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ldervish

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Everything posted by ldervish

  1. avguytx: I think so...when I went looking, there was a paragraph saying "marketplace" was being updated and that a link was normally found at the top of every page. IDK any more than that. I hope it returns soon b/c I have other stereo gear needing a new home. Or, I could subscribe as you did. muel: It's a cinch nothing was going to vibrate loose, they were made to last a lifetime
  2. Thanks, that's a good idea. But I'll have to wait b/c their marketplace software is being upgraded right now. These are a great deal if someone can use them...don't be bashful...
  3. Excellent condition, 13 element, thought to cross at 350 hz and 2500 hz, can handle 15 - 150W @ 8ohm. Bought recently for a project but it turned out I would have had to modify the cabinet to use them; seller said they were pulled from working speakers. Pair is complete including rear connection cups and all connecting wires. Hope someone here can use them. Pay by paypal, shipping by priority mail (U.S. only). Verify excellent rep on the 'bay under same name. $35 for the pair, shipped.
  4. The Mallory has been replaced below deck, but the bias filter quad 75uf looks to be original. After checking, tightening, searching for ground loops and judicious use of deoxit it still had the hum so I followed a couple tips Craig passed along, and ended up swapping the 7199's with a known good (and quiet) pair. Then balanced the outputs "by ear" and was able to reduce it to a barely discernable level. It's not "dead quiet" but the very next thing to it so I'm pleased with the result. It's nice not to hear that hum between tracks of music. I have a Wavetek digital multimeter that performs some of CR functions, but it has limits. Is there a modestly priced LCR unit that I should look at? Thanks for the interest, all of you, I appreciate the help and advice.
  5. Much appreciated, Lucky. I did a search but missed that one. Symptoms are the same, so as time permits I will head to the bench to check potential culprits. Biggest odds are on the multi-caps. One can was obviously replaced during rebuild but the other 2 could be original. I'll have to look under the chassis to see if new components were mounted there.
  6. Correction: The bias is controlled by the pre-amp tube heaters, not the output tube heaters. I have emailed Craig per JJ's suggestion and am awaiting his comment. Thanks.
  7. I am new to this community and hope someone can inform me about my LK-48. It is a brown face, no headphone jack, 7199 phase inverter model which I have been unable to find an exact schematic for. It was completely rebuilt several years ago, at which time it developed a hum that is most noticeable on startup. The rebuilder was unable to clear it. After warming a bit the hum subsides but remains. There are balance trimmers between the output tubes, one for each pair. I have no idea how to use them and have not tried. On this model the output heaters are connected in series to provide the bias voltage and so far as I know there is no "hum balance" in that part of the circuit as there is in some guitar amplifiers. So can someone enlighten me as to where to look for the source? I have some electronics training and basic tools including variac, multi-meter and etc. (no scope or signal generator though) and know about safety 'under the hood'. The s/n is 107460 if that helps. Many thanks for your interest!
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