The most linear stage for large voltage swings - Lender's Circuit

[Wavebourn]

I prefer something like triode strapped 6P15P loaded on a gyrator. 200V of fast and linear swing easily.

On the picture: 120V swing, 300 KHz, no any feedback used.

http://www.diyaudio.com/forums/showt...69#post1892269

[tiefbassuebertr]

Originally posted by KSTR
Pavel (PMA) is using it, too, in the DisPre II. Albeit unbuffered and complementary.
New DISPRE preamp, successor to previous popular version

- Klaus

also the German elektor magazine describt a phono MM/MC preamp circuit based on Lender's Circuit. They calls it "SUPRA" - see
http://www.diyaudio.com/forums/showt...84#post1894284
A commercial product (similare circuit topology) are the RIAA MC/MM phono preamp SUPA 3.0 from German's aufio manufacture http://www.hormann-audio.de/Produkte.htm

[Bigun]

Originally posted by Wavebourn I prefer something like triode strapped 6P15P loaded on a gyrator. 200V of fast and linear swing easily. On the picture: 120V swing, 300 KHz, no any feedback used.http://www.diyaudio.com/forums/showt...69#post1892269

Wavebourn, I have started to read your thread - very interesting. You bring some very interesting hybrid ideas to the table in several threads I have read now.

In particular I support the idea of tubes for voltage amplification stage where they are said to offer better linearity and clipping behaviour.


tiefbassuebertr, I also noticed that common-grid is a popular topology in tube-based phono stages. Perhaps this was something noticed by Lender too.

[nigelwright7557]

I have designed amps for a few years now and have always stuck to fairly simple minimal designs and had very good results.

Looking for another 0.001 less distortion would be wasted on me because I am sure I couldnt hear it. In fact my first amp design had no bias cct and despite there being cross over distortion on teh scope i couldnt for the life of me hear it ! I hastily add I do now use bias stages in all my designs.

The other problem with complex high count transistor amps is the problems like fixing it if it fails. The more complex the amp is the harder it is to fault find.

[Lumba Ogir]

Bonsai,
the grounded base connection brings us closest to the ideal transimpedance amplifier (about 20 times better than the grounded emitter in that role).

[Lumba Ogir]

Gareth,

Perhaps this was something noticed by Lender too.

Probably, however his circuit is a grounded emitter.

[Wavebourn]

Originally posted by Bigun



Wavebourn, I have started to read your thread - very interesting. You bring some very interesting hybrid ideas to the table in several threads I have read now.

In particular I support the idea of tubes for voltage amplification stage where they are said to offer better linearity and clipping behaviour.

Actually, for voltage amplification may be used transformers. Tubes and transistors amplify power. That's why tubes are sometimes preferable: even though transistors have higher transconductance, in order to get the same power amplification factor from stages using tubes VS transistors we need feedback for transistors, tubes perform faster and more linear without any feedback. Also, tube curves are slowly bent, that means low order of transfer function that creates harmonics that are much less audible than distortions created by a transistor stage. Now, if to add a deep feedback to 2-stage tube amp that is already wideband and linear, we are getting equal very strict linearity in the whole frequency band and beyond. And such an amp has high input resistance that is very linear, compared to non-linear input resistance of a transistor stage. Far the more, an asymmetrical design guarantees that the lower is loudness, the less distorted is the sound, that is very significant for audio. Our subconscious perception is much more sensitive than can be found consciously, so even when such distortions can't be caught by people during listening tests, but when listened to the music very fine accuracy of dynamics is vital.
So, using tubes we achieve very low distortions of fine details; adding deep feedback we achieve very low distortions on peak levels that means low intermodulation distortions. Clipping of such an amp would not sound pleasant, it is total b******t that you can read and hear everywhere. However, it is easier to have bigger headroom powering from hundreds of volts than from tens of volts, and it is true, but it does not mean pleasant clipping.

tiefbassuebertr, I also noticed that common-grid is a popular topology in tube-based phono stages. Perhaps this was something noticed by Lender too.

I noticed it is a popular topology in tube-based transmitters that don't care of distortions, but must amplify very high frequencies that is problematic because of tube sizes that means capacitances and inductances.

[tiefbassuebertr]

Originally Posted by tiefbassuebertr

Thank you very much for the additional circuit advices with Lender's topology.



yes, already some years ago. Unfortunately he don't have the orig article

"Power Amplifier with darlingon output stage"
Motorola Inc., Geneva, Switzerland, 7.9.1974.

Erno says. which this article is mainly concerned the application instructions of newly introduced darlingon technology. Lender's circuit was there one of some more topics.
This article only the old, former Motorola employees can look out. Since then the field of power devices transits in the company "ON SEMI", it can also be that this article now by ON-SEMI is archived. This article was only available for large customers and otherwise in those days for internal use only. in any one days by this forum come up this article - so I hope.

Perhaps this time are member here, who has this article (by this try of root up of this thread at the beginning)

[djk]

How about a Lender connection with a cascode around the Vas?

[jcx]

by the thread title you'd be better off pursuing cascodes:

REDUCTION OF TRANSISTOR SLOPE DISTORTION IN LARGE SIGNAL AMPLIFIERS, M.O.J. Hawksford, JAES, vol.36, no.4, pp.213-222, April 1988

http://www.essex.ac.uk/csee/research...%20cascode.pdf