Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: worth on February 18, 2011, 08:30:05 am
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I know some of you guys have built a 5E7. Did you build it as shown in this Ceriatone layout ,with an underfiltered B+ , ( 16uf instead of 40uf ) and no 470 ohm screen resistors on the output tubes ?
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The 5E7 uses a CLC+RC network, not the usual C+LC+RC. CLC gives much better results when it comes to a smooth supply with reduced ripple. I use a 40µF cap for C2 in order to obtain a rock-solid B+.
I you want to play safe, 470R or 1K FP screen resistors can be added with no ill effects.
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I see what you mean, the plates share the same node as the screens. I never noticed that before.
The schematic in Doug's library doesn't show a part number for the choke. Is it the standard 90mA "Big" Fender choke? It seems like the two 6L6's would draw too much current for that choke in this arrangement.
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Worth if you dont have your chassis already I have the ceriatone one its pretty nice I would let it go for $50.00 you pay shipping of course. thats cheaper than what I got it for I had to ship it over from there which is a bit more expensive. I like the 5e7 great classic amp its just ive built that one and there are so many others for me to do. I dont see me using this chassis in the near future .
Thanks Bill
PS. it has a painted chassis plus he threw in a plexi type faceplate thats exactly the same
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The schematic in Doug's library doesn't show a part number for the choke. Is it the standard 90mA "Big" Fender choke? It seems like the two 6L6's would draw too much current for that choke in this arrangement.
Yep, you need a > 3 H / > 150 mA choke with < 200R DCR. I use a Hammond 159S (4 H @ 225 mA 65R, app. $26 retail), but the Triad C-14X, the Weber W014684 as well as others are perfectly suitable.