Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jimlat on April 07, 2021, 08:07:58 am

Title: Silvertone 1484 Reverb going on and off
Post by: jimlat on April 07, 2021, 08:07:58 am

I recently took my 60's Silvertone 1484 amp out to use it after many years. When I turned it on I was getting a bad "hum". I replaced all the original tubes with new ones. The hum went away. But now the reverb keeps going on and off as I play. When I "tap" on the top of the amp head, it comes back on. When I replaced the tubes I sprayed all the pins with CRC Tuner cleaner and moved them in and out a few times. But now I'm reading that the best product to use is DeOxIt D5 so I ordered a can. Does anyone have any suggestions as to what may be wrong and what else I should try? Any input and advice would be greatly appreciated.
Jim

Title: Re: Silvertone 1484 Reverb going on and off
Post by: Soulfetish on April 07, 2021, 08:39:51 am

I'm willing to bet you're getting intermittent contact in the tube socket. Silvertone's have notoriously bad tube sockets.
You can try and wiggle the 6CG7 around in the socket a little to see if that is the issue. If it is, I would first try and spray out the socket with Deoxit. If that doesn't seem to work, you might want to re-tension the socket terminals. But in my experience, the socket often needs to be replaced.

Title: Re: Silvertone 1484 Reverb going on and off
Post by: jimlat on April 07, 2021, 02:38:38 pm

How is the DeOxIt D5? Everybody is telling me to buy it. Does it work better then the other brands like CRC?   

Title: Re: Silvertone 1484 Reverb going on and off
Post by: tubenit on April 07, 2021, 08:14:15 pm

I would be surprised if it's the tube socket.  The Dan Electro amps often used a piezo type reverb and those were pretty flimsy in my opinion and my bet is you may have a short within
that piezo type reverb circuit .


IF you are experienced and know how to work on amps safely, you might consider replacing the Dano reverb with a one tube reverb.  I did that on my Dan Electro Centurian 275 and it turned out great. 


Looking at the back of a 1484 cab head, you will see the piezo type reverb "pan" right behind the preamp tubes. I am wondering if you tap gently on that with a non conductive stick like a wooden chop stick if it will reveal it coming on/off? 


With respect, Tubenit

Title: Re: Silvertone 1484 Reverb going on and off
Post by: scstill on April 08, 2021, 12:20:48 am

I rebuilt my 1484 reverb successfully.
It works great. I like it alot.
https://el34world.com/Forum/index.php?topic=26510.msg290174#msg290174

Title: Re: Silvertone 1484 Reverb going on and off
Post by: terminalgs on April 09, 2021, 05:10:38 am

Plate resistors on the tank driver triodes on 1484s are undersized for the wattage rating. Dano used 1/2W but really needed 1W.


See voltages on schematic. Voltages show 0.5W or 0.6W (can't remember precisely).


Might be your problem if one is failing or failed.