If you can push at least 1mW it may be good enough, even if you can't push 1V into the worst-case load of 16 ohms.
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?
I don't think there is any reason to change it.
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.
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.
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.
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
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
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.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
Invest in a Buffer on the output of your pre so that is can drive a cable and the next stage.
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.
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.
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.
It may help with ESD, but in general it will just increase noise (although noise is probably not a problem here).
Can kuartlotron be used in Sallen-Key type crossover filters which have a feedback loop around the buffer? I mean C1 and R1 - not the opamp FB loop, which I know is unnecessary.
Thanks!
Thanks!


It may have too high output resistance for this application. It should be tested in simulation. I tried it with a notch filter topology which is similar.
EDIT: Nevermind, it seems to work fine.
EDIT: Nevermind, it seems to work fine.
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Thank you so much for simulating it! There are many line level filters like this that your buffer could drive. Active Filters
Are those Kuartlotron boards from dirtyPCBs licensed/legit?
Are those Kuartlotron boards from dirtyPCBs licensed/legit?
I have the new Kuartlotron Superbuffer boards and want to set the DC trim but it does not indicate the value. If I remember correctly the value was 2.7M ohms, but want to make sure.
Thanks,
Brad
Thanks,
Brad
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