Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: shaun on May 26, 2022, 05:13:58 pm
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Heyo,
I'm about to build an SE combo amp. I've started the cabinet and will use a 5E3 blank chassis - see pic. Also, they are probably the trannys I'll use, and I'll most likely use a standard Jensen ceramic C10 spkr. PT: Hammond 270CAX (81mA). OT: Ham 125CSE. I want to keep things as simple as possible so I can add a reverb later if possible.
This will be for personal use, so I'll be able to tweak it in future, but it will be my working amp, so I'd like to get it as close as possible first time around. I've started playing a lot of jazz standards lately (IG: letsbefranksb), and I've been working with a guy who uses a Hendriksen solid state, which is very round and very warm - fat trebles. So I'm aiming for the warmest, fattest sound I can get from my amp cause....fat and warm...mmmmm.
I already have a pretty good Tweed Deluxe 5E3, which is great for blues break-up and rock, but I'm 90% interested in a clean warm tone, not break up. So I'm considering V1 options. I'm leaning toward a pentode simply because I've found them to be warmer, generally speaking, than, say, a 12ax7. Mind you, most 12ax7s I've heard are in front of a mid-scoop tone stack, so maybe I'm simply hearing the tone stack. Maybe the 12ax7 can be made fat and warm, but having tried some vintage amps with pentodes, they seem kind of more in the ballpark. So anyway, enough rambling. My questions is this (subjective it may be, but I value any feedback), which one would you consider the best candidate for a warm fat preamp tone?
EF86 (would be my first choice, but often needs a cath. follower in order to go into a single knob or TB tone stack, and I prefer a tone stack rather than the tone filter option.)
6SJ7 (heard one of these in a '49 Gibson GA30 - very nice, and doesn't apparently need a CF)
6U8A (I like the idea of this tube because it has a built in CF triode, but I'm not convinced it's all that warm when I've used it in the past. The 7199 seems like an expensive/impossible alternative. As many here probably know, there's a whole family of pentode/triode tubes to consider, but I've only ever tried the 6U8A, so please feel free to suggest any of the others and I'll go research them.)
12ax7 (maybe there's a way to get this to function how I want?).
I'm also considering a power section where I can trade the 6V6 for a 6L6, if I need more volume on occasion. I think I will have enough juice from the PT I plan to use, and I have a larger OT available if needed. I've seen this done in a PP amp, but there seems to be criticisms of it in SE design. So I also wondered if anyone has tried that, but I realize that's a whole other question, and maybe even a different thread, so I'm just happy for any preamp tube feedback I can get.
Thank you, and let the games begin :icon_biggrin:
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Hey shaun,
I built this AC4 using that same 270CAX. I replaced the Vox tremolo with the Vibro Champ tremolo, which added the intensity control.
It has an EF86 and one tone control, but would also work with a six-way tone selector rotary switch without needing a CF.
PFD attached below.
You could easily change the EL84 to a 6V6. That would make a cool amp.
David
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Excellent, dwinstonwood. Many thanks. The layout looks like a good starting place, too.
Wow, same OT as well! I like that you have the chassis number there - a good one to keep in mind for future builds. I hate chasing chassis :).