Pars

High Rollers
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Pars last won the day on February 27 2013

Pars had the most liked content!

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About Pars

  • Rank
    High Roller
  • Birthday 05/16/1954

Profile Information

  • Gender
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Converted

  • Location
    Chicago
  • Occupation
    engineer (telecom mktg)
  • Hobbies
    golf, music, cycling
  • Headphones
    AKG K601, Shure SRH840, Modded Fostex T50RP
  • Headphone Amps
    Gilmore dynamic (headamp v2 PCB), Dynahi (still proto stage)
  • Sources
    � Rotel RCD-855 modified (clocking, discrete output stage) � Rotel RCD-991 THS4031 I/V, AD8599 buffers
  • Other Audio Gear
    ? maybe Classe preamp, Odyssey Stratos poweramp, Von Schweikert VR4 Gen.II speakers

Recent Profile Visitors

3,531 profile views
  1. Happy Birthday! Sent from my iPhone using Tapatalk
  2. I dug his RN60 "display"
  3. Congrats Kevin! How soon until u retire? And Happy Birthday if it is indeed your birthday (can't see shit on my phone via Tapatalk) Sent from my iPhone using Tapatalk
  4. Final episode of The Bridge
  5. Yep, watched this one (Black Sails... Thought I had quoted the previous post from4/8) from the beginning season and enjoyed it (mostly). Sorry to see it end. The final season felt a bit compressed and moving too quickly though. Sent from my iPhone using Tapatalk
  6. I haven't built one of these and am not familiar with that particular PSU, but don't you just need a single PSU (dual, which that one appears to be)? Not sure what the other one you refer to is? As for transformer, see the rest of the thread. A dual secondary in the range of 25-27Vac seems to be what is recommended. I posted an Antec AS-0528 above, but an AS-0525 50VA 2x25V might work as well. I'm not sure, but I might be inclined to use a GRLV PSU set for +/-22Vdc for this, with a 2x18Vac transformer. Of course that moves away from a strict clone however. Someone who has built one of these might comment... Sent from my iPhone using Tapatalk
  7. Good one Birgir. What a tool this person is. I don't see any Stax in his headphone inventory... I wonder how he intended to listen to a Carbon?
  8. I've been enjoying listening to this. I decided I wanted to lower the gain, since on more modern hot recordings, the pot was in the 1st quarter of rotation. I changed the 10K resistors to 4.7K, and changed the compensation cap from 10pf to 4pf. Looked fine on the bench including with my load box. I brought it upstairs along with the pair of dynahi boards which just pop right in, and listened to those first. They sounded good. Intending to do a comparison, I put the dynafet boards in. When I plugged the headphones in (10' mogami extension and 10' mogami headphone cables), the protection circuit tripped, and would just keep tripping. Hmm. I determined that the headphone cable and extension alone were enough to do it, without the headphones (T50RP) connected. I took it downstairs along with the cables, and sure enough, oscillation (guess of 70MHz or so based on scope timebase). Amb's zobel networks would keep it from occurring, but lacking suitable resistors, I decided to change how I was reducing the gain. I put the 10K resistors back in, and replaced the 1K with 2K. Now it was fine, so back upstairs it went. I haven't done a proper comparison yet, but still think the FET version sounds better to me. I am going to install the Amb zobels on the board outputs just for safety (47nf cap->22 ohm 2W resistor from output to gnd). Takeaway from this is use a protection circuit (I'm using an Amb e12 modified) use Amb's zobels on the output just in case...
  9. If these are the lt1021 refs, you can buy these direct from linear for quite a bit less than Digikey... Sent from my iPhone using Tapatalk
  10. Happy belated Birthday!
  11. So, any verdict on these? Bonus this year might make me interested. Easy to replace the jacks/recable to make these work well? I liked the LCD-2s of Mike's that I had at home and listened to...
  12. Having the transformer(s) that close to the audio boards/pot probably isn't helping your noise floor at all. AC wiring also appears to be right over the input wiring to the left side of the pic.
  13. Is that shipped or do they want another $8-10 for that? I'd probably try the whining approach, you know, the fucking POS broke Of course they might come back with the ship it in (and pay shipping both ways ) Sent from my iPhone using Tapatalk
  14. Did some work on mocking up the chassis and getting into a more listenable state. I will need to get aluminum top/bottom and rear panels for this (not using the steel ones that it came with). I'm also still a bit concerned with how warm the buffer transistors run, and this is open air. Using a modified amb e12 protector board (with muting). I tested this to see if HF oscillation would trip it, and it did (12V ~70MHz with the feedback set to the mid FB point). Listening-wise, it is likely my favorite amp, even being single-ended. This thing has balls, and seems to open up the recording more than any other amp I have built or used. Since my SE DynaHi boards are a drop-in, I may take another listen to those as well, but from memory, the FET version stomps it. I am going to build up a GRLV for this, and will likely get a 50 or 100VA Antek trafo for it instead of the 120 or 160VA SumR I have in here (a bit in the HC overdo it fashion ).