IXYS depletion MOSFETs: What are they good for?

[tiefbassuebertr]

Originally Posted by flg

O.K. I think we've all seen the Depletion Mode MOSFET Zen Lite variant displayed by N.P. at BA'09. Personally, I did not know that part existed? But, it appears to have some quite conveniant qualities:
Suitable Voltage rating, Current rating, self biasing like the LU1014D, "Idss" of about 2.5A, Rthjc .31 C/W, plenty of S.O.A., fairly linear C in our typical operating range, and by all accounts so far, fairly linear and good sounding. Oh yea, affordable price in small enough orders. Did I miss something?
I'm not so interested in another Zen Lite but as I've seen recently, I'm not the only one interested in creating a monster B1 circuit. I was thinking of paralelled LU1014Ds with car battery rails. This device can take that idea further and easier as Paul Hynes did a few years ago (someone posted an AudioCircle link around here somewhere). I've also played with the Circlotron circuit quite a bit and it's very nice but, with self biasing and ground refrenced input as Paul Hynes has already done also wow
Personally, I can't wait to play with this part. There is a GB thread started to research the interest in obtaining some.
So, I thought I'ld get us all started on a discussion for everyone's benifit. Oh, yea, another great quality, N.P. seems to like this part too...
Any other comments? questions? previous experiance? Ideas?

I have found a distortion removal circuit of the japanese URL
Distortion removal circuit
this circuit could be very interesting for the new IXYS MOSFETs after performing the appropriate modifications for depletion mode versions.
Here the automatic translation in English
Google Übersetzer

[JPeitzman]

Sorry to dig up an old(ish) thread, but I didn't think this belonged in the "DeLite" thread, though the same device.

I am pinking up a few of these to play with (building a DeLite, just to simple to pass up), and had a quick question. Being depletion mode, could one build a bigger, higher current B1 out of these to drive speakers?

Also, I know you are a very busy man Mr. Pass, but any new news from Jack or about the transformer circuit?

Thanks!

James

[flg]

see post #2 Some ones been there done that

[revintage]

Hey flg,
Checked your simplified circuits and it won´t work as shown in the first figure with two similar(?) depletion mode above each other as you have drawn. To define drainvoltage of the lower device the upper FET may be arranged as a voltage-controlled gyrator. Just a matter of adding a few components.

What might be the the biggest challenge is to deal with the high Ciss of the IXTH20N50D that Nelson used. About double of a IRFP240. Maybe one of smaller IXYS with lower Ciss could be used....

[flg]

Well, they were "simplified" idea's. I left some obvious parts out

[revintage]

Still I think we have something going here. Will do an "expanded" schematic of your fig. 1 together with a few sims to get some indications.

[Nelson Pass]

Originally Posted by janneman

Then I got in contact with Jack Elliano of Electraprint Audio. He can do one for about $ 75, and he is willing to sell me a prototype which can be tested and then if necessary to be returned to him for final design. However, the shipping to my home in Holland is $ 50 each way, so I may end up with $ 100 in shipping for a $ 75 xformer. Since I have a perfectly working Nemesis with the original xformers, I think I'll pass for the new xformers.

I suggest that someone in the US will take this on, the shipping will be (much) less, but he/she must be able to measure the xformer as to freq response, undistorted power and preferably distortion versus frequency. Anybody game?

A pair of these just arrived from Jack. I'll let you know
how they work out.

[revintage]

Hey,
Are Jacks transformers also 2:1 as Nemesis?

[JPeitzman]

see post #2 Some ones been there done that

Wow, apparently I need to open my eyes, sorry HA, it even says "monster B1", terrible.


James