[Freo-1]

They're monoblocks, so it's best to get two.    (sorry, couldn't resist )

Nor can I resist saying what a nice pair of Monads you've got there.

se

Why, thank you sir! 

I second that opinion. 

[TONEPUB]

However, you still didn't answer my question.

Does the 300B act as a driver tube for a solid state output stage?
A 300B tube is only capable of putting out about 9 watts...

His website does nothing to explain how it works.

Still interested though

[Freo-1]

However, you still didn't answer my question.

Does the 300B act as a driver tube for a solid state output stage?
A 300B tube is only capable of putting out about 9 watts...

His website does nothing to explain how it works.

Still interested though

It has to have a solid state output stage.  The power doubles from 8 ohms to 4 ohms. The 300B must be the driver stage, applied to the output stage. Would like to know if the output devices are IGBT or MOS-FET.

[Steve Eddy]

Here is another couple of links to chew on:

http://www.milbert.com/TVTFC.bdc
http://milbert.com/tstxt.htm

Even though both are on the Milbert website, the first one says this:

Smooth clipping is widely considered more musical than transistors.

While the second one says this:

A quick look shows that the often versed opinion that tubes overload more gently than transistors is obviously a myth.



Anyway, there's still a considerable amount of apples to oranges comparisons.

For example, in the Hamm article, transistors such as the 2N3391A and 2N5089 are compared to tubes such as the 12AY7 and 12AX7 in single stage amplifier circuits.

The 2N3391As and 2N5089s are 25 volt devices. You think those 12AY7s and 12AX7s were being fed 25 volts or less?

Can't find it right now but there were some folks who ran more apples to apples comparisons between tubes and transistors. They used a very simple, single stage common cathode/emitter/source circuit for all devices.

When the transistors were run at around 15 volts, there was a significant amount of high order distortion products which were not being produced by the tube (a 6SN7 I believe). However when the transistors were run at 180 volts, the same voltage as the 6SN7, while the overall distortion of the transistor was higher, the characteristics of the distortion were the same as for the tube, i.e. a monotonic progression from the second, to the third, to the fourth, with no high order products visible above the noise floor.

Now, given that transistors generally have much more gain than tubes, if you were to add a bit of emitter degeneration (technically feedback but local) to bring the gain of the transistor circuit down to that of the tube circuit, the overall distortion of the transistor would have likely been no greater than that of the tube.

While I agree that comparing topologies is "apples to oranges" , the resultant sound is "apples to apples", and left for each of us to discern what we like and do not like. aa

Well sure, it's fine to say that you prefer this tube amp over that solid state amp. But what I'm speaking against is using apples to oranges comparisons to make sweeping proclamations about the devices themselves. All this does is needlessly prejudice people against transistors no matter how they may be implemented.

se

[jon_010101]

The Monad looks very interesting.

Yes, it does. Just too bad they had to call it the Monad. Makes it a bit difficult or any male who went through junior high school to take it seriously.

se

But fans of Leibniz will appreciate 

[Freo-1]

[

While I agree that comparing topologies is "apples to oranges" , the resultant sound is "apples to apples", and left for each of us to discern what we like and do not like. aa

Well sure, it's fine to say that you prefer this tube amp over that solid state amp. But what I'm speaking against is using apples to oranges comparisons to make sweeping proclamations about the devices themselves. All this does is needlessly prejudice people against transistors no matter how they may be implemented.

se

But of course!


As I've stated in other threads, both tubes and transistors can sound great or terrible.  I DO think it is easier to get good sound from tubes than transistors, due to circuit complexity issues with solid state. A lot depends on one's choice of speaker. Some modern inefficient speakers demand solid state to bring out the best in them. Electrostatics often seem to perform better with tubes (as do Klipschorns, IMHO). 

Sweeping declarations on subjects such as this are doomed to failure (there are ALWAYS exceptions).   

[aerius]

For example, in the Hamm article, transistors such as the 2N3391A and 2N5089 are compared to tubes such as the 12AY7 and 12AX7 in single stage amplifier circuits.

The 2N3391As and 2N5089s are 25 volt devices. You think those 12AY7s and 12AX7s were being fed 25 volts or less?

Can't find it right now but there were some folks who ran more apples to apples comparisons between tubes and transistors. They used a very simple, single stage common cathode/emitter/source circuit for all devices.

When the transistors were run at around 15 volts, there was a significant amount of high order distortion products which were not being produced by the tube (a 6SN7 I believe). However when the transistors were run at 180 volts, the same voltage as the 6SN7, while the overall distortion of the transistor was higher, the characteristics of the distortion were the same as for the tube, i.e. a monotonic progression from the second, to the third, to the fourth, with no high order products visible above the noise floor.

