Build Your Own Clone Message Board

Hello everyone,

I completed my first amp built last month. I'm very very pleased with the little champ, it sounds beautiful.
The only thing is that it makes quite a noticeable hum which gets more pronounced in the 6-9 volume range. Is this normal? I mean, my Bandmaster and AC15 hum a little bit less than the champ.

Is there a mod or something that I can do about it?

Thanks!

I'm sorry about the image size,

I'm new here

maybe tis thread will help
byocelectronics.com/board/viewtopic.php?f=49&t=55796&hilit=champlifier

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Doh! Stupid Diode

Your wiring isn't bad, but there's some room for improvement. Hum (assuming it's not from outside influences such as poor grounding, fluorescent lights, computer screens, etc.) usually comes from the green heater wires. You could tidy those up a bit. Make them as short as possible. Looks like you could take a bit off from the wires between the pilot and the 6V6. And you could untangle the heater wires between the transformer and pilot and shorten those a bit as well.

You could also shield the guts as well. You can get a bit of roof flashing and cut a piece to make a base plate. Or you can add some shielding to the panel of the cabinet that presses against the chassis. I have a roll of copper foil shielding tape that is for guitar cavities that I like to use. You could use roof flashing here again, but you can do something as simple as stapling a piece of screen to the panel....screen like for a screen door or window. It doesn't need to be a solid sheet. You just have to make sure it's made of metal and not nylon....that's what Fender did with some of their brownface era amps.

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*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

I Will perform your recommendations and let you know,

Thanks Keith!

P

There's a wire that goes from the volume knob to the 12ax7 that i replaced with shielded pedal cable wire. It brought my noise floor to almost nothing, and is a cheap fix if it works. Forgive me i don't remember which one, but you can look at the circuit pictures i took in my champlifier thread.

A lot of people will connect the 68k input resistors directly to the input tube socket and bend the other end of the resistor lead into a little loop to be used as a solder lug. Then run shielded cable from the jacks to the resistors. This is standard practice on bigger amps. I've never felt this was necessary on any of my tweed era amps, but it certainly couldn't hurt.

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*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

I agree with Keith on the input wiring. I have some success quieting down a noisy amp both with a shielded cable running from the tube socket to the volume control as robgar91 described and with shielding the inside of the back panel as Keith described.

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MasterDelayer/Reverbrador/Ampaholic/TopJacker

I just completed my champ kit and I have the same exact issue...a little hum from volume 1-4, a crazy amount from 5-9 and then all of a sudden all the hum goes away once the amp is cranked. Did these recommendations resolve the issue? Thanks.

Here is a picture of what I did. I hope it helps solve the issue I’m having.