We continue the program with Soren just having received his MASSIVE 60-watt Edcors, which look great. Anyway, the choke (hammond 193k) hasn't arrived yet, but after looking at some stuff in PSUDII, I have a couple more questions about my choke power supply. With a 47uF input cap and 150uF cap after it, this choke with a H of 2.6, DCR of 21 and mA handling of 300mA sees around 1.9A in a big spike that settles down pretty quickly to 300mA (this is with a 300mA load). I'm just wondering whether I should be concerned with this spike. I can't be overloading the choke with the 47uF input, right?
Try stepping the current from 30mA to 300mA and look to see if there's any low frequency oscillation. Set the time scanned to be 3 seconds or so. Then try stepping from 300mA to 30mA. The stepped load is very good for revealing underdamped power supplies. Juggling the value of the first capacitor often helps.
By the way, motor start capacitors are notoriously unreliable. Use motor run.
By the way, motor start capacitors are notoriously unreliable. Use motor run.
Well I stepped it from 30mA to 300mA after 2 seconds, and still got a spike up to around 1.25A that "rang" above and below 0A with 9 peaks in the first 1/2 second, then it quieted down. The problem is, I already lowered the second cap to 47uF so my CLC was 47uF, 2.6h/21R, 47uF and I'm still having this problem 
Another thing I'm considering (although it would take around $250 more that I don't have just yet) is to go with monoblock config. I realize that the load per channel is 130mA and not 150mA btw. In any case, I'm considering using a 5AR4 for full-wave rectification of a 300-0-300V 272JX. It'd still use a CLC filter, but in this case both C's would be two 50uF 500V sections of a chassis-mount can cap (I'm a sucker for those) and the L would be a Hammond 193J, which offers 10H/82R/200mA. The biggest spike I'm seeing with this config is around 700mA, and it's a lot lower than 1.2A, that's for sure... With soft-start enabled, however, seeing as this _is_ a vacuum rectifier, the biggest spike is 170mA, so I think I might be good
Another thing I'm considering (although it would take around $250 more that I don't have just yet) is to go with monoblock config. I realize that the load per channel is 130mA and not 150mA btw. In any case, I'm considering using a 5AR4 for full-wave rectification of a 300-0-300V 272JX. It'd still use a CLC filter, but in this case both C's would be two 50uF 500V sections of a chassis-mount can cap (I'm a sucker for those) and the L would be a Hammond 193J, which offers 10H/82R/200mA. The biggest spike I'm seeing with this config is around 700mA, and it's a lot lower than 1.2A, that's for sure... With soft-start enabled, however, seeing as this _is_ a vacuum rectifier, the biggest spike is 170mA, so I think I might be good
Try raising the second cap to ~300uF rather than lowering it. Use a thermistor on the primary to cut inrush down.
I think you need to use Hammond 193M (10H, 63R, 300ma) rather than 193J. If your buying all this iron, consider choke input (may need 193Q, 10H, 53R, 500ma $63 from Angela Instruments). You might do something like this stero psu to save money over mono while having good channel separation as so:
........R-C
L-C<
........R-C
The 5AR4 isnt instant on, it should mitigate the startup inrush, should it not? PSUDII assumes the heaters are already hot.
I think you need to use Hammond 193M (10H, 63R, 300ma) rather than 193J. If your buying all this iron, consider choke input (may need 193Q, 10H, 53R, 500ma $63 from Angela Instruments). You might do something like this stero psu to save money over mono while having good channel separation as so:
........R-C
L-C<
........R-C
The 5AR4 isnt instant on, it should mitigate the startup inrush, should it not? PSUDII assumes the heaters are already hot.
Tweeker said:
At this point, I'm fairly certain I'm going to go with dual-mono. This project is probably the only tube amp I'll have until I'm out of college and have a real job, so I don't want to have any regrets. Plus, monoblocks just plain look cool
. In any case, this is the latest iteration of a PSU design. I was considering using a CLCLCR with a 350V transformer but honestly the price would go through the roof. http://img227.imageshack.us/my.php?image=hkul6l6psutd5.jpg
the main reason I can't do that is that my PT is only 275V, so best-case scenario, I can get 364V with _minimal_ filtering i.e. a small choke. If I want to really filter the heck out of the power, I need to start with a higher voltage because of the drop. I'm even considering getting a 350V model, using vacuum rectification, a CLC filter, and a final RC filter to bring the voltage down to something workable. This monoblock style with a 272JX feeding a 5AR4 feeding a CLC filter with the 193M and two 50uF LCR can sections is probaly what I'm going to go with. Just gotta wait a few (many) weeks until I can scrounge the cash. It'll be worth it, I suspect.
One last thing though - if I were to stick a 100+uF motor run cap in the CLC filter just described, it'd be best after the choke, right? I do have a Xicon 47uF 450V axial that I could use instead.
One last thing though - if I were to stick a 100+uF motor run cap in the CLC filter just described, it'd be best after the choke, right? I do have a Xicon 47uF 450V axial that I could use instead.
o i didnt look at that one, the one i have is a toroid from antek that puts out 275v ct into 500mA. i love the current, but the voltage is killing me. in any case, do you recommend the 279X? how much voltage can i expect using a 5ar4 to rectify that 425v in full wave? the circuit specifies 385v, and i'm not sure that i can easily bring 600VDC down to that.. or do the 5ar4 and/or chokes drop the voltage more than their specs entered into psudii would predict? it's getting confusing..
A Graetz bridge with the Antek toroid would give lotsa voltage, probably more than youd want even choke input (~475ish?).
