Looks like it's the normal kind of lamp assembly that can be separated, but grounding one side worked for the original, so should be fine either way.
Might be worth adding screen resistors if the plate voltage is going to be at or above the 6aq5s design maximum. Probably not a bad idea even if you get the voltages down to where it originally was.
Epiphone Pacemaker 50T PT short
Moderators: pompeiisneaks, Colossal
Re: Epiphone Pacemaker 50T PT short
Yes this amp has an assembly that would be tough to isolate. I looked at a fiber washer, but it seems iffy.
Re: Epiphone Pacemaker 50T PT short
Good idea, 1k 3w screen grid resistors.
Re: Epiphone Pacemaker 50T PT short
Still trying to source a PT for this Amp. Owner has this PT, but I cannot find any info. Might you know what this is. It has the usual black primary, red/redyellow plate connections for rectifier, and yellow leads for Rect. (I assume) and green leads for 6v no center tap. I doubt the heater winding is sufficient for this Epiphone?
Also have a 125P23B Deluxe reverb PT here from him. It's a bit larger but has the 3A current capacity for the heater wires. Voltage is high 330v but the zener method might do.... or is that just too much to drop.
Also have a 125P23B Deluxe reverb PT here from him. It's a bit larger but has the 3A current capacity for the heater wires. Voltage is high 330v but the zener method might do.... or is that just too much to drop.
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Stevem
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Re: Epiphone Pacemaker 50T PT short
This is the way you have to do things at times to get a old invalid amp back on its feet and running.
A side benefit of this type of remote mounting is extremely low 60 hz hum!
One time I was forced to mount two separate transformers this way, one for the B+ and the other for filament.
A side benefit of this type of remote mounting is extremely low 60 hz hum!
One time I was forced to mount two separate transformers this way, one for the B+ and the other for filament.
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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!
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!
Re: Epiphone Pacemaker 50T PT short
No idea about your mystery transformer. Are the voltages close to right? Why do you think the heater isn't sufficient?
You can always bolt on a metal plate to the transformer cutout and install a vertical mount on top of the plate. You can even score and snap relatively thick aluminum with a hobby knife if you don't have many metalworking tools. Just takes a bit of patience and prep work. Admittedly, Steve's idea is probably easier if the owner doesn't mind it aesthetically.
You can always bolt on a metal plate to the transformer cutout and install a vertical mount on top of the plate. You can even score and snap relatively thick aluminum with a hobby knife if you don't have many metalworking tools. Just takes a bit of patience and prep work. Admittedly, Steve's idea is probably easier if the owner doesn't mind it aesthetically.
Re: Epiphone Pacemaker 50T PT short
Would you consider a toroid transformer? If so, then this would be a good match and the price $42 is right. I know, it doesn't have an "oldie" look. Steel cages are also available.
https://www.antekinc.com/content/AS-1T250.pdf
https://www.antekinc.com/content/AS-1T250.pdf
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Stevem
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Re: Epiphone Pacemaker 50T PT short
It’s a great price for that PT because it only seems to provide.55A on the B+ secondary side.
That’s really only enough for something like a 5 watt champ if I am
Not mistaken .
That’s really only enough for something like a 5 watt champ if I am
Not mistaken .
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!
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!
Re: Epiphone Pacemaker 50T PT short
That is 550mA. How much does he need? It's a 100VA PT.
Edit: from the schematic, I calculated the amp needs about 91mA B+, with preamp tubes drawing 5 mA each.
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Stevem
- Posts: 5144
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Epiphone Pacemaker 50T PT short
A tube amp power trans that’s rate at 100VA will typically output about 100 ma for the B+, he needs more like 150ma to 170 ma if you care to compare his amp to a blues Jr for example.
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!
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!
Re: Epiphone Pacemaker 50T PT short
Again, that is 550mA to me. The 6X4 rectifier tube can only safely deliver 77mA steady current. Where is the rest coming from?
The schematic says it all and datasheets.
Re: Epiphone Pacemaker 50T PT short
Fender Blues Jr. PT
https://www.tubesandmore.com/products/t ... unior-15-w
If I'm not mistaken, it says B+ 330VDC @ 68mA
Never mind, just saying.
https://www.tubesandmore.com/products/t ... unior-15-w
If I'm not mistaken, it says B+ 330VDC @ 68mA
Never mind, just saying.
Re: Epiphone Pacemaker 50T PT short
Both PT's owner brought over are shorted. Back to square one. I am thinking just go for the hammond and be done with it. Appreciate all the follow up, clearly no hurry at all on this. We'll get it done.
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Re: Epiphone Pacemaker 50T PT short
That torrid has plenty of juice, I think Steve missed a decimal. They have a 200v one that would be a bit closer. https://www.antekinc.com/as-1t200-100va ... ansformer/
Hammond I recommended earlier isn't quite right, Thought it was 250-0-250 instead of 250v ct. That would put your B+ in the 175v range, a bit too low.
Harvard/bronco/champ/Princeton transformers might be fine. Hammond 270DAZ is close. I think I have access to an ao-44 transformer that might be fine, maybe slightly low on current.
Hammond I recommended earlier isn't quite right, Thought it was 250-0-250 instead of 250v ct. That would put your B+ in the 175v range, a bit too low.
Harvard/bronco/champ/Princeton transformers might be fine. Hammond 270DAZ is close. I think I have access to an ao-44 transformer that might be fine, maybe slightly low on current.
Re: Epiphone Pacemaker 50T PT short
So that 270DAZ puts B+ closer to 200, might be just fine, has enough current capability. You think this is the best option?
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