Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Leevi on January 23, 2013, 03:14:50 pm
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This amp is like 5E3 but there has been added some modifications like
possibility to use 6L6 and E34? Also the tone pot is implemented with a dual pot.
Rectifier is GZ34 instead of 5Y3.
Does anyone know the specifications of the PT (or B+)?
/Leevi
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I don't have any specifics about that PT. I know it's a custom Mercury Magnetics. Some detailed gut shots can be found here:
http://www.thegearpage.net/board/showthread.php?t=906560
(http://www.thegearpage.net/board/showthread.php?t=906560)
I actually modded my 5e3 to be pretty close to the Crema Wheat, using those photos. It was just a couple extra changes over the regular volume/tone mod, including split cathodes on V1, 150k plate resistors on V1, 47nF coupling caps, and 360R/25uF on the power tube cathodes. Oh, and it has 30uF filter caps all the way across. It wasn't really my thing in the end, and I went back to something closer to stock.
The Allen TP40D looks like a nice choice for a high-powered 5e3 though, IMHO.
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360R instead of 250R on the cathode might mean a higher plate voltage than in 5E3?
I'm planning to use EL34s as well. I have thought to use the 16 Ohm output with 8 Ohm speaker
in order the get the load resistance to right level.
/Leevi
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It wasn't really my thing in the end, and I went back to something closer to stock:
Thats one thing i have learned over all these years. Mods are interesting and fun to do. But in the end it all comes back to the original old Fender,Marshall,Valco,Gibson,Ampeg Gemini,Silvertone etc tones.
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360R instead of 250R on the cathode might mean a higher plate voltage than in 5E3?
The GZ34 that comes "stock" with the Crema Wheat would give a higher B+ even with a standard Deluxe PT than would a 5y3. I don't know if the Crema PT actually has higher voltage secondaries or not. With 6V6's, a GZ34, and a Deluxe-style PT, I was getting a B+ up around 375 V, so there's not a whole lot of room left to go if you were gonna keep 6v6's in there.
Thats one thing i have learned over all these years. Mods are interesting and fun to do. But in the end it all comes back to the original old Fender,Marshall,Valco,Gibson,Ampeg Gemini,Silvertone etc tones.
Yep. One of these days I'll learn, but not just yet.
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I actually modded my 5e3 to be pretty close to the Crema Wheat, using those photos. It was just a couple extra changes over the regular volume/tone mod, including split cathodes on V1, 150k plate resistors on V1, 47nF coupling caps, and 360R/25uF on the power tube cathodes. Oh, and it has 30uF filter caps all the way across. It wasn't really my thing in the end, and I went back to something closer to stock.
I got the chassis wired and I wonder the different capacitor values 10n and 22n around the dual pot?
Another question is how the dual Tone pot should be wired and what are the capacitor values?
http://s710.beta.photobucket.com/user/L4CESN/media/Tungsten%20Crema%20Wheat/IMG_0251.jpg.html?sort=3&o=11 (http://s710.beta.photobucket.com/user/L4CESN/media/Tungsten%20Crema%20Wheat/IMG_0251.jpg.html?sort=3&o=11)
/Leevi
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I think Ed Chambley did that dual pot TS to 1 of his 5E3 amps.
Brad :icon_biggrin:
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For those that want the option to switch between the interactive 5E3 controls or non-interactive (only tone control on the instrument channel) the following will do it for you.
(http://i406.photobucket.com/albums/pp142/printer2_photo/guitar%20amp/5E3Interactive-Normalmod.jpg)
And a couple ways of wiring the mod.
(http://i406.photobucket.com/albums/pp142/printer2_photo/guitar%20amp/5E3VolumeModLayout03.jpg)
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I think Ed Chambley did that dual pot TS to 1 of his 5E3 amps.
I changed the TS accoding to that and IMO it works pretty well.
http://www.el34world.com/Forum/index.php?topic=14297.0 (http://www.el34world.com/Forum/index.php?topic=14297.0)
If you wonder the switch close to the outputs it's used to set EL34 mode when using EL34 power tubes.
Thanks
/Leevi