Bob,
Semantics is the study of language meaning and doesn't mean what you think it means at all. This was one of the most abused and misused words at diyaudio, like "VAS".
Hello, Bob!
I have a very interesting material on the audio amplifier in which the output stage is also with corrector Hawksford.
The material in Russian, and I have a problem with quality translation, I use Google translator.
you have the opportunity to help me publish it in the journal Audio Engineering Soсiety?
best regards
Alexander
I have a very interesting material on the audio amplifier in which the output stage is also with corrector Hawksford.
The material in Russian, and I have a problem with quality translation, I use Google translator.
you have the opportunity to help me publish it in the journal Audio Engineering Soсiety?
best regards
Alexander
Quibbling about semantics keeps us sharp.
Hi Edmond,
BTW, for what its worth, Randy Slone uses the term VAS as well
.Cheers,
Bob
Hi Alexander,
Yes, you should contact the AES directly (Editor of the Journal of the Audio Engineering Society).
Cheers,
Bob
You should know better. It is a TIS at all frequencies of interest. So there!Hi Edmond,
BTW, for what its worth, Randy Slone uses the term VAS as well
Cheers,
Bob
You should know better. It is a TIS at all frequencies of interest. So there!
Hi Mike,
Guess we'll just have to agree to disagree on both the acronym and on whether it is really a transimpedance stage at all frequencies of interest in all power amplifier designs.
Cheers,
Bob
Hi Edmond,
BTW, for what its worth, Randy Slone uses the term VAS as well
Cheers,
Bob
Hi Bob,
If you mean his infamous circuit with the ill defined standing current, well, it's neither a TIS nor a VAS. It's a POC.
Cheers,
E.
The problem with the term TIS is that it refers to the operational mode or mechanism of part of a model amplifier circuit. Transimpedance does not spring to mind as a useful audio electronics term with much currency, whereas Voltage Amplifier is both descriptive of function and readily identifies a specific section of the amplifier, regardless of mechanism - ideal for the layman, technician or student.
Regardless of policies decided here, it seems inevitable that the life of a term like TIS or even Transconductance Stage for the IPS will be short and not particularly helpful in introducing or describing amplifier behaviour.
Is it really necessary to use terms that are perhaps too specific in defining the mechanism used for a certain function? If those supporting the general use of the term need to remind us of the mechanisms every time they refer to schematics, perhaps we are missing a lot more than an obscure acronym.
Regardless of policies decided here, it seems inevitable that the life of a term like TIS or even Transconductance Stage for the IPS will be short and not particularly helpful in introducing or describing amplifier behaviour.
Is it really necessary to use terms that are perhaps too specific in defining the mechanism used for a certain function? If those supporting the general use of the term need to remind us of the mechanisms every time they refer to schematics, perhaps we are missing a lot more than an obscure acronym.
Hi Bob,
If you mean his infamous circuit with the ill defined standing current, well, it's neither a TIS nor a VAS. It's a POC.
Cheers,
E.
Hi Edmond,
Ha ha
. Randy used it in the general sense.I don't recall what Ben Duncan called it, but I'm quite sure it was not a TIS.
Consider an amplifier that uses a resistively-loaded LTP input stage followed by a VAS with a preceding emitter follower (what I sloppily refer to out of convenience as a Darlington VAS). Consider that amplifier does not use Miller compensation, but rather lag compensation at the collector of the VAS. That VAS is certainly not a transimpedance stage.
Consider also a no NFB amplifier with no compensation and with a resistovely-loaded VAS. That VAS is not a TIS either.
Cheers,
Bob
VTS = Very Tough Sell.
I think the IRs acronym should be changed to FTC (F_ing Tax Collector).
Oops, that is already taken
.Cheers,
Bob
Okay, I'm a slow learner. Maybe it has to do with my recently diagnosed attention deficit disorder, but it sure took a long time to soak into my thick skull. I do have an awful hard time with the learning process, and studying abstract subjects like electronics.
I'm finally cluing in on cascoded amplifiers, and somewhat on how they greatly improve on a transistor's inherently non-linear behavior (but not completely, of course on Class B non-linearity at cutoff), before negative feedback is applied. For all the decades of building and enjoying Marshall Leach's amplifier, I'd ignored his 'Super Amplifier' and its rather different Version 2 iteration simply because I was just looking at it as a much higher powered amplifier I didn't think I needed.
Between Bob's book, Leach's amplifiers that employ cascoding to one degree or another, and Nelson Pass's designs, it's sunk in like a firmly applied baseball bat to my noggin. I'm surprised the practice isn't much more pervasive.
Of course, there's quite an increase in transistor parts count if cascoding is fully applied--those Krell and Pass amplifiers are >expensive<. But I coulda had a Leach Superamp by now if I'd only thought it through back in the 80s or 90s.
Forget error correction design for the moment. Any suggested reading on the subject of cascoding? I've been struggling for a long time on how to go beyond Leach's Low TIM "little" amplifier but never stumbled onto a newer design that really appealed to me, even though error correction seemed to have possibilities. Leach's amplifier worked a little >too< well, alas.
I'm going back to basics, the heart of a transistor's non-linearity. Maybe there's a downside I've not discovered about cascoding, but that's part of the learning curve, too. Time to rethink.
(For the moment and because of outright poverty, I'm having to settle for applying Thermaltrak transistors to my prototyping chassis and seeing how these faster and more linear perforated emitter devices sound and measure.)
I'm finally cluing in on cascoded amplifiers, and somewhat on how they greatly improve on a transistor's inherently non-linear behavior (but not completely, of course on Class B non-linearity at cutoff), before negative feedback is applied. For all the decades of building and enjoying Marshall Leach's amplifier, I'd ignored his 'Super Amplifier' and its rather different Version 2 iteration simply because I was just looking at it as a much higher powered amplifier I didn't think I needed.
Between Bob's book, Leach's amplifiers that employ cascoding to one degree or another, and Nelson Pass's designs, it's sunk in like a firmly applied baseball bat to my noggin. I'm surprised the practice isn't much more pervasive.
Of course, there's quite an increase in transistor parts count if cascoding is fully applied--those Krell and Pass amplifiers are >expensive<. But I coulda had a Leach Superamp by now if I'd only thought it through back in the 80s or 90s.
Forget error correction design for the moment. Any suggested reading on the subject of cascoding? I've been struggling for a long time on how to go beyond Leach's Low TIM "little" amplifier but never stumbled onto a newer design that really appealed to me, even though error correction seemed to have possibilities. Leach's amplifier worked a little >too< well, alas.
I'm going back to basics, the heart of a transistor's non-linearity. Maybe there's a downside I've not discovered about cascoding, but that's part of the learning curve, too. Time to rethink.
(For the moment and because of outright poverty, I'm having to settle for applying Thermaltrak transistors to my prototyping chassis and seeing how these faster and more linear perforated emitter devices sound and measure.)
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