Grateful Dead Music Forum

A place to talk about the music of the Grateful Dead 

 #133691  by Winterland
 Thu Oct 31, 2013 2:52 pm
Hey everybody..Have an issue with my SMS. When I come out of the output and into the rocktron. I get a
poping crackling sound from my speaker. I hooked up another pre amp and have no issues. Any ideas if this
is a issue I can fix?

In 85 at this time I was in SC waiting for a show to begin. Crazy how time flies!
 #133693  by Jon S.
 Thu Oct 31, 2013 4:47 pm
Apologies if I'm being dense but what exactly do you mean by "When I come out of the output and into the [power amp]?"
 #133694  by HeadSpace
 Thu Oct 31, 2013 4:51 pm
Bad tube in the SMS? If so, easily fixed by you.
 #133699  by tcsned
 Thu Oct 31, 2013 6:01 pm
sounds like it might be tube related, you're using the same cables for both preamps right?

I was at that 85 Halloween show - that was some fun :-)
 #133702  by Winterland
 Thu Oct 31, 2013 6:38 pm
I am running a 1/4 in patch cable from the output of my SMS to the input on my rocktron amp.

I thought the SMS's were SS with no tubes? I may just send it back to Brad. I didn't know if it
was just something I can do myself.

By this time in 85 I had my face blown off by the space werewolves opener! Had to add that sorry for the digression. Thanks for the input.
 #133703  by Winterland
 Thu Oct 31, 2013 6:40 pm
Yes same cable for the other Preamp. It's an FDY tube preamp.
 #133705  by tcsned
 Thu Oct 31, 2013 6:45 pm
If the other preamp uses 12AXs you could swap them.

Replacing tubes is pretty much like changing a lightbulb.

I did all the shows from the Fox through Richmond, what a run of shows - did a few others on that tour too . . . and, not surprisingly flunked out of college :)
 #133706  by Winterland
 Thu Oct 31, 2013 6:52 pm
I got smoked that semester too! Gloria was a treat in Richmond.
 #133712  by Coldshotblues
 Thu Oct 31, 2013 9:17 pm
I had the same issue with my SMS I swapped out one of the tubes inside problem solved. It
really is like changing a light bulb.
 #133732  by Winterland
 Fri Nov 01, 2013 3:04 pm
Fixed! thanks guys. I put a 12 ax7 Russian in there.