Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: panhead on November 07, 2011, 07:09:11 am
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I'm thinking of building something along the lines of the 5C3. I've built a few 5E3 type amps and they're pretty gritty soudning. Anybody have any experience with the 5C3?
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I built a 5C3 circuit into a friend's old amp chassis about a year ago.It is indeed gritty and rich sounding.It does not like pedals because of the grid-leak bias on the tubes;they just overload.But if you just plug in your guitar and play they are as sweet as can be.Older low-output pickups excel here.Modern les-pauls and hot humbuckers are too hot IMHO.
My wide-range pickups in my 72 tele deluxe shine with that amp and a strat is lovely.Use a lower powered alnico speaker.
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I've built a couple of them. If you can find glass ones, 6SC7's are by far my favorite preamp tube. Phsyconoodler's right on in his description. I'd just add that you really wouldn't want or need pedals for this amp. I recorded a few things with one using a Yamaha SHB-400, which is their version of a Gibson SG. Listen to Scotty Moore on "It's Alright, Mama", from Elvis' first album. That's almost exactly what it sounded like. My only problem with it was a lack of clean headroom. It's the only amp that made me seriously consider carrying 2 amps with me, one 5C3 and another for clean. It's a sweet sounding amp.
Dave
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> lack of clean headroom
What happens if you jumper the first 10k resistor in the power supply with say 2K?
By the tube data, the G2 (and preamp) voltage falls 100V at max clean power, and more in overload. With just 16uFd at G2, even transient overloads may be ducking G2 voltage severely, limiting the post-transient clean power.
All of which may be part of the 5C3 magic, but a switchable smaller G2 dropper gives the option of the more overload-robust power dynamics of later "stronger" Fenders, without actually lugging two amps.
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"but a switchable smaller G2 dropper gives the option of the more overload-robust power dynamics of later "stronger" Fenders"
Great idea! I'd forgotten about that. I did that on the first amp I ever built. It was 40 watts and I couldn't really hear much difference so I'd forgotten about it. I just raise the PI and preamp voltage automatically in my Deluxe clones for that very reason but I hadn't put 2 + 2 together with amps I built a few years ago. You know, a footswitchable relay for that might be just the ticket. That goes up on my list. I still have a few glass Tung Sol 6SC7's waiting for a project.
Thanks!
Dave