Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: timmyjoe on May 25, 2021, 09:31:43 pm
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I've got a Mojo Tone 5e3 kit. However, I would like to simplify the front panel of the amp to make it more stream lined look. Amp cabinet is going to be a mahogany cabinet with some art on the front. Here are some changes I'm planning. My worry though is that it will add noise the amp in that my components won't be in the ideal location anymore. I'll make a drawing of the original and planned layout soon.
Here's the changes I'm planning though.
*Make the volume dial into a duel purpose on and volume pot
*Place the ground switch in the back panel
*Place the 4 inputs in the back panel
*Move the on light to the top of the head to light interior of amp cabinet. This will light a translucent face inlayed into the wood.
Maybe I should make another shielded box for all the inputs going into the back of the amp head?
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I've got a Mojo Tone 5e3 kit. My worry though is that it will add noise the amp in that my components won't be in the ideal location anymore.
No worry with a good wiring
Maybe I should make another shielded box for all the inputs going into the back of the amp head?
Yes !
What do you do with the holes in front pannel ?
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Using a volume/power switch is indeed used on some old amps. However, it will bring high-voltage noisy mains AC very close to a very sensitive and relatively high-impedance signal. I'd say it has a high risk of causing hum.
The ground switch with the "death" cap should not be used at all! I'd recommend putting the on/off switch in the same location you intended to put the ground switch.
Having the 4 inputs on the bottom seems a bit awkward to operate. You could use just one input and jumper internally to both channels.
Sounds like a cool project! I'd love to see pictures of it when your're done!
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I'll make a drawing of the original and planned layout soon.
Please do. It's difficult to make any specific comments without seeing chassis and tubes, controls, transformer, etc. layout. Most of us are familiar with the 5E3 tweed style chassis, but I get the feeling you have something entirely different in mind.
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Timmyjoe,
Is it you first amp built ? If yes you are better to built like original desing.
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FYI the ground switch is totally unnecessary.
As are 4 input jacks, unless you’re intending to plug 4 things into it. 1 input per channel, or a combined input for both channels, would be fine.
The Mojotone kit and build manual has been designed and written by a person incompetent in the basics of electrical safety, it’s extremely regrettable that such people feel empowered to design and publish mains powered equipment plans / instructions.
The integrated vol control and power switch is a really bad idea. Even apart from the noise issue, the 5E3 vol control is a hair trigger at the beginning of the track, exactly where the switch actuates.
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The integrated vol control and power switch is a really bad idea.
And there are not many choice of pot resistor
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The kit comes with the ground switch. For safety, should I just bypass that switch? Hate to leave it a dummy switch. Any ideas for a use? Maybe it could run the power to the LED light for the lit up face?
So no go on the volume switch idea. Thank you for heads up.
Is it a big deal to have the tubes in a vertical orientation? The kit chassis is for a combo, but I'm thinking of putting the controls in the front.......which would put the tubes on their side. Maybe I need to just make my own chassis.
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The changes you want require you to start with a blank chassis. Are you up to the task? Hoffman sells this one that is perfect for a 5E3 size amp in a head format.
(https://hoffmanamps.com/MyStore/catalog/images/IMG_8591.JPG)