The Kuartlotron - keantoken's simple error-correction superbuffer

For historical references only, here is the older version of Kuartlotron that doesn't use the inductor. http://www.diyaudio.com/forums/atta...d1373696842-mpp-kuartlotron-dc-stabilized.png
P.S.
I have a model that is older than that and it still outperforms a chip. :D
P.P.S.
Post #26 has an easy way to build the inductor for the new model.

Yes, I eventually chose the inductor because it did not cause distortion or impair sonic focus. I actually posted that old schematic by accident, because I thought it was the Kuartlotron's fault that Joachim's setup was ringing. Actually it was the output cable resonating in it's series mode, causing that telltale cusped rising square wave edge.

The Kuartlotron may be fine without the inductor as long as you have the 47R output resistor, which is basically what Dan's using.
 
HF Booster

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 ? ;)
 

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Thank you Daniel.

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.
 
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Joined 2006
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View attachment 400501 Hallo Joachim, hallo Keantoken

just give you a picture of my working place and a "certain " :D:D
buffer in it
The sound has a level of undisturbed, clear information, that is only mached by the very best line stages I came accross in my "Audio Life"
the "musical correctness" in tonality, dynamics, punch, details, focus and imaging is just striking! - in my system the height matters and now, with the newer version its there and also 3D is there ( soundsources/instruments are placed before, behind, above and in between my speakers)
and when this happens a lot of things went into the right direction...
( I use a ZDL 5 way, time correct, and " almost" phase linear speaker as my main monitor and played this weekend with the Kiso speakers - which created a lot of fun - actually real "Joy")

Thanks for your work ....
and my "Amplifier" thanks you too, as it loves being provided with signals from such a wonderful source

Martina
View attachment 400501
hi Martina

Do you use the buffer just to drive long cables ?
 
Her system is so high gain that we use the buffer as the line stage.
There is a 10kOhm TKD pot before that regulates the volume.
Actually we made several buffer shoutouts that way.
That included the Piglets Dad, the Hawsford, the Calvin, the Paradise and another buffer designed by me.
I study buffers since many years because i found they have a profund impact on the sound also from the technical data that should not be the case.
 
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.
 
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.
 
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.
 
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.