bipolar (bjt) transistor families for audio power output stages

[tiefbassuebertr]

Originally Posted by [B

Originally Posted by Piercarlo post # 575[/B]
Have you elaborate some hypothesis of what mav be the cause of this state of things? In many years I have reasoned on many clues of that it should be, everything containing a bit of truth but nothing holding the entire truth. Surely it's not impossible build solid state amplifiers that sound very closely as tube sound but as much surely the path for achieving this is not written in stone somewhere. My only certainty about this is that a sound "tube sounding" may really obtained only by carefully designed amplifiers, no matter if equipped with tubes or with solid state devices. In other word only state-of-the-art design may lead to appreciate the true character of a kind of amplifier (and its limit of course).
I'm interested in knowing your thoughts about this theme.
Originally Posted by wahab post # 576
indeed, a solid state amp must be very "carefully" designed
to produce as much distorsion as a tube amp...
it s the only way to sound "tube" like, doesn it?..
Originally Posted byTelstar post #597]
Vacuum tubes dont have only disadvantages and a good push-pull triode amp can produce <0.1% THD.

The main reason why in real life the tube amps sound much more better than solid state amps (at least in most cases), is primarily therefore because most solid state amplifiers runs not far enough in Class-A mode (in contrast to tubes). By both kinds of amps there are 20mA until 50mA quiescent current through the output stage. In case of solid state output voltage supply goes from 50V - 120V but in case of tube output stage from 250V to 600V (except OTL - this is through the current control output again not directly comparable).
Secondly, the so-called "true complementary" solid state amplifiers also not comparable with the tube amp in class-A operation (even not in pure class-A), because there are no P-CH tubes. Already through this fact tube amps for audio must be better in general cause the better matching of the two halves.

This means clearly that only "Single Ended" and CSPP (PPP, Circlotron) solid state power stages in Class-A mode (by "Single Ended" unavoidable) are to compare with tube power stages, for avoiding to compare apples to pears or oranges.

In light of these conditions, solid state amplifiers clearly outperform each tube amp in every respect. Otherwise there are heavy design error(s) in the solid state amplifier.

Unfortunately there are not a wide range of such commercial solid state amps on the marked; commercial and diy (kit) examples I have listed there:
URL Collection of Commercial Single Ended Integrated and Power Amplifier Devices
and there
URL collection of Totem Pole and CSPP (Single Ended related) Solid State Output Stage
But nobody could show me until this day a commercial tube amplifier, which clear outperform the biggest single ended solid state amp series from Nelson Pass, the "Aleph" - e. g. the "Aleph 1.2"

To outperform a normally solid state Amplifier in Class-AB mode with low transition aera from "A" to "B" (independend of the price class) is easy to show with most average tube amp, independend whether there are an ultralinear-, Single ended-, or PPP topology.

Sadly but true is that the largest percentage of solid state audio amplifiers uses small amounts of quiescent currents and so called "True complementary" output devices in the output power stages. I love this by theoretical explantations for beginners and on the schematics, but I hate this in real life .

This is for me even the only reason why so many music lovers (rightly) say's, solid state amplifier did sound unmusical (even in traditionally measured THD values that are extrem low and therefore hardly detectable). They have never heard unfortunately the other solid state amps like Aleph.

[Piercarlo]

Originally Posted by traderbam

Tube sound is just a smear away.
The Altmann "Tube-o-lator" lacquer

The best thing in that link is "Attention: This product is no longer available for sale".

A good news by time in time...

Piercarlo

[SQLGuy]

Originally Posted by tiefbassuebertr

Secondly, the so-called "true complementary" solid state amplifiers also not comparable with the tube amp in class-A operation (even not in pure class-A), because there are no P-CH tubes. Already through this fact tube amps for audio must be better in general cause the better matching of the two halves.

This means clearly that only "Single Ended" and CSPP (PPP, Circlotron) solid state power stages in Class-A mode (by "Single Ended" unavoidable) are to compare with tube power stages, for avoiding to compare apples to pears or oranges.

?

Unless I'm really misunderstanding you, which is certainly possible, you seem to be saying that one reason that tubes are better is because they use the same polarity of output devices in both halves of the push-pull configuration. But there are a lot of solid state amps that have done this as well, like the Phase Linear 300, or the SUMO The Nine.

If you find PNP/P-Channel devices undesirable, you can certainly build a solid state (any class) amplifier without them.

[Bonsai]

tiefbass,

please stick to facts, not opinions, when discusing SS vs Tube.

[jan.didden]

Originally Posted by Bonsai

tiefbass,

please stick to facts, not opinions, when discusing SS vs Tube.

??? I thought his post was pretty factual. You (or I) may not agree, but that's not the point is it.

jd

[traderbam]

Originally Posted by Bigun

If you Google for high speed BJT you'll find a lot of stuff, the one I quoted was here:

Bipolar transistors achieve speed record.(GLOBAL DESIGNER) - EDN Asia | Encyclopedia.com

So let's compare about output devices. I would expect the fastest transistor to be faster than the fastest tube if for no other reason than physical size and inductance. That's fine but we're talking about output devices in audio amplifiers. What happens if we compare devices by normalizing them by power output?
I'm no tube expert but I believe the KT88 is used a lot in audio output stages and I think it is a 40W device. How fast is the KT88 compared with n-channel 40W BJT, MOSFET, JFET (is there a 40W JFET?), IGBT?

[jcx]

I believe even "fast" audio power output bjt are device physics limited

metal gate Mosfet "speed" however is primarily package parasitic limited in popular TO-220/247 leaded packaging

IXYS RF: HF/VHF Linear MOSFETs

[tiefbassuebertr]

Originally Posted by SQLGuy

?

Unless I'm really misunderstanding you, which is certainly possible, you seem to be saying that one reason that tubes are better is because they use the same polarity of output devices in both halves of the push-pull configuration. But there are a lot of solid state amps that have done this as well, like the Phase Linear 300, or the SUMO The Nine.

If you find PNP/P-Channel devices undesirable, you can certainly build a solid state (any class) amplifier without them.

Bonsai: :d :d :d
tiefbass, please stick to facts, not opinions, when discusing SS vs Tube

You don't misunderstanding this but I think you misunderstand the whole.
What means "a lot of" for you ??
SUMO "The NINE" could be one of few exceptions, because it is an CSPP topology (see attachement), but I don't know about the idle current values. If it runs typically arround 50mA, nevertheless you cannot compare with tube amp.
The Phase Linear 300 use low idle current values and therefore, it is not comparable anyway to any tube amp.

To make long explanations short - the conclusion of my statement from previous is follow:

By compare SS amps with tube amps, it is important to know, to allow only "Single Ended" and CSPP (PPP, Circlotron) solid state power stages in pure Class-A mode.

This means first, that solid state Class AB modes are not to allow for compare (independend of topology), because I have never heard about tube amp devices for home hifi in Class AB (except any few OTL's)
Secondly true complementary (also quasi complementary) SS in pure classA are also not to allow for the aim of comparsion to tube amp, because there are no tubes with reverse polarity.

By breaking this rule the audible differences causes first through basically different operating modes and circuit topologies, but many musiclovers still believe to the superior properties of the tubes.

Bonsai, all what I say are facts, not opinions - so I think.
But if you want to convince me otherwise - please, be happy;
I look forward to this.
What means ":d :d :d" - please let me know
I'm no expert for the typical abbreviations in the "Forums" language - sorry

[jacco vermeulen]

Plinius ?

[tiefbassuebertr]

Schematic SUMO NINE PLUS second try