Thanks Salas and Andrew for your comments and instructions.
Did some tests on a sample of 28 transistors.
I used a 9V battery with 100R in series to Drain, with G and S shorted to battery negative.
Measured also resistance from D to S and found always values in the region of thirties ohms.
The values were read with my DMM on both resistor terminals as bellow:
- 0,840V. - 0,984V. - 0,647V. - 0,938V
- 0,770V. - 0,944V. - 0,830V. - 0,804V
- 0,730V. - 0,638V. - 0,900V. - 0,965V
- 0,684V. - 0,957V. - 0,655V. - 0,925V
- 0,720V. - 0,884V. - 0,720V. - 1,014V
... And so on.
What do you think? If I use I=V/R, in one of the values, say 0,840V divided by 100R, I get 0,00840A. Is this correct?
I believe that the higher values are the most suitable, correct?
Thanks once more, I will try to show you my wok as this goes on.
Did some tests on a sample of 28 transistors.
I used a 9V battery with 100R in series to Drain, with G and S shorted to battery negative.
Measured also resistance from D to S and found always values in the region of thirties ohms.
The values were read with my DMM on both resistor terminals as bellow:
- 0,840V. - 0,984V. - 0,647V. - 0,938V
- 0,770V. - 0,944V. - 0,830V. - 0,804V
- 0,730V. - 0,638V. - 0,900V. - 0,965V
- 0,684V. - 0,957V. - 0,655V. - 0,925V
- 0,720V. - 0,884V. - 0,720V. - 1,014V
... And so on.
What do you think? If I use I=V/R, in one of the values, say 0,840V divided by 100R, I get 0,00840A. Is this correct?
I believe that the higher values are the most suitable, correct?
Thanks once more, I will try to show you my wok as this goes on.
How well did your battery hold it's "starting" voltage till the completion of the 28 measurements?
If it started @ 9.0V and held at >8.9V till the end then Vds was in the range ~8.3Vds to 7.8Vds. Good enough for rough batching to 2 sig fig.
However if the battery voltage fell to ~8V, then the Vds range changes to ~8.3Vds to 6.8Vds. This range of Vds being very significantly different from the 10Vds specified for Idss will increase the "errors" in your results and between your results.
A quick scan of your 20 posted results shows Idss between 6.3mA and 10.1mA
If it started @ 9.0V and held at >8.9V till the end then Vds was in the range ~8.3Vds to 7.8Vds. Good enough for rough batching to 2 sig fig.
However if the battery voltage fell to ~8V, then the Vds range changes to ~8.3Vds to 6.8Vds. This range of Vds being very significantly different from the 10Vds specified for Idss will increase the "errors" in your results and between your results.
A quick scan of your 20 posted results shows Idss between 6.3mA and 10.1mA
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Hi Salas,
I'll be building one more preamp for the second arm I'm about to add to my TT. This time, HO MC Micro Benz Silver, 2mV cartridge will be used. I was wandering shall I go RIAA-V1102F0 route again or is there a more suitable design of yours, for 2mV cartridges?
Thank you
I'll be building one more preamp for the second arm I'm about to add to my TT. This time, HO MC Micro Benz Silver, 2mV cartridge will be used. I was wandering shall I go RIAA-V1102F0 route again or is there a more suitable design of yours, for 2mV cartridges?
Thank you
That in the PDF is OK. If you will need say 45dB instead of 43, you can scale down first stage's Rs a bit.
Remove every component to the right of C4.
Apply a 9V battery.
C4 could probably be increased to 100uF.
Apply a 9V battery.
C4 could probably be increased to 100uF.
Finally I do the Low MC pre-pre with 7809 reg. as per schematic, I did'nt soldered R1, voltage emitter BC550C positive C2 to ground 7.58V wihtout load, I hoped more than 9V?
