The Kuartlotron - keantoken's simple error-correction superbuffer

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#842
I'm about to start building my next Kuartlotron buffer preamp and was thinking of using a 50k step attenuator with the buffer and wanted to know if is made sense to change the 100k resistor to a 50k? Is there any benefit or will 100k work fine?
 
#844
Destroyer OS said:
I don't think there is any reason to change it.
Click to expand...

Destroyer,

Thanks. That's what I was thinking as well. I purchased 2 eBay DACT attenuators this time, one 50k and the other 100k. I'm not sure that either will make a difference, but thought I would try the 50k.

The other changes are to build the buffer with 2 RJM S-regs, which is a shunt-series voltage regulator for low current audio circuits, instead of the onboard shunts.
 
#845
I use 10k with no issues, if that helps. The most important thing is to finish it and enjoy!

The circuit isn't fussy in the least. It's actually probably one of the most adaptable buffers around. I've run multiple amps off of each channel, and had zero issues with sources or volume devices. It just sounds great.
 
#846
Destroyer OS,

Thank you. Not sure which value attenuator I will go with. My phono preamp just likes to see something over 25k. I will probably add a second set of output for my sub and see if it sounds better than the high level input.

Brad
 
#847
BRN said:
Destroyer OS,

Thank you. Not sure which value attenuator I will go with. My phono preamp just likes to see something over 25k. I will probably add a second set of output for my sub and see if it sounds better than the high level input.

Brad
Click to expand...
If the pre is showing symptoms of struggling with less than 25k, then you shopuld be looking at what a bit of cable capacitance is doing to performance.
Invest in a Buffer on the output of your pre so that is can drive a cable and the next stage.
 
#848
Hi Anthony

I am going to use your kuartlotron buffers in my new preamp.
These buffers will be used for the tape recording output so they will be connected directly in parallel with the preamps inputs.

These inputs are also connected to the volume pot and to the DCG3 preamp from Salas.

Now, the pot has 50k ohm
DCG3 has 300k input impedance
I would like to increase the kuartlotron input impedance to minimize it's inpact on the overall input impedance for the preamp.

Can I increase R8 to 500k without having issues with the offset ?

Should I also include a series resistor in the input to avoid interactions between the two circuits connected in parallel ?

I am working on the layout I will post later to clear any doubts about the connections.
 
#849
This is what I have in mind:
 

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#850
As long as the Kuartlotron input has a DC path through the 50k pot to ground which doesn't get disconnected, you will be fine. 500k alone could cause a lot of offset. But with the 50k pot there, you don't really need the 500k unless you plan to disconnect the two circuits.
 
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