Silverface Deluxe Reverb Hum

[ampdoc1]

Stevem. Thanks for the apology,...it takes a man to say I'm sorry.

My apologies to you and our TAG brothers.

a'doc

[gui_tarzan]

I had to go back to see what I missed. I've stopoed reading his posts because of his insistant use of the exclamation mark, rather than the period to close every friggin sentence. Shouting everything you say smacks of a superiority complex, in my estimation.

And Jim, i disagree: Sometimes a public 'spanking' is exactly what is needed to GZ34 a situation.

Oh crap, did I say all that outoud? I'm sorry, I thought I was just thinking it...

I don't disagree (too much) Jazz, but there are many smart, experienced people that don't use punctuation (or spelling or grammar) correctly, and after participating in online forums since the BBS days I've learned to overlook it, even when it makes me cringe.

Yes, sometimes that is necessary, however I believe that should be taken private and let the discussion continue without the crap. Sometimes we have bad days, those are better spent NOT being online in my opinion. It does take a big person to admit when they were wrong and I appreciate both guys taking that step.

My worry was more that someone in need of help would get discouraged by the comments and go elsewhere for help.

[Structo]

Generally the freeze spray is used on SS components to see if there is a heat related problem causing a component or connection problem.

[Stevem]

Thank you for accepting it!

[Structo]

Another tool for the box is a laser thermometer gun.

You can quickly find a component or area of the amp that is getting too hot.


http://www.amazon.com/gp/product/B00837 ... ge_o01_s00

[BungleSim]

This isn't a great post so I apologize in advance for its lack of a definitive solution to the problem. I noticed a few different things wrong with the amp so I just fixed all of them at once and the hum went away. One thing was one of the 16uF power caps (changed to 30uF by a tech before me who did an awful job with the installation) had a broken leg. Replaced that. Replaced the 50uF bias cap as it was dry. Lastly, I replaced the rectifier tube as it had what appeared to me to be a break in its vacuum and would spark a beautiful purple hue every time the amp was taken off standby. It seemed to work just fine but I figured it would eventually fail so may as well replace it now. I replaced the reverb tank cable but at that point it didn't matter because the runaway feedback/hum was gone. Thanks for everyone's help and it looks like we learned something here about freeze spray and manners.

[Leo_Gnardo]

This isn't a great post so I apologize in advance for its lack of a definitive solution to the problem. I noticed a few different things wrong with the amp so I just fixed all of them at once and the hum went away. One thing was one of the 16uF power caps (changed to 30uF by a tech before me who did an awful job with the installation) had a broken leg. Replaced that.

30 uF instead of 16 was no big deal, but a broken lead? yes that's a hummer, and without the filter a place for signals to travel in unplanned ways from stage to stage, possibly causing your runaway reverb hum.

Replaced the 50uF bias cap as it was dry.

Good, as they always are dry & on last legs in old amps, I just replace 'em as a matter of course. Wouldn't have had any effect on reverb hum.

Lastly, I replaced the rectifier tube as it had what appeared to me to be a break in its vacuum and would spark a beautiful purple hue every time the amp was taken off standby. It seemed to work just fine but I figured it would eventually fail so may as well replace it now.

Rectifier wouldn't have worked at all if the vacuum was broken. You'd have seen the silver looking flash areas gone milk white. Replacing a sparky rectifier, always a good idea.

I replaced the reverb tank cable but at that point it didn't matter because the runaway feedback/hum was gone. Thanks for everyone's help and it looks like we learned something here about freeze spray and manners.

Definitely, when the flood waters recede in OK, let's go on a catfish noodling expedition with ampdoc. Learned all about noodling from another son of Oklahoma, Arthur Smith. Sounds like fun! Leave the freeze spray at home, just bring chilly beverages.

[Structo]

A good thing to check after a rectifier or power tube failure is the socket.
Sometimes the tube will short out and arc between pins.

After replacing the tube there may be a carbon track created on the socket.

Check to see if there are any carbon tracks between the pins.

[Richie]

A good thing to check after a rectifier or power tube failure is the socket.
Sometimes the tube will short out and arc between pins.

After replacing the tube there may be a carbon track created on the socket.

Check to see if there are any carbon tracks between the pins.

Yep, and usually it will also put the arc on the tube base, so don't try to use that tube in anything else,or you will have other problems.
And most times it will leave a burnt smell.

I have an old Ouha amp here that the old vintage socket has the burnt spot or arc between heater and plate. And also on the 6v6. They said the amp was smoking..

[Tone Snob Geezer]

For what it's worth, I had a cracked solder joint on the bias diode on my '64 Deluxe Reverb that caused all kinds of hum as well as well as other very bad behavior. A bad bias cap can cause hum as well.

[Stevem]

Your gonna love this one!
If you turn up the controls on the normal channel, one at a time with nothing plugged into the normal channel does the hum diminish ?