Hi All,
I would be very interested in an Itch PCB,
My Itch is currently not working, my point to point skills are terrible. I would really appreciate getting this up and running again as it sounded great!
Would love it to be optimised for the SSHV2 psu, and easy swap out of tweakable components.
Most importantly, low noise.
Many thanks
Ian
I would be very interested in an Itch PCB,
My Itch is currently not working, my point to point skills are terrible. I would really appreciate getting this up and running again as it sounded great!
Would love it to be optimised for the SSHV2 psu, and easy swap out of tweakable components.
Most importantly, low noise.
Many thanks
Ian
I'm still tinkering with this. Here is an updated mock up. Two layer board, 170mm L x 152mm W. Red is the top layer, blue is the bottom layer.
Major changes:
Removed heater tracks
Pushed the ground track to the bottom layer and added a copper pour (the big blue rectangle)
Added a second capacitor in parallel to C3 to make it easier to use two capacitors to get to 15.75 nF (Marked as C3A and C3B -- C3A is spaced for a .015 uF film; C3B is spaced for a 750 pF Silver Mica).
Other changes are giving the B+ traces some more width and breathing room. I've moved around a number of other components to simplify the signal traces.
The other idea I'm considering is removing the valve footprints from the board entirely, allowing a more symmetrical layout with the intention of wiring the valve sockets offboard.
Major changes:
Removed heater tracks
Pushed the ground track to the bottom layer and added a copper pour (the big blue rectangle)
Added a second capacitor in parallel to C3 to make it easier to use two capacitors to get to 15.75 nF (Marked as C3A and C3B -- C3A is spaced for a .015 uF film; C3B is spaced for a 750 pF Silver Mica).
Other changes are giving the B+ traces some more width and breathing room. I've moved around a number of other components to simplify the signal traces.
The other idea I'm considering is removing the valve footprints from the board entirely, allowing a more symmetrical layout with the intention of wiring the valve sockets offboard.
Awesome -- thank you for the feedback! Updated version attached with revised part sizes and some mounting holes that should align to the 10x10 grid on the HiFi2000 base plates.
Are the R8 grid resistors too far from V2?
Separately, as I prototype my PSU, I read on the SSHV2 thread (post 4797) that voltage dividers can potentially mess up the force/sense mechanism in the SSHV2. Is it recommended that the voltage divider for the V3/V4 heater ground actually come off the rectified, filtered DC before it goes into the SSHV2? Just want to confirm.
Thanks again.
Yes the R8s are far and there is space to place them closer. You could use new blue traces for that purpose.
That divider move was a recommendation for a reported problem with B+ sag on a different phono. The guys in this thread used the voltage divider for heater elevation normally at the output of the reg I think. Merlin, where have you located it in your builds? At raw DC or after the SSHV2 at B+?
That divider move was a recommendation for a reported problem with B+ sag on a different phono. The guys in this thread used the voltage divider for heater elevation normally at the output of the reg I think. Merlin, where have you located it in your builds? At raw DC or after the SSHV2 at B+?
Not really, unless it has bad quality for the job. Its for filtering noise that may couple at the heater elevator line. Choose a low 100kHz impedance type. Or you may use a film cap instead. Because B+ dividers for heater elevation reference are high impedance its easy to filter them with few uF. Film cap filters more HF than any quality lytic, especially if its legs are kept short.
Thanks — Force/Sense lines connected to both the voltage divider and B+, correct?
Thanks again — test PSU is working great with the SSHV2 and an LT1083 running at 6.3v on elevated ground (divider after the SSHV2). I have a bunch of eBay acquired LT1083 variable circuit PCBs that I’m using for the PSU prototype, but they aren’t sufficiently heatsinked, so just good for now for testing. I’ll definitely take a crack at a PSU board once I get the main one figured out.
Hi Again,
Can I make request regarding the PCB's?
Salas very kindly did a relay input circuit so one could switch between MM/MC.
Valve Itch phono
Could this be incorporated, and a way to connect step-up transformers?
And a power LED.
Thank you so much for your efforts!
Ian
Can I make request regarding the PCB's?
Salas very kindly did a relay input circuit so one could switch between MM/MC.
Valve Itch phono
Could this be incorporated, and a way to connect step-up transformers?
And a power LED.
Thank you so much for your efforts!
Ian
