sunn solarus tube failure

[danbress]

I was playing with my band in our basement last night, when I noticed my sunn solarus start to really really sound HORRIBLE.  It was unplayable when I had my distortion turned on, and was getting alot of speaker displacement even when I wasn't playing.  I turned the amp into standby and let it chill out for a minute.  Then I turned it on, and the lights flickered.  So i turned it all the way off.  And let it chill out for a minute.  Then when I turned it back on again, we blew a circuit.  So I moved it over to another circuit, and was still having horrible horrible interfernece, and I looked at one of my power tubes only to see ALOT of blue glow.

Any ideas about this?

I just had the amp serviced and had all the tubes replaced on 12/29/01, less than 3 weeks ago.

If I want to replace the tubes, can I just buy a pair of matched 6550's, and put them in without any problem?  Or will I have to re-bias them?

Also I was looking at some groove tubes, and noticed some say 6550C and 6550R and other stuff, what do these letters afterwords mean?

Also how does the hardness of the tube play into this.

[Fred Cook]

Hopefully the technomavins will spring to your aid, but in the interim:

- The tube with the blue glow is leaking, that is, your vacuum tube no longer has a good vacuum. Tube has probably failed.

- Unbalanced push pull leads to bad sound.

Take the beast to a tech quick. In the meantime - lots of mojo for a quick amp recovery.

[Bill Matthews]

That's what you get for using bullshit Russian/Chinese tubes..It sounds like  one of your output tubes shorted heater to plate.This is very common for those cheapo/BS tubes.  Do yourself a favor, and throw them in the trash can where they belonged right out of the box. Then what I would do is scheckle up and buy a pair of NOS GE6550's, bias them right, and forget about them for the next 20 years.

[danbress]

thanks for the help.  Can anyone give me some info as to how to bias the sun solarus?  and to what voltage?  I have never done this before, but am not afraid to try.  If someone can give me some alright instructions that would be fantastic.  Thanks.

Where can i find the NOS GE6550's, and how much do they cost?

Dan Bress

[Tom Loizeaux]

Find a decent tube amp tech. I recommend  Precison AudioTaloring here in Baltimore, 410 863-0091
...or give me a call at 410 466-2223, I service Sunn tube amps and have lots of nos Tung-Sol 6550s.

Tom

[Fred Cook]

Danbres,

For what it is worth, my '69 Sceptre is still running on the original RCA 6550's.

Does "motorboat" at about "8" but the old RCA's sound at least as good as the Svetlanas that I bought. Seem to have a better bottom.

NOS tubes may well be a very good idea.

[danbress]

thanks for the help.  I am actually in Rochester, NY.  And I am not sure if I know anyone up here who I trust with my amp.  I would also like to learn how to bias my amp myself.  If someone who knows how to do this the "right" way, by checking the voltage difference, please let me know.  Thanks

[danbress]

Tom L:  I forgot to mention this, but I did get my amp serviced by Jeff at Precision Audio Tayloring on 12/29/01.  Less than 1 month ago.  My amp is at the practice space right now, and I dont remember what kinda tubes Jeff put in it.  But do you think he would put cheap tubes in it?  I am looking to get some tubes here in Rochester quickly.  But If I have no luck I might be interested in buying a pair of those tubes off you.  Let me know what a fair price would be.

[Anonymous]

Check out the Lord Valve bias FAQ on how to properly bias your amp.  BE CAREFUL and don't do it unless you are sure you know what you're doing!!  You could get zapped or worse.

http://www.duncanamps.com/technical/lvbias.html

Also, the Usenet ng alt.guitar.amps is a good place to find technical information of the guts of your amp and suggestions on tubes.