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Sorry i posted to thread about dc heaters and thought maybe i should have made a new one here
Doesn't appear to have obvious problem , but I can't believe it could make it to market like this
haven't found anyone else with one to compare , I did try replacing all filter caps , very little difference
contacted soldano , they suggested a resistor change , [ or sending it back to them ] little difference
best results i got were changing the pcb grounding [ separating the psu from the preamp and grounding back
at the transformer , any experience or ideas ? tia
-other post - i made to d.c. heater thread
Let me know if I should start another thread , but I have a hum problem with a friend's Japanese soldano sp 77
Separating the psu and preamps grounds reduced the hum by 50% [ all one pcb ] but there is still some higher frequency hum left
which is regardless of preamp gain , but becomes more obvious with master vol settings , even with the last of 4 tubes left in
you can hear it once master pot reaches the 1/2 way mark then gets worse as it gets higher .
the filaments are a.c. heated and just centre tapped to ground , so
I wondering if anyone can suggest an " easy " circuit to convert to d.c. ?
not sure how much it may help so straight forward would be appreciated , tia
Doesn't appear to have obvious problem , but I can't believe it could make it to market like this
haven't found anyone else with one to compare , I did try replacing all filter caps , very little difference
contacted soldano , they suggested a resistor change , [ or sending it back to them ] little difference
best results i got were changing the pcb grounding [ separating the psu from the preamp and grounding back
at the transformer , any experience or ideas ? tia
-other post - i made to d.c. heater thread
Let me know if I should start another thread , but I have a hum problem with a friend's Japanese soldano sp 77
Separating the psu and preamps grounds reduced the hum by 50% [ all one pcb ] but there is still some higher frequency hum left
which is regardless of preamp gain , but becomes more obvious with master vol settings , even with the last of 4 tubes left in
you can hear it once master pot reaches the 1/2 way mark then gets worse as it gets higher .
the filaments are a.c. heated and just centre tapped to ground , so
I wondering if anyone can suggest an " easy " circuit to convert to d.c. ?
not sure how much it may help so straight forward would be appreciated , tia