if you want to use your existing 500VA Donut , why not
on your boots , I would use separate Greatz bridges and cap banks per channel, which will give you at least partial benefits of proper dual mono arrangement
yes, wiring like shown in Papa's schematic
if you need more details, say
on your boots , I would use separate Greatz bridges and cap banks per channel, which will give you at least partial benefits of proper dual mono arrangement
yes, wiring like shown in Papa's schematic
if you need more details, say
I understand that duel PSU's are a good thing, but I was hoping to use these in my (ZenMod's Babelfish XA252 SIT) in a joint channel PSU of :-
450VA (22V)--Bridge---0.4mh---15,000UF 100V----2mh---330,000UF 40V (bypassed) to feed both channels. Bleed resistors used too.
As one can see, the large caps are huge, using a soft start and even possibly a S/S relay to let things settle before turn on. I imaging it's overkill to a degree, but having bought them some time ago, think they should at last be used.
(Apologies but I only mention this here because a similar issue was raised)
450VA (22V)--Bridge---0.4mh---15,000UF 100V----2mh---330,000UF 40V (bypassed) to feed both channels. Bleed resistors used too.
As one can see, the large caps are huge, using a soft start and even possibly a S/S relay to let things settle before turn on. I imaging it's overkill to a degree, but having bought them some time ago, think they should at last be used.
(Apologies but I only mention this here because a similar issue was raised)
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you know, when having so lucrative and tempting idea, there is no use of really going too much analytical
just go with way which is keeping your heart warmer
I remember having eeny Quad 33 preamp for few years - with (of course) outboard cap of 120mF; darn thing was singing 10mins after pulling mains plug
maybe even double that - can't remember really
now - little more analytical - not that you can't make XA252 with 22Vac secondaries ..... but I believe - for purity sake - that 24Vac secs are lowest advisable, thinking about puck capacitances and all
however, joy of building and using whatever you have&can&want is priceless
at least first 2V of difference ( between 24 and 22) are mostly of academic importance ...... but really not clever going more down
just go with way which is keeping your heart warmer
I remember having eeny Quad 33 preamp for few years - with (of course) outboard cap of 120mF; darn thing was singing 10mins after pulling mains plug
maybe even double that - can't remember really
now - little more analytical - not that you can't make XA252 with 22Vac secondaries ..... but I believe - for purity sake - that 24Vac secs are lowest advisable, thinking about puck capacitances and all
however, joy of building and using whatever you have&can&want is priceless
at least first 2V of difference ( between 24 and 22) are mostly of academic importance ...... but really not clever going more down
"darn thing was singing 10mins after pulling mains plug".
That REALLY made me laugh!
I have 25v toroids, so will possibly test both and aim for the desired rail voltage. Thanks.
(I've had these things for some time, they cost peanuts too, but they keep calling.."Use Me, Use me" who am I to say no!)
That REALLY made me laugh!
I have 25v toroids, so will possibly test both and aim for the desired rail voltage. Thanks.
(I've had these things for some time, they cost peanuts too, but they keep calling.."Use Me, Use me" who am I to say no!)
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if choice is between 22 and 25Vac Donuts - use 25
you'll end with approx. 31V5-32V5 ........... perfect
you'll end with approx. 31V5-32V5 ........... perfect
Thanks ZM
I also have a couple of dual rail cap multiliplier boards I could used - anyone any thoughts or experiences in this type of amplifier?
1. you need hefty final cap cell, same in size as in case without cap multiplier; think about dynamic reserve
2. think about additional dissipation - voltage sag across mosfet in cap. multi, roughly equal to Ugs of mosfet used; think of resorting to fat darlingtons instead, to decrease dissipation
cap multipliers - for A Class amps - they're regularly going in and outa fashion; I did tried them, and I'm not using them - but that's me; didn't found benefits greater than added complexity, at least when using overkill approach with same ol' PSU
Thanks again ZM. I have some of prasi's LT4320 CRC boards that could use - they're nice and chunky with space for caps up to 40mm diameter - or maybe just use some big screw terminal caps and hard wire something.
I've just seen your mail too, thanks - I'll sort out a payment this evening.
I've just seen your mail too, thanks - I'll sort out a payment this evening.
