don't think
400mA times 24V is 9.6W
Means the devices would heat up to >80C + temperature rise of the heatsink. (22.5C ambient)
Keeping the dies under 100C would require a 2C/W heatsink for each output device.
Check for yourself how large the heatsink would be.
(or a 0.33C/W heatsink for 6 devices)
Juma, as described in the Serbian forum, used a Fischer SK 56 (30 x 15 x 4 cm) heatsink and reported a temp rise of 21°C.
That heatsink will suffice to dissipate the 9.6W x 6 without becoming too hot (>50-55°C)
That heatsink will suffice to dissipate the 9.6W x 6 without becoming too hot (>50-55°C)
Means a minimum die temperature of 94C at 25C ambient.
Raise the dissipation to 9.6W and die temperature will reach 110C !
(me head count, do the exact math yourself)
Raise the dissipation to 9.6W and die temperature will reach 110C !
(me head count, do the exact math yourself)
As Jacco noticed, power dissipation was my primary concern when I decided to use cap multiplers to lower the PS voltage to +/-20V DC (the transformer I used is 2x19V AC). Not that these MOSFETs are that fragile, but I don't like running things on the edge - reliability is my fetish, I drive Japanese cars only... 😉 Soon I noticed that amp sounds better with cap multiplers so I kept them.
Juma, you convinced me, thanks.amp sounds better with cap multipliers
Jacco, as you quoted, I don't think, while you've done the math 😀
I've checked RS, Farnell and Mouser, but I can't find the output Mosfets. Any idea about their availability? Can they be substituted with K1058 and J162? Thanks.
...Can they be substituted with K1058 and J162?...
It will work, but it won't be the same amp...
Juma
you have lowered power lowering rails to 20 V
Is 400 mA @ 20 V the sweet pot
can power be increased If we add more pairs and use original F5 24 V rails
have you think to do balanced amp
you have lowered power lowering rails to 20 V
Is 400 mA @ 20 V the sweet pot
can power be increased If we add more pairs and use original F5 24 V rails
have you think to do balanced amp
Juma
you have lowered power lowering rails to 20 V
Is 400 mA @ 20 V the sweet pot
can power be increased If we add more pairs and use original F5 24 V rails
have you think to do balanced amp
It's 400mA per MOSFET = 1.2A per channel. Raising the rail voltage, adding more pairs, bridging, going balanced, SuSy - they are all viable options, but I already found what I like the best.
thx for your reply
can I change original F5 1 pair with 3 pairs 2sk2013/2sj313
power supply Is unregulated 23 V total bias 1.6 A
will I get better sound running with more than 1.2 A
regards
can I change original F5 1 pair with 3 pairs 2sk2013/2sj313
power supply Is unregulated 23 V total bias 1.6 A
will I get better sound running with more than 1.2 A
regards
go back one page and read ;
it's already asked and already answered
think about dissipation per mosfet
it's already asked and already answered
think about dissipation per mosfet
I have to say, I find this idea very interesting. Are there any other reports listening reviews from people that have replaced the native outputs of the F5 with 3 2sk2013/2sj313?
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