Well that sucked.

[boogietone]

The Pastor of our Church found out I play guitar. Asked me to play in their band. Sure. Why not? So I practiced with them a few times and this morning was my first time playing during service. I haven't been onstage in a long time. Anyways, got through two songs. Then the choir sang and right after their song ended the loudest, most annoying squeel let loose. It lasted for about ten seconds and then faded away. Hundreds of people looking on with bewildered looks on their faces. I hoped it wasn't by beloved MKIV. I really hoped. It was. It was mic'd backstage and I couldn't get to it till after the set. Got it home and discovered it was dead and one preamp tube was not lit. Replaced it. Amp worked fine. Put the tube in question in my MKIII. Nothing. Is it normal for a preamp tube, or power amp tube for that matter to make such a horrific scream as it dies? I wanted to crawl under a rock and disappear. Kind of emabarrassing. Oh well. Should I be worried of an underlying problem with the amp? Or does this just happen once in while? Sorry for this really long post. It was a Tungsol 12AX7 from Musician's Friend. Maybe M.F. was my mistake?

 

[Nick_cor]

Reading your story made me wanna crawl under a rock and die. I feel horrible for you! I can only imagine what it would feel like for something like that to happen. But hey! look on the bright side, you were at church! I'm sure they'll forgive you. :roll:


PS: Isn't it weird that when one plays a gig that's when all the bad things happen? I was playing a gig outside a bank once with a jazz group and 2 of my patch cables died during the middle of two different songs! and to make it worse my guitar strap ( strap lock part ) cracked during the break between sets! I had to sit on the half stack during the second set, and go figure, everything that failed was from planet wave. So I wrote them an angry letter, and I'm never buying their **** again.

 

[boogietone]

Thanks Nick. I am kind of lucky that my amp was backstage because it sounds like most of the congregation thought it was the P.A. system. Still sucked though. FWIW though, I did get lots of complements the two songs I did play. After the incident I stayed up there and played along with the band though there was no sound. There was another guitarist playing acoustic. Anyways, I am going to send the amp in to M.B. because R1 is getting noisy. And the amp was made in 1992. Probably could use a check up. I was using R2 with low gain set for cleans BTW.
Yup, straps and patch cords can make life a little difficult. I too have had a strap fail. Thankfully, it was a very, very cheap guitar (Hondo) whose headstock went crashing to the floor.

 

[Nick_cor]

Yeah, well if you live close than that would be the best thing to do. The Mark IV I have was sent in because it was getting noisy as well and I believe MB cleaned it all up and changed a resistor and a few caps. I don't remember what was changed but now there's no more excess noise.

I don't have a guitar or cabinet though, I've sold off all the recording gear and guitars to fund for my new rig. But I also bought a new acoustic and unfortunatly I had to put all the money towards that guitar so now I don't have enough money to buy the cab. So now I have a mark IV on my shelf with no guitar or cab. Grr!!!

 

[boogietone]

So I have a mark IV on my shelf with no cab or guitar. Grr!!!

That's torture! :wink:

 

[6L6C]

The amp is from 92? Have the tubes been changed since then. If not go for a whole new set, treat yourself treat the Mark IV, treat the church.

 

[boogietone]

The preamp tubes are fairly new. So I was surprised one went out. I thought it was going to be a power amp tube. The power amp tubes are STR 454's and I don't know how much life is in them. I like them though and wish I could find more. Are Tungsol preamp tubes reliable or should I be looking for some different ones to help prevent this from happening again? I really don't care to relive that squeal!

 

[6L6C]

I have three Tungsol preamp tubes in my Mark IV and have no problems and they sound great but then again you can read threads were people are having tubes fail. It’s basically a crap shoot cause QC on tubes suck. Might want to look into some NOS tubes.

 

[boogietone]

Might want to look into some NOS tubes.

I just might do that. Do you have any preferences on brands or where to get them?
Thanks!