So, with two 300 mm x 165 mm MODUSHOP heatsinks joined as nautibouy has with u channel aluminum = I would use 6 inches channel depth - would this be sufficient for SINGING BUSH?
I figure everyone is reading these threads simultaneously so I posted here.
I am assuming devices would be mounted on each heat sink and not the channels? Doesn't matter to me - which is the best way? Mounting devices to the channels would be easier ...
Another assumption is that some kind of thermal goo would be between heat sinks and channels?
I will be using my fan for cooling so assumption number three is that no anodizing is needed for the channel pieces? Would like to avoid having to have that done since minimums for anodizing would make this a very expensive proposition.
Would that get the ZM's GOOD HEAT SINKING SEAL OF APPROVAL?
I figure everyone is reading these threads simultaneously so I posted here.
I am assuming devices would be mounted on each heat sink and not the channels? Doesn't matter to me - which is the best way? Mounting devices to the channels would be easier ...
Another assumption is that some kind of thermal goo would be between heat sinks and channels?
I will be using my fan for cooling so assumption number three is that no anodizing is needed for the channel pieces? Would like to avoid having to have that done since minimums for anodizing would make this a very expensive proposition.
Would that get the ZM's GOOD HEAT SINKING SEAL OF APPROVAL?
I can't answer about the singng bush but some info on my project.
150mm/6inch U channel is what I have used
I'm planning on mounting the devices on the sides of the U channel so they'll be positioned as close to the centre of the heatsink as I can manage.
That's my assumption too.
I want to avoid fans if I can. I'm not sure what to do with the interal chanels yet. I don't think they need to be anodised as I think they just need to conduct any heat to the finned heatsinks rather than be efficient at radiating heat - that doesn't seem desirable inside the chassis?
Is this what you're after?
150mm/6inch U channel is what I have used
I'm planning on mounting the devices on the sides of the U channel so they'll be positioned as close to the centre of the heatsink as I can manage.
That's my assumption too.
I want to avoid fans if I can. I'm not sure what to do with the interal chanels yet. I don't think they need to be anodised as I think they just need to conduct any heat to the finned heatsinks rather than be efficient at radiating heat - that doesn't seem desirable inside the chassis?
Is this what you're after?
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two pieces of 300deep, 165 high - these two are good for one channel of Singing Bush
you don't even need to spread them thermally together, it is enough that they're contained in same box ( sides) and that is enough of thermal spread
if you have 4 pieces of these, you're good for SB
sorry if that's the case (having 4 pcs) and I didn't got it earlier
Should I be concerned about the length of the wires that will connect the Tokin THF-51S devices to the PCB pads? I ask because I need to finalise where I am going to mount them on the heatsinks. I'm not advocating anything excessively long, perhaps 10-12cms.
covered elsewhere, zillion times, but anyway ...... I even forgot where
yup, no worries, just take care that SIT gate resistor is close to gate - soldered on end of thinner wire and heatshrinked
yup, no worries, just take care that SIT gate resistor is close to gate - soldered on end of thinner wire and heatshrinked
Only two pieces - will have to order another pair.
I am not using a metal case so I have no choice but to use channel or something? OR ...
If one put each device on its own heat sink will that suffice? I thought maybe the second heat sink needed to assist the SIT.
Thanks, nautibuoy for your notes.
The fan I am using is 12 inches in diameter/approx. 30 cm - using a step down transformer it cools a J2 mono and an SIT 1 - to just above warm - you can touch the SIT 1's heat sinks indefinitely without discomfort. Impossible to hear from three feet away - my chair is six feet further back (usually)/
It does take up more space than those little fans but I think it cools the amp more evenly.
I have made it obvious I am a bachelor using this. Only a most enthusiastic audio woman would put up with the extra clutter.
Just had a thought - since I have to order two more heat sinks I will get a pair of the largest ones Assuming the incomparable ZM thinks we should not use the channel pieces for mounting devices.
I am not using a metal case so I have no choice but to use channel or something? OR ...
If one put each device on its own heat sink will that suffice? I thought maybe the second heat sink needed to assist the SIT.
Thanks, nautibuoy for your notes.
