• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

what are the pros and cons of valve amps?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
A properly designed ad built tube amp does not need biasing adjustment but once in a blue moon.

look at all the amps (Guitar and stereo) that have withstood 50 years or more and are still operating.

Fixed bias amps need more attention than cathode bias amps. fact.

How many of you have blown a tube? Other than abusing them?

I've beat the crap out of tubes where transistors would have been a whimpering slag pile and the tubes continues operating within their design specification.

How many transistors will recover from 200% power dissipation for 30 seconds?

Why should hum creep in? Unless the al Electrolytics are drying out? That is not the tubes fault.

It is semiconductors that are fragile, not tubes.
 
Last edited:
I understand it's all a matter of taste, so all I can do is speak for myself. After purchasing a pretty good high-end ss system, after several years I found that I was listening less and less. For me, a relatively inexpensive EL-34 push-pull tube amp brought back the magic. Less harsh, not fatiguing. Since then, I've gone to hell in a handbasket, less and less power, more and more pleasure. Douglas Self would spit on me, but I don't care!

"Douglas Self would spit on me..."

Oh, he's already done that (figuratively, not literally) to me over in the SS forum. I've done both: hollow state and solid state. Regarding the latter, I have my own ideas of how it should be done, and needless to say, my ways aren't Doug's. In the end, it's the sound that truly counts.

There is no reason SS has to sound as hideous as it all too often does. I've done SS designs that sound a helluvalot better than any Big Box system I've ever heard. Yeah, a low bar indeed. It's simply amazing what you don't hear on a BB system: whole passages simply fade into the same, bland background, even if you know they're there and listening for them.

I've also gotten quite close as well, but hollow state simply sounds better, even if it's by a slender margin. I have no idea as to why that is, but that's definitely what I hear. Maybe it has to do with more linear devices not requiring so much gNFB correction, or that SS designs, since they don't have OPTs, can utilize gobs of NFB. It would seem that when it comes to NFB, there's a gray area (~ 13dbv ) where that much ruins the sound quality, but way more improves it again. One design I did included variable gNFB, and right around 6dbv seems like the right amount: enough to take the "edge" off, but not quite so much as to deaden the sound.
 
I've heard a SIT amp (solid state devices with more tube-like characteristics) which is every bit as good as any tube amp we could put alongside it - 300b SETs and so on. I don't know why SIT devices didn't stay in production - they sound great. I haven't heard Nelson Pass's version, just the original Sony device. It runs single ended on a massive heatsink, but once it's built you can just use it and forget about it - no maintenance.

For a total system, a good solid state amp with planar speakers is also hard to equal, particularly something like Apogee full-range ribbons but including Maggies, electrostatics and all the rest of them.

Otherwise, for lower volumes in a smaller room I'm very happy with my PSE all-4P1L amp. The 4P1Ls are cheap DHTs and I have 150 of them. I can use my amp forever - I don't even bother turning it off. Sounds great - very clean and detailed and superb voices.

One day I'll build my SIT amp - I have the parts. But I don't need to.
 
PKGum, If you are still the OP after all these years,

I have only noticed this after the long >10 year interval. I have been designing audio amplifiers since the tube era, then with semiconductors

.....and I cannot really think of a reason why one topology should inherently be aurally better than the other! The reason is that one cannot compare tubes with transistors per se without bringing the design into the picture. Any difference - and there quite often is, not denying that - is far more dependant on the circuit design than whether tubes or transistors are used. (Within limits of course; comparing a 400W instrument of one vs. the other is a different affair.)

I haven't read all the preceding posts, but very generally it is easier to design a flawless tube audio amplifier than a transistor one, despite views to the opposite. But there are many commercial examples of both with audio influences which has little to do with whether tubes or transistors have been used.

My contribution would mainly centre round cost. A tube amplifier is going to cost you an order more than an equivalent transistor one. Other differences like bandwidth, feedback, "speed" and the other clichés are secondary if relevant at all.

With respect to members, feedback within limits can only deteriorate music when applied to a mediocre design to begin with. And regarding concepts like depth, warmth, soundstage, etc., there is no contribution that any half-decent amplifier can make. If an amplifier is so dramarically misconceived that it can present several 10mS delay at some audio frequencies and not at others.... otherwise the mentioned effects have entirely to do with the original recording, loudspeakers and room effects.

Let me stop there. As said by others a number of minor factors exist about which one can go on for 10 screensful; one needs to focus on what is inherent to your question and what has little if anything to do with tubes/transistors per se.
 
Last edited:
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.