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Post by Mikeyguitar on May 23, 2020 17:11:11 GMT -5
I'm not sure what year the amp was made (they were made from 1996-2002)...but it's been many years since I've played it. Is there anything I should be aware of before firing it up? I recall people saying something about changing caps to avoid having a transformer melt down (or something like that - it's all electronics mumbo-jumbo to me) if a tube amp hasn't been played for a long time.
Any advice?
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Post by Leftee on May 23, 2020 17:28:46 GMT -5
Turn the volumes down and turn it on and let it warm up a couple minutes. It’ll work or it won’t. My guess is it will sound fine. 😊
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Post by Mikeyguitar on May 23, 2020 17:33:46 GMT -5
Turn the volumes down and turn it on and let it warm up a couple minutes. It’ll work or it won’t. My guess is it will sound fine. 😊
Oh, I think it will work...but I'm wondering for how long? Will I fry anything since it hasn't been used for the past, oh, 15 years or so?
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Post by Leftee on May 23, 2020 19:09:52 GMT -5
Only one way to find out.
I’d bet it will be fine, though.
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pdf64
Wholenote
Posts: 556
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Post by pdf64 on May 24, 2020 11:14:42 GMT -5
I think that everyone with a (mains powered) gear collection, some of which may only get fired out once in a blue moon, should build / buy a light bulb limiter. And a few, various wattage incandescent bulbs, while they’re still fairly easily available. Then if something hasn’t been powered up in many months / years, use the limiter for the initial power up after that. Ideally, progressively increase the limiter bulb wattage. But right now you may want to get on with it, if so I suggest using the linked procedure www.londonsound.org/Vintage%20valve%20hi-fi.htm |
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Post by Mikeyguitar on May 24, 2020 12:41:24 GMT -5
I think that everyone with a (mains powered) gear collection, some of which may only get fired out once in a blue moon, should build / buy a light bulb limiter. And a few, various wattage incandescent bulbs, while they’re still fairly easily available. Then if something hasn’t been powered up in many months / years, use the limiter for the initial power up after that. Ideally, progressively increase the limiter bulb wattage. But right now you may want to get on with it, if so I suggest using the linked procedure www.londonsound.org/Vintage%20valve%20hi-fi.htm
Thanks, but I'm ignorant to electronics in general. I have no idea what a "light bulb limiter" is and would probably be scared to use it. lol I do, however like the advice given in the link you provided. THAT, I can do.  Thanks! |
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Post by stratcowboy on May 24, 2020 22:06:56 GMT -5
I suggest using the linked procedure Doesn't say anything that relates to a standby switch/mode. Is there any difference in procedure when there's a standby circuit? |
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Post by Mikeyguitar on May 25, 2020 11:35:37 GMT -5
I suggest using the linked procedure Doesn't say anything that relates to a standby switch/mode. Is there any difference in procedure when there's a standby circuit?
Good point - pdf64? What say you?
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pdf64
Wholenote
Posts: 556
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Post by pdf64 on May 25, 2020 14:53:46 GMT -5
I think it regrettable that Fender ever introduced the concept of a HT standby switch to tube audio amps.
Especially so in regard of amps with tube rectifiers, as standby scuppers the smooth ramp up of the HT they provide.
But he did, players seemed to like it, and it now features in almost every tube guitar amp.
The best thing is just to ignore it, leave it permanently in the ‘operate’ mode, and power up / down as required, using the power switch only.
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Post by stratcowboy on May 25, 2020 16:41:49 GMT -5
Thanks for the info!
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pdf64
Wholenote
Posts: 556
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Post by pdf64 on May 26, 2020 7:23:32 GMT -5
I'm not sure what year the amp was made (they were made from 1996-2002)...but it's been many years since I've played it. Is there anything I should be aware of before firing it up? I recall people saying something about changing caps to avoid having a transformer melt down (or something like that - it's all electronics mumbo-jumbo to me) if a tube amp hasn't been played for a long time.
Any advice?
Just noticed that the Prosonic has a GZ34 rectifier mode, so definitely ignore standby, and just power up in that mode, for this ‘wake up’ process especially, and preferably thereafter. GZ34 / 5AR4 have an indirectly heated cathode, which has the benefit of not putting heater hum on to the HT, and of an especially slow smooth ramp up of the HT voltage. Try monitoring it with a meter sometime, it takes about 25 seconds for Vdc to appear at the cathode, then about another 25 seconds to reach its full level. By which time all the other valves will be conducting, and all voltage and current surges will have been minimised / eliminated. It’s absolutely the best, least stressful power up a circuit could possibly have, but one which is totally counteracted if standby is used. If preferred, you can flip to the solid state rectifier mode after the start up in GZ34 mode is done, eg after a minute; no need / benefit to move it into standby while changing rectification mode. However, it would be better to power down before flipping from fixed to cathode bias, giving the GZ34 a minute or so to cool down before powering up again. The back panel refers to the cathode bias mode as ‘1 = Tube A’. FYI those class designations are nonsense, in all settings the amp is operating in AB1. el34world.com/charts/Schematics/files/Fender/Fender_prosonic.pdf |
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Thanks!
