Sound & Comfort MC/MM Phono preamp

[spaceistheplace]

Eager to see your progress here. The arduino control is a much needed update to Phono designs I think.

 

[Koifarm]

One year later and still i have the arduino controll not ready. Yhis winter i am rebuilding the house of my daughter. Just spare time to read the forums, no time to diy audio.

 

[Sodacose]

Hi Koi, I started exploring a similar opamp+tube idea this summer but haven't implemented it yet. I'm really happy to see you found success with this approach.

One thing I'd like to do is derive opamp power from a 6.3V winding. I'd employ a doubler, LM7812, and rail splitter to make adding the opamp RIAA section simple for tube-based builders (where 6.3Vac is ubiquitous). It requires a couple more caps, of course, but that seems like an ok price to pay for power supply simplicity to me.

Do you have any thoughts on this or did you explore any similar ideas? Would love to read your thoughts/experience.

 

[Koifarm]

Hello Sodacose, i never use voltage doublers. They have much bigger voltage rimple with you need the surpress/regulate. Best i like battery supply for first stage in phonopre. The tps regulaters for the opamp in the sound & comfort amp are one of the best. Humm is my biggest dislike.

 

[Sodacose]

Thanks for the thoughts, Koifarm! I do plan to regulate after the doubler, though I agree that usual FW bridges are preferable. This is a compromise to try to avoid another power transformer. Will have to see if it works ok.

I'll take a look at the TPS parts, too. Good tip!

 

[Koifarm]

See post 1