SRPP layout

[solder slinger]

Hi,all-

Long time lurker,first time poster.I've decided to build am amp based on the Kismet 3 seen here:

http://www.positive-feedback.com/Issue1/Kismet.htm

I figure I'm gonna learn how to implement power supplies,for sure

Assuming a two-channel amp with a single power supply in one chassis,my question -(and this may simply be a thoeretical exercise)is there any advantage to configuring the 2 voltage amplifiers in one twin-triode envelope and the two plate load regulators in the other envelope?

I'm thinking of using the 6N1P which is shieldeed between triode sections so it really does,nt matter all that much,but I'm curious!(and maybe naieve.)Of course,I'm open to any alternative suggestions to the 6N1P-
Thanks,I've learned a lot so far hanging here at this site(or not

Sincerely,Joe

[fdegrove]

Hi,

You could use the triode's sections that way but keep in mind that often those small double triodes are twin triodes.
I.e. they're supposed to be matched.
This important to to good operation of a circuit that tries to mimic P-P operation.
L and R channel tubes are therefore best kept separated. It also keeps the chance of interchannel crosstalk to a minimum, depending on your layout.

Furthermore, the SRPP circuit does not exhibit good power supply rejection. So, if you decide to go for a common supply, you'd better make a good one.

Also, there's an error in the Kismet schematic in that the grid of the upper triode is left floating. It should be connected to the bottom of the uppermost cathode resistor.
There is no mention in the text about heater to cathode voltages but in general you should check the tube data about this.

Contrary to the author's method of making the amp seem faster by reducing the filtering caps, I'd rather see the cathode bypass cap across the SRPP's bottom cathode resistor removed.
It will reduce gain a little but it will sound cleaner and exhibit better transient response IME.

Cheers,

[solder slinger]

Thanks,Frank!...off I go,then

Joe