Hi Walt,
If they are rated for 200 V or more, I'd just plug them into a AC outlet for a few days.
Cut a power cord in half, solder the caps between live and neutral, wrap it in a plastic bag for safety, and plug it in. Or you can install them temporarily in the phonoclone power supply, across the transformer primary. Whichever is easiest.
/R
all wired up and ready for the daughter board 
An externally hosted image should be here but it was not working when we last tested it.
My VSPS single board is running and it is surprisingly good. I'm using NE5532 at the moment (I think that's it) and will try OPA2134s, OPA2107s, OPA2227s as well as a few others. I don't expect a ton of difference with these. I may even try OP27 with a single to dual adapter (OP27 is a single, no?). Curious to play around with bipolar vs jfet input versions.
have a problem.. lol as always.
i have just measured the voltages one side is (36.9/V++V-- and 20.7/V+V-) the other is (17.9/V++V-- and 9.2/V+V-) at the boards and supply ends.
so with these measurements i take it one of my bridge rectifiers is fubar.
also the powersupply is buzzing like a good one.
i have just measured the voltages one side is (36.9/V++V-- and 20.7/V+V-) the other is (17.9/V++V-- and 9.2/V+V-) at the boards and supply ends.
so with these measurements i take it one of my bridge rectifiers is fubar.
also the powersupply is buzzing like a good one.
ok i made some bridge rectifier boards up but i seems i never done it right and blew the tracks off the board lol.
so here is my next try but before i go making these up could someone check to make sure i have it right this time.
thanks Bibs
so here is my next try but before i go making these up could someone check to make sure i have it right this time.
thanks Bibs
An externally hosted image should be here but it was not working when we last tested it.
output cap question
I am trying to wrap my head around what is needed to calculate what and why my the input impedance will be in my setup. I built a basically stock VSPS 300 except the output caps I want to use are 1uF multicap RTX. My tube linestage uses a pair of 12sn7's and the 100K input resistor connects to the grid of the tubes. I have been told that since the VSPS uses a shunt resistor (to bleed off the output cap, actual readings are around 68K) that that must be considered in the mix and the combined circuit will result in the VSPS output caps seeing an approx load of 42K. Does this sound right? Where would I measure this? I was trying for a -3db corner freq of 2 but this ends up around 3.8. What if a changes the line stage input impedance to 150K instead of 100K.
I am trying to wrap my head around what is needed to calculate what and why my the input impedance will be in my setup. I built a basically stock VSPS 300 except the output caps I want to use are 1uF multicap RTX. My tube linestage uses a pair of 12sn7's and the 100K input resistor connects to the grid of the tubes. I have been told that since the VSPS uses a shunt resistor (to bleed off the output cap, actual readings are around 68K) that that must be considered in the mix and the combined circuit will result in the VSPS output caps seeing an approx load of 42K. Does this sound right? Where would I measure this? I was trying for a -3db corner freq of 2 but this ends up around 3.8. What if a changes the line stage input impedance to 150K instead of 100K.
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i found my problem. i had the COM and V-- from separate rectifier boards switched round as i never checked the continuity of my wiring threw the cable/plug loom i made up. simple mistake as i had turned the plug upside down when soldering the wires on.. lol
luckily the boards acted like a fuse so its now just a case of making new boards which is fun anyway.
so my lesson learnt is always check for continuity before you go plugging things in.
luckily the boards acted like a fuse so its now just a case of making new boards which is fun anyway.
so my lesson learnt is always check for continuity before you go plugging things in.
everything up and running again.
phonoclone test values (as per instructions):
board 1 (left)
IC1, G + Pin4 = -9.9, G + PIN7 = -6.8
V++/V-- = 34.3
In+/In- = 0, Out+/Out- = 0.
board 2 (right)
IC1, G + Pin4 = -9.6, G + Pin7 = +9.6
V++/V-- = 34.3
In+/In- = 0, Out+/Out- = 0.
so it seams that there is something wrong.
phonoclone test values (as per instructions):
board 1 (left)
IC1, G + Pin4 = -9.9, G + PIN7 = -6.8
V++/V-- = 34.3
In+/In- = 0, Out+/Out- = 0.
board 2 (right)
IC1, G + Pin4 = -9.6, G + Pin7 = +9.6
V++/V-- = 34.3
In+/In- = 0, Out+/Out- = 0.
so it seams that there is something wrong.
Just wondering, if I turn off my VSPS before shutting down my amp (or even close enough that the caps have not sufficiently discharged) I get a turn-off buzz. It's quite short, but also quite loud (close to the sound of a loud record). Is this typical behavior? I added two caps for + and - supplies at the output of the PS before going through the power umbilical (and before the board) - I think they were @1000uF but not sure. Could they cause this?
Thanks. It's not a big deal but it'd be good if it didn't happen.
Thanks. It's not a big deal but it'd be good if it didn't happen.
@Bibio
My guess is IC3 is fried.. or inserted backwards?
@Carlp
No, haven't come across that and I can't see what could cause it. I advise you follow standard practice and mute the outputs when turning upstream components on or off. Note that a dull "thud" or "thump" on power up/down is normal, though with the VSPS its pretty mild: the LM7xxx regulators and op amps are designed to handle shut down gracefully, and the circuit capacitance is small.
My guess is IC3 is fried.. or inserted backwards?
@Carlp
No, haven't come across that and I can't see what could cause it. I advise you follow standard practice and mute the outputs when turning upstream components on or off. Note that a dull "thud" or "thump" on power up/down is normal, though with the VSPS its pretty mild: the LM7xxx regulators and op amps are designed to handle shut down gracefully, and the circuit capacitance is small.
Attachments
Thanks, Richard. The buzz is almost more like a zap that's drawn out for a second or two. Higher than 100hz (it's not 60 Hz hum). I wondered if it were related to extra PS capacitance I added, but that doesn't make sense to me. Anyway, my little 6BM8 DIY amp has no way to mute the outputs and has a bit of PS capacitance, so I almost always turn off the amp first, but the amp can still put out some punch after 15 seconds or so. If I'm in a hurry, I get the buzz/zap. On a 100 wpc home theater amp I got from the dump the other day, it was quite startling when it happened!
Anyway, I can live with it, but would love to get rid of it too. If I figure anything out I'll report back.
Anyway, I can live with it, but would love to get rid of it too. If I figure anything out I'll report back.
Sorry I can't help. The VSPS has an output coupling cap, so theres really nothing nasty that should come down the pipe on shutdown except for a very light, brief transient. I can only suggest its some sort of ground/earth problem specific to your system.
Try the guide, perhaps it might get you thinking in the right direction.
Try the guide, perhaps it might get you thinking in the right direction.
I get the same if I turn off my Preamp before I turn off the Power amp.
Solution? Never turn them off. I dont (unless I am away for 7+ days) then always turn the Power Amp of first and allow the PS caps to fully discharge before turning the rest off.
Could do with the VSPS, but the other is a tube amp. Not gonna leave those heaters burning all day and night. Plus I prefer to use energy consciously.
I can live with the shut-off noises if I have to, but if there's an actual fix I'd like to implement it. First step I should probably scope the output and see what's going on at shutdown (note I don't get any noise on power up). But I'm a bit over my head here, so any guidance from users out there would be appreciated.
I can live with the shut-off noises if I have to, but if there's an actual fix I'd like to implement it. First step I should probably scope the output and see what's going on at shutdown (note I don't get any noise on power up). But I'm a bit over my head here, so any guidance from users out there would be appreciated.