I would just make a 2 pair out of your design. The 2 pair mt-200 (or
semelab MGxxxx) would be a healthy 200W+ OPS.
In the space where the middle pair is - place the OP inductor.
I plan on keeping 2 of my old 5 pair OPS's in 3 pair mode - they are
nearly perfect thermally on a 3U.
I really want someone to build the new 5 pair OPS , even "blow us away"
with the maximum ( a 80V rail 5- pair MT-200 ultra monster).😀
OS
That will not be me as i don't see what i will do with that monster in 15m² listening room. The +/-50VDC choice in fact is because i have 4 nice 500Va 2x35V Rcore trafo. I will use one per chanel.
For MT200 what would be your choice : 2SC2922/2SA1216 or 2SC3264/2SA1295?
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That sounds like a good one for you to build. Are you rebuilding you big amp or is this another project?
Nice trafo's !!
2922 vs. 3264 = almost the same.
Cob and ft are similar.
3264 is a bit faster/newer model.
3264 is higher voltage , better SOA @ 60V.
With your 53-54V rails ( I have a 35-0-35 as my tester trafo) ,
both would be the same.
OS
My big amp would most likely keep on ticking for 20 years , If I did not
bring it outside or party with it.
I'm scared if I do , my center pair will fail if I push to my thermal limit.
I have my protection sensor right over the center output - because I
know that one is the weak link.
I also know without distributing that heat equally , I don't have as powerful
an amp as should be (derating). Centers are 10C hotter than outers.
I don't need that much power , an "ultimate monoblock" wealthy builder
could buy a 1KVA trafo for each channel , embellish with 100Kuf.
He would then have 2 Pass X250's to power his 10K$ speakers.😀
OS
So more "Uni", inductor in the midle, but keeping the other package possibility as the pair output....
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Ostripper, why didn`t you use diamond input OPS, you got about 2 x 0.7V bias voltage canceling and easier connection with gain stage at only one spot, perfect current amplifier module block 🙂 . IMHO it sounds better too.
I'm your man.....would only need to put the os together and could go right into it's home. +-82 volt 800 watt supply and big heatsinks.
Then with the extra space left over near the fuses , reposition and
allow for a 16-18mm main decoupling caps.
18mm is still the same 7.5mm LS and can be 2400uf@ 63V/1800@80/1K-100.
16mm can be 1800/1200/820u.
Those electrolytics at the output collectors are not essential. If they are too
small , your rails will "ring".
My idea for these on the slew V1.x came from the edmond stuart "camp".
They used no main decoupling , Just 4 smd 100-100V units at the collectors.
No inductance before the collector pads.
Omit them and just use a big 1Kuf at the beginning of a 30A Imax rail , you
would see the same signal at the collectors.
The secondary decoupling that feeds the driver/pre-driver rail is 4.7R -10R
plus a 47-470uf R/C combo. (below 1) green = R/C at drivers , red= the cap multiplier output.
The multiplier is a real good edition (below 2)green = input pair pssr , red= the final amp output after NFB.
This with a CFA !!! -120db is very good. That is why no slewmaster blows
up. Also , the ops is the best to compare with ... as CFA and VFA are
both have quite low PSRR. Some VFA's can drop to -150db using the multiplier.
OS
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Hi
Is these type of transformer better quality than Plitron LONO.
I have to order 2PC 32V 100VA transformer. I know Plitron great quality but I never had the chance to test one like yours on the picture.
Greetings
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You realize the V2.0 OPS will even fit the same bolt holes ?
Not much redrilling. Use the same HS's.
The secondary decoupling can be 2X 470u and the primary can be 2 X 1000uF.
A 500W amp like this would need .01-.03C/W (7U 300+mm) of sink.
There is no way a V1.x OPS could dissipate that amount of heat.
All 5 would be in the thermal space of just positions 2-4 on the new OPS.
Pair 1 and 5 on the new one would be 200mm apart.
ONLY 50mm left to each end of the sink. ALL the outputs would therefore
have about the same dissipation area (on a 300mm extrusion).
PS- .01 would be a 20C rise at <2KW. .02-03 would max out at 65C.
This would be absolutely necessary to dissipate up to 2KW. Even
with a 7U , you might need a bit of fan to help convection.
This amp would be in the realm of ESP #117 -Project 117
The warnings apply to the new slew , as well.
About half of it. 500/800W. Best power to size ratio.
For ESP's project , 1500W is in the realm of class D or H.
OS
My current set uses per channel:
8" of this heatsink 10.080" Wide Extruded Aluminum Heatsink - HeatsinkUSA
800va transformer
two bridge rectifiers
crc fiilter 27000uf .0825ohm 27,000uf
The heatsink with the OS attached just slips up out of the chassis. If it is needed I could slip in a longer piece of the heatsink extrusion.
I need to get thermal interface for the big transistors.
E
8" of this heatsink 10.080" Wide Extruded Aluminum Heatsink - HeatsinkUSA
800va transformer
two bridge rectifiers
crc fiilter 27000uf .0825ohm 27,000uf
The heatsink with the OS attached just slips up out of the chassis. If it is needed I could slip in a longer piece of the heatsink extrusion.
I need to get thermal interface for the big transistors.
E
Thermal interface comes with Sanken devices. If it doesn't, email them and complain. I got 10 free pairs that way.
That will work. So you are 8" X 10" ,wide that is 1.6X what I have. If my
150W OP's were spaced , my whole HS would idle at <40C.
230W (devices) would idle at the same temp biased to 60ma. Your extra area
would be reserved to dissipate actual audio wattage.
You would be low 30's on idle , might bump 55C if you pushed 1/2kw
for a time. Music would be 40's.
The new board is exactly 10" , BTW. Your wires at the interfaces would be
right at the edge of your heatsinks. You seen it , huh ?
OS