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previous: Jack The 9v power is your problem. Crank... -- 10/26/1999 11:12 PM

Re: FET Electrical Performance

11/4/1999 9:50 PM
Scott	Re: FET Electrical Performance I tried your suggestion of higher supply voltage and found the following. The voltage source was two batteries, about 18.6V. 1. The higher voltage required a different ratio of drain to source resistors to get correct drain voltage. At 9V, I used 2.2K and 470, and for 18V, 10K and 1K. 2. This means that signifigantly higher gain is available at the higher supply voltage. 3. With the 18.6V supply, 10K drain resistor, 1K source resistor, no bypass cap and Vout = 1 Vrms, gain was 10 and distortion was 0.2% THD. Much better than the 9V supply performance. This may all be obvious to some, but as I mentioned above my main experience is with tubes, so this was an interesting exercise to me.

11/4/1999 9:50 PM

Scott

Re: FET Electrical Performance

I tried your suggestion of higher supply voltage and found the following. The voltage source was two batteries, about 18.6V.

1. The higher voltage required a different ratio of drain to source resistors to get correct drain voltage. At 9V, I used 2.2K and 470, and for 18V, 10K and 1K.

2. This means that signifigantly higher gain is available at the higher supply voltage.

3. With the 18.6V supply, 10K drain resistor, 1K source resistor, no bypass cap and Vout = 1 Vrms, gain was 10 and distortion was 0.2% THD. Much better than the 9V supply performance.

This may all be obvious to some, but as I mentioned above my main experience is with tubes, so this was an interesting exercise to me.

Replies:

Jack q{With the 18.6V supply, 10K drain ... -- 11/4/1999 11:33 PM