'72 Bassman 100
- Thread starter jimh
- Start date
jimh said:
If you think of the four tubes as two sets of two, you need to pull one of the left set and one of the right set. They usually say pull the outer two, leave the inner two, but it really doesn't matter, so long as one is from the left set and one is from the right set.
As for the rebias - yes. Chances of getting it perfecto are nil. Also, unless the amp has been fixed up for bias level, then you're bias routine is not gonna work. So that needs to be checked out. And before you bias, go thru the filter caps and see what kind of shape they're in.
mayfly said:theklanch said:
Yeah it did get get molested a while back. It was a gift from my dad I never asked him what he paid for it till the other day, he told me $200. I think he got a deal, even if the tolex got painted.....
Jeeze and I thought it was just real dirty! I take back my "unmolested" comment, but it's sill a nice ampccasion14:
I know that I'm coming to this thread rather late, but I am interested in CB's expertise. He says that a 16 ohm load could jeopardize the output transformer with a 4 ohm secondary. I am certainly no expert so I'd like to know how lowering the current would hurt the transformer. I'm new to this forum so I don't know if CB will be automatically notified. I'd appreciate knowing anyway.
Thanks
Murf
Thanks
Murf
Its not current in the way we think of it. Think of it more as load balance between the plates and the speaker, instead of a pure resistive load. You know, there is no "impedance" of a transformer, only its ratio
If you take a tube amp, using an output transformer, and run that transformer into nothing... an open circuit... it will self destruct sooner than later, and depending on the transformer MUCH sooner.... If you take a tube amp, with an output transfomer and run it into a dead short, nothing happens. I know.... its a leap of faith, just go with it. The EXACT OPPOSITE is true for capacitor coupled amps (rare) or for amps with silicon solid state output. You can run those higher impedance loads all day long, but not lower. Back to tube amps - Marshall, early classic ones with "Radio Spares" transformers are notorious for burning up when you mis-set the impedance plug. Part of their tone, is the lack of headroom, the ability to turn electricity into magnetism, in the output transformer. They also had light windings... the mismatch of impedance, plus little in the way of overkill... and poof. Its also interesting to note, that the poof occurs almost always on the primary side, not the speaker side. Makes ya go hmmm. Fender uses a switched jack, such that if you dont have a speaker plugged in - it goes direct short - hot to chassis ground. And they'll sit there all day and night, for about forever, without burning up the transformer. If you lose a speaker cable, or blow the voice coil on a single speaker amp... it will take a while, but it will go poof in a Fender. Its not nearly the fast blow a Marshall has, because Leo very generously oversized his transformer. A Fender, or at least the classic ones, will generally handle a 2x mismatch just fine. More than that, you're in more dangerous territory... Going lower, no problem though.
If you take a tube amp, using an output transformer, and run that transformer into nothing... an open circuit... it will self destruct sooner than later, and depending on the transformer MUCH sooner.... If you take a tube amp, with an output transfomer and run it into a dead short, nothing happens. I know.... its a leap of faith, just go with it. The EXACT OPPOSITE is true for capacitor coupled amps (rare) or for amps with silicon solid state output. You can run those higher impedance loads all day long, but not lower. Back to tube amps - Marshall, early classic ones with "Radio Spares" transformers are notorious for burning up when you mis-set the impedance plug. Part of their tone, is the lack of headroom, the ability to turn electricity into magnetism, in the output transformer. They also had light windings... the mismatch of impedance, plus little in the way of overkill... and poof. Its also interesting to note, that the poof occurs almost always on the primary side, not the speaker side. Makes ya go hmmm. Fender uses a switched jack, such that if you dont have a speaker plugged in - it goes direct short - hot to chassis ground. And they'll sit there all day and night, for about forever, without burning up the transformer. If you lose a speaker cable, or blow the voice coil on a single speaker amp... it will take a while, but it will go poof in a Fender. Its not nearly the fast blow a Marshall has, because Leo very generously oversized his transformer. A Fender, or at least the classic ones, will generally handle a 2x mismatch just fine. More than that, you're in more dangerous territory... Going lower, no problem though.
I sold mine years ago for...250€...And my standard black strat RW for less than 400€...What a shame...But I needed money...
I used to play with my strat on that Bassman 100 and it sounds very good ! Warm !
I used it to play with my bass of course but it was not powerful enough in certain circumstances (big rooms, etc...)
I wonder how much it is for such an amp now...
I used to play with my strat on that Bassman 100 and it sounds very good ! Warm !
I used it to play with my bass of course but it was not powerful enough in certain circumstances (big rooms, etc...)
I wonder how much it is for such an amp now...
=CB= said:
Know this is a zombi threed, but U seem to know your bassmans. I have been getting the bassman 100, and the normal channel rocks big time, the bass channel is ok, but I am more into the chime of the normal channel, do U know any good mods to give the bass channel more of the sparkle, even if it is similar to the normal channel, just not identical, some say to keep away from silverface bassman's, but mine sound's better than any other amp I have owned, the HRDx sound's no ware near as good as this, my PR is not as good either, anyway thanks bud, and look forward to your comments
