Anyone Ever Do Something Real Stupid To Their Tube Amp? Fender 100T

Did the manual say not to do that?

I have a Vox Night Train tube amp and I learned the hard way that switching between triode (7W) mode and pentode (15W) too rapidly seems to have a malign influence on the innards. Since that first incident I now am careful to first switch it to standby, wait a few seconds, and then switch it to one of the operating modes.

It was a floor model and didn't come with a manual. GC even wanted to gyp me out of a power cord and they couldn't find the carrying bag or the instructions, because their stockroom is a black hole where useful items apparently get sucked into a vortex to disappear forever.

 

That's potentially electrically analogous to driving down the highway and then suddenly slamming your transmission into first gear.

I couldn't find a schematic for the 100t or its output section but I did find a block diagram from the manual. Fender Bassman 100T Owner's Manual (Page 11 of 44)

But yes, what you said: take it to a tech.

It does not say not to switch it while in use.... you might have an argument there.: Fender Bassman 100T Owner's Manual (Page 7 of 44)

The one linked above is the same as Fender's up to date manual on their website: https://www.fmicassets.com/Damroot/Original/10001/2249100_bamp_manual_all.pdf

Absolutely. I listened to cries of "turn it up" running my old V4 into a quad of '60's Ampeg SVT speakers with a 5 string bass on a holiday gig. I could hear the speakers and amp were unhappy because I was already on the limit before turning up once more. The speakers quickly started to die and took out the output transformer and tubes along with. And then they let me run through the ridiculously loud PA like I'd asked to do in the first place. Cost me like $600 in parts and hours of my time.

 

And cue the chorus of "Please turn on your video camera and do it again!" Just kidding. I've done far worse. I'm lucky to be alive. Thanks for the reminder.

 

Things happen. A well designed amp will anticipate things like this.

Check the switch that caused it all, it could be locked in silent recording. Check the 5W screen resistors on the output tubes. There are a lot of other possibilities. See the schematic below.

 

Anyone Ever Do Something Real Stupid To Their Tube Amp?

I sold it! That was really stupid!

Maybe not a bad idea. (better than blowing more tubes and fuses)

When you don' t know where to look ask someone who does.


greetings

Wise(b)ass

 

The recommendation of seeking a service tech is a good one. Let me add that I would suggest a Fender authorized service center that is experienced with this particular amp because it is a very complicated amp/design with a LOT of tricky electronics that will be way beyond what a typical "tube tech" will be capable of handling.

There is a servo bias system that looks at several operating parameters and modes, if this fails tubes may also fail and continue to fail. There are also power supply control components that can fail as well and require specialized knowledge and serious tech chops to correctly diagnose.

 

The guru is back!


greetings

Wise(b)ass

 

Welcome back Andy. We all missed you.

 

I think he rather Guru on us all!

 

Not sure what you want here, suggestions for more things to try?

Just in case......

Plugged in, volume set, started to play.......nada.

Checked the instrument, increased volume.......still nada, but drummer did notice the quartet of tubes glowed brighter with my hitting the strings and then going back to normal as the string quieted.

Dimed it! This time, everybody was really quiet and when I hit a chord, the tubes got even brighter and the amp head made a little noise.

Being curious this was done several more times each time same "little noise"before...........I realized cabinet was unplugged.

I lucked out.

 

Welcome back. Hope all is well.

 

Yep. RTFM is good advice. Read it, know it, love it, live it. You’re probably not the first guy to do this - FMIC now includes a warning right on the amp as well:

I guess they figure if they haven’t saved you from yourself at that point, then it’s a lost cause. Standby is your friend.

Hope you get it sorted.

Welcome back Andy!

 

Good to know! Thx and welcome back AH.

 

Anyone Ever Do Something Real Stupid To Their Tube Amp?

Yes indeed I have! I lent a BF Showman head to a now ex-guitar friend.

 

Anyone Ever Do Something Real Stupid To Their Tube Amp? Fender 100T

I wish I still had the old 60s Fender bassman tube amp that I bought used in the early 70s …

 

Absolutely. The circuitry for user bias setup in SVTs is simpler and yet just as confusing if you don't understand it.

Welcome back, Andy. @Wasnex has been doing yeoman's duty while you were away. He could use a break.

 

Was a GC employee from ‘04-‘14. Can confirm.

 

Beat me to the punch, lent it out to a guitarist.

 

Heeeeeee’s baaack!!!

Good to see you again. You were missed.