SET amp owners thread

[Atmasphere]

I see examples were done in commercial amps and preamps. I tested them in my amps and found that the combination sounds better with bypass as it gets the best in clarity and bass slam. Of course, if I can get away with one cap, that would be ideal and cheaper.

The issue is the choice of capacitor. If its got problems, bypassing it might actually sound better. IME its better to just give it your best shot with the best cap you can. This usually means Teflon as it has the best characteristics at audio frequencies. Polystyrene can be pretty good too- if you can get some made with a properly thin film. To my understanding the Germans made the best film but got out of it a good 20 years ago or so leaving just the Chinese film which is about 6x thicker. That might have changed in the last 20 years- I've not followed it.

Oil-filled parts can also sound very nice but run the risk of electrical leakage which can wreck havoc no matter where they are in the amplification train. The only part I've seen that doesn't have this problem is the V-Cap ODAM but there may be others. The Teflon has better performance though.

I agree with @sparkie 's assement about resistor noise. You have a better shot if you simply have a single resistor with a much higher Wattage value than needed (that was how they got low noise in the old days) or by using a wirewound, since its inductance is likely not a problem at audio frequencies.

 

[sparkie]

I agree with @sparkie 's assement about resistor noise. You have a better shot if you simply have a single resistor with a much higher Wattage value than needed (that was how they got low noise in the old days) or by using a wirewound, since its inductance is likely not a problem at audio frequencies.

What I find with non-inductive wirewounds when deployed in the plate and cathode circuits is that there anti- inductive properties have a tendency to increase slew rate and settling time in tubes. The tonality improvements by putting them in the cathode circuit is a product of them eliminating phase shifts from the grid circuit.
In the plate circuit, they have a tendency to lower the tube RF hash noise, thus improving transient gain properties.

 

[we421a]

The issue is the choice of capacitor. If its got problems, bypassing it might actually sound better. IME its better to just give it your best shot with the best cap you can. This usually means Teflon as it has the best characteristics at audio frequencies. Polystyrene can be pretty good too- if you can get some made with a properly thin film. To my understanding the Germans made the best film but got out of it a good 20 years ago or so leaving just the Chinese film which is about 6x thicker. That might have changed in the last 20 years- I've not followed it.

Oil-filled parts can also sound very nice but run the risk of electrical leakage which can wreck havoc no matter where they are in the amplification train. The only part I've seen that doesn't have this problem is the V-Cap ODAM but there may be others. The Teflon has better performance though.

I agree with @sparkie 's assement about resistor noise. You have a better shot if you simply have a single resistor with a much higher Wattage value than needed (that was how they got low noise in the old days) or by using a wirewound, since its inductance is likely not a problem at audio frequencies.

I would agree. Currently testing the ODAM vs Deulund tinned copper cast PIO 0.47 without bypass in between the driver and output 300b. The size matters . Deulund has fuller sound and deeper bass. The ODAM has the clarity . I added 0.01 Audyn copper max with .47 vitamin Q and it sounds better than ODAM as it gets the best of both end. Just for my own experiment and playing around

 

[Argonaut]

Tuning a circuit to one’s taste via rolling capacitor types , and resister type , can be fun … and at times quite an ear opener , at other times something of a wabbit hole , in many respects if one is confident enough with a solder iron , for my part I prefer such tuning via components before tuning via valves .