 

[6L6C]

One of those things I have always threatened to do but have not, but you might want to shoot a PM over to user “stokes” he’s a big NOS guy he can steer you in the right direction for sure! I think I need to start collecting myself. The preamp tubes are no problem but the power tubes are different matter chances of finding them in a mesa range: good luck! That’s were an adjustable bias is helpful.
At one point and time I was thinking of having my Mark IV modified so it had an adjustable bias, however I discovered there is allot of compromise involved (and talked to someone who did it)
The compromise is you never really get the bias in spec when you run class A or simul-class and also tweed the bias keeps changing so it’s a bit of a balancing act.

 

[6L6C]

I had a new preamp tube (form Dougs Tubes) that was bad to begine with!! Happened about three weeks ago. It was the lead channel preamp tube in a C+, horrible squealing sound etc. Literally new had only been in the amp an hour!
So it does happen from time to time.
(Doug replaced it for free - no questions asked)

Doug is awesome got a tube set for my Mark IV from in, the amp never sounded so good!

 

[devilrob1979]

I feel for you man. I was onstage one time playing someone else's rig as I was just sitting in and my buddy tells this chick she should go grind on me. She managed to unplug 3 patch cables in less than 5 seconds and get they weren't labeled. I got through the song, packed up my guitar and walked out.

 

[boogietone]

Oh dude...was she at least good looking?

 

[ursinus]

Hey boogietone, did I sell you the EV loaded theile? Is it working out for you?

Anyway, I had a strange experience this last Saturday with my MKIII. We had a Xmas party/jam at Tone Merchants in orange. We had four guitar rigs on stage as well as a bass rig and drum set, but my MKIII would lose its volume when it would warm up. This never happened before. It turned out it was a bad preamp tube. Unfortunately, the MKIII was not able to be used, so we weren't able to have as many guitarist on stage as we wanted. The good news is that the MKIII got rave reviews from guys that usually slam Mesa's.....

 

[edward]

Bummer ...and I feel for you! Tubes are like light bulbs: they work great ...until they don't

I would definitely go with a good set of NOS tubes ...not "that" much more than Mesa stock replacements, and in some cases not even any more $$ at all. KCA Tubes has been my personal source: Mike is very knowledgable, friendly, and really knows his stuff. He's an avid poster on TheGearPage and enjoys a superb reputation there, for all the right reasons.

Anyway, back to your tubes. Replace them with good NOS-ers which will likely give you both better longevity and smoother tone. Get some recommendations, especially from Boog owners, and take all those recs with a grain of salt as everyone has their own personal idea of "great tone." Know, too, that no tube purchase, even of the nicest NOS, is a guarantee of anything. Think of light bulbs again. Hope this helps. BTW, how'd your pastor take it? Equip failure "happens" BTDT ...part of life

Edward

 

[boogietone]

Thanks for all the input everyone. I'll hunt down some NOS tubes I guess. As far as the Pastor and Church, I think they all think it was something with the P.A. system that made the noise. It wasn't until I said my amp was a possibility that my equipment even crossed their minds. They had turned on a huge movie screen to show some short movie or something right when it happened. This Church is big and has tons of audio/video equipment. I wonder if turning on the big screen may have caused a surge and fried the tube? Is that possible? Just that my amp has played so well and suddenly without warning...BOOM! Actually-squeeeaall!

 

[boogietone]

Hey boogietone, did I sell you the EV loaded theile? Is it working out for you?

Anyway, I had a strange experience this last Saturday with my MKIII. We had a Xmas party/jam at Tone Merchants in orange. We had four guitar rigs on stage as well as a bass rig and drum set, but my MKIII would lose its volume when it would warm up. This never happened before. It turned out it was a bad preamp tube. Unfortunately, the MKIII was not able to be used, so we weren't able to have as many guitarist on stage as we wanted. The good news is that the MKIII got rave reviews from guys that usually slam Mesa's.....

Yup. I got your Thiele. Sounds great. However I think I like my 2X12 cab a bit better. I may be letting that Thiele go. Still haven't decided. I could use it with my MKIII but I might get rid of that too, though I swore I never would.