Depends of the input amps, output cap calculator link:
Coupling Capacitor Calculator by V-Cap
Cheers
Felipe
Coupling Capacitor Calculator by V-Cap
Cheers
Felipe
Hi Doug
Do not go below 0.47uF because you will loose bass response.
This one forms a frequency dependent voltage divider with th 1M gate resistor in second stage.
It also interacts with the riaa curve response.... Follow Salas advice for a well equilibrated response.
But plugging 1Meg and 0.47uF into the output cap calculator link which merlin posted, gives you 0.34Hz. Which is surely, unnecessarily low?
So why can't you reduce it to 0.1uF ... which produces a result of 1.6Hz - which meets the "x10" rule?
Regards,
Andy
Hi Doug, we have been talking about that in the last posts.... You should not deviate from the spec because the interstage cap is calculated according to the other riaa fiter values.
Rload from first stage + 47k + 6.8k + 47n + 15n + 100n + 1M are all interrelated
Hi phonograph fans !
Still nosing around & getting more components for the NJFET.
Have just been looking at various 'air-caps'.
3 main types have been found.
1. Cheap AM radio type > 100pF
2. Better quality radio type = about 120pF
3. Philips precision teflon - 7 to 100pF
Reason I've been looking mostly...
...is to put one on the cartridge load.
If after figuring out the cable pF and attempting to get 'ZERO' point ideal...
...having a 100pF 'air-cap' set at 50%, I think would give an easy, solder-free way of tweeking the cartridge response.
I have seen various 'DIP switch arrays' used for similar purposes...
...But the R load here ( I think ) only needs to be for 1 cartridge...
...and the 'air-cap' could be used for 'subjective-tone'.
Thus avoiding DIP-switches with resistors altogether.
What you guys think about that...
...anyone tried 'air-cap' front-end tuning ?
Air-cap question #2...
...I had also wondered about 'ZEROing' the RIAA HF cap, with a small value pF or two...
...and then having a 100pF 'air-cap' there too.
100pF, +50 -50, 0.1nF total adjustment here though, doesn't seem much, compared to possible cartridge-load use.
Anyone tried 'air-caps' there in the RIAA HF position ?
How much 'tweeking' of the RIAA HF cap are people doing ?
Also...
...is anyone bothering to 'tweek' the RIAA LF cap at all ?...
...I don't think I have EVER heard anyone talk about this.
( could be wrong though )
Any comments peoples ?
Cheers
Si.
Still nosing around & getting more components for the NJFET.
Have just been looking at various 'air-caps'.
3 main types have been found.
1. Cheap AM radio type > 100pF
2. Better quality radio type = about 120pF
3. Philips precision teflon - 7 to 100pF
Reason I've been looking mostly...
...is to put one on the cartridge load.
If after figuring out the cable pF and attempting to get 'ZERO' point ideal...
...having a 100pF 'air-cap' set at 50%, I think would give an easy, solder-free way of tweeking the cartridge response.
I have seen various 'DIP switch arrays' used for similar purposes...
...But the R load here ( I think ) only needs to be for 1 cartridge...
...and the 'air-cap' could be used for 'subjective-tone'.
Thus avoiding DIP-switches with resistors altogether.
What you guys think about that...
...anyone tried 'air-cap' front-end tuning ?
Air-cap question #2...
...I had also wondered about 'ZEROing' the RIAA HF cap, with a small value pF or two...
...and then having a 100pF 'air-cap' there too.
100pF, +50 -50, 0.1nF total adjustment here though, doesn't seem much, compared to possible cartridge-load use.
Anyone tried 'air-caps' there in the RIAA HF position ?
How much 'tweeking' of the RIAA HF cap are people doing ?
Also...
...is anyone bothering to 'tweek' the RIAA LF cap at all ?...
...I don't think I have EVER heard anyone talk about this.
( could be wrong though )
Any comments peoples ?
Cheers
Si.