Hi Pavel;
here is one more idea: to eliminate batteries from a guitar pedal I powered it from pair of current sources; actually there was one current source and couple of current mirrors from plus and minus rails. The pedal contained a bi-polar shunt regulator only, and was connected by one shielded wire and one naked pair for both plus and minus. Output dynamic resistance between ground and both powering wires was huge.
This trick may be used to power your MC preamp as well, with no ground connection of the power supply at all.
here is one more idea: to eliminate batteries from a guitar pedal I powered it from pair of current sources; actually there was one current source and couple of current mirrors from plus and minus rails. The pedal contained a bi-polar shunt regulator only, and was connected by one shielded wire and one naked pair for both plus and minus. Output dynamic resistance between ground and both powering wires was huge.
This trick may be used to power your MC preamp as well, with no ground connection of the power supply at all.
pma:
any plans to update the jfet distortion pages of your website with pre standard two preamp research?
mlloyd1
Unfortunately I have not updated the pages yet . But I have some partial PCB photos. These 2SK389/2SJ109 are great sounding parts.
Attachments
Thank you . I wish I had such a stock of 2SK389/2SJ109
Regarding spectrum, it is at the limit of my measurement possibilities. Now I am showing CCIF IMD of the preamp.
Unfortunately, I have not found any correlation between THD, IMD, square wave responses and resulting sound. I have a bipolar preamp and JFET-MOSFET preamp that measure quite same in all known parameters and measurements, but they still sound very different ...
Regarding spectrum, it is at the limit of my measurement possibilities. Now I am showing CCIF IMD of the preamp.
Unfortunately, I have not found any correlation between THD, IMD, square wave responses and resulting sound. I have a bipolar preamp and JFET-MOSFET preamp that measure quite same in all known parameters and measurements, but they still sound very different ...
Attachments
I have recently tested the bipolar preamplifier vs. the FET preamplifier both in a same conventional, 1U 440mm case. The sonic difference is easily audible.
Regarding the milled Al case - compared to the conventional case, it makes some difference. I would say like a difference between link level cables. That means, the difference in sound of bipolar vs. fet preamplifier is higher than the contribution of the milled Al case.
Regarding the milled Al case - compared to the conventional case, it makes some difference. I would say like a difference between link level cables. That means, the difference in sound of bipolar vs. fet preamplifier is higher than the contribution of the milled Al case.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Amplifiers
- Solid State
- pre standard two preamp, and development of measurement methods