The fan I am using is 12 inches in diameter/approx. 30 cm - using a step down transformer it cools a J2 mono and an SIT 1 - to just above warm - you can touch the SIT 1's heat sinks indefinitely without discomfort. Impossible to hear from three feet away - my chair is six feet further back (usually)/
It does take up more space than those little fans but I think it cools the amp more evenly.
I have made it obvious I am a bachelor using this. Only a most enthusiastic audio woman would put up with the extra clutter.
Just had a thought - since I have to order two more heat sinks I will get a pair of the largest ones Assuming the incomparable ZM thinks we should not use the channel pieces for mounting devices.
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@Rick
well, if for nothing else, then just for better sleep sake - I think there must be some heat-spread between output devices
per my experience, them being on separate heatsinks but in same box- is enough
how everything is going to behave not being contained in common thermal cell, I can't tell nor predict
now - your sinks (300deep, 4HE high) are OK for SissySIT, one per channel - if assisted with your humongous fan
for Singing Bush, counting on elevator Tokins , means measly 140W of heat per channel - I believe biggest Modushop (5U/500) should suffice ........ but I believe that one is made of 2 pieces of 250mm
anyhow - maybe entire Modushop case 5U/500 is nice and viable solution for you
though, I really need to look again at pics of heatsinks you sent me ...... sorta too much fuzz in my head these days, so forgetting is easy ........
........ and I did found them , and did took a look again - for SB - try first with those Dynaco sinks you have - you have 2 , so one per channel; if they're creeping above 55C even fan-ed, then you can say that you tried and you know you must change
if they're good, they're good
well, if for nothing else, then just for better sleep sake - I think there must be some heat-spread between output devices
per my experience, them being on separate heatsinks but in same box- is enough
how everything is going to behave not being contained in common thermal cell, I can't tell nor predict
now - your sinks (300deep, 4HE high) are OK for SissySIT, one per channel - if assisted with your humongous fan
for Singing Bush, counting on elevator Tokins , means measly 140W of heat per channel - I believe biggest Modushop (5U/500) should suffice ........ but I believe that one is made of 2 pieces of 250mm
anyhow - maybe entire Modushop case 5U/500 is nice and viable solution for you
though, I really need to look again at pics of heatsinks you sent me ...... sorta too much fuzz in my head these days, so forgetting is easy ........
........ and I did found them , and did took a look again - for SB - try first with those Dynaco sinks you have - you have 2 , so one per channel; if they're creeping above 55C even fan-ed, then you can say that you tried and you know you must change
if they're good, they're good
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Well, my Scots blood (thrifty is just an euphemism - we are simply CHEAP) compelled me to take a look at the heat sinks I had posted about earlier.
They actually weigh 14.25 pounds.
The area most likely to be used for mounting the two devices is approx. 7.5 mm in thickness.
That thin in width area of heatsink is at least 10 mm thick - doubt I would use that.
There is a small shelf section that is very thin - 2 mm? 25 mm deep 120 mm width - just guessing - but these are good guesses.
First photo shows the area I think I will use - this is 7.5 mm thickness area. This also shows the area with the very thick but narrow heat sink depth.
The second photo is missing that narrow thick area but shows the area I would think most useful for mounting the two devices. I figure SIT in the center - hockey puck to the right of it.
Third photo illustrates the think heat sink area and how narrow it is. About 70 mm.
I would think these are sufficient for the SINGING BUSH and with the fan more than adequate.
My thanks to JOTOM 750 for his 10 pounds of advice.
They actually weigh 14.25 pounds.
The area most likely to be used for mounting the two devices is approx. 7.5 mm in thickness.
That thin in width area of heatsink is at least 10 mm thick - doubt I would use that.
There is a small shelf section that is very thin - 2 mm? 25 mm deep 120 mm width - just guessing - but these are good guesses.
First photo shows the area I think I will use - this is 7.5 mm thickness area. This also shows the area with the very thick but narrow heat sink depth.
The second photo is missing that narrow thick area but shows the area I would think most useful for mounting the two devices. I figure SIT in the center - hockey puck to the right of it.
Third photo illustrates the think heat sink area and how narrow it is. About 70 mm.
I would think these are sufficient for the SINGING BUSH and with the fan more than adequate.
My thanks to JOTOM 750 for his 10 pounds of advice.
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