The Kuartlotron - keantoken's simple error-correction superbuffer

Finally put together my my Kuartlotron buffer. I fired it up and the LED came on and there was no smoke. I ran through the adjustments with no problem. I built the buff in an ebay aluminum chassis that has internal measurements of W 9-5/8" x H 2-1/8" x D 6-7/8" with three inputs.

eBay link:Silver 2606A Full aluminum preamp chassis Power amp box /DIY case | eBay

I'm using RJM Audio's X-reg with the recommended toroidal power transformer to power the buffer in the same chassis.

When I turn my stereo on I get humming through both speakers. It is not real loud, but can be heard from the listening position. The strangest thing is when I turn the buffer off and leave the Folsom TDA7297 amp powered on I get a loud hum and on the second input I'm picking up a radio station.

I'm pretty sure that the transformer is the culprit, but not sure what I want to try in order to fix the problem. I can get some MuMetal to isolate the power supply or I can move the power supply into a different chassis. If I move anything into a different chassis it would most likely be the transformer and regulators. I would leave the X-reg with the Kuartlotron buffer.

If anyone has any other suggestions or thought on this problem I'm open to ideas to fix the problem.

Thanks,
Brad
 
This is a picture of the build.
 

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Try measuring the ACV at the inputs and outputs of the buffer to see if the hum is coming from the buffer or if it's something else. If you are using it for phono, then you may need a better PSU and careful chassis construction to keep noise low.

Hum or unusual behavior is no surprise when turned off. There is no muting circuit. EMC problems with your chassis could be contributing to the RFI.
 
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Finally put together my my Kuartlotron buffer. I fired it up and the LED came on and there was no smoke. I ran through the adjustments with no problem. I built the buff in an ebay aluminum chassis that has internal measurements of W 9-5/8" x H 2-1/8" x D 6-7/8" with three inputs.

eBay link:Silver 2606A Full aluminum preamp chassis Power amp box /DIY case | eBay

I'm using RJM Audio's X-reg with the recommended toroidal power transformer to power the buffer in the same chassis.

When I turn my stereo on I get humming through both speakers. It is not real loud, but can be heard from the listening position. The strangest thing is when I turn the buffer off and leave the Folsom TDA7297 amp powered on I get a loud hum and on the second input I'm picking up a radio station.

I'm pretty sure that the transformer is the culprit, but not sure what I want to try in order to fix the problem. I can get some MuMetal to isolate the power supply or I can move the power supply into a different chassis. If I move anything into a different chassis it would most likely be the transformer and regulators. I would leave the X-reg with the Kuartlotron buffer.

If anyone has any other suggestions or thought on this problem I'm open to ideas to fix the problem.

Thanks,
Brad

This is a picture of the build.
quite a lot of twisted pairs used to reduce loop areas.
The hum must be due to a wiring error.
Disconnect one channel completely and sort the working channel.
Then disconnect that corrected channel and sort the other channel.
Once you have both channels wired correctly you then need to test again with interconnects attached to both inputs.
 
Being very satisfied with my Kuartlotron with Sulzer regulator type I was wondering if the regulator Nazar would be an excellent choice by incorporating it directly on the PCB.

I haven't read all the pages, so probably this question is already answered. Is it possible to eliminate L1?

L1 is part of a noise filter, right? Even if for an LC it should be before the cap.

Using a regulator (series, shunt) or cap multiplier wouldn't filter noise and allow deleting L1?

A Sulzer reg would probably be the almost ultimate regulator for this application, so what would a Nazar regulator improve over Sulzer's?

When you say incorporate on the pcb, you mean all the two Nazar's regulators?
 
I will check the connections again to make I have everything wired correctly and measure the ACV on the inputs and output.

The layout of the chassis is not the most optimal so I used a shielded cable from the power inlet to the switch.

I will try the buffer without any inputs to see if that makes a difference. I had my DAC, phono preamp, and TV connected. The phono preamp has not been powered on. I will connect the buffer with no inputs and see if anything changes. The switch is a 3T4P, so signal and grounds remain isolated from each other.

I think that I will just move the PS into a different chassis, but before I do that I will remove the PS and use batteries to see what happens.

Does a

It's just a matter of finding the time to make the changes.
 
Finally put together my my Kuartlotron buffer. I fired it up and the LED came on and there was no smoke. I ran through the adjustments with no problem. I built the buff in an ebay aluminum chassis that has internal measurements of W 9-5/8" x H 2-1/8" x D 6-7/8" with three inputs.

eBay link:Silver 2606A Full aluminum preamp chassis Power amp box /DIY case | eBay

I'm using RJM Audio's X-reg with the recommended toroidal power transformer to power the buffer in the same chassis.

When I turn my stereo on I get humming through both speakers. It is not real loud, but can be heard from the listening position. The strangest thing is when I turn the buffer off and leave the Folsom TDA7297 amp powered on I get a loud hum and on the second input I'm picking up a radio station.

I'm pretty sure that the transformer is the culprit, but not sure what I want to try in order to fix the problem. I can get some MuMetal to isolate the power supply or I can move the power supply into a different chassis. If I move anything into a different chassis it would most likely be the transformer and regulators. I would leave the X-reg with the Kuartlotron buffer.

If anyone has any other suggestions or thought on this problem I'm open to ideas to fix the problem.

Thanks,
Brad
Hello

Not clear that here come from here but we will say that the cards are supplied with a one after the other. I think they should be fed separately.
 

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I'm sure my issue is due to the transformer location. It is not bad and it is not audible from the listening position. I'm going to try isolating the transformer with MuMetal and see if that eliminates the hum. I may try moving the transformer to see what affected it has.

I'm listening now and my analog setup has never sounded better.