Thanks! I am looking forward to listening to this piece. The last thing I want to do is screw up placement of the 2 most difficult to obtain parts! I am going to arrange them as Teabag suggested.
As many others have done, I bought the CMR 2.2 uF 400 volt caps, still considering which for the other cap position, looks like Mundorf is popular there. I need to study others comments on those.
Russellc
As many others have done, I bought the CMR 2.2 uF 400 volt caps, still considering which for the other cap position, looks like Mundorf is popular there. I need to study others comments on those.
Russellc
Another happy UFSP builder. I finished the raw built today.
A big thank to Salas and Tea-bag for their excellent work!
I adjusted the raw psu to 35V and has arround 9V reading on t. p.
Only after I reduced the voltage to 30V it was possible to set the 4V at the t. p.
So far so good.
Stupid as I am I have then switched the input switches under voltage and t. p. was 0V
I'm afraid I killed the 2sk369, or what is the weakest part in the input stage?
A big thank to Salas and Tea-bag for their excellent work!
I adjusted the raw psu to 35V and has arround 9V reading on t. p.
Only after I reduced the voltage to 30V it was possible to set the 4V at the t. p.
So far so good.
Stupid as I am I have then switched the input switches under voltage and t. p. was 0V
I'm afraid I killed the 2sk369, or what is the weakest part in the input stage?
Just tested my RAW power supply, from ground to either side 44.5 v, from side to side also 44.5 v (which did surprise me).
Can the regulator portion be fired up while not connected to the amp board, or does it need some kind of load?
Looks like leaving the links from the reg board to the amp board would do this, but assuming (like usual) power supply can be fired up with no load. Taking no chances with this nice piece of kit...
Russellc
Can the regulator portion be fired up while not connected to the amp board, or does it need some kind of load?
Looks like leaving the links from the reg board to the amp board would do this, but assuming (like usual) power supply can be fired up with no load. Taking no chances with this nice piece of kit...
Russellc
The raw PSU is unregulated and 44~45v is normal, I think anything <50v is ok (Salas should confirm). The difference between loaded and unloaded voltage will really depend on the xfmr and how much sag it has under load. It is a odd that you measured 44.5v between poles and also to ground, not sure what to think of that?
Another happy UFSP builder. I finished the raw built today.
A big thank to Salas and Tea-bag for their excellent work!
I adjusted the raw psu to 35V and has arround 9V reading on t. p.
Only after I reduced the voltage to 30V it was possible to set the 4V at the t. p.
So far so good.
Stupid as I am I have then switched the input switches under voltage and t. p. was 0V
I'm afraid I killed the 2sk369, or what is the weakest part in the input stage?
Hi, is it an MM configuration? That one usually tends to want lower rail voltage setting. You normally can't kill something with operating the input load switches under power. Unless you manipulated the gain/bias configuration rest of switches. Try with more rail voltage to see if TP rises again before its sure something has broken. Check that gain mode switches and your preferred input load switch are set adequately before powering up.
Those are two independent positive raw supplies, each one uses a different AC secondary, has its own rectifiers and own DC zero return point (cold). They are not symmetrical to double from hot to hot. As they are floating at the moment they have no common ground.
Because of the moderate 0.1A current limit in the shunt regulators CCS section when R1 is 5.6R you can test them without load. But they should be bolted and insulated to chassis for sinking. M2s will be dissipating 3.5W each at 35V output when unloaded. Shunt regs share power with their load. Without one they consume it all by themselves.
I'm getting 45 volts off the RAW PS board. I didn't describe how I measured very well.
With black multimeter lead on center ground and red on the + pad on either side produced 45 volts with variac "set" at 120 volts.
So no load is needed on phono amp side, leaving the PSU in and PSU out unlinked? I can then test regulator, or is another way best to proceed?
Thanks
Russellc
Salas do you think since it's a single xfmr with the same primary and split secondary they are somewhat balanced so once rectified they are probably both floating about the same from ground and each other?
There is a 10 Ohm common reference to PE riding Yin Yang diodes. A safe mains ground lift. So they float about the same from that ref point.
Ok that makes sense and I now remember the 10 ohm resistor to ground - does that explain the same reading to ground and supply to supply? Or is it just happenstance?