The 425-0-425 would give somewhere around ~375V with 5AR4s and 193J choke input.
Im cant give very exact answer due to transformer regulation / source resistance vagaries I cant model without more data on 279X.
The 425-0-425 would give somewhere around ~375V with 5AR4s and 193J choke input.
Im cant give very exact answer due to transformer regulation / source resistance vagaries I cant model without more data on 279X.
just for fun I ran a PSUDII with the 550V (series) connection on my toroid, with impedance of 44 ohms in the wiring.
Rectifier
BRIDGE of 2 5U4GT's
CLCLCRC filter
C1 40 600V
C2 20 600V
C3 20 600V
C4 20 400V
L1 10H 53R .5A 1KV (Hammond 193Q)
L2 5H 26R .5A 800V (Hammond 193P)
R1 620R 20W
output B+ = 381V @ .001V hum
Obviously this is an insane schematic but I guess that if I really wanted to run stereo, I could do this.
Rectifier
BRIDGE of 2 5U4GT's
CLCLCRC filter
C1 40 600V
C2 20 600V
C3 20 600V
C4 20 400V
L1 10H 53R .5A 1KV (Hammond 193Q)
L2 5H 26R .5A 800V (Hammond 193P)
R1 620R 20W
output B+ = 381V @ .001V hum
Obviously this is an insane schematic but I guess that if I really wanted to run stereo, I could do this.
I bought some of those Antek toroids on E-bay. I have that one, and I get about 325 volts using a 5AR4 (resistor in series with one of the 6 volt windings to make 5 volts), or 350 volts with SS FRED diodes. I would think that a series connected winding (550 volts) would give you far too much voltage even with a choke input.
There is a bigger toroid that I got also (don't remember the exact specs, and Ebay is blocked at work). I get almost 500 volts from that one while running a stereo 6L6GC SE amp using SS rect and 460 volts with a 5AR4. It has plenty of capacity to run a stereo PP amp.
There is a smaller (100VA) toroid that has two 200 volt windings. I got two of them thinking that I would use one for each channel with a bridge rectifier on the series connected windings. I am currently running the amp (both channels) off of one transformer and the only thing that gets hot are the 6L6's. I am feeding them 485 volts. The plates glow dimly with the room lights off, but it sounds so good, and the tubes cost $4 each, so I have been running it that way for a while. The transformer runs cooler than the Hammond that was there previously.
The 279X looks very nice, but are you sure that 150mA is enough for one channel? According to some folks on diyTube, the wattage on this schematic was limited by the OPT, and as mine is capable of 60W, I can theoretically hit the circuit's actual maximum power of 40W. If this were to be the case, would I need to have a bigger PT in order to accommodate that realized potential? If not, I'm ready to start sketching up plans with this PT.
One question: where do I stick the 100uF motor run caps? Do I really need all that capacitance? What kind of voltages are we talking about here on the caps? I'm looking at a nice can cap by JJ that offers 40+20+20+20uF at 500V, would that be all right?
One last thing - are you absolutely sure I should use the 279X? One slightly lower-voltage model, the 274BX at 375V/175mA, looks nice and is even cheaper... In PSUDII I found that a 300VAC PT through a 5AR4 and a medium-sized choke put out around 370V into .13A, I'm guessing this isn't quite correct?
Anyway, I look forward to hearing your feedback. I've learned a fair bit since i've started, but very very far from all
One question: where do I stick the 100uF motor run caps? Do I really need all that capacitance? What kind of voltages are we talking about here on the caps? I'm looking at a nice can cap by JJ that offers 40+20+20+20uF at 500V, would that be all right?
One last thing - are you absolutely sure I should use the 279X? One slightly lower-voltage model, the 274BX at 375V/175mA, looks nice and is even cheaper... In PSUDII I found that a 300VAC PT through a 5AR4 and a medium-sized choke put out around 370V into .13A, I'm guessing this isn't quite correct?
Anyway, I look forward to hearing your feedback. I've learned a fair bit since i've started, but very very far from all
The 279X is 186VA, you can come much closer to this rating when using choke input.
Rect-L-C. 375Vish would be on the caps, but dont use 400V unless you already have them, Id use 450V or 370VAC. You could get away with less at the cost of higher filter Q, possible ringing. The caps are cheap enough it didnt make sense to skimp on them, but I dont know chassis space. I like oil motor runs better than elcos, and so far as filter performance goes more is better, but space may constrain this.
Added: you need to make sure your modeling with an LC filter in PSUDII for choke input, change that first filter section.
OK, I'm getting nice results with a choke-input filter. Just to make sure, I'm posting a schematic of what I think you mean.
C1 can either be a nice 470uF 400V Rubycon I have or maybe two paralleled sections in a 200+200uF 500V LCR can.
However, the voltage that I simulate is around 360. Would it be at all possible to use the 282X at 500VAC, keep that choke input filter and tack on a 330-ohm resistor at the end? Kind of like this:
I could also make the last resistor 470 ohms and get an end result of around 373VDC into .13A if that's preferable.
An externally hosted image should be here but it was not working when we last tested it.
C1 can either be a nice 470uF 400V Rubycon I have or maybe two paralleled sections in a 200+200uF 500V LCR can.
However, the voltage that I simulate is around 360. Would it be at all possible to use the 282X at 500VAC, keep that choke input filter and tack on a 330-ohm resistor at the end? Kind of like this:
An externally hosted image should be here but it was not working when we last tested it.
I could also make the last resistor 470 ohms and get an end result of around 373VDC into .13A if that's preferable.
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