I got interested in Toshiba's 2SK2013/2SJ313 MOSFETs last year when estman, a forum friend, sent me generously a set of dozen j313s. They impressed me with their superior linearity of transfer characteristics but not until recently (when I got the N-channel complements - k2013) I could not try them in classical push-pull circuit.
Using them in F5 (3 pairs per channel at +/-20V, 400ma per MOSFET for total bias of 1.2A per channel) transformed it into amp that leaves no wishes open.
Schematics and pics are here:
Novi amp sa 2SK2013/2SJ313 - DIYAudio.rs
Using them in F5 (3 pairs per channel at +/-20V, 400ma per MOSFET for total bias of 1.2A per channel) transformed it into amp that leaves no wishes open.
Schematics and pics are here:
Novi amp sa 2SK2013/2SJ313 - DIYAudio.rs
I'm sure the Mastah will also enjoy your creativity.
Can't help mentioning the 6 amp peak output current limit, 5 pairs would be costly but balance the SK56 more, which is also expensive.
(If Dorian Grey would still be around he'd likely start a lengthy itinerary about 10 pair/ch balanced TXF5.
)
Bravo again, the dirty dozen rules the forum galaxy.
Can't help mentioning the 6 amp peak output current limit, 5 pairs would be costly but balance the SK56 more, which is also expensive.
(If Dorian Grey would still be around he'd likely start a lengthy itinerary about 10 pair/ch balanced TXF5.
) Bravo again, the dirty dozen rules the forum galaxy.
Just like other Japanese trannies, they are actually quite cheap if you buy in sufficient quantity.
The price of this pair I get from Avnet is even quite a bit cheaper than IRFP240/9240.
So everyone should be able to easily afford a dozen unmatched pairs without dropping a sweat.
The price of this pair I get from Avnet is even quite a bit cheaper than IRFP240/9240.
So everyone should be able to easily afford a dozen unmatched pairs without dropping a sweat.
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Thanks Jacco,
yes, 3 pairs per channel seems thin, but it's all I got right now
Nevertheless, amp drives happily my speakers (Canton ct-1000 and Epos M5 which go down to 3.5 Ohms) and in burn-in test (24 hours at max power - 18Vpeak, driven with 10khz sine wave and loaded with RCL combo of 3.5 Ohms) temperature on MOSFETs never rose more than 26 degrees Celsius above ambient, so I think it's safe to build and use this amp.
Hi Patrick,
remember, we are still waiting for the result of "beast with 1000 JFETs"
yes, 3 pairs per channel seems thin, but it's all I got right now
Nevertheless, amp drives happily my speakers (Canton ct-1000 and Epos M5 which go down to 3.5 Ohms) and in burn-in test (24 hours at max power - 18Vpeak, driven with 10khz sine wave and loaded with RCL combo of 3.5 Ohms) temperature on MOSFETs never rose more than 26 degrees Celsius above ambient, so I think it's safe to build and use this amp.
Hi Patrick,
remember, we are still waiting for the result of "beast with 1000 JFETs"
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After this one, I tend to even more agree with device's-linearity-is-everything philosophy, and I finally have not a slightest complaint about the amp.
I might yet build a SuSy circlotron with LU1014 out of curiosity, but fiddling with ZVP/ZVN and similar small devices is definitely not my thing
I might yet build a SuSy circlotron with LU1014 out of curiosity, but fiddling with ZVP/ZVN and similar small devices is definitely not my thing
Hi,
Would this version,with a pair of output, be good as a lineamp?
Bests
Of course it will, actually that's the first thing I've done - headamp with 1 pair
It's very silent amp (even without cap multipliers) but you have to be aware of the heat
I did play with the value of the bias current and, to my ears, these MOSFETs sound best at Id between 400 and 500 mA. If you are brave and lower a PS voltage a bit (say +/-16V) at Id=600mA you'll have additional advantage of zero tempco.
Also, in this case you don't have to worry about low Vds becaus parasitic capacitances are very low (compared to usual HEXFETs) and you just want to drive a single pair.
If you do it please post your results, it would be great to see a lineamp getting hotter than many power amps...
...... a lineamp getting hotter than many power amps...
that's familiar to me , in more than one occasion and from more than few reasons .....
Yeah, that's the one - supplied with shunt regs, it gives a small contribution to a global warming process...
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