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DLH Amplifier: The trilogy with PLH and JLH amps
DLH Amplifier: The trilogy with PLH and JLH amps
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Old 28th August 2017, 09:56 AM   #21
AndrewT is offline AndrewT  Scotland
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Could this circuit be used with a high performance opamp wrapped up into a composite with global feedback?
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Old 28th August 2017, 04:54 PM   #22
diegomj1973 is offline diegomj1973  Argentina
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Thank you very much, Hugh, for the valuable information on precedents related to the subject. I will try to find them and see if there are similarities with what I post here.

AndrewT: Could you give an outline of what you would try to do? I can not see the need to use an OPAMP, unless I do not understand you.

The basic idea was to keep design as simple as possible, maximizing performance, as far as possible.

The weak point could be the offset, although that is easily solvable. Otherwise, the design reaches more than interesting parameters.

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Old 28th August 2017, 05:29 PM   #23
AndrewT is offline AndrewT  Scotland
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The composite using either a gain stage, or a Current Buffer for the second stage usually offers increased performance.
W.Jung has written extensively on this. Our Member Tomchr has produced such a composite and to date his achieved performance is way above what any plain Jane 3886 could achieve.
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Old 28th August 2017, 06:29 PM   #24
Ketje is offline Ketje  Belgium
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Quote:
Originally Posted by diegomj1973 View Post
Excuse me, but your subcircuit is not like the one I posted . Check it out, since it's not like mine . In your schematic you are connecting - V with ground, among other things ---> Booooommmmm !!! .

Anyway, this subcircuit could be arranged visually so that everyone can understand it better .

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I don't understand, where is it different ?
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Old 29th August 2017, 12:22 AM   #25
diegomj1973 is offline diegomj1973  Argentina
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Old 29th August 2017, 12:34 AM   #26
diegomj1973 is offline diegomj1973  Argentina
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Quote:
Originally Posted by AndrewT View Post
The composite using either a gain stage, or a Current Buffer for the second stage usually offers increased performance.
W.Jung has written extensively on this. Our Member Tomchr has produced such a composite and to date his achieved performance is way above what any plain Jane 3886 could achieve.
It would be interesting to analyze how it would be implemented in my circuit and try to verify if it improves the current parameters, see to what degree it could improve them and if it justifies more circuital complication.

Welcome who wants to contribute ideas and in this way to be able to improve it.

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Old 29th August 2017, 05:30 AM   #27
PRR is offline PRR  United States
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> The circuit was first described by Christopher Rush in 1964.

I have it, uncreditied, in a book from 1966?

I re-invented it a decade ago except as two inputs (put a resistor between the emitters to define gain). It makes a differential input where 2nd does not cancel. THD is tiny for low gain but if you open it up as a mike-amp you get usual low-NFB BJT curvature.

> nothing is new under the sun

The ancients are always stealing our inventions. Especially in audio.
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Old 29th August 2017, 11:07 AM   #28
Ketje is offline Ketje  Belgium
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Quote:
Originally Posted by diegomj1973 View Post
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Yes, i missed that .You made your point (or not )
The schematic i posted before has the same problem The ground symbol on the most negative side has to go.
Mona

Last edited by Ketje; 29th August 2017 at 11:15 AM.
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Old 30th August 2017, 09:45 AM   #29
juma is offline juma  Germany
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Something similar, also nice:
http://www.andiha.no/articles/audio/.../nostalgia.pdf
from this site:
Audio
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Old 30th August 2017, 09:53 AM   #30
scottjoplin is offline scottjoplin  Wales
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The ancients are always stealing our inventions.
A creature with a "rotary engine" Flagellum - Wikipedia
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