that an Ampeg SVT is an all tube amp. Diodes or not. You are subtly mixing the idea of diodes as used for overcurrent protection and for signal clipping such as used in distortion pedals. All signs and expert input point to the diodes in the SVT are not part of a distortion circuit. There is no conspiracy happening here.

"All tube" amps universally are referring to the devices used in gain stages. The things that amplify. Diodes do not amplify.

 

[seamonkey]

"All Tube" is signal path. i.e. power supplies don't count, but putting them in the signal path is different.

No expert has yet to say the diodes here don't clip. And from the thread above, other tube amp users have found that adding diodes does change the sound. Marshall too.

Maybe % wise there very little SS in the signal path, but it still can be contributing a larger % to the output sound.

What's it going to hurt for someone to measure them?
I'll wait for the measurements.

 

[RickenBoogie]

Well, if that were the case, I doubt there are ANY ALL TUBE AMPS then.

 

[seamonkey]

Well, if that were the case, I doubt there are ANY ALL TUBE AMPS then.

There are plenty

Caps and resistors don't count.
Anything Solid-State does, Passive or active, contributing to the signal.

 

[metron]

Dude thats a non sequitur. By your definition there is no all tube amp. Your bass signal is influenced by lots of things that are not tubes in all amps. I believe the only meaningful definition of all tube is referring to what is amplifying or providing gain. Its not logical to say that that a clamping diode that turns on when an amp is pegging in the red zone is providing "tone". The inductor in the mid circuit is far more influential on the amps sound but its presence doesnt mean an svt isnt all tube.

With all due respect it seems that you want to stir some pot yet keep your head in the sand.

 

[UncleFluffy]

Its not logical to say that that a clamping diode that turns on when an amp is pegging in the red zone is providing "tone".

Correct, but that not what he's saying - seamonkey's claim is that the diodes are on during normal operation, not just under overload conditions. There's been a lot of opinions posted one way or another but 0 solid data.

To bend a car analogy into shape, it's like a bunch of people arguing about how many cylinders some type of car has. Some of these people have driven this kind of car and have made a guess based on the noise it makes, some haven't even done that. Not one of them has lifted the hood and taken a look.

 

[paganjack]

1) I like the way tube amps respond to my playing. They feel...bouncier, for lack of a better term. More dynamics come through and it just sounds sweeter.
2) I prefer the way tube amps take distortion. Or, on the off chance that I need to destroy some eardrums, how they sound when completely dimed.
3) I am a young strong man so I don't mind carrying my heavy-as-balls rackmounted 400+ around. I will be very sad if/when I get to that age where I cannot haul my own delicious-sounding gear around. Honestly, I kinda LIKE lifting heavy stuff. It gets the ol' blood pumping before getting on stage.
4) I have played through SS amps before and liked them for a while, but I'm just never as happy playing through them!

If you disagree and/or feel that SS is the only way, then don't let me stop you. So much of perception is entirely subjective and influenced by preconceived notions it's kind of a foolish thing to try and argue about it.

 

[metron]

Oh my bad. I thought the guy who built his svt stated in another thread that they are clamping diodes that dont kick in until the power section is at full output.

Internet forums...

Correct, but that not what he's saying - seamonkey's claim is that the diodes are on during normal operation, not just under overload conditions. There's been a lot of opinions posted one way or another but 0 solid data.

To bend a car analogy into shape, it's like a bunch of people arguing about how many cylinders some type of car has. Some of these people have driven this kind of car and have made a guess based on the noise it makes, some haven't even done that. Not one of them has lifted the hood and taken a look.

 

[UncleFluffy]

Oh my bad. I thought the guy who built his svt stated in another thread that they are clamping diodes that dont kick in until the power section is at full output.

Internet forums...

Yeah, that's certainly persuasive, but not conclusive. There's no guarantee that it's operating the same as a factory SVT. ("This car looks and sounds like that one. This car has four cylinders. Therefore that car has four cylinders."). Maybe it is, maybe it isn't.

Like I said earlier, if no-one else takes a look at theirs in the next six weeks I'll go grab mine from the rehearsal studio and open it up, find out, and post photos of what I find. Until then, things seem to have got awfully heated about something pretty trivial.

 

[John D]

... and I'm telling you that under normal, by the book, usage SS amps are GENERALLY more reliable...

... the average SS piece will outlast the average tube piece...

How in the world can one argue with this level of specificity?
How about using some of these little thingies so we can tell what you really mean.

Seriously, a little data would go a long way toward proving your point.

 

[GrowlerBox]

I've been trying to ascertain how many circles have been gone 'round in this thread, but I've lost count. I continue to read lots of unsubstantiated stuff from seamonkey, claims which he continues to make despite the absence of measurements which he continues, somewhat perversely, to demand. I still haven't heard anything concerning why he cares so much about which amplifiers other people use.

 

[Chef]

Moderator Insert:
If y'all can't make your points respectfully and politely, then this thread is done.
I'm getting tired of being called in here every day to clean up insults and rudeness.

There is no point that can't be made politely.
There is no need to resort to name-calling and bickering.

Behave, or it's closed

 

[seamonkey]

I've been trying to ascertain how many circles have been gone 'round in this thread, but I've lost count. I continue to read lots of unsubstantiated stuff from seamonkey, claims which he continues to make despite the absence of measurements which he continues, somewhat perversely, to demand. I still haven't heard anything concerning why he cares so much about which amplifiers other people use.

See post 67
And UncleFluffy's replies above.
And a big thanks to UncleFluffy for volunteering to measure.