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About joeBerlin

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  1. Now (2 years later) I found some time for the project, but... Module 1: has SJ79-trouble - 2 sets went off in smoke, obviously in the power up phase. Maybe during power up + and - behave somehow differently or whatever, at least I think I have to deal with the situation that somehow more than the allowd 200V U_DS (with the 15 mA limited current) can occur. As protection I thougt of 1) 2* 1N53718 60V Zeners (20 mA Iz-test, the 120V Version has only 10mA) parallel D--S and 2) some Rv for the Gate. In the SJ79 specs the biggest C I found was 120pF without fully understanding it. Anyway: Even if t
  2. Meanwhile the 1st order for parts is out, as transformer for HV I found only a 2x350V centerd one, (Hammond 373DX, which has also the advantage of 200, 210, 220, 230, 240V primary connectors, we have 230V, so some freedom is left for fine tuning the secondary voltage). Anyway, now I must reguate V- too. To my oppinion this should work with the 600V IXTH10P60 (I orderd 3 if somethind goes wrong a the first place). On then same order I put 4x 150uF film caps (47 EUR each). I think about a C--R--C--MOSFET--small_C_at_Load arrangement. Is that ok? Some people recommend fast diodes for the rectif
  3. An explanation could be that the 10m90 could have a build in enhancement MOSFET, just because enhancement is more common. When operating the gate pulls/builds the channel close to itself - this MIGHT cause higher capacity than in a depletion type, which closes the channel when working, especially the parts close to the gate. See page 4 here: https://www.fairchildsemi.com/an/AN/AN-9010.pdf At least it's hard to find comparable enhancement types with comparable good Ciss. Enhancement types must be biased for a CSS, in http://www.fetaudio.com/wp-content/uploads/2003/09/Mu-Stage.pdf its describ
  4. Ok, thx. I phoned mouser, they have some fedex-Germany-agreement so that I can order there. (Otherways one gets a notification "get your stuff from customs", you have to go there, get a waiting-number-ticket, wait 2 hrs...) You think it's worth to implement the mu follower AND 10M90S with a jumper? If only a phase shift in the high freqs is to be expected the answer is "no" for me. I can do that with a FIR filter as well. If mysterious changes in the sense "more stable soundstage", "more relaxing hearing" etc. things are to expect, it could be interesting.
  5. Hopefully I'm at the right place this time. I want to build a kevin gilmore blue hawaii amp. As a starting point I found the original http://headwize.com/?page_id=751 and the more recent http://gilmore.chem.northwestern.edu/BlueHawaii-T2-Servo-v1-2.zip (needs LTSpice). Is there a recent version without servo, with PCB's and all that? CCS is yet partly diskussed, has someone experiance with "mu follower Output" to decouple the complex loads partly from the tubes (see schematic)? What about a PS if no 500V pnp is found? From the PSRR viewpoint I'd start with the concept: "care about high
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