Fender Bassman 100T Chapter 3

[Freight Train]

Also I was thinking of using the 100T as a preamp in studio mode for a high wattage solid state head. Seems like it would work and I wouldn't be relying on tubes for volume thus bypassing the whole issue of fartiness. I would just dial in the clean tube sound and not over drive it.

That would be a really interesting setup with the DI being post power tubes, but the thing that I'd guess might shoot a hole in it is that there is speaker modeling as well. If you had more like a good full-range p.a. speaker type of setup that might work. But with a standard cab I'm not sure it'd translate. But I'm only guessing. You'd have to try it and see what you get. With just the right bass cab it might sound great.

 

[shwashwa]

is this normal? i have a brand new 100t, literally one week old. i was playing awhile today on the 25 watt setting and all the lights were green. i left the room for a half hour without putting the amp on standby, but the bass was muted and there was no sound being played. when i cam back one was orange and one was red. i shut the amp off, waited about a minute and turned it back on. after turning on the standby switch the amp did the blinking light thing and all tubes were green again. i dont know how long that would have lasted because i had to leave.

 

[Freight Train]

is this normal? i have a brand new 100t, literally one week old. i was playing awhile today on the 25 watt setting and all the lights were green. i left the room for a half hour without putting the amp on standby, but the bass was muted and there was no sound being played. when i cam back one was orange and one was red. i shut the amp off, waited about a minute and turned it back on. after turning on the standby switch the amp did the blinking light thing and all tubes were green again. i dont know how long that would have lasted because i had to leave.

No, something's up. Like the manual says, the red light should indicate that tube is fried, and the orange should be the other tube of the pair that has turned off so the amp can continue on the remaining pair. If you cycled the power and it worked, my guess is either one of the new tubes had a momentary short, which as the manual says will sometimes happen but the tube may be fine after that. However I don't know for sure if that would cause the red/0range state. Otherwise it might be a hint that your bias board is about to go south. I would reset the auto bias (while in standby hold down both the up & down bias arrows for a few seconds) just to give everything a fresh start.

 

[hdracer]

I had that happen to me when a power tube was lose in the socket after hauling the amp around in my back seat.
Try seating the tubes.
It could also be a tube going out. Had that happen too.

 

[shwashwa]

I had that happen to me when a power tube was lose in the socket after hauling the amp around in my back seat.
Try seating the tubes.
It could also be a tube going out. Had that happen too.

ill check to make sure they're in tight, but it seems a pain to take everything off the back. do you think id have a tube go bad after a week?

 

[Tim1]

ill check to make sure they're in tight, but it seems a pain to take everything off the back. do you think id have a tube go bad after a week?

Quite possible and it can happen to any amp manufacturer.

 

[hdracer]

ill check to make sure they're in tight, but it seems a pain to take everything off the back. do you think id have a tube go bad after a week?

The stock GT's that come in it are notoriously iffy.

 

[RobSatFender]

is this normal? i have a brand new 100t, literally one week old. i was playing awhile today on the 25 watt setting and all the lights were green. i left the room for a half hour without putting the amp on standby, but the bass was muted and there was no sound being played. when i cam back one was orange and one was red. i shut the amp off, waited about a minute and turned it back on. after turning on the standby switch the amp did the blinking light thing and all tubes were green again. i dont know how long that would have lasted because i had to leave.

Hi shwashwa,
Sorry to hear you're having problems. Sounds like either a tube problem or the ribbon may be loose. Since it's only been a week or so, returning to the dealer and getting a replacement should be an option, or take it to a Fender Authorized Service Center and have them check it out (it's warranty work and shouldn't cost you).
Hope that helps.
All the best,
rob

 

[shwashwa]

Hi shwashwa,
Sorry to hear you're having problems. Sounds like either a tube problem or the ribbon may be loose. Since it's only been a week or so, returning to the dealer and getting a replacement should be an option, or take it to a Fender Authorized Service Center and have them check it out (it's warranty work and shouldn't cost you).
Hope that helps.
All the best,
rob

great, thanks a lot. where do i find a list of fender authorized service centers?

 

[RobSatFender]

great, thanks a lot. where do i find a list of fender authorized service centers?

