70 solarus head with a problem or two

[sunngri-la]

The bias is set and this thing KICKS.  Very very clean and wonderful. I do have a couple more questions though.  The reverb has that scratchy control thing going on but when on 10 there is still absolutely no reverb and it makes the amp hiss.  Is that the 12au7? or maybe a faulty tank? I did get a new cable for the reverb and that didn't change anything.  Also the tremolo doesn't work until the amp has been on for a while--bout 10-20 minutes after it comes off standby.  Is that supposed to happen?  It just seems like it has to warm up the circuit or something and when it does work, it sounds beautiful.  Sorry to ask so many questions. I feel like a little kid that keeps asking "why?  why?  why?"  Thanks for your patience with me--once again.
mike

[JoeArthur]

It sounds like you are saying that you get absolutely NO reverb, at any control setting.  If you get any reverb, I would first clean that dirty control.

The 12AU7 tube is the reverb driver, the front end of the reverb section.  Any hiss or noise in the reverb would be coming from the recovery side, which is a transistor and the reverb control.

Have you tried "gently nudging" (a slight whack on) the reverb unit?  If you get the reverb boing sound, I would first suspect the 12AU7.  If you don't get the boing sound, or only a very faint sound, first check the reverb cables to make sure they go to the correct reverb unit connections (sometimes they get connected backwards).  If all that seems fine, then I would try swapping out the reverb unit with another one.

The tremolo is a slight mystery.  It's all transistor.  Two possibilities come to mind - did you swap out the 2 1000/35volt electrolytics?  The tremolo receives power from a separate filtered supply, and these could be bad, taking some time to build up a charge.  I would first check the voltage at the positive end of both of these electrolytics - with the tremolo not working and working.  

The other possibility is some intermittent connection that makes contact after some part heats up.  This is not so simple to find.

[sunngri-la]

Null the previous posting.  All is well and working exactly as it should.  Thank you guys so much.  ANOTHER SUNN RISES!!!
I feel like Dr. Frankenstein.  (Mwa ha ha ha) Just in time for the next gig.

[Anonymous]

Thanks for the info on the tremolo.  It hasn't acted up again and I've been playing through it alot just to see if/when/what will go wrong (constant monitoring for problems.) I did change the 1000@50 caps and FYI the reverb was the cable being hooked up wrong (undersized brain o' mine) It seems my labels are reversed or dyslexic or something--backward nonetheless.  I also turned the gutted shell of the footswitch back into a working restoration.  I kinda freaked yesterday because my VOM had a low battery and kept getting these really-off-the-wall numbers. I replaced the 9v this morning and got a new 12ax7, gz34, and new 6550s. They're not the best in the world but they're all I could get my hands on today.  They didn't cost much either.  As soon as I can, I'll get the other two tubes and some kt88s.  I'm going to keep an eye on the tremolo and if something goes wrong I'll know what to look for.  Thanks again, Joe, and the rest of you guys too.  I think I've found a new interest, or maybe hobby, or even profession if the rock-star thing doesn't work out. I know, I know, I have a lot more to learn.  Rock on everybody, a little cleaner, and a little louder.
Mike

[Fred Cook]

FWIW - I am running JJ KT88's and am very happy with the sound.