It is said that the Bias has unusual, low coils resistance for an MM. Something around 170 Ohm. I would use a 50K trimmer instead of an input load resistor. No extra capacitor than what the TT cables bring themselves. I would hunt with the trimmer for anything 2kOhm up for best balance. Its probable that you will soon agree that is a much more productive method for shaping MM/load curves, once you will try it. I wouldn't be surprised if its nicer around 8k-10k in the end. You can sub the trimmer for brown Dale anywhere you will settle.
No 12AX7 please. Possible grid leakage and other noises problems. Use the input tubes listed. They are dirt cheap to get anyway.
If you mean kinda vintage coloring cap, then maybe vitamin Q.
No 12AX7 please. Possible grid leakage and other noises problems. Use the input tubes listed. They are dirt cheap to get anyway.
If you mean kinda vintage coloring cap, then maybe vitamin Q.
I'm collecting parts for the SSHV Mofet Shunt reg. for my Valve Itch. I still have some IRFP9240 from a previous project (Steve Bench phono). Can I use these in place of IRF9610 (Q1)? My regulator version will be that of the Evolution/Update link in the SSHV thread.
Many thanks and regards.
Many thanks and regards.
Hi Salas,
Appreciate the advice, doesn't make sense to push the reg too hard or bump up distortion in 2nd stage.
To run 6n1p @ 150V, 7mA would I need to change R9 & R11 ? Even though it's supposed to be near replacement of 6h8c, it has very different plate curves at that op. pt. : ~ -2.3V versus 6h8c's ~ -4V.
This from data @ Tube Tester Files - 6N1P - 6H1?
At 300V B+ would you still recommend some sort of clip-on heatsink for the MPSA94 ?
Thanks,
Peter
Make the 6N1P cathode resistors 330R so it runs at 100V across, 3mA, 1V cathode. The supply should be divided equally across tubes and 33k load.
Use the SSHV schematic as included in this thread in Fran's .xls with BOM. Since the MPSA is TO-92 and its going to get 210mW with 5K6 load, better put some makeshift fin or proper TO-92 hat on it, they fall fast from dissipation spec once in hot surroundings.
Use the SSHV schematic as included in this thread in Fran's .xls with BOM. Since the MPSA is TO-92 and its going to get 210mW with 5K6 load, better put some makeshift fin or proper TO-92 hat on it, they fall fast from dissipation spec once in hot surroundings.
OK guys, hope your 1% Riaa caps will arrive well. I took the GB posts out as discussed with Merlin so the thread cleans up after you concluded your mini GB.
I'm fixing to build one of these, this looks like a great project. I've built a few amplifiers but never studied a phono pre, so this is somewhat new territory for me. Exciting stuff. I really appreciate all the effort that's been put into this thread.
I wonder if someone could tell me what I would need to do to use a MM cart instead of MC. Is it as simple as just dropping the step up transformer and bringing the input as a voltage across R1?
I wonder if someone could tell me what I would need to do to use a MM cart instead of MC. Is it as simple as just dropping the step up transformer and bringing the input as a voltage across R1?
Oh yes. I've built or repaired a number of amplifiers. I just finished one Monday night. My new amplifier is the reason I'm ready for a new phono pre. All of a sudden my existing phono pre sounds very inadequate.
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