Here ya go: Invalid Link Removed

All the best,
rob

 

[bas20hz]

That would be a really interesting setup with the DI being post power tubes, but the thing that I'd guess might shoot a hole in it is that there is speaker modeling as well. If you had more like a good full-range p.a. speaker type of setup that might work. But with a standard cab I'm not sure it'd translate. But I'm only guessing. You'd have to try it and see what you get. With just the right bass cab it might sound great.

I'm currently doing the amp modeling thing with a B3 into a QSC 800 watt head into a Carvin 15.3 full range cab. I can come somewhere close to the tone of my '66 Fender Black face into the same cab but not the same. The Fender tone is awesome, just too quiet.
I dunno maybe I'm barking up the wrong tree. I'm going back to GC with my bass and going to fiddle with the diming the volume and bringing the input gain up for a good clean tone. Maybe that will do it. Or maybe I need something else.

 

[Freight Train]

I'm currently doing the amp modeling thing with a B3 into a QSC 800 watt head into a Carvin 15.3 full range cab. I can come somewhere close to the tone of my '66 Fender Black face into the same cab but not the same. The Fender tone is awesome, just too quiet.
I dunno maybe I'm barking up the wrong tree. I'm going back to GC with my bass and going to fiddle with the diming the volume and bringing the input gain up for a good clean tone. Maybe that will do it. Or maybe I need something else.

It's a cool idea, I think it's just a matter of finding a nice flat full range cabinet to reproduce it. BTW, I do not agree at all with diming the master and bringing up input gain. That is totally contrary to proper gain staging and especially if you're using the head in 'post' DI position for recording or in your case driving a flat amp with a full range cab, it should for one thing be noticeably noisier doing that. Almost all solid state and tube preamp designs since Christ was a corporal usually have a preferred gain setting where they will give the best distortion vs. signal-to-noise ratio as well as sound quality. (Assuming that the output of the source isn't hitting the input too hot or too low.) In that case preamps usually give their best performance when they are working around 1/3 to 2/3 opened, or in Fender knob terms around 4.5 to 6.5 or so on the volume knob. I can definitely hear on my 100T that the sound opens up when I get to 5 on the vintage channel's volume, and begins distorting if I go past 6.5. Of course if you want some crunch from the preamp it's fine to overdrive it as much as you like, but there's really no reason to run it low. The master volume is not the level control of the power tubes, it is the final output volume of the preamp. So if you run input low and master high, or input high and master low, the 12AT7 and the power tubes see absolutely no difference in the level you're hitting them with. The only difference is if you're running the input low you're going be amplifying more preamp noise, and the preamp will not be working in the 'sweet spot'.

 

[bas20hz]

It's a cool idea, I think it's just a matter of finding a nice flat full range cabinet to reproduce it. BTW, I do not agree at all with diming the master and bringing up input gain. That is totally contrary to proper gain staging and especially if you're using the head in 'post' DI position for recording or in your case driving a flat amp with a full range cab, it should for one thing be noticeably noisier doing that. Almost all solid state and tube preamp designs since Christ was a corporal usually have a preferred gain setting where they will give the best distortion vs. signal-to-noise ratio as well as sound quality. (Assuming that the output of the source isn't hitting the input too hot or too low.) In that case preamps usually give their best performance when they are working around 1/3 to 2/3 opened, or in Fender knob terms around 4.5 to 6.5 or so on the volume knob. I can definitely hear on my 100T that the sound opens up when I get to 5 on the vintage channel's volume, and begins distorting if I go past 6.5. Of course if you want some crunch from the preamp it's fine to overdrive it as much as you like, but there's really no reason to run it low. The master volume is not the level control of the power tubes, it is the final output volume of the preamp. So if you run input low and master high, or input high and master low, the 12AT7 and the power tubes see absolutely no difference in the level you're hitting them with. The only difference is if you're running the input low you're going be amplifying more preamp noise, and the preamp will not be working in the 'sweet spot'.

That makes sense. I usually set gain structure the way you describe. I was going off of the advice of a previous poster. I assumed they knew something magical about tube amps that I didn't. I don't know too much so that's a good assumption. My cab is a three way full range cab. It's got a 15-8-tweeter configuration and is way flatter than a 410 or something like that. I'm sure it's not as cool as a greenboy but it does do a good job of representing what I put into to it.

