Recent content by zwack
  1. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    I have a good feeling that the tubes will work out.  Next Friday a friend of mine is coming over to listen the amplifier. I will probably be building another MiniMAX if he really likes it! 
  2. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

      I just read that my tubes where shipped. Thanks for all the efforts to serve my request! Very much appreciated!   Regarding the spikes. They're actually not that bad. Just a soft click when the relay is actuated. The click is a bit louder when the relay opens again, but certainly not...
  3. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    Well I finished my build. It was a fun build and I'm very pleased with it. I published an article (complete with pictures) about it on my website:   Here's the link: http://ce-designs.net/index.php/my-projects/headphone-amplifiers/articles-the-millett-hybrid-minimax   please note that I...
  4. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    All clear. I did order some new tubes indeed.    The bias of my tubes stops dropping after half an hour or so. They drop half a volt. Another thing I noticed is that the "louder" tube also sounds a bit more sparkling or better said: the other tube sounds like there is a curtain hanging...
  5. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    Quote: Definitely no wax in my ears. Reversing my headphone also reversed the louder channel . I ran a 60hz sine wave through the amp and this revealed that the AC measured (at the output) at the right channel was indeed higher. Measuring at the input before and after the pot revealed that...
  6. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    Currently listening the the third album using the MiniMAX. I'm very pleased with it, but compared to the left channel the right channel is just a tiny bit louder. I'm using the 12FM6 tubes with are not matched (left: 85, right:90). Can the small volume offset be the result of the unmatched...
  7. zwack

    The "Ampduino" project

    Perhaps a onboard I2C isolator like the ADuM1250 or similar. Especially very useful when driving DAC chips or other devices that are sensitive to noise.
  8. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    Thanks a lot for the explanation.    After I became aware of the tube matching service I ordered two matched 12FK6 tubes along with some other stuff I still needed. These tubes are both rated at 75 and do come from the same manufacturer. I will try these after some time to get used to the...
  9. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    And there is music! I temporary hooked it up to my computer using some old RCA connectors, just for testing. Sound is a bit thin, but that could well be coming from the computer's soundcard. When I finished the build I will be using my left-over Rega DAC in combination with my CD-pro transport...
  10. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    PROBLEM SOLVED!    After some time studying the relay-delay circuit, the only thing that I could come up with was that QM2 was not functioning like supposed to be. It was not going full open or something like that. That would also explain why the voltage difference between the negative side...
  11. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    I just did a test with another 12V relay I have lying around. I put it on a breadboard, put a diode over the coil and connected the negative side to ground from the Minimax and the positive side to the 12V side of DM2 (Where the text "DM2" is printed onto the PCB). The relay actuated just fine...
  12. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    I got it working now . Thanks again. DB and tubes are biased and it's now running at 27V. The only thing that doesn't work is the relay circuit. I did a quick search and came across another thread started by someone who had the same problem.   I'll quote some of your (tomb) posts from that...
  13. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    Thanks, it's shot with a 5 year old "Canon IXUS 860 IS". That little photo camera still amazes me.        Here's the connection. It's putting the fuse in circuit.       Fixed that!       I had checked it, but guess what! I overlooked the letter "k" before...
  14. zwack

    New Millett Hybrid MiniMAX (what happened to this thread?)

    I finished my build and decided to fire it up. I measured the DB bias first and these where almost 0 mV, which seemed a bit odd to me. When I measured the power supply voltage I noticed that it measures 1.4 Volts, no matter in which direction I turn the potentiometer (RR3). I verified that the...
  15. zwack

    BJT Diamond Buffer JFET question

    Thanks. I will use the J310's that are matched at 38 and 40 Idss, assuming that the match is close enough.
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