This is what I did say
Just do the counter measures, e.g. add the 4 capacitors, it does not harm anything. After that you will be sure it does not oscillate
These are the most important/relevant messages regarding PSU and Pre-Reg.
- Mpp #4375 PSU-pre-regulator.
- Mpp #4610 V2 Schemas UPS and Amp.
- Mpp #6506 CCS fine-tuning.
- Mpp #6462 PSU with my notes.
- Mpp #6809 Do not try to feed the CVS of the CCS of the shunt with a regulated power supply.
- Mpp #7127 More about transformer selection.
- Mpp #7635 Single and dual transformer wiring (also corrected drawing) (See also #7733).
- Mpp #7733 Grounding (PSU, RIAA and Player).
- Mpp #7810 35V PSU for the CroMagnon.
- Mpp #7830 The PSU explained.
- PradiseBuilders #13 Schema's and assembly guide.
- PradiseBuilders #155 Vdc input voltage minimum simulated.
- PradiseBuilders #970 PSU oscillates; posible solutions?
- PradiseBuilders #983 Compensating the PSU for oscillations.
- PradiseBuilders #1130 Updated 'Paradise R3 assembly guide'.
- PradiseBuilders #1173 Fixing oscillations (up to #1182).
Thanks for your considered opinion, however the matter has already been rasied much earlier in the thread and I know two other builders using one transformer secondary shared across two rectifier boards who had hum.
Well established grounding techniques are more than sufficient to ensure complete absence of hum in a single transformer PS. In this respect the Paradise is no different to any other high gain phono pre. The dual mono design may simplify grounding in particular circumstances but is most definitely not a requirement. It may, otoh, have sonic benefits, although taking into account the separate regulators i wonder how much could it possibly help.
After playing around with grounding the R3 now is almost hum-free except at high volume but i suspect that is just with any phono stage. Will still be looking at the compensatory caps-Thanks Frans and the Faraday cage suggestions as per Alfred.
good to hear, many thanks
the "cage" idea is actually the result of one of JG' s postings over at the "blowtorch" thread to which john curl responded. JG uses blnk PCBs for that purpose, i found (relatively) cheap copper sheet metal at the local home depot for the same thing...
credit where credt is due ;-)
Thanks guys and my thanks in return for designing the Paradise 
At the moment the p/s consists of a 50VA transformer;two bridge rectifiers and two 10,000uf caps feeding both channels and is completely silent.The finished article will have dual supplies with CLRCLC p/s pcb's[thanks Simon]
Once again a big thank you to all; back to listening.
At the moment the p/s consists of a 50VA transformer;two bridge rectifiers and two 10,000uf caps feeding both channels and is completely silent.The finished article will have dual supplies with CLRCLC p/s pcb's[thanks Simon]
Once again a big thank you to all; back to listening.
You can build a one-transformer-psu that does not hum. See the grounding schemes that are posted and see what RCruz (and others have accompliced)
My 2 cents if I may
I have been using dip switches for quite a while and the same as you do
but you have to many wires there as clever paradise boards have spare set of input pins nothing is stopping you to solder the compensation there
after all you just putting a resistive value in parallel to the cartridge winding.
and if constant fiddling is not required this can be done on Little daughter board to fit perfectly maybe even with smd components.
what about same capacitors loading?
ahhh, many thanks to hinting me on that. I understood and will change. signal direct to pcb and the loading in extra line between the spare input option.
, clever.best regards,
stefan