 

[Tim1]

Diming the master and using gain to control volume is useful if you want the absolute maximum volume clean tone you can get. On the other hand, as Freight Train rightly points out, most gain stages do have a sweet spot. It is common practice with Ampeg afficianadoes who use an CVT CL and want to cop the tone of the original SVT which did not have a separate gain control. Might be less applicable with the 100T??

 

[Freight Train]

That makes sense. I usually set gain structure the way you describe. I was going off of the advice of a previous poster. I assumed they knew something magical about tube amps that I didn't. I don't know too much so that's a good assumption. My cab is a three way full range cab. It's got a 15-8-tweeter configuration and is way flatter than a 410 or something like that. I'm sure it's not as cool as a greenboy but it does do a good job of representing what I put into to it.

Diming the master and adjusting level with input gain, like a lot of misconceptions, comes from what started as good advice but was misinterpreted. The idea is, if you are pushing the limits of your amp, then yes you should absolutely run the master higher, or max it, and try to keep the input gain below the point where it distorts. This is to prevent the preamp stage from distorting. But no, there is not some magical sound that comes from maxing the master and running the preamp input gain low. As I pointed out, running the input gain low can prevent you from getting max sound quality and signal-to-noise ratio from your preamp.

 

[Freight Train]

I wanted to wait and do gigs in two familiar rooms after switching back to Groove Tube 6L6's before I reported on my situation. If you don't know the story, I've posted it below in case you care and want the details.
So after verifying that my auto bias is working correctly, it turns out the problem then was that I just do not like the sound of the Winged C's at all compared to the stock GT's. Not saying they sound bad, especially on the roundwound bass, but my preference hands down is the GT's. I think I said before to my ear the GT's sound round, full and warm. The =C='s I would still describe as dry. What I described before as the =C='s sounding 'plinky' was obviously from them not being biased properly. But for me, even with proper biasing they still do not have the roundness of the GT's, and the upper mid's/high's are just too forward and I guess aggressive for what I want.
To reinstall the GT's I had to buy a replacement, and of course there is no such thing as the GT-6L6-GC that my 100T came with. That is a Fender production part and isn't available by that number otherwise. And yes, I'm all aware that GT isn't actually a manufacturer and the suffix indicates the country/manufracturer or whatever. But anyway in contactting Fender support they assured me that it didn't matter what suffix of GT-6L6 i used. So I just guessed it might be the GT-6L6-C and ordered one of those. It immediately was a freak out because the C is a smaller bottle than the GC's. But after plugging it in, the amp biased up like it should and the sound is back to what I loved about the amp from the start.
This doesn't mean that anyone who prefers the =C= over the GT is wrong. It's a matter of personal preference, and also would have a lot to do with the tonal quality of the cabs being used. But this is what REALLY bothers me - there apparently is what is close to mass hysteria about Groove Tubes, that they are below garbage, are the rejects of other manufacturers, are made by the Taliban, or what the hell ever. So after experiencing this first hand what I immediately recall is guys on this board reporting they bought the 100T, jerked the GT's out without even turning it on, and replaced them with whatever the masses accept as tubes you should like. What I'm saying is if you prefer the sound of the =C= over the GT that is great. But to not even listen to the GT's first, I don't understand that.

THE STORY: I purchased my 100T/410Neo rig in April of 2012 and have gigged steadily with it since. A month or so ago at the end of a gig it fried, blowing both the mains and a screen fuse. Getting into at home, 6L6 A1 had blown. I replaced the whole quad with a set of highly-spec'd Winged C's that I had bought almost two years ago and had just socked away. Played a gig in a familiar room and hated the sound. Didn't appear the auto bias was doing its thing, and the tubes weren't biasing properly. Took the head in and it was the ribbon cable problem. Tech tested the amp and said it was dialing in the bias perfectly. Picked it up for gig that night. Tried it at home and it did not auto bias. Before panicking I reset the auto bias circuit, and since then it has biased as normal. Played two gigs in familiar rooms and was not getting the sound from the rig as before. Decided best move was to buy a replacement GT and go back to them to remove the variable of the new tubes.

