Nice pix, Do. Those blue caps look nice and the heatsinks much larger than I would have guessed. Do they get hot?
Wolfsin looked high and low for the shot of MP3 & poutineI still order feijoada when I can find a Brazilian restaurant that serves it.
The blue caps are ClarityCap MR. The sinks are 2" high and they get to +/-55 Celcius. You can lower your Bias if they get too hot.
Keep looking for those pictures!
Ciao!
Do
Maybe yes, maybe no, there isn't any real data on Hynes' PSU.
Anyhow, I doubt if anything can beat the combination of TeddyRegs cascaded by Salas Shunts, while that combination is way cheaper than the Hynes' PSU.
How do you keep the ice off the one that gets to -55C? Which ones get hot and which get cold?
I must, of necessity, get vewy serious now. Finally located my pools of A970 and 2240 and should have one supply chain up with the 24v dual secondary r-core so I can check the margin available for sag on the 30v rails. Is any of that 30v-24v=6v available for sag or must the Kubotas hold a rock-solid 30v?
It is wonderful having some new faces here on the thread. Wolfsin promises to at least try to contain himself
It is wonderful having some new faces here on the thread. Wolfsin promises to at least try to contain himself
I must, of necessity, get vewy serious now. Finally located my pools of A970 and 2240 and should have one supply chain up with the 24v dual secondary r-core so I can check the margin available for sag on the 30v rails. Is any of that 30v-24v=6v available for sag or must the Kubotas hold a rock-solid 30v?
It is wonderful having some new faces here on the thread. Wolfsin promises to at least try to contain himself
What are the DC gain ranges for your A970 and 2240's? I have a bunch of each also.
The Kubota now works and easily holds 30v no-load. I had never previously used the transformer, rectifiers, or regulator so wanted to build and check the power chain for one channel. The load on the transformer will be about 50% of max as Do runs his. Unloaded it is generously above 24vAC. I will use some 24vDC bulbs and load the Kubota down and investigate the impact of common mode chokes before declaring it suitable and ordering parts for the second channel. As it is, my cost to replicate parts for one channel is ~US$90 shipped when the r-core can be found on sale (that seems to happen about once a month).
All I could think about all day was the power consumption, size of heat sinks, and their temperature. You really did me a major favor by posting pix of a finished unit, Do. I would never have allowed enclosure space for such large sinks. When they reach 55c is that encased or standing in open air?
@ticknpop "600,000uf Panasonics 1 mhy chokes and final 100,000uf Blackgates" How much do those chokes weigh. Are they common mode?
@dirkwright Gr. Alternates in Kubota BOM. BOM silent on gr or bl.
Stanton assured me that neither crd nor lm334 was 'right on' so I settled between them using 18.3 and 36.5r without adding tempco = 0 circuitry.
All I could think about all day was the power consumption, size of heat sinks, and their temperature. You really did me a major favor by posting pix of a finished unit, Do. I would never have allowed enclosure space for such large sinks. When they reach 55c is that encased or standing in open air?
@ticknpop "600,000uf Panasonics 1 mhy chokes and final 100,000uf Blackgates" How much do those chokes weigh. Are they common mode?
@dirkwright Gr. Alternates in Kubota BOM. BOM silent on gr or bl.
Stanton assured me that neither crd nor lm334 was 'right on' so I settled between them using 18.3 and 36.5r without adding tempco = 0 circuitry.
I believe it was open air but even enclosed with adequate ventilation they don't reach higher temps.
100000uF of Blackgates = 1000000000000$$$ Outch!
Try this store in France for R-Core. They have excellent pricing
http://www.selectronic.fr/c/lab/ele...urs-blocs-secteur/transformateurs-r-core.html
Do
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I meant for your particular stash of transistors. Mine seem to be bunched around a certain gain range, but one set barely overlaps the other so it's hard to find matches.
Chokes are Ei cores. Not very big 2 x 2 1/2 inch - got them surplus. Just picked up some .8 mh 20 amp ones on EBay.
