Chuck D. Bones
Circuit Wizard
Are you talking about a power supply choke or a choke in the audio signal path?
Bastardized '49 5b4 Super
- Thread starter geekmacdaddy
- Start date
geekmacdaddy
Well-known member
Power supply.. high B+ and screens
geekmacdaddy
Well-known member
Exactly what I don't like about the 5E3. You might have just given me the push to finally build one. What value for the 22k dropping resistor next to it? Thanks Hamish
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My pleasure! I've always left the 22K as-is, but also use the "PaulC" mod, which is to change the phase inverter to fixed bias, also known as the Ampeg mod. I'm sure you've heard of it, but you can google it easily enough. Maybe I should have thought about that - but the ams sound great! I use 22µF filter caps - not really very outrageous I know.
The other big difference from stock is use a Mercury Magnetics "Fat-stack" power transformer. It's remarkable what a difference it makes. I've been told on other forums that it won't make any difference because the voltages are the same, but it's the amount of current available which makes the difference. It's very noticeable and makes the 5E3 a joy if you don't want all that mush.
The other big difference from stock is use a Mercury Magnetics "Fat-stack" power transformer. It's remarkable what a difference it makes. I've been told on other forums that it won't make any difference because the voltages are the same, but it's the amount of current available which makes the difference. It's very noticeable and makes the 5E3 a joy if you don't want all that mush.
geekmacdaddy
Well-known member
[QUOTE="HamishR, post: 22315, member: 174"
The other big difference from stock is use a Mercury Magnetics "Fat-stack" power transformer. It's remarkable what a difference it makes. I've been told on other forums that it won't make any difference because the voltages are the same, but it's the amount of current available which makes the difference. It's very noticeable and makes the 5E3 a joy if you don't want all that mush.
[/QUOTE]
There are many choices. I'll be using Schumacher OT, pull from a lowery organ that was used for 7591's and 7868's. Which PT, andd what spec choke, if you don't mind me asking? Would a 4h 50mA do the trick, factoring possible SS recto?
The other big difference from stock is use a Mercury Magnetics "Fat-stack" power transformer. It's remarkable what a difference it makes. I've been told on other forums that it won't make any difference because the voltages are the same, but it's the amount of current available which makes the difference. It's very noticeable and makes the 5E3 a joy if you don't want all that mush.
[/QUOTE]
There are many choices. I'll be using Schumacher OT, pull from a lowery organ that was used for 7591's and 7868's. Which PT, andd what spec choke, if you don't mind me asking? Would a 4h 50mA do the trick, factoring possible SS recto?
Ha! I don't know, but I use a BF Deluxe style choke. I would be careful with using a SS rectifier unless the Schumachers have a low enough B+. Maybe it's because of where I live - we have 240V 50Hz AC which often varies between 235 and 245V - but I often have issues with the B+ voltages being higher than spec.
The power tranny I last used was the Mercury Magnetics FTDP-E-FS. The E denotes Export I guess, which is what I need. The FS stands for Fat Stack which I am a huge fan of. You can also get Fat Stack output trannies but I find they suck all the character out - they're efficient and they do what they say but I don't care for the tone. But Fat Stack P/T? Yeah, I like 'em for Fender style amps cuz they seem to deliver enough current to produce low end and not fartiness. I don't really know why they work to be honest, but they do IMO.
I just looked at MM's range of 5E3 power trannies - man, they have a lot of options! I like the idea of a P/T with two different B+ windings.
The only reason I use MM is because of the options. One of the best sounding amps I have ever built was a '68 50W plexi clone with Marstran/Heyboer trannies - it sounded so much like a friend's '68 Plexi it was unreal. I don't have access to Lowery organ tansformers!
And I'm not in Chuck's league where tech knowledge is concerned - I'm a photographer, not an electronics guy. But I have built a lot of amps!
The power tranny I last used was the Mercury Magnetics FTDP-E-FS. The E denotes Export I guess, which is what I need. The FS stands for Fat Stack which I am a huge fan of. You can also get Fat Stack output trannies but I find they suck all the character out - they're efficient and they do what they say but I don't care for the tone. But Fat Stack P/T? Yeah, I like 'em for Fender style amps cuz they seem to deliver enough current to produce low end and not fartiness. I don't really know why they work to be honest, but they do IMO.
I just looked at MM's range of 5E3 power trannies - man, they have a lot of options! I like the idea of a P/T with two different B+ windings.
The only reason I use MM is because of the options. One of the best sounding amps I have ever built was a '68 50W plexi clone with Marstran/Heyboer trannies - it sounded so much like a friend's '68 Plexi it was unreal. I don't have access to Lowery organ tansformers!
And I'm not in Chuck's league where tech knowledge is concerned - I'm a photographer, not an electronics guy. But I have built a lot of amps!
geekmacdaddy
Well-known member
Cool man. Thanks for sharing.