Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: labb on June 19, 2019, 09:11:28 pm
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Have any of you SUPRO 6424 fans ever built this amp using EL84's as the power tubes and if so what did you think about it.
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Hi Labb,
I have not built a 24 with EL84s, but I do have some experience with those amps, so thought I'd jump in with some questions and comments. I've restored two of them (labelled Gretsch; National) and built a lite version with no trem. I'm curious as to your interest? What I have found with the 24 is that it sounds great cranked up loud. At lower volumes - not so good; kind of flat; not a lot of character. I only play at home, so cranking it all the time is not an option. I have built an amp with the 24 power section and a 5879 pentode preamp that I really like at lower volume, but that's another story.
Adapting the schematic to EL84s would be pretty easy, mostly a matter of different pinout and a few tweaks to resistor values. I'm not guessing it'd be an amp I'd like, but its all personal taste, eh?
Valco did make 2 versions of a 1624T one with 6V6s, one with 6973s. I've been tempted to build that 6V6 version.
Vintage Guitar has an article online by Dave Hunter that discusses the 6424 and the 6973 vs EL84 tube sound. You might find that interesting.
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Thanks for your reply. As to your question, I have a Marshall 18 watt IIB lite that I built years ago that I want to gut and build something else out of. Looks like the 24 would be a good fit.
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Yes, it would be. You have a lot of options. Unless you are opposed to using 6973s, I'd be tempted to first try keeping the Marshall preamp and convert the power tube sockets for 6973/6CZ5 tubes and see what you think. But again - lots of options.