Fender Bassman ext. speaker out

[dazzlindino]

Have been running a silver face Fender Bassman 50w thru the extension speaker out into a webber 150, with nothing plugged into the regular speaker out,tried it on speaker out and it dosnt sound as marvelous....but will this kill a transformer or something?
Thanks,Dazz

[Chuck H]

dazzlindino,

That amp shouldn't operate a speaker from the ext. jack with nothing plugged into the standard mains jack. The mains jack in a shorting jack across the OT secondary. Nothing plugged into that jack should short the output from both the ext. and main jack. Also, the ext. speakers and main speaker jack should be on the exact same OT termination. So if your amp does work with nothing plugged into the main jack, and truely does sound different between the main and ext. speaker jack, then something is fishy and I can't really give advice.

Chuck

[dazzlindino]

it works perfect when plugged into a cabinet with speaker out..Fender Clean
it barely drives a speaker cab with ext. speaker only, but is distorted......
so...now ext. speaker out, plugged into an antenuator, then line out to another amp..
it all works / sounds good....a little noisy but ..............

[Chuck H]

it works perfect when plugged into a cabinet with speaker out..Fender Clean it barely drives a speaker cab with ext. speaker only, but is distorted......so...now ext. speaker out, plugged into an antenuator, then line out to another amp..it all works / sounds good....a little noisy but ..............

I'm not sure I understand what your saying.

Are you saying that the regular speaker jack works perfectly. And the extention speaker jack works with nothing plugged into the regular speaker jack, but is quiet and distorted? And that the way your using the amp is to plug the extention speaker jack into an attenuator and then to another amp, with nothing plugged into the regular speaker jack?

Chuck

[dazzlindino]

I'm not sure I understand what your saying.

Are you saying that the regular speaker jack works perfectly. And the extention speaker jack works with nothing plugged into the regular speaker jack, but is quiet and distorted? And that the way your using the amp is to plug the extention speaker jack into an attenuator and then to another amp, with nothing plugged into the regular speaker jack?

Chuck

Yessir...that is what i am saying......
Now using ext speaker only, why would this hurt the amp, or will it hurt the amp?

[Chuck H]

Well, it may hurt the amp. I'm not sure because your amp is not behaving normally. With nothing plugged into the normal speaker jack there should be no output from the extention speaker jack. Since you do have output from the extention speaker jack (with nothing plugged into the normal speaker jack) I cannot be sure.

Here's the deal, as it should be in a stock Bassman 50. The normal speaker jack is a ground fault switching jack. That means that when nothing is plugged into it the output transformer secondary + speaker lead is grounded. The extention speaker jack is a non switching mono jack that is connected to the same output transformer secondary. So if the normal jack has nothing plugged into it the extention jack also has it's + lead grounded. So there should be no output. Even if the normal jack were replaced with a non switching mono jack both the normal and extention jacks should sound the same because they are in a parallel circuit. But they do not. So I have no idea what is going on inside your amp. I can't visualize any part failure causing this. So I suspect someone has rewired the output transformers connection to the jacks in some unusual way. So I cannot really say if it's safe or not. If you understand some basic electronics you can check it out for yourself. If not you should take it to an amp tech to see whats going on and if its safe to run it the way you are.

Chuck

[Enzo]

If the shorting jack on the main output was perfect or ideal, there would be zero ohms across the output transformers and there would be no output at all.

In the real world, sound can leak out past this. it will tend to be weak and distorted.

I cannot count how many times I have encountered someone with a Hot Rod DelVille or one of the others in that series complaining of weak and distorted output - or none at all - and I ask them to make sure the speaker was not plugged into the extension jack. Usually is.

And in this case, it is possible the shorting jack is not shorting all that well.

This is not the most healthy way to run the amp if this is the case.

[dazzlindino]

Well thanks for the replies , this is an untouched,since 74, perfectly working
74 bassman 50w head.I got it from the original owner..it still has all the original tubes, the back has never been off. It is sweet for what it is.
Tried doing this after reading about some guy named Eddie Van Heflen orruther doing it, with a Bandmaster. The signal is extremely weak when powering a cab, but it has a strange distortion as well. Trying it into another amp resulted in a yucky distorted tone, however going into an attenuator, then line out,then into another amp, Boy Howdy.......
n'Thanks againaroo...

[Chuck H]

It's good to have guys like Enzo here to keep things real. When I look at the schem I see a dead short. But Enzo does repairs and has seen this before. So I would go with his take on it.

That includes his mention that it's not the healthiest way to run the amp. The way you have been using it, it's operating into a (virtually) dead short. I wouldn't do that myself. And if I were talking face to face with a friend I would tell them that they were going to blow up their amp sooner than later if they continued doing it. I hesitate to do it here because there's always someone that pops up saying they've been doing it with no problem, or something like that. And then it would become a technical discussion about weather or not it's OK to run your amp into a dead short.

Chuck

[dazzlindino]

It's good to have guys like Enzo here to keep things real. When I look at the schem I see a dead short. But Enzo does repairs and has seen this before. So I would go with his take on it.

That includes his mention that it's not the healthiest way to run the amp. The way you have been using it, it's operating into a (virtually) dead short. I wouldn't do that myself. And if I were talking face to face with a friend I would tell them that they were going to blow up their amp sooner than later if they continued doing it. I hesitate to do it here because there's always someone that pops up saying they've been doing it with no problem, or something like that. And then it would become a technical discussion about weather or not it's OK to run your amp into a dead short.

Chuck

Its only an amp....Ill run like this for awhile, and report bach, I mean back.

[Enzo]

I'll be Bach...


I'll be Haydn...