G Randy Stone Design Help

SteveT said:
I want to build an amp from "The audiophiles project sourcebook" Project 6.19 ,but need some help with component ratings. I need to know what type and voltage rating caps to use and also what resistor wattage. Has anybody built one of these designs.


Hi SteveT,

I am building a Slone Amp but from his other book (High Power Audio Amplifier Construciton Manual, design from figure 11.4) but the principles are general and apply. Here is what I've understood in his schematics:

- You can use 1/2 W resistors unless otherwise specified.

- Capacitors' type are not specified but you should choose high quality capacitors depending on its function on the circuit. Ex:

* Rail decoupling capacitors: voltage rating = confortably above Rail supply voltages Type = I've used metallized poliester , should do fine (maybe overkill) but I think a ceramic one would do no harm. Other decoupling capacitors follow similar idea...

* Input coupling capacitors: in the design I am building he specifies 2 x 22uF electrolytic capacitors. I wanted to use a different type but I didn't have much choice since it's hard to find (at least here in Brazil) better capacitors types with such high values. I've used Panasonic high quality electrolytics but I am not sure hoe it is going to sound. Voltage rating is 63 V each.

* Feedback path: here I tried to find the best capacitor types I could. In the design I am constructing they're 5 pF, 150pF and 300pF. I used Polypropilene type, voltage rating can be low maybe around 50 V - not sure.

Well, I hope that helps. I am really looking foward in getting the amp to work and hear how does it sound. Many people say a lot of good things about Slone's designs.

Best regards,

João Pedro
I realize this is 16 years too late, however I was lucky enough to have received a few of the “totem pole” design boards and managed to assemble the amp. If you’re interested, I could disassemble the box and take detailed photos of the boards - I believe they were double sided. The amp sounds amazing and has been in use nearly the entire time since ‘05.

I’m pretty sure these were the boards that were intended for the zus audio amps (not sure if they ever made it into production). I got the PCBs from Brad Wilson, however it’s been so long that I’ve lost the email correspondence that we had.