Bingo.  Also, when transistors are run at wimpy solidstate voltages it's fairly easy for them to get slammed right into the voltage rails, wham, there's your squared off clipping waveform.  Your typical vacuum tube has a couple hundred volts of headroom to play with, transistors are lucky to get a few dozen.

Interesting story.  A little while back I was corresponding with a guy on another message board, he'd given me the schematics to one of his tube amps but I was having trouble getting it to work.  He agreed to let me drop by his place so he could put 'scope & other stuff to it and find out what's wrong.

While I was there I got to hear his high voltage transistor amp, runs at something like 160V and uses output transformers just like a tube amp.  Measures and sounds almost exactly like his tube amps while being a hell of a lot smaller and cheaper to build.  By the way, his tube amps measure a heck of a lot better than 99% of the stuff out there today and sound better than anything else I've ever heard.  Push-pull pair of 300B's, puts out 15W in class A1 with less than 0.2% distortion, and 30W in A2 with a bit over 2% with no NFB.  Contrast this with your typical 300B tube amp which has 10-20% distortion at full power.

[PaulFolbrecht]

While I was there I got to hear his high voltage transistor amp, runs at something like 160V and uses output transformers just like a tube amp.  Measures and sounds almost exactly like his tube amps while being a hell of a lot smaller and cheaper to build.  By the way, his tube amps measure a heck of a lot better than 99% of the stuff out there today and sound better than anything else I've ever heard.  Push-pull pair of 300B's, puts out 15W in class A1 with less than 0.2% distortion, and 30W in A2 with a bit over 2% with no NFB.  Contrast this with your typical 300B tube amp which has 10-20% distortion at full power.

All you are describing is a difference between the single-ended and push-pull topologies.  The "typical" 300B amp is single-ended and SE amps do not cancel out even-order harmonics.  Also, a "typical" zero-feedback 300B SET is putting out more like 5-7% THD at full rated power, most of that 2nd harmonic.

It turns out that up to 5% or so of 2nd-order HD is nearly inaudible, and not objectionable anyway.

It also turns out that many people feel that the odd-order *only* HD composition of PP amps (tube or sand output stage) is an *unnatural* sound that is less realistic than a comparable SE amp.  There's something about those odd-order peaks the ear/brain seems to dislike.

PP amps can sound great in their own way.  But those souls who are able to look past silly numbers that do not necessarily have any correlation with sound quality or realism often find SE amps preferable.

Paul
Norvinz FR

[Freo-1]

The (potential) technical advantages (less electronics required, direct digital stream fed to the output) would seem worth exploiting.

I agree. 

The connection chain you described is odd IME (understatement, no? ), but I'd love to have been there to hear it!

I'm toying with the idea of buying a dedicated iMac for use in my room.  It'd replace the first two pieces of the far-removed computer (HDD --> wireless router) --> modified Transporter --> amps --> speaker set-up I have now.  I'd love to be directly wired at all points, but the computer noise potential worries me. 

Even so, the myriad of interesting experiments and comparisons via different types of connectors and outputs I could perform intrigues me greatly!

Here is a link to explain how the unusual interface setup works with the ES line (it's a bit of a puff piece, but does provide some high level technical background).


http://www.learningcenter.sony.us/assets/hpd/hdtv/downloads/ES_STR_05_Final.pdf

I do think that in the future, this type of setup could be the way ahead.

[PaulFolbrecht]

Here are some random observations about amplifier topology that have been (mostly) not yet touched up on in this thread.

1) Feedback sucks.  One thing that often makes tube amps sound better is greatly reduced or no negative feedback.  All transistor amps need moderate to high levels of feedback.  Transistors are inherently less linear amplifying devices and need artificial linearization to perform acceptably.

2) That said, a typical moderate-feedback PP tube amp sounds *a lot* like a typical moderate-feedback SS amp *if the sand amp has much greater power reserves and is not forced to clip*.  One thing I do *not* understand completely is how or why tubes clip "differently" or "more gracefully" but this is *true* in the real world.

3) Single-ended amps (tubes or sand) generally sound better than push-pull. 

4) Single-ended tube amps generally sound best of all because, in addition to running in class A (as do some PP amps as well) and having a natural distortion specra, we are using very linear output devices that allow zero feedback and also great simplicity in the circuit.  I love to flip over my Fi 45 monos and look at the circuit - it's the input tube, output tube, and output tranny!  Other than the power supply that's all there is.

Now, (3) and (4) are obviously matters of opinion.  But my opinion is the correct one.  I don't want to say anything controversial or insulting, but anybody who disagrees with me on this is likely a wife-swapping atheist or something equally unsavory.

