@peppennino
I got a PSU pcb gerber from Ben Mah.
https://www.diyaudio.com/community/threads/diy-front-end-2022.394339/post-7313031
I got a PSU pcb gerber from Ben Mah.
https://www.diyaudio.com/community/threads/diy-front-end-2022.394339/post-7313031
I'm getting a huge DC voltage at R5 (16.83V), where it has been advised to measure DC offset. Is this normal?
I am using the meanwell 36V power supply used for the Sony VFET amp, as I wanted to test this for using as a front end in that amp. It is running through Mark Johnson's TUBA filter. The voltage out of that filter comes out to 33.95V. So, PSU is single ended and input signal is also single ended.
I have R7 = 332, R6 = 750R, R1 & R2 = 10K
It plays fine if I let the DC voltage bleed off before turning on my amp.
I have taken the following measurements:
Comp Value Voltage Voltage across R
R5 100R 16.83V 0
R6 750R 32.53 .742
R7 332R 1.335 1.334
R8 100R .859 .857
R9 46.7R 33.28 .671
R13 10R 33.16 .115
I am using the meanwell 36V power supply used for the Sony VFET amp, as I wanted to test this for using as a front end in that amp. It is running through Mark Johnson's TUBA filter. The voltage out of that filter comes out to 33.95V. So, PSU is single ended and input signal is also single ended.
I have R7 = 332, R6 = 750R, R1 & R2 = 10K
It plays fine if I let the DC voltage bleed off before turning on my amp.
I have taken the following measurements:
Comp Value Voltage Voltage across R
R5 100R 16.83V 0
R6 750R 32.53 .742
R7 332R 1.335 1.334
R8 100R .859 .857
R9 46.7R 33.28 .671
R13 10R 33.16 .115
Attachments
Finally got around to finishing my FE 2022.
I went with matched 2SK170s from punkydawgs. Panasonic 3.3uf polypropylene caps with WIMA 0.1uf FKP under the PCB. Had an Audio Note 100K volume pot in my stash so I used that. Using a Mean Well 48VDC SMPS with the DIYAudio Store SMPS filter. Bought a matching case to my Darlington Labs MP8B phono preamp to package everything in.
Powered it up and it’s already making really good music. Will take a while powered up for the caps to settle in until I can fully evaluate. But it’s sounding pretty damn nice from the start. But there is a slight increase in the noise floor compared to the el cheapo Nitsch Piety I was using to control volume before. Probably replacing the 100K pot with a 10K one will cure that.
Still to do:
DIY is fun!
I went with matched 2SK170s from punkydawgs. Panasonic 3.3uf polypropylene caps with WIMA 0.1uf FKP under the PCB. Had an Audio Note 100K volume pot in my stash so I used that. Using a Mean Well 48VDC SMPS with the DIYAudio Store SMPS filter. Bought a matching case to my Darlington Labs MP8B phono preamp to package everything in.
Powered it up and it’s already making really good music. Will take a while powered up for the caps to settle in until I can fully evaluate. But it’s sounding pretty damn nice from the start. But there is a slight increase in the noise floor compared to the el cheapo Nitsch Piety I was using to control volume before. Probably replacing the 100K pot with a 10K one will cure that.
Still to do:
- Add 3mm blue power-on LED
- Counterbore front panel then anodize black to match my Darlington Labs MP8B
- Replace AN 100K pot with TKD 2CP-2511 10K unit.
- Experiment tapping into my amp’s B+ for 44VDC to replace 48VDC SMPS
DIY is fun!
Attachments
