I have a switch installed.
Will run it for some time before messing with it.
First time since start that i feel like i´m ahead of it.
Thats great!
I'm really looking forward to your progress..
Regards
M. Gregg
Just a few tests,
1st stage CCS now has CC 330 Ohm + Ferrite bead.
2nd stage CCS still 270 Ohm + Ferrite bead.
The bead is insulated from the resistor leg (on the gate side) with PTFE sleeve.
No instability and highs are more open..
New 716 orange drop in the PI output to 6C33C's just for a test...burn in taking place...curiosity!
Looking at cathode CVS across existing resistors....
Regards
M. Gregg
1st stage CCS now has CC 330 Ohm + Ferrite bead.
2nd stage CCS still 270 Ohm + Ferrite bead.
The bead is insulated from the resistor leg (on the gate side) with PTFE sleeve.
No instability and highs are more open..
New 716 orange drop in the PI output to 6C33C's just for a test...burn in taking place...curiosity!
Looking at cathode CVS across existing resistors....
Regards
M. Gregg
Measurements tells that bias voltage in the output stage must be stabilized.
The amp delivers about 10watts before it drifts due to lack of stability.
It drifts of into classB land when run hard.
A zener referenced fet will do the job as constant bias voltage i hope.
Another way is to run it hotter someone experienced please shout if i´m on the wrong track.
The amp delivers about 10watts before it drifts due to lack of stability.
It drifts of into classB land when run hard.
A zener referenced fet will do the job as constant bias voltage i hope.
Another way is to run it hotter someone experienced please shout if i´m on the wrong track.
I'm currently experimenting with a MOSFET with a zener in the cathode-circuit replacing the resistor, a pot between the gate and the earthy end sets the bias, 'fine-tune'.
I have retained the de-coupling-cap, but guess it could be omitted....
Initial results are promising....
The fet is definately 'fast' enough to respond to changes in cathode-current on its own.
I left the de-coupling-cap in for fear of possible stability issues, as when I tried something similar a few years ago, I suffered from some hideous oscillations that at that time I could not cure.
I cant remember if I had a de-coupling-cap in circuit at the time though...
The cap certainly wouldn't be detrimental as I see it, The fet referenced zener replacing the resistor completely...
The perceived sound is certainly extremely good, I havent noticed any real change in it so far....
I left the de-coupling-cap in for fear of possible stability issues, as when I tried something similar a few years ago, I suffered from some hideous oscillations that at that time I could not cure.
I cant remember if I had a de-coupling-cap in circuit at the time though...
The cap certainly wouldn't be detrimental as I see it, The fet referenced zener replacing the resistor completely...
The perceived sound is certainly extremely good, I havent noticed any real change in it so far....
Now there´s equal pieces of sand and glas in the amp
Interesting....
Have you done any measurements yet?
I guess no
....I see a difference two of them have more diodes?
So is the bias setting different?
Regards
M. Gregg
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I´m fiddling around with bias.
Lets say one channel is heating the house better then the other right now.
I want to run them a bit hotter but i have no clue where they perform the best and when they start dieing prematurely.
I´ll try some different settings and see how it goes.
Please chip in with some guidelines here
Lets say one channel is heating the house better then the other right now.
I want to run them a bit hotter but i have no clue where they perform the best and when they start dieing prematurely.
I´ll try some different settings and see how it goes.
Please chip in with some guidelines here
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