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  • Re: Your not going to believe this!

    mhardy6647 wrote: »
    verb wrote: »
    I saw this on CL advertising original Advent Speakers. Hmmm... Can anyone tell what model this is ??? :)

    That's an Original Large Advent (OLA) -- real walnut enclosure, as opposed to the Utility Large Advent.

  • Re: Admit it, you bought something from DAK industries ...

    Thunder Lizards!

    oops, my mistake -- Colossuses (Colossi?) indeed.

    oh, all y'all'll love this...

  • Re: Thinking about going tubes

    It's a little hard to take a good photo of a red-plating tube; here's a pretty good one from a guitar amplifier (via Google) :)


    The EL34 on the left is red-plating pretty severely; it's push-pull pal on the right is also red-plating, though not as much.

    This is an unhappy amplifier.
  • Re: Thinking about going tubes

    I don't know much about this particular amplifier (the Rogue) but, by and large, the vacuum tube amplifiers are phenomenally simple devices -- easy to troubleshoot & repair (and very forgiving of things like power surges). As long as the transformers are all OK, there's not much to be afraid of in terms of buying an iffy amplifier.

    Now, this isn't to say that any needed repairs will be inexpensive -- but they should be straightforward.

    As to tubes, yes, there are many ills (some pretty serious) that can be caused by tired or bad tubes. This said, even modern production vacuum tubes are pretty robust little gizmos (despite anti-tube marketing used in the 1960s to sell the consumer the benefits of glorious transistor sound). The output tubes can certainly get tired -- especially if a given amp runs them "hard" (near, or past, their specified operating limits). And tired/bad output tubes can have a multitude of effects, from audible degradation to damage of other components. But they're also easy to change (if not necessarily cheap)!

    The small signal tubes (phase splitters, preamp tubes, and voltage amp/driver tubes) - again, given prudent circuit design - can and should last for thousands (even 10s of thousands of hours).

    Especially for small signal tubes, if an amplifier has, e.g., one weak channel, or noise in one channel, an easy & valuable troubleshooting tool is to simply swap tubes between channels, and see if the "trouble" follows a tube, :)

    This approach can also work for power amp tubes, but in some amplifier circuits, rebiasing may be required. I don't know what bias scheme the Rogue amps use, sorry.

    I hope this soliloquy is reassuring and not just incomprehensible ;)

    Good luck!

    EDIT: Oh, two things about testing "unknown" tube amplifiers.
    1) Always connect a load to the outputs -- either test speakers or dummy loads (8 ohm power resistors, ideally noninductive ones). Transformer-coupled amplifiers don't like open circuits, and output transformers tend to be expensive. :(

    2) Be on the lookout for red plating output tubes. A number of pathological conditions can result in one (or more) output tubes dissipating way more power than they're meant to. In such a case, the tube's plate structure can get red hot. This is a sign of pretty severe trauma; don't operate an amplifier with a red plating tube (or tubes)!
    The problem could just be a tired tube that cannot hold bias, or a bad coupling capacitor, or issues with the bias supply circuit (or the bias level, if adjustable) -- but it's bad, bad, bad. :|

  • NPR: "Too Much Music"

    My son sent me this link -- it's kind of rambling, somewhat predictable, but still, I'd opine, an interesting read. Not long, but not short either. (and it name-checks Rega, for whatever reason).

    Offered "as-is" and FWIW.

    a little sample text (taken way out of context... but I like the thesis as a point to consider):
    A friend once floated a theory that I've grappled with ever since. She claimed that we only ever really love 10 albums, and we spend the rest of our listening lives seeking facsimiles of those 10, pursuing the initial rush, so to speak. At the time, I argued with her, mostly because I didn't want this to be true. But even as I protested I began recalling how many times I compulsively "added to cart" an item whenever some savvy vinyl-hustling mountebank deployed the phrase "Velvets-y" or "Royal Trux-ish," and how many times I'd bought reissues promising the "holy grail" of "private press proto-doom" only to discover tepid bar rock that sounded like a warmed-over Bad Company. Our individual dragons may vary — Sabbath or Coltrane or Beatles or Beefheart — but we're all chasing 'em.

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