dave

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Everything posted by dave

  1. dave

    Man caves...

    I think 30m2 max without planing permission.
  2. dave

    2020 Spreadsheet Now Live

    Is there a date?
  3. Would £50 include the cost of repairs or just the purchase price?
  4. dave

    great show!

    Sorry Richard for picking this out, but the idea amuses me. I am sure that was an auto-corruption. Actually reminds me of my only Kegworth photo.
  5. dave

    DAC "reconstruction" filters

    I wouldn't loose any sleep over non oversampling distortion figures. I measured one on an old school distortion analyser. Now granted this is no longer total harmonic distortion as indicated, but distortion it is. Anyway, it rises steadily to 33% (or more, I can't quite remember) at 20kHz. I took that to Scalford in 2017, I am sure some people would keel over and die rather than say they enjoyed 33% distortion, 😀 if only they knew. I do worry about putting those fast edges into a transistor feedback amp though.
  6. dave

    DAC "reconstruction" filters

    The ear works in the time domain as well and 44.1kHz and reconstruction filters make a mess of that.
  7. dave

    DAC "reconstruction" filters

    Highly simplified Dave version. The sample rate is not high enough on CDs etc (unfortunately) to reproduce the high frequencies sensibly. Mankind tries to fix this flaw after the effect with different filters. Some work better for some recordings, some better for others. Highly subjective and a bit of a cludge. Was hopeful mqa could have fixed it but not convinced anymore. Open minded at present.
  8. dave

    Laskys and Tandy

    Genexxa lx5's from Tandy's in Letchworth, still got them, the best speakers with a bit of tweaking, and there was a franchise in Hitchin, called Kotecha giftronics.....
  9. dave

    Measurements, Compatibility and Ears 👂

    Certain high end manufacturers have the balls to resist the persuit of measurements, such as the Ayre, Dartzeel, Dan's metrum continuum thing, to name a few, these seem to be perceived as pretty good, and who's measurements share some similarities with the Croft mentioned earlier. At the other end Halcro don't seem so loved these days representing the low distortion.
  10. dave

    Measurements, Compatibility and Ears 👂

    If I was a less techy version of me (I make my own amplifiers) and contemplating a new amplifier purchase, the measurements could be used to rule out ones, that experience has showed me, I would be less likely to enjoy, i.e. low distortion and low output Z. Not that these qualities are inherently bad, and am quite interested in hearing Bruno Putzey's latest....
  11. Pair of Acoustic Energy ae109. Not pristine, and bases a bit bashed, but good working order. No grills. £50...
  12. dave

    Measurements, Compatibility and Ears 👂

    Me too. I got given my amp, it's seems to be 2 watts, it drives my speakers just fine. I bought them because I liked the big old wharfedales. Turns out I got lucky
  13. I met a very clever man that was convinced that this was the case, so much so that he manufactured an amplifier briefly with most of the semiconductors (weren't that many) were running at 160oC iirc.
  14. You need a big push pull valve amp..
  15. I am pretty sure electrolytic capacitors "improve" with uses and also how long had bias applied, but I have no proof. They are electro-chemical devices, and they are "formed" during manufacturing by hooking them up to electricity, so it is not too much of a stretch to imagine that they reform a bit over time after powering up?
  16. dave

    Leak Sandwich 250 Speakers an Active project

    I think you mean 900Hz
  17. dave

    Leak Sandwich 250 Speakers an Active project

    Seems a bit high. Be interesting to hear how you get on with the purple tweeter in the 21st century.
  18. dave

    I think I may be turning into a believer...

    ok, i don't know everything.... https://www.iconoclastcable.com/index.htm and this document in particular: https://www.iconoclastcable.com/story/time.pdf
  19. dave

    I think I may be turning into a believer...

    It will be, it just hasn't happened yet. The first step is having a repeatable experiment, which seems to be the case. I very much doubt a sine wave measurement will find anything though.
  20. dave

    Cable question (groan)

    When I first encountered this in 1996, I had no preconceptions. I was building a prototype valve amplifier (0.08% distortion with 8dBs of feedback from a pentode wired 6l6 incidentally). I could not work out why it sounded so bad. Then i swapped with some trepidation (because I did not believe) the lab test leads that I was using to connect to my speaker, to the (recommended by a respected audio designer) telephone cable based speaker wires I had been using, but weren't really that convinced by. I was surprised.
  21. dave

    Cable question (groan)

    One of my first engagements on this forum, some body asked a similar question. I answered something along the lines of: It helps to understand that the music (AC signal) travels through the insulation, the space around the conductor..... I got shot down for that statement...... I am a techie, and I don't know and haven't measured yet, whats going on, but I might stumble across it one day. The disbelievers should bin their mobiles.....
  22. dave

    Cable question (groan)

    I will back you up here as I have experienced the same thing and recognise your description in the change of sound. The Van Damme 6mm type cable really is the worst speaker cable, except for ohm meter wielding measurists. I swapped over to cat5 or similar, wired for low inductance, on my own and several friends systems. Silly better is as good a description as any. Note these improvements were using SE valve amps. Bit more subtle on solid state.
  23. dave

    DC Offset different on both channels

    it could come from "un matched" transistors in the input diff amp, or maybe a leaking (dc) cap in the feedback circuiut. if it seems fairly stable wouldn't worry about it that much.
  24. dave

    Capacitor Tolerance

    They all sound fine (probably), but you need ESR (equivalent series resistance) to be truly useful, especially for power supply caps. I think tolerance is only important in filter circuits (as a gross generalisation). My cheap one, which I think was based on someone's home project, and then mercilessly cloned by the Chinese, measures ESR at the same time as capacitance.