Mr Pass's other new creation - the J2 - only has a measly 4 JFETS, but they are very special JFETS indeed, with a price to match. There is a group buy building up at the moment on diyaudio, estimated price $50 each (sic) if anyone is interested. Super expensive for a transistor, but what would you pay for an exceptionally good valve . . .
Anyways Nelson reckons the J2 is the best First Watt yet, which means its must be an outstanding amplifier, and 25 wpc to boot.
First Watt J2
#1 First Watt J2
"Its good enough for Government work."
#2
yeah but no but yeah but.......
Papas being a bit more cautious with this one, there won't be any schematic until the last one has gone out of the production shop
+
the semisouths are not actually available yet and he has the first order for them
+
he's teasing the OT mob to try and second guess the actual schematic from the modular diagram in the owners manual....
this all adds up to a non practical projatct at the moment afaics cos there will be a few expensive guesses to begin with......
unless I've missed something more recent
Papas being a bit more cautious with this one, there won't be any schematic until the last one has gone out of the production shop
+
the semisouths are not actually available yet and he has the first order for them
+
he's teasing the OT mob to try and second guess the actual schematic from the modular diagram in the owners manual....
this all adds up to a non practical projatct at the moment afaics cos there will be a few expensive guesses to begin with......
unless I've missed something more recent
There's nowhere you can be that isn't where you're meant to be
#3
Ed
you are right, he has got p****d off with people ripping off his designs so he is going to build/sell 100 before he releases the full schematic. I don't reckon it will take him long to do that. In the meantime the Group Buy organiser does seem to be in a position to make a bulk purchase.
cheers
Ian
you are right, he has got p****d off with people ripping off his designs so he is going to build/sell 100 before he releases the full schematic. I don't reckon it will take him long to do that. In the meantime the Group Buy organiser does seem to be in a position to make a bulk purchase.
cheers
Ian
"Its good enough for Government work."
#4
Nice, solid state µ follower, though the block diag looks more like a SRPP. There is almost the same shape on page 6of the device specs
http://www.semisouth.com/products/uploads/AN-SS1.pdf
http://www.semisouth.com/products/uploads/AN-SS1.pdf
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
#5
Some extracts from the FW Information Sheet on the J2 (minus the diagrams referred to):
Here is a slightly simplified schematic of the J2 circuit. It could be a classic tube amp, except that the P channel input JGETs would have to be fabricated from anti-matter.
The single-ended Class A output stage is "second harmonic†in character, and it uses about half the feedback of a comparable MOSFET circuit but with half the distortion and twice the bandwidth.
The J2 power amplifier is simple, clean, and measures astonishingly well. The design is extremely reliable and will never need adjustment. It achieves a sound which is warm and relaxed, combining precision and detail without sterility. With a pair of sensibly efficient loudspeakers, it will give you a toe-tapping experience that other solid state amplifiers do not.
I love the anti-matter reference.
Here is a slightly simplified schematic of the J2 circuit. It could be a classic tube amp, except that the P channel input JGETs would have to be fabricated from anti-matter.
The single-ended Class A output stage is "second harmonic†in character, and it uses about half the feedback of a comparable MOSFET circuit but with half the distortion and twice the bandwidth.
The J2 power amplifier is simple, clean, and measures astonishingly well. The design is extremely reliable and will never need adjustment. It achieves a sound which is warm and relaxed, combining precision and detail without sterility. With a pair of sensibly efficient loudspeakers, it will give you a toe-tapping experience that other solid state amplifiers do not.
I love the anti-matter reference.
"Its good enough for Government work."
#7
Ian mentioned this to me in a email yesterday, great minds and all that. Looks like the SJEP120R125 is obsolete now.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
#8
there are loads of guys on diyaudio who have bought quantitys and are packaging them up for sale in 2s and 4s matched, teabag immediately springs to mind...
prices are ultra reasonable. I'm currently creeping up on an F2J, hence the sale of a rocky to make space....there are 2 SS jfets that currently drop in, the original is still available but there is a newer replacement...I forget the number, but think it might be R100.or R170...
checkout the group buys and pass section on diyaudio.
prices are ultra reasonable. I'm currently creeping up on an F2J, hence the sale of a rocky to make space....there are 2 SS jfets that currently drop in, the original is still available but there is a newer replacement...I forget the number, but think it might be R100.or R170...
checkout the group buys and pass section on diyaudio.
There's nowhere you can be that isn't where you're meant to be