Hi Minoas, I got your name from hr. Piersma. I can offer you a nearly complete 2 ulti-amps PCB's and components without enclosure and heatsinks. Are you still interested? You can mail me freddyjazz freca@casema.nl bye Fred
Recently came back to this build as well as the ultra folded phono. Finished the phono, now finishing up this one. Just need to wire from IEC outlet to transformer primaries and secondaries to power supply board. Also need to wire the mounted volume control to I-select. and output rca to pre board's outs.
Is there a diagram of the dual transformer hook up to the power supply? I am using two Antek AS 0518 transformers. All boards are mounted, power supply wired to pre board, just need to finish this up to go with the new phono!
Thanks, Russellc
Is there a diagram of the dual transformer hook up to the power supply? I am using two Antek AS 0518 transformers. All boards are mounted, power supply wired to pre board, just need to finish this up to go with the new phono!
Thanks, Russellc
Nope, same questions. I used to have all this stuff ready to go, book marked. New lap top, time goes by. going through thread, cant remember how secondaries are grouped where they go into Power supply. should have finished this a long time ago. Really pleased with the phono unit.
Russellc
Russellc
Thanks! Almost ready to fire up, I re-found the fire up instructions Can't weight to hear it with the phono unit.
I have a chassis mounted fuse by the IEC plug, is that the fuse you are referring to?
Yep. Put 2.5A slow blow there. Should be good for two 50VA trafos on 120VAC mains.
Not quite ready yet, just finishing up. I got this thing 80 percent done and stopped. Same with the phono pre. I'm on a roll, finished phono pre and now finishing out this one. Too many back logged projects, Im powering through some. Then on to unfinished power amps! Beginning to see the top of my dining room table. Before power up I will retest power supply, submit a good pick of my units insides after I've starred at it back and forth. then fire up, adjust Dc, add eight legged creature....I will probably have another question before then Im sure.
Russellc
I use a variac to fire up as well, little by little look, measure temps voltages, little more...with this unit as well as the phono unit, I bought the big packages with all the matched parts, the last thing I want to do is destroy one of those parts. I start to get paranoid and ask more questions right before fire up.
Will double check fuse. Seems like I remember asking this before and using that value. I had this thing mostly done and didnt get time for it. Looking forward to getting this in system.
Russellc
Ok, reached one of those places where I need to stand back for a minute, and look again. I have previously tested power supply, which worked properly at the time. It was not in the case, but the LEDs on the board all lit up, voltage was fine.
Have it in box, but I have done something wrong. Double Antek 50 VA transformers, like many here have used here. on primary side, black leads from primaries together, red primaries together.
Secondary side, secondaries pairs, one green, one blue together, other green and blue separate making the three points to go to preamp board. For right now, they are attached to a terminal block. Thought it might be a good idea (turns out it was) to temporarily hook up variac to primaries and make sure secondaries are measuring correctly. As I dialed up the variac, I started seeing voltage, but the transformers were heating up like crazy and I shut it down.
Stared at it for stupid hook up trick for some while, so started undoing secondary leads from terminal block, and it occurred to me that on many of the DIY Pass amps I've built, proper grouping of secondaries is crucial. I dont know if it would make a difference, but I don't know if I (already disasembled before this occurred to me) "grouped" the two wires, one green one blue improperly that go together or if it would make a difference?
These transformers both got quite hot, like the metal washer was darn warm! If the grouping could possibly do it, I will dive back in. You would think I would of had a fiftly/fifty chance of getting one of them right darn it.
Russellc
Have it in box, but I have done something wrong. Double Antek 50 VA transformers, like many here have used here. on primary side, black leads from primaries together, red primaries together.
Secondary side, secondaries pairs, one green, one blue together, other green and blue separate making the three points to go to preamp board. For right now, they are attached to a terminal block. Thought it might be a good idea (turns out it was) to temporarily hook up variac to primaries and make sure secondaries are measuring correctly. As I dialed up the variac, I started seeing voltage, but the transformers were heating up like crazy and I shut it down.
Stared at it for stupid hook up trick for some while, so started undoing secondary leads from terminal block, and it occurred to me that on many of the DIY Pass amps I've built, proper grouping of secondaries is crucial. I dont know if it would make a difference, but I don't know if I (already disasembled before this occurred to me) "grouped" the two wires, one green one blue improperly that go together or if it would make a difference?
These transformers both got quite hot, like the metal washer was darn warm! If the grouping could possibly do it, I will dive back in. You would think I would of had a fiftly/fifty chance of getting one of them right darn it.
Russellc
Sorted the secondaries, about to try again. at 100 volts I can begin to feel the warming up, never noticed how quickly and how warm a preamps transformers got. Better hold off until I get some feed back. Feeling them now, having been turned off a few minutes the transformers are still warm. Not hot, but they got warm so fast I am suspicious. At one time, I had the transformer bolts undone and tipped the case up, transformers slide and rolled out of case. Not extreme, but did exert pressure on the primaries, perhaps the were damaged, I dont recall them getting hot when previously tested.
Russellc
Russellc
If the transformers will work alright disconnected from the board terminals but they still heat up when connected, see if a fuse has gone on the DCSTB PSU indicating some problem further down the line like a bridge diode maybe is broken or something's wrong with a ground or a shorted DC output exists, or a broken PSU transistor, something.