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Fender Bassman 100T Chapter 3
- Thread starter Chef
- Start date
Scare of my life Saturday night when my rig fried. But what a trooper, she hung in through a four hour gig, rocked the last song, and then fizzled out as we were about to play an encore. Turned out to be a blown power tube, which also took out the tube fuse and the mains fuse. Since there was some discussion many moons back about the grade of the stock GT tubes, turns out my were 7's. I've had a quad of Winged C's socked back for a rainy day, which are 19's, so I just decided to roll the whole bunch. One thing I notice right away is the filament in the base of the tubes, which glowed like beacons on the GT's, are very dim on the WC's. Amp seems to be working fine. Is that normal? Have a gig coming up Friday and would like to go in with a little more confidence.
edwinhurwitz
Supporting Member
The punch line is, our guitarist just wound up playing and singing a slow Willie Nelson (I think) song for the encore, and after it this guy came up and tipped us $50! I said play that mf'er again!
Now I'm in distress. Played first gig with the Winded C 6L6's last night and I hated it. Maybe they just need to get burned in, but it threw me off the whole evening. It's a place we've played several times, no FOH support required, so I'm very familiar with the room. And it's the room I first played an entire gig at 25 watts and it was beautiful. But last night at full power I could not get it dialed in. It really wasn't so bad on the roundwound bass, but on the flats it was night and day. Where I'd call the Groove Tubes "warm" and "round", I'd call the WC's "dry" and "plinky". Too much top end for one. Before I've been able to easily adjust for each song with minor tweaks the bass's tone control. Last night it was either too much or not enough - I couldn't find the sweet spot. I guess I'll give them another couple of gigs to see if they settle in, but I'm ordering a 4th Groove Tube to replace the blown one so I have a quad ready if this keeps up.
Something is wrong.
Everyone (myself included) love the =C=
Mine have been in for as long as I have owned it with no problems and sound much better than the GT's
Everyone (myself included) love the =C=
Mine have been in for as long as I have owned it with no problems and sound much better than the GT's
What pre tubes are you running? You could have one of them going too if they are the stock GT's
I enjoyed the Winged Cs in mine when I first put them in, but I must confess that when I put the originals back in to sell it I was surprised that I preferred the originals. Too long ago now to remember exactly why, sorry, but it taught me a lesson. Nonetheless, the weight of opinion is clearly that Winged Cs are the shizz but you have to make your own final call. Also I think the Groove Tubes in mine were graded 5 whereas a lot of 100Ts came out with 1s or 2s IIRC, so that could also influence things. The player who bought my 100T still cannot believe his good luck, it was one of the first off the line and has performed flawlessly from day one.
If you go to the Groove Tubes web site grades 1-3 are more for guitarists who want early distortion, 8-10 will stay cleanest and I suppose this is better for bass. I can't remember exactly as it was a while ago but my 100T had 5s or 7s. A few people posted that theirs were in the very low numbers and there was a bit of discussion on this in the original thread. I think the numbers were on the base, written on a GT sticker, but I may be wrong on that.
Just checked my 100T and it has grade 5 GT's in it. My original 100T was purchased in September 2012 and replaced in April of this year after multiple attempted repairs. Biasing has worked perfectly on the replacement. The 5's sound pretty clean to me but I have had nothing else to compare them with.
After extensive fiddling with the amp this morning it looks like it's developed an auto-bias issue. Switched to 25watt mode and right away thought things were weird as it did not rebias, lights all stayed solid green. Plugged in and got about 5 fuzzy watts out of it. Did a hard restart but tried resetting the auto-bias (again) by holding down both + and - bias controls for a few seconds while in standby, switched on and same results with no blinking - straight to green. Just on a whim tried the reset thing with power on, though that's not what the manual says to do, and it came up to full power, though it still didn't rebias. Powered down and switched to 100 watts, powered up and out of standby tube 1A stayed solid green while the other three blinked showing they were biasing. Also during this the (I guess) auto-bias circuit was making an audible hum, like a transformer, which immediately stopped when the blinking lights went green. It may be coincidence, but tube 1A was the tube that blew at the gig.
Whatever, there's obviously issues so in the shop it goes tomorrow morning.
--- Edit --- This actually makes more sense because the one time I sat in on a friend's tube rolling testing session (with the bribe of many beers) I never heard much difference between the power tubes, though I did the pre tubes, so I was surprised at the gig this past Friday how much difference I heard in the Winged C's. On reflection what I was hearing was tubes that were working but severely out of bias.
Whatever, there's obviously issues so in the shop it goes tomorrow morning.
--- Edit --- This actually makes more sense because the one time I sat in on a friend's tube rolling testing session (with the bribe of many beers) I never heard much difference between the power tubes, though I did the pre tubes, so I was surprised at the gig this past Friday how much difference I heard in the Winged C's. On reflection what I was hearing was tubes that were working but severely out of bias.
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DTJ, you are correct. On initial start up the amp should not go solid green while still in stand by. That was the issue my original amp had and it was determined that it had an incorrect/earlier version of the bias circuit.
It will only do the auto biasing when out of standby yes. And if you want to bias it hotter or cooler with the bias buttons that should be done out of standby as well. But the manual states that to reset the auto bias - to give it a fresh start - you should hold down both up and down bias buttons for a few seconds while in standby, then switch out of standby. But when I was experimenting with mine this morning, after getting extremely low distorted power in 25 watt mode, and after trying to reset the auto bias in standby per the manual, I tried resetting it out of standby and the amp came up to full power. But after power down and back up it was low and fuzzy again, and showed no signs of biasing after going out of standby - went straight to solid green lights.
I made a mistake one time by turning the power off before going to standby, later when I went to play the amp the auto-bias lights were not acting right but I cannot not remember what they were doing but anyway I just pressed both arrows until it went all green and it went back to normal operation and has been fine since. Would not hurt to try it freight Train, hope it helps.
Thanks DTJ, I've done that several times both in and out of standby desperately trying to make it come back to its senses, but it has a problem. Leaving to take it to the shop as we speak.
I hate to hear that, hopefully its an easy fix and a quick fix, keep us posted and good luck