Paul
Norvinz FR

P.S. Just having a little fun at the end there.  Don't flame me.   

[Freo-1]

Here are some random observations about amplifier topology that have been (mostly) not yet touched up on in this thread.

1) Feedback sucks.  One thing that often makes tube amps sound better is greatly reduced or no negative feedback.  All transistor amps need moderate to high levels of feedback.  Transistors are inherently less linear amplifying devices and need artificial linearization to perform acceptably.

2) That said, a typical moderate-feedback PP tube amp sounds *a lot* like a typical moderate-feedback SS amp *if the sand amp has much greater power reserves and is not forced to clip*.  One thing I do *not* understand completely is how or why tubes clip "differently" or "more gracefully" but this is *true* in the real world.

3) Single-ended amps (tubes or sand) generally sound better than push-pull. 

4) Single-ended tube amps generally sound best of all because, in addition to running in class A (as do some PP amps as well) and having a natural distortion specra, we are using very linear output devices that allow zero feedback and also great simplicity in the circuit.  I love to flip over my Fi 45 monos and look at the circuit - it's the input tube, output tube, and output tranny!  Other than the power supply that's all there is.

Now, (3) and (4) are obviously matters of opinion.  But my opinion is the correct one.  I don't want to say anything controversial or insulting, but anybody who disagrees with me on this is likely a wife-swapping atheist or something equally unsavory.

Paul
Norvinz FR

P.S. Just having a little fun at the end there.  Don't flame me.   

Suggest you review the link on the ES amplifiers.  That topology does not fit int your comparisons.  (The output stage does not fit the typical arguments). 

[aerius]

All you are describing is a difference between the single-ended and push-pull topologies.  The "typical" 300B amp is single-ended and SE amps do not cancel out even-order harmonics.  Also, a "typical" zero-feedback 300B SET is putting out more like 5-7% THD at full rated power, most of that 2nd harmonic.

If it's competantly designed, such as say, a Wavelength Cardinal.  If it's a typical RC coupled amp with a 6SN7, 12AU7, or 6DJ8 cathode-follower driver stage, then good luck.  The driver stage runs out of headroom & clips while the 300B draws grid bias and screws the bias all to hell.

It also turns out that many people feel that the odd-order *only* HD composition of PP amps (tube or sand output stage) is an *unnatural* sound that is less realistic than a comparable SE amp.  There's something about those odd-order peaks the ear/brain seems to dislike.

Impossible to get odd-order harmonics only from a P-P tube amp.  Tube pairs never match exactly, and as such perfect cancellation of even order harmonics can't and doesn't happen.  In real life, you'll have about 25dB or so cancellation of even order harmonics, which results in a roughly even distribution of even & odd harmonics; the 2nd & 3rd will be about even as will the 4th & 5th, and so on.  Now if the designer is smart and uses the Western Electric "harmonic balancer", the odd-order harmonics can be reduced by a further 10-15db, with the reductions increasing with higher harmonics.  In other words a P-P amp can now have a very similar distortion spectrum to a SE amp, except the overall levels will be much lower.

PP amps can sound great in their own way.  But those souls who are able to look past silly numbers that do not necessarily have any correlation with sound quality or realism often find SE amps preferable.

Been there, done that, heard'em.  I lean towards the P-P camp on both sound and technical reasons.

[Steve Eddy]

It also turns out that many people feel that the odd-order *only* HD composition of PP amps (tube or sand output stage) is an *unnatural* sound that is less realistic than a comparable SE amp.  There's something about those odd-order peaks the ear/brain seems to dislike.

What do you mean by "odd-order *only* HD composition of PP amps"? Most all push-pull amps I've seen have also had significant amounts of even-order distortion products in addition to the odd-order products.

se

[PaulFolbrecht]

It also turns out that many people feel that the odd-order *only* HD composition of PP amps (tube or sand output stage) is an *unnatural* sound that is less realistic than a comparable SE amp.  There's something about those odd-order peaks the ear/brain seems to dislike.

What do you mean by "odd-order *only* HD composition of PP amps"? Most all push-pull amps I've seen have also had significant amounts of even-order distortion products in addition to the odd-order products.

You are both, of course, correct, and I misspoke.  There is cancellation of even order HD but not complete.  Sorry I worded that poorly.  But, my point was that many feel that this cancellation is
'unnatural', complete or no.

My tongue was in my cheek (which I thought was evident) re: the strength of my words.  I think P-P amps can sound great - with low or no feedback anyway.  The AES Six Pacs come to mind.  Those things sing and will drive nearly anything to boot.