Yes 100,000 uf Blackgate is big ouch $.
8 x 10,000 uf FK series (20,000 per rail) then 4 x 2,200 uf/100 v N series (1 per rail). Then 16 x 220/160v N for local decoupling on output Fets with lots of 0.47 NX. Driver board is all BG N. Good thing they stopped making them now I can waste money on things like rent, food, women etc.
Yes 100,000 uf Blackgate is big ouch $.
8 x 10,000 uf FK series (20,000 per rail) then 4 x 2,200 uf/100 v N series (1 per rail). Then 16 x 220/160v N for local decoupling on output Fets with lots of 0.47 NX. Driver board is all BG N. Good thing they stopped making them now I can waste money on things like rent, food, women etc.
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Thanks guyz for all that info. Yes, Do, ticknpop likes his Blackgates and the French r-core prices are as good as any I have seen. I am using experimenting with a bridged matching circuit so no longer know, or write down, the actual currents dirkwright. You choose a part, drop the rest in one by one and hope. It is much more efficient and you will get better matches doing it your way but the drifting and waiting did me in for power supply matches.
Your chokes are huge compared to the tiny cm choke I plan to use. If I wire the part as a differential choke I think it will not cancel since the current flows on opposing rails should be more or less opposite for high frequency noise so I think I should wire the 'dots' of both sides closer to the rectifiers. The schematic that elicited John's praise in the torch I thread has a broken link :-(
i
Your chokes are huge compared to the tiny cm choke I plan to use. If I wire the part as a differential choke I think it will not cancel since the current flows on opposing rails should be more or less opposite for high frequency noise so I think I should wire the 'dots' of both sides closer to the rectifiers. The schematic that elicited John's praise in the torch I thread has a broken link :-(
i
I used Nichicon Super Through on my AMB B24 amp. They're pretty good as well. But if you really want to spend good money, the Mundorf M-Lytic are really good!
Do
Auto parts stores are not particularly friendly places to shop for audio power supply loads. They can search by application or part number but the mention of current, watts, or anything but 12v brings blank stares or worse. Fortunately I have some low wattage path lights and did find a two-pack of auto signal lights so will be able to cobble something together. I have never bothered to watch a scope trace for noise previously but with a passive resistive load it shoud all be attributable to the supply.
The underside of the rectifier and caps board has a pair of parallel bars, one on each rail and then on the ground plane. SMD ceramics have been recommended for that location and there are locations on the top for larger caps. These are to limit high frequency transients but I am concerned that they will be at one end of the cable that will run several feet to the Kubota. Words of wisdom appreciated on choice of values for these.
The underside of the rectifier and caps board has a pair of parallel bars, one on each rail and then on the ground plane. SMD ceramics have been recommended for that location and there are locations on the top for larger caps. These are to limit high frequency transients but I am concerned that they will be at one end of the cable that will run several feet to the Kubota. Words of wisdom appreciated on choice of values for these.
NPO it is, then. At the other end the cable hits WiMA MKP2 then electrolytics again on the regulator. AFAIK neither of these boards was designed with several feet of stranded copper envisioned between them.
When loaded between 200-300ma the rectifier and caps board emits an audible hum. At first I thought it was the Kubota but definitely not. Tested both rails separately but not at the same time with same result. It will be housed externally and is barely audible but I was surprised. Loading with a series pair of 12v 4w path lights on one rail brings current nicely into range for testing.
It would be a little depressing if those of us posting in this thread turn out to be the only ones to build or have built JC-80s. It would make Do's offer to assist in procurement a breeze
When loaded between 200-300ma the rectifier and caps board emits an audible hum. At first I thought it was the Kubota but definitely not. Tested both rails separately but not at the same time with same result. It will be housed externally and is barely audible but I was surprised. Loading with a series pair of 12v 4w path lights on one rail brings current nicely into range for testing.
It would be a little depressing if those of us posting in this thread turn out to be the only ones to build or have built JC-80s. It would make Do's offer to assist in procurement a breeze
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