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[bruno putzeys]

Spot on, Larry.

[Larrchild]

If you are going to forgo feedback, it's probably a smart move to use the most linear device you can obtain, as a starting point.

The venerable Western Electric 300B triode is just such a device.
No pesky cathode to muddy the electron water and a big, honkin close-spaced plate for low Rp. This allows for a lower ratio output xfmr.
It has a rabid following among those content with 1000 BTU's/Watt in efficiency.
 
Here's a typical ZFB design: http://www.electra-print.com/300bamp.php

[Sahib]

I had a quick look at the links. Seems like all single ended lovers' paradise.

DC, Pass comes back to the feedback at the end. His bulb CCS interesting though. Why not? May be we should look into increasing the number of LEDs in the biasing to light up the christmas tree at the same time. Hanging the speakers on the Christmas tree would be a challenge though.

Larry, I didn't know you had allergy for cathodes. I'll pass pink light through 5534 and start a new thread to see if Max can predict the sound.

I was hoping to find more serious designs but I couldn't find any. I came across with an interesting statement from Audionote though, which summed up Bruno's first post.

Quote:

The M2 line balanced utilises simple but sonically effective circuitry using vacuum tube technology rather than complex techniques using impure semi-conductor type devices, so common in the audio industry.

Guess what? Another single ended lover.

Regards,

Cemal

[bruno putzeys]

And then they come to the transformer and the load line this presents at, say 20Hz, and how linear the amp is after that. Transformers for push-pull amps can be made to have a fantastically high primary inductance, so under a resistive load the primary looks still pretty resistive at 20Hz. A SE transformer has a much lower primary inductance. At low audio frequencies its reactance will dominate and it will not store sufficient energy to deliver anything near rated power. (Refer to various explanations by Menno Vanderveen on the subject). SET lovers may love the valve, but they should learn not to ignore the transformer.

[Larrchild]

http://www.acoustic-dimension.com/tango/tango-iso-output-tra nsformer.htm

They don't ignore them. Nothing this expensive can be ignored.

[dcollins]

Larrchild wrote on Wed, 04 April 2007 09:34

If you are going to forgo feedback, it's probably a smart move to use the most linear device you can obtain, as a starting point. The venerable Western Electric 300B triode is just such a device. No pesky cathode to muddy the electron water and a big, honkin close-spaced plate for low Rp. This allows for a lower ratio output xfmr. It has a rabid following among those content with 1000 BTU's/Watt in efficiency.

The unkindest cut for true audiophiles is that the triode has inherent NFB!  And no amount of Shakti stones can remove it....

I like to think of the SET as an 8-8-8 device.

8 Watts at 8% distortion for $8000.

Such a deal.

DC

[Larrchild]

 A Shakti Diode will. however.

[Terry Demol]

dcollins wrote on Sat, 07 April 2007 07:29

Larrchild wrote on Wed, 04 April 2007 09:34 If you are going to forgo feedback, it's probably a smart move to use the most linear device you can obtain, as a starting point. The venerable Western Electric 300B triode is just such a device. No pesky cathode to muddy the electron water and a big, honkin close-spaced plate for low Rp. This allows for a lower ratio output xfmr. It has a rabid following among those content with 1000 BTU's/Watt in efficiency. The unkindest cut for true audiophiles is that the triode has inherent NFB!  And no amount of Shakti stones can remove it.... I like to think of the SET as an 8-8-8 device. 8 Watts at 8% distortion for $8000. Such a deal. DC

It's good to laugh at these poor folks, and it's easy humor
in the pro fraternity - we don't really need to go there.
We all know the technical limitations of SET, it's been done
to death.  

What you guys here really need to consider is why so many people
who have owned very HQ SS amps often end up with SET's.

The answer often comes back to the recording process and
engineer. If someones paid good money for a few 1000 CD's they
have every right to enjoy them - not just 5% of them.

cheers

Terry

[dcollins]

Terry Demol wrote on Mon, 09 April 2007 18:59

[ What you guys here really need to consider is why so many people who have owned very HQ SS amps often end up with SET's. The answer often comes back to the recording process and engineer. If someones paid good money for a few 1000 CD's they have every right to enjoy them - not just 5% of them.

And no one would ever question personal preference!  But in my world, the amp is another tool in the 'ol kit, and accuracy comes first.

I have to admit to very limited experience with the SET, mostly laughable demo rooms at CES where the horn-loaded speaker may have been making more distortion that the SET amp.  I did have a client bring a Cary to a session once, as my modified Mac 240 was clearly not up to his professional standards.  It was impressive, but not in a good way.

DC

[Larrchild]

I like FET amps for making records and Tube amps for enjoying them later.  Sometimes.

I've heard a few SET amps that were nice and open.
A horn-loaded system rattling your Eustachian tubes is not the correct setting for distortion perceptions.

[bruno putzeys]

Terry's sadly right. Most recorded music sounds awful when listened to without gobs of distortion. Even more disturbing is that many engineers are already applying distortion to their own work to make it palatable (cfr outboard summing).

Had a non-audiophile friend over last week. One evening he got curious about "the speakers". He skipped through a few CD's and asked "what's the point of having a nice sound system if this is all there is to play over it". In response I got out a good classical recording. He ended up listening to the whole album without saying a word. A few more people could use that treatment.

[ruffrecords]

Larrchild wrote on Wed, 04 April 2007 17:34

If you are going to forgo feedback, it's probably a smart move to use the most linear device you can obtain, as a starting point. The venerable Western Electric 300B triode is just such a device.

There's lot of folk will tell you triodes have a built in feedback mechanism so you can never get  ZFB.

Ian

[Larrchild]

Absolutely. I don't understand the mechanism completely, but as explained to me, the electrons that hang out between the grid and cathode create free degenerative NFB.

[dcollins]

Larrchild wrote on Thu, 19 April 2007 15:24

Absolutely. I don't understand the mechanism completely, but as explained to me, the electrons that hang out between the grid and cathode create free degenerative NFB.

Last time I posted this they made fun of me!

http://www.next-power.net/next-tube/articles/Stockman/Stockm an.pdf

DC

[Larrchild]

I think, in summary, that if you can live with about point two percent THD and wish to experience what listening without the minor disadvantages that feedback gives, great.

What's worse is small amounts of degenerative feedback (external), because that excites the feedback loop with sub-multiples of the original harmonics.

When you use feedback, you have to use enough to drive those multiple spikes into the dirt.