Bassman 50 questons

[Shadrock2]

So I'm working on a silver face Bassman 50...
and I've got it back to working but my customer also complained about a thump
when the deep switch was activated. In my opinion it is not much of a thump and I was wondering whether or not just putting say a 220k resistor across the switch would be an acceptable fix.

Also, is the ground switch and cap across the power cord the so called "Death Cap"?
If so what is an acceptable solution for this?

These amps sound so good that I am loath to make changes in the circuit.

[The Dude]

My $.02:

I've heard that thump before on amps with deep switches. My take is that it's not a big deal. Who turns that on and off while they're playing anyway? It's more of a "set it and forget it" switch.
The cap from the ground switch to ground is the death cap- the .047. The "U.L." designation likely means it's an X cap and safety rated, so it's probably ok. Do make sure you have a grounded AC cord. If you want to be "super-extra safe", you can clip out the cap. If you have a grounded AC cord, it serves little purpose anyway. You'll get arguments either way on whether safety rated caps are actually safe.

[Justin Thomas]

Who turns that on and off while they're playing anyway?

I do. I kick my reverb-equipped amps while I'm playing, too - my special effects aren't very special...

Sorry... But yes, these ARE damn fine sounding amps! Anybody been working on it previously? Maybe it's the one I sold a couple years ago after making it stock after someone "broke" it by Mosquito-Marshallizing it.

Personally, I like to just have the grounded power cord, no extraneous caps, no extraneous switches hooked up. I disconnect the ground switch, but I quit removing them after I nearly jammed a pinky in the hole one day while fumbling for the Standby Switch... Coulda been FUN! I just leave the grounded power cable going straight to the center of the fuse holder, no more.

Justin

[Randall]

And bright switches on Fenders also make a noise when switched. Not really a big deal, and probably have done so from the beginning.

[The Dude]

...... I kick my reverb-equipped amps while I'm playing, too......

I played "The Thunder Rolls" with a cover band for a bit. I used to crank the reverb and smack the amp for a thunder effect.

[nosaj]

I played "The Thunder Rolls" with a cover band for a bit. I used to crank the reverb and smack the amp for a thunder effect.

I thought that was called the Enzo Whack?

nosaj

[Shadrock2]

For me the thump wouldn't be a big deal but the amp owner specifically complained about it.

The power chord was replaced along with one screen grid resistor. I was thinking I might did up another 5W 470 ohm cermet and replace the other carbon comp. one as a preventative. Otherwise it looks pretty much stock to me.
I replaced one bad .01uF cap to get it working.

It has a good three wire chord now so maybe I'll just clip out the "Death Cap".

[Enzo]

Enzo whack is only in the shop.

The customer made it his complaint, but it is still normal. You can tell him this is normal behavior for the amp or you can spend a bunch of labor trying to come up with a fix. A fix the factory didn;t see as worth the time. I have a service bulletin from Fender about hum in CHamp amps. They told us "Stop trying to fix the hum, it is normal".

However, you are probably right, though I'd choose a 1 meg resistor across the switch instead.

I clip off the ground cap, but leave the switch in the hole. It will be there for some future use, but if nothing else a useless switch looks way better than a hole in your panel.

[Mick Bailey]

I had a similar complaint about a Fender '96 Twin. The customer bought it back twice for reverb noise. There was a service bulletin for the problem stating that the rework would "reduce but not eliminate the noise". He wasn't happy with the situation at all, but stuff does what it does.

[Leo_Gnardo]

For me the thump wouldn't be a big deal but the amp owner specifically complained about it.

Then apply your solution of placing a resistor across the switch. I'd use a 1 Meg but I'm sure your 220K will work fine. Same thing with those bright switches - I've seen boutique brands use a 10 Meg to keep the pop to a minimum & I follow suit for those who complain about the pop noise.

[Shadrock2]

Thanx all.
I'll find a 1 meg resistor to use. I was just guessing on the value so I appreciate the input.

I was planning on leaving the Ground Switch in place.

[Mick Bailey]

That ground switch location could be a good place to install a HT fuse.