[Kevin Haskins]

It also turns out that many people feel that the odd-order *only* HD composition of PP amps (tube or sand output stage) is an *unnatural* sound that is less realistic than a comparable SE amp.  There's something about those odd-order peaks the ear/brain seems to dislike.

What do you mean by "odd-order *only* HD composition of PP amps"? Most all push-pull amps I've seen have also had significant amounts of even-order distortion products in addition to the odd-order products.

se

And they are all dwarfed by the distortion products in the loudspeaker.   

I'll take a little even order with my music though.  I'm not dogmatic... I like it.

[Steve Eddy]

1) Feedback sucks.  One thing that often makes tube amps sound better is greatly reduced or no negative feedback.  All transistor amps need moderate to high levels of feedback.  Transistors are inherently less linear amplifying devices and need artificial linearization to perform acceptably.

Let's think about this for a moment.

If you take a triode, and add a screen grid and a suppressor grid, you end up with a tube that has higher gain but is somewhat less linear.

If we work backwards from this, it would seem that a triode has some sort of internal feedback mechanism which linearizes the tube at the expense of reducing its gain.

Now, a transistor also generally has much more gain than a triode tube and is also generally less linear.

So what if we add a bit of emitter degeneration to the transistor, bringing its gain down closer to that of the triode which would also linearize the transistor?

What would the fundamental difference here be?

One thing I do *not* understand completely is how or why tubes clip "differently" or "more gracefully" but this is *true* in the real world.

Care to show us? The Hamm paper seems to demonstrate in the real world that this is a myth.

4) Single-ended tube amps generally sound best of all because, in addition to running in class A (as do some PP amps as well) and having a natural distortion specra...

What exactly is a "natural" distortion spectra? Do you mean simply even-order dominant distortion? If so, what makes that somehow more "natural" than odd-order dominant distortion? Have you looked at the spectra of various acoustic instruments?

...we are using very linear output devices that allow zero feedback and also great simplicity in the circuit.

Is there really zero feedback? Or is it really just an illusion because any internal feedback mechanism in the tube isn't drawn out in the schematics?

I love to flip over my Fi 45 monos and look at the circuit - it's the input tube, output tube, and output tranny!

Have you seen Nelson Pass' Zen amp? Doesn't even have an input transistor. Just an output transistor.

se

[Steve Eddy]

You are both, of course, correct, and I misspoke.  There is cancellation of even order HD but not complete.  Sorry I worded that poorly.  But, my point was that many feel that this cancellation is
'unnatural', complete or no.

Sure. But you can also find those who feel otherwise. Lynn Olson for example seems very big on push-pull.

Just goes to show that when it comes to people's subjective sonic, technological and philosophical preferences, absolutes are rather hard to come by. Which is fine by me. Vive la difference!

se

[Steve Eddy]

And they are all dwarfed by the distortion products in the loudspeaker.   

I'll take a little even order with my music though.  I'm not dogmatic... I like it.

Woof! Woof!

se

[Steve Eddy]

By the way, it's perhaps worth noting that you can add a simple cascode to a transistor to dramatically linearize it without using negative feedback. Of course you can also use cascoding with tubes, just pointing out that feedback isn't the only way to produce a more linear transistor circuit.

se

[Double Ugly]

The computer noise is an issue. Maybe a forward thinking audiophile could develop a server where the output is sufficiently isolated so that noise is not a big issue. Hmmmmm....   What do you reckon?? 

I reckon. 

However, you still didn't answer my question.

Does the 300B act as a driver tube for a solid state output stage?
A 300B tube is only capable of putting out about 9 watts...

His website does nothing to explain how it works.

Still interested though

"I could offer some (barely) educated guesses, Jeff, but I'll leave the guesswork to those better equipped and simply offer a link."

If I was equipped to answer your questions, I'd have offered something more substantive than the above.  I felt I made that very clear.

"Mum's the word" has been BK Butler's philosophy when asked about topology specifics, even with those of us who own them.  If he won't explain it to me, I can't explain it to you.

Perhaps the manual - easily found on the Butler website - will prove more informative.  If not, aside from suggesting you get BK drunk the next time you see him, I can't help you.

Here is a link to explain how the unusual interface setup works with the ES line (it's a bit of a puff piece, but does provide some high level technical background).


http://www.learningcenter.sony.us/assets/hpd/hdtv/downloads/ES_STR_05_Final.pdf

I do think that in the future, this type of setup could be the way ahead.

Thanks, Freo! 

I've saved the .pdf, but I'm too wiped to digest anything tonight (spent half the day and night driving to my parents' home in TN).  I may not get to it for a few days, but I'll definitely spend some quality time with it when life allows.  My interest is definitely piqued! 

Thanks again!