Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: JGk on March 18, 2015, 12:26:19 am
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I am trying to decide which to build the 2 channel DR or the single. I'd like to build the single on a Princeton sized chassis with the vibrato has anyone done this I was thinking of adding the extra tube next to the input similar to an allen accomplice. My other question is in looking at the layout for a 2 channel with Mid controls the second input on both channels of a DR chassis is used for a pot am I thinking correctly here. Thanks JGK
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Out of curiousity what would you use the 2nd channel for?
I've used the same super reverb for 25 years and NEVER used the normal channel?
I do use 2 channels the amp I use for echo
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Agree w/Toxo. If you own such a 2-ch amp, Fender or not, have you honestly *ever* used the other channel?
Ans: Yes, once in a very great while I have played a CD player (cassette, back then!) through ch 1 to help figure out a tune. But that was 1974. Nowadays I would be using headphones through my TASCAM GT-1.
There are hazards associated with trying to cram too much into a small chassis. Mostly noise, hum.
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Keep in mind that using both channels at once can be problematic, as they are out of phase with each other (There's an extra stage in the tremelo channel).
One thing you can do is pull out the reverb return wire and plug it in to the normal channel. then you can get EQ control on the reverb, which can give you some interesting tone. but once again, you still have some phase issues.
Guitar amps aren't hifi. There isn't a "wrong" way to do anything. It's just different.
If you aren't trying to make an exact clone, you could put the space for a second channel to a different use. Perhaps build a preamp with some more gain to give you some earlier breakup. OR maybe add an effects loop if that would be of use.
EDIT: Your idea of an extra tube could be used to correct the phase issue as well.
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Just saying, Allen's princeton sized chassis has an extra knob for a mid (or other) control and a cutout for a Fender style bright switch which is a nice bonus.
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I was thinking of doing the hoffeman board because I love the sound of bias driven vibrato and would do a deluxe amp tone stack on the normal channel
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I was thinking of doing the hoffeman board because I love the sound of bias driven vibrato and would do a deluxe amp tone stack on the normal channel
If you're going to do a two channel Deluxe Reverb, I suggest that you put reverb on both channels. Your bias vary tremolo with be on both anyway. So leave the Vibrato channel stock and experiment with the "Normal" channel (or vice versa). 220k plate resistor with 2.7k cathode. Voice switching on the tone stack and/or cathode resistor/cap combinations. There's a lot you can do with a "Bright" switch that's a lot more interesting than stock Blackface.
Otherwise you can build a Princeton Reverb with a Mid control. Beef up the power supply and filtering. Upgrade the OT to one appropriate for Deluxe. If you must have the long-tailed phase inverter, use two MOSFETs for the tremolo -OR- use only 1 triode to drive the reverb tank (12DW7 tube). Either way you can keep the 9-pin tube count at 4.
Cheers,
Chip