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  1. Jerm111

    Papa Rusa Tube Headphone Amplifier

    By the way, that EL84 Head/Speaker amp you had listed is really cool. My next amp was going to be a SE2A3 following JE Labs' "Radiotron 2A3" Schematic. I'd love to be able to add a headphone output as well, what is the best way of achieving this? I've seen a few schematics for resistor...
  2. Jerm111

    Papa Rusa Tube Headphone Amplifier

    Thank you. No I didn't make any more adjustments. I figured I should try and test the tubes I had and probably try sourcing a better matched pair. I inherited a very nice AVO MK4 tube tester but haven't had time to sit down and work out how to use it. I did briefly look into the book and found...
  3. Jerm111

    Papa Rusa Tube Headphone Amplifier

    Here are some photos of the finished amp... I've run into a technical issue which I was hoping someone on here might be able to clarify for me. I was measuring he plate voltages and noticed they varied quite a bit between channels, 117V (L) and 153V (R). When I switch the...
  4. Jerm111

    Papa Rusa Tube Headphone Amplifier

    I'm glad you enjoyed, it was a very satisfying project, a lot more work than I thought though!
  5. Jerm111

    Papa Rusa Tube Headphone Amplifier

    Thanks so much for the detailed run-down. I haven't had time to have a good listen or a decent comparison with my other amps but my first impression is that this amp sounds very good. This talk of improved transformers has me very intrigued at what the potential could be though. I will see...
  6. Jerm111

    Papa Rusa Tube Headphone Amplifier

    Thanks for the info, very interesting. I'd love to try some Lundhahls.. I have been looking at their website and they only seem to list 3 headphone specific models, none with an input impedance of 10k and suitable secondaries. I think I could try and work it out with respect to turns ratio but...
  7. Jerm111

    Papa Rusa Tube Headphone Amplifier

    Thank you! Do you think upgraded OTXs would make a big difference? Where is the best place to source Cinemags or Lunahls, I could be tempted if I can fit them into my enclosure and they aren't too pricey. I am located in New Zealand, shipping can be prohibitive. Where can I find the schematic...
  8. Jerm111

    Papa Rusa Tube Headphone Amplifier

    Thanks, yeah I really enjoy trying to make the wiring really clean.
  9. Jerm111

    Papa Rusa Tube Headphone Amplifier

    Thanks! Yeah I really like that feature as well, I think it's really worth the trouble :)
  10. Jerm111

    Papa Rusa Tube Headphone Amplifier

    I spent many hours over the last couple of days troubleshooting a minor hum problem, it's dead quiet now and sounding great! I still have a few aesthetic things to finish off, painting the knob and top-plate etc. See photos below, these were taken prior to fixing the hum. I ended up changing...
  11. Jerm111

    Papa Rusa Tube Headphone Amplifier

    That's interesting, I will keep it in mind. Yeah I'm actually significantly less than 400V as well.
  12. Jerm111

    Papa Rusa Tube Headphone Amplifier

    That’s interesting, are you sure? The kit I am using (see below) has a screw insulating washer and the insulating film is “Thermasil III” material, according to the data sheet it has a “dialectic breakdown voltage” of 26,300 volts/mm. I assume this is relating to the thickness which is 0.15 mm...
  13. Jerm111

    Papa Rusa Tube Headphone Amplifier

    Hi Everyone, This is the first build thread I've done on Head-Fi, thought I'd give it a try. I'm building a 'Papa Rusa' HPA which is a design published by Wauwatosa Tube Factory. I have already built an OTL amp but was looking for something that would work with all different impedance...
  14. Jerm111

    Custom OTL Headphone Amplifier / DAC

    Thanks! Hey, this is off topic but I noticed in your sig you list some campfire IEMs and also the TIN series. I've been reading and watching online and it has made me really curious about what a real high end set of IEMs like the Campfires are like. My budget would barely stretch to the IOs...
  15. Jerm111

    Custom OTL Headphone Amplifier / DAC

    Cool that's good to know, I might be keen to get some more. There's a theory that minimising metal mass has sonic benefits and these are about the most minimal RCA plugs I've seen.
  16. Jerm111

    Custom OTL Headphone Amplifier / DAC

    Thanks. They are just really minimal rca plugs, my Dad had them in stock so I used them. They are basically just a metal shell with a pin in the middle that you solder on to. I've had a look but I can't seem to find them for sale, i'll see if I can find out. for the switch I just used a basic...
  17. Jerm111

    Custom OTL Headphone Amplifier / DAC

    Thanks! Yes as the amp was to reside mostly on my desk at work plugged into my Dell PC the integrated DAC was a no brainer. Interestingly, during initial tests before I mounted it inside the case I was running it via a fairly long RCA cable into the input on the back of my amp, it sounded ok...
  18. Jerm111

    Custom OTL Headphone Amplifier / DAC

    Hi everyone, I've been a member of Head-fi for a while and have visited sporadically over the years. After finishing my first DIY amp build I thought i'd come and share it with you guys. I'm a novice when it comes to electronics, especially tube amps, so I am fortunate to have the help of my...
  19. Jerm111

    Sennheiser HD25 SP

    Great, thanks MisterX   As long as the don't fall at with the lightest tug on the cable, which is what the Cardas ones seem to do.
  20. Jerm111

    Sennheiser HD25 SP

    Oh god. I'm an idiot for not properly reading the listing. Thanks MisterX.   Before I go ahead and order one, can anyone please confirm that the plugs on this cable are a nice tight fit on the SP version??
  21. Jerm111

    Sennheiser HD25 SP

    Hi Everyone,   I have a pair of Sennheiser HD25 SPs and became sick of breaking cables and ordering costly replacements. I decided to construct my own custom using Mogami cable and the Cardas Sennheiser plugs. I had never seen these plugs used on the SP version of these headphones (only HD 25...
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