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About mwl168

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  1. Technical Assistance/Advice Thread

    Yes, you need a quad potentiometer for two channel, balanced inputs.
  2. Part Sourcing Assistance/Advice Thread

    Thanks Chris for the great summary of the Dynafet information. It does look like more than I can handle at this time. I don't know if CFA or CFP is proper name for it. It's a current feedback amp and the boards stated so as well. But the Gerber file name says "CFP". I'll send you a PM about the CFA boards
  3. Sennheiser HD660S Releasing in November

    Don't understand the rationale of going through the trouble to develop a 5-pin TRS connector when a 5-pin XLR connector would have serve the job better and is readily available. I guess one of the rationale is the pentacon connector can be made to be backward compatible with a typical 3-pin TRS connection.
  4. Part Sourcing Assistance/Advice Thread

    Thanks for checking Chris. That is a beautiful Dynalo built. What sands does the DynaFET use? Does it use obsolete parts?
  5. Part Sourcing Assistance/Advice Thread

    I have like 200 of those original Dynalo output resistors in my house - got carried away trying to match the PNP to the NPN sands. Eventually gave up because they are horrendously mismatched. The completed amp works just fine regardless.
  6. Part Sourcing Assistance/Advice Thread

    Find them Chris!!! My CFP boards for your Dynalo board
  7. The Menace

    I actually have 8 or so 6C33C in my house that I bought like 10 years ago, not yet find an application for them. These things are big and requires ~ 7A filament current. I read getting good tube sockets for these tubes are challenging, most sockets simply deteriorates quickly due to excessive heat. The Menace's simplistic circuit also lands itself well for a point-to-point construction which also makes circuit experimentation easier.
  8. The Menace

    Yes, I've always wanted to build an OTL amp for my dynamic headphones and that's what lead me to this Menace thread. The Menace's simplistic circuit is also very attractive to me. With that said, I do like the idea of the CCS and I have experienced what good CCS can do to with JimL's SRX Plus. My plan is to build a simple Menace OTL as close to Nate's published schematic as possible. Once that's working properly I will be able to experiment and add on more sophistications. That, to me, is a big part of the DIY fun!
  9. Part Sourcing Assistance/Advice Thread

    To my knowledge the original Dynalo PCB is obsolete. I bought mine from AMB and they ran out of it long time ago. I have never seen a published Gerber file of the original Dynalo. I would love to have another board or two myself if possible.
  10. The Menace

    Thanks! That makes more sense (re: the plate to cathode voltage). Maybe I should sell my NOS BlackGate over at eBay or the other site. I've seen them advertised for silly money... Can you elaborate on what can be done to improve the circuit?
  11. The Menace

    A few more questions: The 6AS7G and 6080 are both recommended output tubes for this amp. They are both rated 250V for max plate voltage. Would applying the 270V B+ direct to the plates of the output tubes as shown on the schematic shorten the life expectancy of these tubes? What other output tubes are recommended to use for this circuit? I have a few 150uf/350VDC rated BlackGate caps on hand. Is it a good idea to use them for PS bypass for this amp?
  12. current feedback electrostatic amp

    This looks very nice and intriguing. Where is the connector for outputs?
  13. The Menace

    Thanks Jim and Nate! Did some reading on the motor run caps. Looks like they are often chosen for audio purpose when high capacitance and high voltage are needed in critical positions. They are actually film caps and often oil impregnated polypropylene. No wonder their size.
  14. and now for something completely different part 3

    I have some CFP boards made for my own use - I plan to build a balanced CFA. I have some extras so PM me if you are interested. These are 2mm and 2oz copper boards.They are about 101mm x 94mm. EDIT: Here is an image of the board. I believe the Gerber file is cfp2gmt. Kevin may have laid out a full balanced board which includes an unbalanced-to-balanced converter on the board that uses THAT340 but I am not certain. I plan to build my balanced CFA using two pairs of boards as I believe that's what congo5 has done.
  15. The ultimate DIY? A Stax SRM-T2!

    I recall these 78xx regulators some times overshoot without load. Maybe try putting a load on the output and re-measure?