Burning Hot deluxe transformer

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naciketas
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Burning Hot deluxe transformer

Post by naciketas »

Hi,
I finished a clone build of a BFDR, everything's fine except the PT that after an hour of playing at low volume is really hot as that part of the chassis.
It is a Classic Tone for all that matters, I'm afraid it'll bring to some sort of failure or am I too anxious because it is "normal" for that amplifier?
Thanks
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xtian
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Re: Burning Hot deluxe transformer

Post by xtian »

If it is too hot to keep your hand on the transformer, yes that's a problem.
I build and repair tube amps. http://amps.monkeymatic.com
Stevem
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Re: Burning Hot deluxe transformer

Post by Stevem »

One it gets up to those temps is your heater voltage less than 6.2 vac?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!

Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
naciketas
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Re: Burning Hot deluxe transformer

Post by naciketas »

Sorry, but I've been away for this weekend.
Voltages seems ok, 414v b+1 and so on, heaters around 6.2, but after about 40 minutes/1 hour of low volume noodling I can't leave my hand on the transformer's lamination for more than 5 seconds. It really sounds good, last thursday at rehearsal I even cranked up till 7, LesPaul at full blast and the guys were amazed. Really don't understand, maybe a failed/failing transformer?
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rp
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Re: Burning Hot deluxe transformer

Post by rp »

Wrong rectifier tube, 5U4 with 2A trannie? In 50HZ country with 60Hz PT? I've stuck my hands on plenty of vintage Fender trannies, I hate heat and am a fussbudget, and with the smaller Fender amps the PTs get stupid scary hot. A fair part of it in the combos is just the heat coming up from the tubes and baking the whole chassis. But they worked that way for 50 years. Maybe the MC is a sadly too accurate reproduction? Hopefully it'll prove vintage Fender reliable despite the heat. If you find nothing wrong it may just be the way it is. Maybe peeps here with that MC PT can chime in.
Rob Livesey
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Re: Burning Hot deluxe transformer

Post by Rob Livesey »

Just for info, I have a '65 BFDR that I have owned and gigged as my main amp for the last 20 years. It's a 110v amp that I imported, so I run it on a step down here in the UK. My mains tranny has always got really hot. When you said you couldn't hold your hand on it for more than 5 seconds, well that would be a hell of a long time to hold your hand on mine. All my voltages check out, I've recapped it, swapped in various tubes over the years and even ran it with 6L6WGB's for about 5 years. It's still going strong and gets gigged almost every week. I wouldn't worry about yours unless you smell smoke.

Rob.
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Rob Livesey
Manchester, UK
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Stevem
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Re: Burning Hot deluxe transformer

Post by Stevem »

Shoot the Trany when hot with a thermal gun, if it's over 140 degrees due to its own generated heat or that combined with output tube heat, I would get a small fan mounted somehow to blow the heat out!!
Remember each 20 degree drop in temp will double the life of circuit components!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!

Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
naciketas
Posts: 29
Joined: Mon Jul 16, 2007 8:12 am
Location: Firenze

Re: Burning Hot deluxe transformer

Post by naciketas »

Back from work and I saw the posts, nice return home!
It seems it's supposed to work that way, so no new tranny for the moment and all I have to do is play and wait, good.
Thanks
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Baxtercat
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Re: Burning Hot deluxe transformer

Post by Baxtercat »

I've owned a bunch of DRs, one got warm like yours. Voltages were always good though. [yes, 5 secs. isn't that abnormal]
I installed a fan anyway. Bet that thing is still running good somewhere.
Guitar Bob
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