 

[DTJ BASS]

Freight Train I am glad to see you back up and running, I know it stressed you out as it would with anyone, good luck and keep on rocking .

 

[Tim1]

I wanted to wait and do gigs in two familiar rooms after switching back to Groove Tube 6L6's before I reported on my situation. If you don't know the story, I've posted it below in case you care and want the details.
So after verifying that my auto bias is working correctly, it turns out the problem then was that I just do not like the sound of the Winged C's at all compared to the stock GT's. Not saying they sound bad, especially on the roundwound bass, but my preference hands down is the GT's. I think I said before to my ear the GT's sound round, full and warm. The =C='s I would still describe as dry. What I described before as the =C='s sounding 'plinky' was obviously from them not being biased properly. But for me, even with proper biasing they still do not have the roundness of the GT's, and the upper mid's/high's are just too forward and I guess aggressive for what I want.
To reinstall the GT's I had to buy a replacement, and of course there is no such thing as the GT-6L6-GC that my 100T came with. That is a Fender production part and isn't available by that number otherwise. And yes, I'm all aware that GT isn't actually a manufacturer and the suffix indicates the country/manufracturer or whatever. But anyway in contactting Fender support they assured me that it didn't matter what suffix of GT-6L6 i used. So I just guessed it might be the GT-6L6-C and ordered one of those. It immediately was a freak out because the C is a smaller bottle than the GC's. But after plugging it in, the amp biased up like it should and the sound is back to what I loved about the amp from the start.
This doesn't mean that anyone who prefers the =C= over the GT is wrong. It's a matter of personal preference, and also would have a lot to do with the tonal quality of the cabs being used. But this is what REALLY bothers me - there apparently is what is close to mass hysteria about Groove Tubes, that they are below garbage, are the rejects of other manufacturers, are made by the Taliban, or what the hell ever. So after experiencing this first hand what I immediately recall is guys on this board reporting they bought the 100T, jerked the GT's out without even turning it on, and replaced them with whatever the masses accept as tubes you should like. What I'm saying is if you prefer the sound of the =C= over the GT that is great. But to not even listen to the GT's first, I don't understand that.

THE STORY: I purchased my 100T/410Neo rig in April of 2012 and have gigged steadily with it since. A month or so ago at the end of a gig it fried, blowing both the mains and a screen fuse. Getting into at home, 6L6 A1 had blown. I replaced the whole quad with a set of highly-spec'd Winged C's that I had bought almost two years ago and had just socked away. Played a gig in a familiar room and hated the sound. Didn't appear the auto bias was doing its thing, and the tubes weren't biasing properly. Took the head in and it was the ribbon cable problem. Tech tested the amp and said it was dialing in the bias perfectly. Picked it up for gig that night. Tried it at home and it did not auto bias. Before panicking I reset the auto bias circuit, and since then it has biased as normal. Played two gigs in familiar rooms and was not getting the sound from the rig as before. Decided best move was to buy a replacement GT and go back to them to remove the variable of the new tubes.

Delighted to hear that it all worked out for you, Freight Train. It is interesting that we both came to the same conclusion about the Winged Cs in the 100T, your observations pretty well match mine at the time. Too often we sometimes hear "different" as "better" only to discover too late that it was not the case. Well done for listening objectively and having the courage of your convictions and +1 about the Groove Tubes too, it seems popular to put them down but I have never had a problem with them in bass or guitar heads.

 

[loveboatcaptain]

So without going over old discussions... We know that flat is 2-10-2 on the vintage channel. If I'm honest the whole "boost/cut/boost" eq tone stack confuses a bit.

Can someone please tell me what settings on the vintage channel would give a "smiley face" type eq?

 

[Moosehead1966]

Hello all, just wanted to report no further problems with my 100t since last February 2014 when Rob handled everything and the amp was fixed. I have rocked the 100t twice weekly since that time and the provided GT Selects ( nice touch from Fender) have worked impeccably since. Love this amp! Just bought a V3 Rumble 500 head as a backup just to have piece of mind. Wishing everyone in '100t land' well this 2015. Marc