5E8A vs. 5F6A

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ElectricMud
Junior tube assistant
Posts: 4
(2/17/04 5:05 am)
  5E8A vs. 5F6A
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 I've been doing my research and I'm considering building my own amp with the help from a tech that I've spoken to. I've seen all the various board kits and what not on the net, but I can't seem to find one for the 5E8A low powered Tweed Twin amp. Ampwares has a kit for the 5F8A high powered twin. I've never actually had the opportunity to play one of these old amps, but I've heard great things about them. I was also curious about some differences between the Tweed Twin and the Bassman. I have a pair of brand new Vintage 30's that have been sitting in their boxes for about a year now, and I'd like to put them to some good use. I'm curious about the various power and output transformers for these models of amps, as well as similarities in tone and/or circuits, pros, cons, etc... If anyone would like to share some info, I would greatly appreciate it.

Gram


 
Jlwctn
Junior tube assistant
Posts: 17
(2/17/04 12:50 pm)
  Re: 5E8A vs. 5F6A
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 www.ampwares.com/ffg/schem/twin_5e8-a_schem.gif

www.ampwares.com/ffg/schem/twin_5e8-a_layout.gif

www.ampwares.com/ffg/schem/bassman_5f6-a_schem.gif

www.ampwares.com/ffg/schem/bassman_5f6-a_layout.gif


 
Andy Poupart
Senior tube assistant
Posts: 119
(2/17/04 4:12 pm)
  Re: 5E8A vs. 5F6A
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 I've built both, from scratch. Of the two, I prefer the 5F6A, but I'm happy with the 5E8A, too.

The 5F6A is a familiar circuit, using many circuit elements that crop up over and over again on Fender and Fender-derived designs. The 5E8A is not like that at all. It's a unique circuit that basically was used for a year or so and then disappeared. I built it because it was different.

The 5E8A is a wasteful design in the preamp. Each of the four inputs uses half a 12AY7. It has a split load driver instead of the LTP driver, and, of course, it uses 6L6G power tubes. Don't forget the dual 5U4G rectifier set up, too. Also, the output transformer is a unique design. Having said that, it was a lot of fun to build, and it gets used regularly.

The 5F6A is a bolder sounding amp, it breaks up differently, and pushes more air. Mine gets used a lot (it get borrowed a lot!).

Build the 5F6A, then give the 5E8A a try if you want something different!


 
wayneosdias
Senior tube assistant
Posts: 239
(2/17/04 5:13 pm)
  asdf
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 Thnaks for clearing that up Andy, I just took a look at the 8a this mourning and walked away baffled. What a waste of stages, and then sharing the same cathode C/R between the first 2 preamps? Seems like if your just gonna burn a tube youd at least mix it up a little. With that recto setup could you pull one of the 5u4g's and then use 6v6's?

wayne

 
JTM
Junior tube assistant
Posts: 90
(2/17/04 5:14 pm)
  Re: 5E8A vs. 5F6A
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 I helped a friend patch up a 5F6A he bought off ebay and I liked it so much I'm building one now.
 
Andy Poupart
Senior tube assistant
Posts: 120
(2/17/04 7:38 pm)
  Re: asdf
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 Wayne,

I don't think you'd need to pull one of the 5U4Gs. The extra one is there to provide additional current capability, and also has the effect of stiffening the power supply quite a bit - no sag. As long as you manage the plate voltages correctly, I don't see why you couldn't run 6V6s in a 5E8A circuit.
 
 
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