The light bulb limiter thing

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crianlarich
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The light bulb limiter thing

Post by crianlarich » Thu Sep 03, 2020 10:49 pm

What do you think: will it work with hybrid amps?

Such as my Music Man. Haven't plugged her in for ten years. Was squealing then, uncontrollably at least in "High"-Mode.

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46346
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Re: The light bulb limiter thing

Post by 46346 » Wed Sep 09, 2020 3:51 am

sure, if you mean using a 120v light bulb on the AC line in, it's not just for tube amps. i've used it on higher voltage solid state gear as well. i would expect it to work properly on my MM amp, i believe it's a HD 130. it should detect any significant shorts, mis-wirings, etc. just be ready at the switch if the bulb burns brightly for more than one or two seconds. it will normally burn brightly for only a flash, before settling down. cheerio!
Dream Apes, ACME, Malcolm Mooney, Cat Museum, Cooling Time

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Re: The light bulb limiter thing

Post by 46346 » Sat Sep 19, 2020 11:29 pm

crianlarich wrote:
Thu Sep 03, 2020 10:49 pm
What do you think: will it work with hybrid amps?

Such as my Music Man. Haven't plugged her in for ten years. Was squealing then, uncontrollably at least in "High"-Mode.
funny, my MM HD130 started squealing in Hi Power mode. playing Bass. sounds fine in Low.
i'm pretty sure Low Power only uses two of the four EL34's, and that's how i always liked it.
so i haven't bothered looking into it yet. my guess was that one of the power tubes has gone microphonic or is failing.
i'm curious of you learn anything!

cheers.
Dream Apes, ACME, Malcolm Mooney, Cat Museum, Cooling Time

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Re: The light bulb limiter thing

Post by crianlarich » Sun Sep 20, 2020 4:03 am

Thanks a lot for your replies!
Power mode in amps like mine is achieved through different plate voltage. Which is over 700 Volts in "high" mode! This makes me reluctant to deal with it at all. Amp needs to go no matter what.
So options for listing it are

1) letting a tech sort out the problems first
2) checking (with all safety measures I can come up with) if it runs in "Lo" mode, offering as project
3) doing nothing, offering as broken

not sure if 1) would be viable economically as buyers like to fix things (but MusicMans are tough!!) and pay a good price regardless.
Tubes were replaced and power section repaired in '95 (radio technician), they don't have many hours on them, as I started using a nice little Dynacord shortly after. Off course electrolytics should be critical.

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Re: The light bulb limiter thing

Post by andy_tchp » Sun Sep 20, 2020 3:32 pm

I feel like a fully serviced/repaired amp with a clean bill of health from a reputable tech is an easier sale than something that's obviously not working at 100% for unknown reasons, which leads to buyer unease and low-ball offers.
"I don't know why we asked him to join the band 'cause the rest of us don't like country music all that much; we just like Graham Lee."
David McComb, 1987.

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