Wreck mod for Bassman?

[GtrWiz]

I read on another forum that the Bass channel on a BF Bassman is very similar to an Express circuit. Is there anyone that does this, or what would I need to bring to a tech to have it done?

[sliberty]

Which Fender Bassman circuit do you have? From a topology point of view, the biggest difference is probably the lack of a MID pot on the Bassman. If you just give your tech the schematic for the Express, he can make the few part value changes needed for the circuits to be basically the same. The trannies of course will still be different, but it would be interesting to see how close it comes with just the circuit changes.

[RJ Guitars]

GtrWiz,

Welcome to the amp garage. It's a good bunch of fellows (even a few very knowledgeable females as well) here and a great storehouse of collective knowledge.

I know of two close similarities with Fender Amps and Trainwrecks.

1) From Steve Ahola's work - You can change just a very few parts on an old Fender Princeton and get an Express... http://www.blueguitar.org/new/schem/tra ... rek_pr.pdf

2) From "Zippy" - The Trainwreck Rocket has a preamp and drive section almost identical to a 59' Bassman. You could also say that an AC-30 has a preamp and drive section almost identical to a 59' Bassman. Swap the output tubes and add cathode biasing and it will all start to look very familiar.

rj

[BigFun3]

I'm glad you made it, GtrWiz. I didn't want to get too technical over at HRI, but if you are patient, I can reassemble everything I've done to massage a couple BF Bassman amps its Express variants (actually and express channel and a good old Fender channel).

BF3 (AKA AL)

[rooster]

The similariity is that there are 3 gain stages available in the 'Bass' channel. This is true for the blonds and all the 45-50 watt BFs. The Bassman 100 is not a player in this game.

Thing is, these basic channels are very tweekable where they stand and many BF Bassmans have been modded for a bit more gain or grind. Rather than twist this around to an Express, I would think this path would be the better one to take.

I mean, for me as a player, conversions vs. the real deal TW clone is not as exciting and - in the end - even though you might have the Bassman in hand as this begins, which might save some money - throwing the Express down, or Rocket, for that matter is just more satisfying I think. Well, at least for me. Besides, done correctly by a competent amp builder (WTF is a 'tech' anyway in regards to something like this?), I don't see you saving a lot of money. I know when people ask me about this type of thing - converting a different amp or rebuilding a Ceriatone, I just pass. That or demand enuff $$ to make it worthwhile - which is pretty much the same price as buying a good clone. Man, am I a prick or what?

Eh, so I am not much help here maybe. In the end, unless you were a BIG artist with an endorsement deal that had to play a certain amp based on looks alone, I don't see the point. OK, maybe harsh but my .02. As far as I'm concerned, walking in the back door with a $400 Bassman and hoping to spend $50-300 for a TW conversion ain't gonna happen. Not at my house anyway.

BTW, (and not to insult RJ for presenting it - stuff like this is out there), that PR schematic is just a wish I think. That PR amp would sound no more like something KF built than a cow could fly. I see it as an interesting amp idea put forth at best, but I clearly don't see it tied to anything KF designed or built. And when you consider that a BFPR will sell for $1200 even in this financial climate, why would you do something like this? Again, my .02.

[Zippy]

Man, am I a prick or what?

Eh, so I am not much help here maybe.

I have to agree with you on this one.

[RJ Guitars]

BTW, (and not to insult RJ for presenting it - stuff like this is out there), that PR schematic is just a wish I think. That PR amp would sound no more like something KF built than a cow could fly. I see it as an interesting amp idea put forth at best, but I clearly don't see it tied to anything KF designed or built. And when you consider that a BFPR will sell for $1200 even in this financial climate, why would you do something like this? Again, my .02.

I am hard to insult so no harm no foul... lets talk about amps.

Look at this again and look at the schematic. Consider that it's possible that there is a significant piece of Trainwreck history here, provided by a credible person who is filling in the blanks so to speak. It's not just the chance to gather some history but also bring out some useful info.

Among the very top tier collectible Trainwreck amps is at least one modified Princeton, other modified amps, then the actual Trainwrecks themselves. Rumor has it that Ken Fischers brother has the cherished Princeton and I'll wager that despite it's makeup of old Blackface parts and unlikely appearance, it sounds killer and will remind you very much of the Trainwreck amps that came later, in both circuit and sound.

What this points out to us is that Trainwreck amps are neither Rocket Science nor dark masses of mojo (my apologies to the hardcore believers). Trainwreck amps are fundamental and simple. Basic technology and not entirely new and unique. Say "thank you" to Leo Fender for some great work on tone stacks and go back to the RCA handbook and you've got the building blocks of a Trainwreck. That's not to say that any simple amp will sound like a Trainwreck, you've got to add Ken Fischers genius to know which simple circuit and common parts to put into which simple arrangement. All of a sudden a few variables build the complex equation...

Back to the point of the thread? You can modify a Fender into a Trainwreck circuit but it might be easier & yes cheaper to produce an original amp once you've got the main idea established.

rj

[dehughes]

Great post, RJ. Wheels need not be re-invented in order to bring the magic out of a simple design.

[rooster]

Woah, prick here, back for comment.

Any, RJ, are you saying that this schematic is a representaion of a PR that was rebuilt/modded by KF?. Hm. OK, if this is true then you know something I do not. Is this true? If this is true, I would still have to wonder why KF would even bother with this amp. And I say this because the PR is a very sweet little amp turned on '10' with the right speaker - if you're keeping all the iron. Larry Carlton, Mike Campell, etc., use these to great advantage in their stock form, of course.

Now, I do know that the first 'Boogie' was a converted PR (maybe just a 'P', dunno), but here it was gutted and retro fitted with 6L6s and different trannys. And also the first Diaz 'production' amp was a PR fitted with 4 6L6s and new trannys for 100 watts. But here the thing was 'small package' BIG power, the basic mindblow kinda thing. I get this for the cartage thing and for the basic element of plain shock. But again, why would KF even bother with such an amp?

But OK, I will take your word for it. As I said, I don't see anything in the schematic that smacks of outright KF. And if you point this out as a 'sign' that this is a 'roots' thing for KF, then of course it is interesting. As you suggest, RJ, I will look it over again.

[mcrracer]

GtrWiz,

Welcome to the amp garage. It's a good bunch of fellows (even a few very knowledgeable females as well) here and a great storehouse of collective knowledge.

I know of two close similarities with Fender Amps and Trainwrecks.

1) From Steve Ahola's work - You can change just a very few parts on an old Fender Princeton and get an Express... http://www.blueguitar.org/new/schem/tra ... rek_pr.pdf

2) From "Zippy" - The Trainwreck Rocket has a preamp and drive section almost identical to a 59' Bassman. You could also say that an AC-30 has a preamp and drive section almost identical to a 59' Bassman. Swap the output tubes and add cathode biasing and it will all start to look very familiar.

rj

Hwy RJ, Do you know if anyone ever tried building an amp from that schematic you posted here?

[RJ Guitars]

MC,

I think Steve Ahola is the guy to ask about that... Fundamentally it is an Express, so in many ways yes, there are a lot of builds like that out there. Exactly I dunno. Look for Steve over at Blue guitar and ping him a bout it. He is a good guy!

rj

[mcrracer]

Thanks RJ