Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: joesatch on March 31, 2023, 09:13:11 am
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i bought a dagnall PT but it is missing the cover. anyone know where to get one of these and what it's called?
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Its called an end bell - search on that - easy to find
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Perhaps more important, it's missing the bolts that hold it together!
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lovely. looks like i gotta order the parts from europe. why do i do this to myself? :dontknow:
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Just 3D print a cover
Get a friend to do that if you don't have one
Some plastic tolerates heat better than others
Use threaded rod and nuts for the bolts
Probably 8/32 will work depending on the hole size
Cut them to length, grind the end smooth
Lowe's, Home depot, Ace hardware all have threaded rod
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Use Stainless or brass bolts, and insulation washers on one end
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Use Stainless or brass bolts, and insulation washers on one end
:hijack1: sorry :icon_biggrin:
Why insulation washers?
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Haha, always thought end bells are an american thing, you don`t have them on european transformers and they are hard to get i thought. Were would you order them in europe i wonder.
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These folks claim to make repros of Marshall spec Dagnall PTs - you may want to try them
http://www.merrenaudio.com/marshall_power_transformers (http://www.merrenaudio.com/marshall_power_transformers)
Although I am intrigued by the 3d printer thing.
always thought end bells are an american thing, you don`t have them on european transformers
Huh?
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The transformer bolts can be found at Home Depot and other hardware stores.. example https://www.homedepot.com/p/8-32-x-2-1-2-in-Combo-Round-Head-Zinc-Plated-Machine-Screw-4-Pack-803151/204274619
That one is 2 1/2" in length they probably have up to 3" or more. A little too long is ok.
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Use Stainless or brass bolts, and insulation washers on one end
:hijack1: sorry :icon_biggrin:
Why insulation washers?
Belts and braces approach to avoiding hotspots from stray eddy currents (from the bolts going ‘across’ the laminations) YMMV
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Bolts and nuts yes, but do you really need bell covers. Lots of OT’s don’t have them. I’ve had recording mixers with PT’s without bell covers..?
If you’re not into looks, you could buy light gauge steel, and make a cover..? Ace and the other HW stores sell light gauge small sheets of steel.
But, me l’d just use the PT without a cover
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man if this were a little over a year ago before i moved i probably would've been able to source you a suitable cover from the pile of solid state organ transformers i couldn't bring myself to part with, until i did (for a couple weeks the scrappers made out like bandits from the buckets full of mixed metal i left at the curb)
i would get the bolts from ace hardware because then you can source stainless instead of whatever trash metal the regular machine screws are made out of. i like using stainless for everything
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i bought stainless #10-24 bolts and some fiber washers as well nylon locking nuts. Going to install the PT minus the bell cover. hopefully will be ok. It's a marshall head so it will look like shit, oh well
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it will look like shit
And it will always bug you. Been there. Best to do it right.
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nope i aint ordering parts from europe
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Did you try Merren?
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i looked but they sell complete high end trannys. anyway i got the thing all put back together
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Good - I hope it sounds great.
Merren - I know what they sell. I was just suggesting that you pick up the phone and ask if they could help you out with the part you needed. Sometimes people like to help others out - its not as rare as some folks think. And all they expect is a simple thanks.