Tea-Bag's IXYS Depletion Mosfet Group and SemiSouth R100 JFET group buy.

[Tea-Bag]

J2?
I am just a parts man, not an idea man.

[william2001]

yeah, I know... just wishful thinking on my part. I'm just a lowly solder slinger / music enjoyer....

[carpenter]

My Semisouth jfets arrived... can't thank you enough, Tea-Bag. You'll never be old, over used, and washed-out in my book.

[generg]

Originally Posted by Tea-Bag

gernerg, Sorry these took so long to get. We had a several month lead time.

The one's I sent you are matched at 1.57vgs @ 1.3A at 24V.

I would suggest using a two set's of four on the negative rail. (output) You don't want the R100's as the current source.
You can lower the source resistor to .5R or .33R to bring more current to less parts. I can of course sell you more parts, maybe a set of sex with close Vgs, even two. if you want to trade your's back.
I would of course try to get a channel running successfully before ordering more. Make sure it's what you want to hear!

hi tea-bag,

the signal from front end goes through the set of three transistors connected
with the positive rail, the current sources, so the sound is also influenced by this parts?

[Tea-Bag]

Sorry Generg,
I think I had it backwards, so top is output.
from BA-1 article.
There is also a bias system for the negative half of the output stage formed by R216, R217, R218, R219, C207 and Q204. Q204 is a generic NPN transistor which sees the voltage appearing across the 1 ohm Source resistors of the negative half of the output stage and sets their value at about 0.6 volts, locking them in at a constant current value of 0.6A each. R219 is not ordinarily used here, but can be added if you need to reduce the current in an amplifier which is running too hot. If you need to use it, you can try values starting with 47 Kohm or so, decreasing the resistance for less bias current.


So the IRF240's would go on negative rail. D- is signal path and only goes to top half.

Does this make sense? I have not played with BA-1 since you caught the power labeling issue with right front end, my caps on the front end are blown

I did deploy this techique on the Mini-A, using R100 as output, and it sounds pretty nice.

[tubesguy]

Got 'em. Thanks for putting this together. - Pat

[generg]

[/QUOTE] .....
So the IRF240's would go on negative rail. D- is signal path and only goes to top half.

Does this make sense? I have not played with BA-1 since you caught the power labeling issue with right front end, my caps on the front end are blown

I did deploy this techique on the Mini-A, using R100 as output, and it sounds pretty nice.[/QUOTE]

Thank you tea-bag for correcting the statement, irritation is gone... I´am eager to try it. Your set of R100, I am waiting for it!

[drjbf1]

Thanks Tea-Bag, fets have arrived!

Does anybody know if F2 boards are still available from somewhere?

Thanks

[generg]

hi tea-bag,

maybe I just heard half of the heaven J2 promises....

I got your semisouth and put them together with the semisouth I got from magura in a BA-1. I left the IRF240 on the negative side doing the job as a current source and ,like Nelson would say, not to spoil the performance of the output stage by the gainstage I changed the IRF610 by a semisouth R100.

Wonderful performance, more details, voices totally different and subtle.

So I can wait for J2 in any version much better!

[Tea-Bag]

This is great news!
What did you do with the IRF610? That's a P-channel device, so R100 shouldn't work there. How many output's did you use? When I had this setup together, I used only one per channel, being cheap.
A picture!