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Pars

High Rollers
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Pars last won the day on August 20

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

5,151 profile views
  1. Pars

    KGSSHV Carbon Build Thread

    What did you pay for it? That is where I would start...
  2. Pars

    RIP some fuck or another

    RIP Stan... 😢
  3. Pars

    Happy Birthday Mikey!

    Happy Birthday!
  4. Pars

    Happy Birthday Dreadhead!

    Happy Birthday Chris! I hope you have a great one!
  5. Pars

    The Multi Amp aka Dynalo Mk2

    Something I noticed in the mini BOM was that the power switch listed (8161SH9AV2BE2) isn't rated for AC power duty. Instead, use either the "G" or "Q", which are both rated for 120/250VAC. Use 8161SH9AV2GE2 or 8161SH9AV2QE2 instead. Mouser stocks the "Q".
  6. Pars

    HC Bike/Cycling Thread

    The SLX might be slightly stiffer. The seamed Columbus tubing (Chromor, Aelle, etc.) is pretty good riding stuff though. So much so that back in the ‘90s a mag did a test with some riders on identical frames other than material and the Chromor frame won IIRC (think it was Chromor, but it was one of the seamed tubes). The back bike in the picture looks like it was a bit small for the rider judging from how high the seat is. That’s some serious drop! Sent from my iPhone using Tapatalk
  7. Pars

    The Multi Amp aka Dynalo Mk2

    Yeah, just seems like the AC voltage measurements on the Fluke 89 at least are RMS. I used my bench HP 3269 or whatever it is for this though. I was just trying to correlate the AC current draw with the DC biasing conditions but I can see that would get into a fairly complex calculation involving factors you mentioned and more probably. Just knowing the current dropped with the heatsinks in place was enough confirmation. And 10mA AC is probably more significant that it seems. Sent from my iPhone using Tapatalk
  8. Pars

    And now what did you do TODAY?

    Sent from my iPhone using Tapatalk
  9. Pars

    RIP some fuck or another

    Yeah, that really sucks, and glad your kids weren't around there Greg! Hits close to home.
  10. Pars

    The Multi Amp aka Dynalo Mk2

    Ran a test after taking one amp back to its original config (402R, LTST-C170CKT and 255R bias resistors). I placed an ammeter in place of the fuse, and ran it for 30 minutes when it was no longer increasing. It showed a max of 245mA AC (is that RMS?). I checked the bias on this one and it was right around 15mA (300-315mV). I then installed the heatsinks and did the same test. Current draw had dropped to 235mA at a stable condition. So my theory: having the heatsinks on seems to reduce the transistor temperature a bit, resulting in lower current draw (a bit). For these two tests I was not able to have the top in place but did set it there as best I could.
  11. Pars

    RIP some fuck or another

    Sorry to hear as well Todd.
  12. Pars

    The Multi Amp aka Dynalo Mk2

    Yes, I had considered doing this (insert DMM in amps mode in place of fuse) in order to estimate bias (@15mA should be 4 * (4 * 15) or ~240mA + a bit for the other circuitry). I thought this way I might be able to estimate the bias with heatsinks attached. Sound reasonable? Sent from my iPhone using Tapatalk
  13. Pars

    And now what did you do TODAY?

    Ted had better lose... another pos that needs to lose is Nunes. Fucking traitor (among traitors)...
  14. Pars

    The Multi Amp aka Dynalo Mk2

    Understood... thanks for the data. Those are the other LEDs I have. I was thinking about trying the 402R with current C170 LEDs ( which I am getting 17- 18mA bias) and dropping the 255R down to 240R and see what I get when warm. One thing I don’t quite understand about the operation of these CCSes is the increase I see in bias of around 5mA or more between cold and hot. Is this caused by the LEDs being heated? Doesn’t seem very “constant” to me... EDIT: Put 240R in one channel. After warming up 30 minutes, it was right where I wanted it (290-304mV or 14.5-15mA). The other channel was at 340-360mV, or 17-18mA. This is 402R and the LSTS-C170 LEDs. My one concern is at startup, bias is only in the 8-9mA range, which from experience sounds a bit flat. EDIT2: And to my last previous question, I guess the output transistors heating up probably have more to do with the bias increasing with heat than the LEDs do.
  15. Pars

    The Multi Amp aka Dynalo Mk2

    Nice! So you’re using 422R and the LTST-C170 LEDs? 255R bias resistors? What are you getting for V drop across the LEDs initially and after 30 mins or so? And what bias on the 20R output resistors (V drop / 20)? If everyone building these could post this info, it would be appreciated! Maybe I’ll toss a google sheet up to record this so everyone can access. Sent from my iPhone using Tapatalk
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