He probably hasn't.
The only limiting feature of the SIT amp is the lower power rating and the lower damping factor making speaker selection more critical.
On the right speakers I can't imagine anything much better than SIT1 and 2.
The only limiting feature of the SIT amp is the lower power rating and the lower damping factor making speaker selection more critical.
On the right speakers I can't imagine anything much better than SIT1 and 2.
"The output impedance (including 6' of speaker cable) was low, at 0.08 ohm at 20Hz and 1kHz, rising very slightly to 0.1 ohm at 20kHz"
😀😀😀
I always wanted to know what is impedance of Atkinson's 6' of speaker cable 😀
It looks like he should to change those 6 ' of twisted pairs 🙂
😀😀😀
I always wanted to know what is impedance of Atkinson's 6' of speaker cable 😀
It looks like he should to change those 6 ' of twisted pairs 🙂
Very impressive!
I might be wrong, but at first glance it looks like the FE isn't really dissimilar from the DIY Sony VFet amp... and component values are silkscreened 😀
I might be wrong, but at first glance it looks like the FE isn't really dissimilar from the DIY Sony VFet amp... and component values are silkscreened 😀
The pics are beautiful. Why the 6 x 1 ohm resistors between the drain and the power supply? My guess is that this the only way to measure the bias current through the transistor since there are no degeneration resistors at the source.
It could also be part of the 10A protection. Or both used to set bias and a place to monitor current during operation.
It could also be part of the 10A protection. Or both used to set bias and a place to monitor current during operation.
A small revision on the boards and I put the values on. Nelson has them all in his head I don't.
Ooo these tease pics are always fun!
So we've got output zoble network now and those little silver caps make a reappearance.
I know that all the real magic is in the output stage but the front end voltage gain is also intriguing. based on the description in the latest owners manual, the front end sounds like mini F5 with cascoded input Jfets ?
So we've got output zoble network now and those little silver caps make a reappearance.
I know that all the real magic is in the output stage but the front end voltage gain is also intriguing. based on the description in the latest owners manual, the front end sounds like mini F5 with cascoded input Jfets ?
I just saw Massimo's post and yes the front end does look to me like the diy vfet front end 😀
but all the mystery here is the op stage and its biasing arrangements ...
but all the mystery here is the op stage and its biasing arrangements ...
I wonder if there are any advantages of the boards revisions in terms of performance, or mostly due to manufacturing/cost/and other mass production things?
Per the picture, the OPS looks to me to be biased by 2 x TL431, no degeneration, and 6 // 1 ohm resistors between each drain and the power supply to monitor current in the OPS.
At 10A peak, the parallel resistors will consume 1.67v of the power supply. Any voltage greater than 1.67v across this resistor bank will trip the protection circuit.
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