Should be possible, but I would be concerned about introducing noise. Either line noise, or RF. It would need to be in its own shielded enclosure. Is the loading cap in parallel with the lead from the TT? You would also be "tuning" the end of the transmission line and I suspect that the compensation needs to be as close to the cartrage as possible.
i thought of the rf sheilding wouldnt be a problem......was planing on it for dust too.
yes it is in parallel, im thinking alephOno.
"You would also be "tuning" the end of the transmission line"
can you explane more on this?
would it be any diffrent than say.... loading plugs or dipswitch to change values?
thanks to all
"As firechief says you will need to screen it from hum fields."
side question/confirmation
extra noise in this situation cause of the huge fins acting like lots of antennas right?
and the loading cap types doesn't matter (for sound quality)cause the audio that goes through it goes to ground/- and not to the amp stage right?
side question/confirmation
extra noise in this situation cause of the huge fins acting like lots of antennas right?
and the loading cap types doesn't matter (for sound quality)cause the audio that goes through it goes to ground/- and not to the amp stage right?
You could try the tuning capacitors used in the cheap little transistor radios. They have plastic dielectric between the capacitor plates and they are completely enclosed in a plastic case. They don't look very susceptible to vibration or microphonics. They used the plastic dielectric so they didn't have to space the plates apart like they had to do with air dielectric tuning capacitors so they can make them very compact to fit in the transistor radio case.
If the vanes vibrate then the capacitance will vary. Fortunately it probably won't have a DC bias but it is at a relatively high impedance point so it could modulate the signal. Nothing to do with RF or antennas. The screening is for 50/60Hz fields, as a variable capacitor can be quite large so could pick up hum.
The loading cap quality could, in principle, affect the audio because it is imposing a load. In practice the signal levels are low so any non-linearity will be very small even for a poor quality cap.
The loading cap quality could, in principle, affect the audio because it is imposing a load. In practice the signal levels are low so any non-linearity will be very small even for a poor quality cap.
Romy uses air caps in his phono stage with good results: Romy the Cat's Audio Site's Maifesteo
yes me too.
thanks again to all
peter thank you for the link.
who is that in your avatar?
ive been trying to figure it out for years.
looks like James Belushi, but im sure its not.
I used a much simpler alternative: a short piece of "air core" coax.
The total capacitance is obviously proportional to length, so cut a length that corresponds to your maximal required capacitance. To adjust, simply pull the centre conductor out of the coax shield as far as is required. Job done.
The total capacitance is obviously proportional to length, so cut a length that corresponds to your maximal required capacitance. To adjust, simply pull the centre conductor out of the coax shield as far as is required. Job done.
ha ha...i like that. so simple it hurts.
but i want to be able to ajust for diffrent carts loading on the front panel, insted of flipping switchs.
unless i missed somthing from you post?
i will remember that trick!
It's me from 3 years ago
http://www.diyaudio.com/forums/atta...36d1250811420-aleph-j-x-pcb-group-buy-pd0.jpg
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