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-   -   The Kuartlotron - keantoken's simple error-correction superbuffer (https://www.diyaudio.com/forums/analog-line-level/251413-kuartlotron-keantokens-simple-error-correction-superbuffer.html)

keantoken 18th February 2014 07:34 PM

Quote:

Originally Posted by Zero D (https://www.diyaudio.com/forums/analog-line-level/251413-kuartlotron-keantokens-simple-error-correction-superbuffer-post3824072.html#post3824072)
I tried various Caps in the following position, & the 1nf boosted the HF -3dB up to over 1GHz ! THD was still below 0.001% @ 20kHz with 1V RMS :)

Whether this would be stable etc in Reality ? Even if it's OTT for audio, it "might" be a useful technique for video ? ;)

That works great with low source impedance, and a source that's willing to drive the entire buffer at 1GHz. But it causes negative input resistance which turns your input cable into an RF transmitter, or at the least cancels the loss of the preceeding wiring and boosts RFI reception.

Salas 18th February 2014 07:34 PM

Quote:

Originally Posted by RCruz (https://www.diyaudio.com/forums/analog-line-level/251413-kuartlotron-keantokens-simple-error-correction-superbuffer-post3824575.html#post3824575)
philosophical ?

Yes, in my view, bcs it exploits philosophy on intrinsic semiconductor characteristics than brute force to attend its goals.;)

keantoken 18th February 2014 07:50 PM

Quote:

Originally Posted by RCruz (https://www.diyaudio.com/forums/analog-line-level/251413-kuartlotron-keantokens-simple-error-correction-superbuffer-post3824124.html#post3824124)
I am planning to use the Kuartlotron just after a jfet common source high gain amp stage.

It outputs 10v DC offset modulated by signal.

Maybe I can build the stock buffer with simetrical psu (so I will loose output cap) but would like to increase it's input impedance to 1mega so I can use a small cap in the input.

What is signal ground referenced to? If it's on the same supply, I need to know where the reference is. If isolated supply, then I can make a single-rail version without coupling caps. It may be that you will end up needing caps in the signal path if you want to power it from the same supply as your Jfet circuit.

keantoken 18th February 2014 07:53 PM

Quote:

Originally Posted by Salas (https://www.diyaudio.com/forums/analog-line-level/251413-kuartlotron-keantokens-simple-error-correction-superbuffer-post3824597.html#post3824597)
Yes, in my view, bcs it exploits philosophy on intrinsic semiconductor characteristics than brute force to attend its goals.;)

Yep, I think the Kuartlotron is very philosophical in that sense.

forr 18th February 2014 08:30 PM

The princinple of the circuit is similar to the one shown by figure #12 :
( source : entree )


Joachim Gerhard 18th February 2014 09:02 PM

" There is nothing new under the sun "
Salomon

keantoken 18th February 2014 09:15 PM

Nice! The lowest-distortion output point for this circuit is the emitter though, not the collector. Still, it behaves like an ideal transistor and could go in virtually any place you'd use a transistor, for instance LTP, drivers, buffers, and so on.

Kindhornman 18th February 2014 09:56 PM

So is this the answer to the question of what to put in front of the OP section Ostripper has designed, or H/k if we want to give them the credit? Would this complete the CFA amplifier design?

keantoken 18th February 2014 10:13 PM

Kindhornman, I'm not sure.

I notice many people slap on different topologies of input, VAS, etc onto an amp without actually checking if that stage is even a significant source of distortion in the design.

I would say the Kuartlotron as a CFA frontend would be great IF it were shown that the input stage was a source of distortion in the first place and that the Kuartlotron would not cause the same distortions. I'm inclined to believe that the input stage of a CFA amplifier is not a significant source of distortion unless it is a very low-gain input stage - in which case, any high-gain input stage will work well, not just the Kuartlotron.

All these things depend to an extent on the specific amplifier. Some CFB amps may be improved, others may not.

Kindhornman 18th February 2014 10:23 PM

Thanks Keantoken,
It seems like we have come down to perhaps this type of input section or the diamond for the front end of the CFA. I haven't seen to many proposing the LTP type of input for the CFA but perhaps I have been misinterpreting that? I am just an observer here so I am trying to learn and see what a few of you gurus seem to being directing this end towards. The triple output section seems to be the most relevant but I understand that the double EF can also be made to work.


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