Thinking of doing a 5b6 Bassman. Thoughts/etc?

[Dreams]

Hey. Title sez it all.

I've got almost all of the parts, why not? Not interested in doing any other circuit revs at the moment. There's not much talk about these, just wondered if anyone had anything to say. Cheers.

[Dreams]

The schemo I'm looking at can be found here:

www.prowessamplifiers.com/schematics/fender/Bassman_5b6-Schematic.html

[tubenit]

Lots of discussion about that amp on The Amp Garage

http://ampgarage.com/forum/viewtopic.php?t=20117

http://ampgarage.com/forum/viewtopic.php?t=20072

http://ampgarage.com/forum/viewtopic.php?t=20213

With respect, Tubenit

[plexi50]

George Fullerton, was quoted as saying, "The 5B6 was probably the best guitar amp we ever built."

Id say go for it. 15" speaker! I bet it is a wonderful amp. Dont skimp on capacitors. I got raped $$$ buying the Jupiter Astron style caps but they have a tone that is truly old vintage to my ears. The mass (size) of a tone cap = sustain and tone. There is a big difference in a tone caps ability to provide that old vintage tone. Another thing i have learned is that if you have a capacitor tester you will find that any given tone cap may not even be close to it's stated value. If your going to build this do it right and spend the extra dollars. You will hear where those extra dollars went

Now you have me wanting to build one to* The Fender layout has my brain all scrambled. Like in reverse

Doug could make a killing if he made those Astron caps and sold them. I cant imagine sitting all day in one spot making caps. I would go insane. It is probably a very boaring job

[P Batty]

In 1976 one of the guys in our band got one for $50! It sounded great- snarly with plenty of top end.  He turned it for a 100% profit- $100!

[HotBluePlates]

This Bassman had the complete amplifier in the bottom of the cabinet, tubes up, with an umbilical to the control chassis in the top cutout.

Just pointing that out in case people hadn't seen that before.

That cap on the power switch was also probably not original to the amp, especially given it's hand-drawn on the schematic.

[rzenc]

Paraphase P.I. rules!! 5E9-A uses it and kicks!!!

http://www.el34world.com/charts/Schematics/files/fender/TREMOLUX_5E9A.pdf

Hope this helps!

Best Regards

R.

[VMS]

This Bassman had the complete amplifier in the bottom of the cabinet, tubes up, with an umbilical to the control chassis in the top cutout.

Just pointing that out in case people hadn't seen that before.

Guitarpoint has some pictures of the amp:

http://shop.guitarpoint.de/en/Vintage-Amplifier/Fender/1954-Fender-Bassman-Amp-15-Wide-Panel

[Dreams]

Coooool.

I checked out those TAG links. Mostly just opinion and stuff I was probably already gonna try, but a few gems. Thanks.

The amp I'm ripping apart for this has a boatload of huge molded caps (you know those ones that look like big resistors? With the color bands and everything) so I'm gonna use those if they aren't leaky or anything.

One of my favorite pastimes was buying garage sale tube amps with the idea that I would turn 'em into guitar amps one day. That day has come, eh? I'm just kinda working through them, and this one I'm looking at has everything but the first tube (6sj7 I think? Blanking at the moment) and a few other little things that I'm sure I have lying around.

Anyway, I'm just gonna build to what I have, not what I want most. WAY cheaper. I estimate total cost for this build (head only) will be around $40. $50 if I factor in solder and electricity and hand soap and wear/tear on tools and future medical bills for carpal tunnel.

Word. I'm gonna get to this soon, probably over the weekend. I'll stop back and let ya'll know what's going on.

I'll see about making a schematic with the things I've done (probably mostly minor stuff). Until then.

[HotBluePlates]

The amp I'm ripping apart for this has a boatload of huge molded caps (you know those ones that look like big resistors? With the color bands and everything) so I'm gonna use those if they aren't leaky or anything.

I assume you mean the Sprague bumblebee caps, with a black body and stripes on them.

I haven't tested a bunch of them, but they have a nasty reputation on radio restoration forums for being almost universally leaky. Radio guys rip them out and throw them in the trash without testing because they turn out to be leaky so often.

That said, if you find any with color bands Red, Red, Orange starting from one end, they are 0.022uF and you should probably sell them on Ebay. Les Paul fanatics pay silly money for them because they were the cap used on the tone controls of the 50's Les Pauls.

See the pic below for reference. The extra color bands after Red, Red, Orange indicate voltage and tolerance, which will probably not be relevant in a guitar tone control.

[Dreams]

Yeah, those. 'Cept mine are blue... Same thing? Different thing? I'm gonna throw 'em in and measure 'em. It won't take too long to replace them if they're bad and at least I can assuage my curiosity. I've never seen these blue ones before, dig? If they work ok I just saved some buxxx.

Also, I've seen the black ones, but not very many compared to other similar types. I don't find them to be more or less likely to be leaky, but that's just my own limited experience.

Thanks, though. I never knew who made them.

[HotBluePlates]

I don't know who made ones with a blue body, or how similar they are.

I also never came across bumblebees much, until I got some McIntosh power amps and HP tube test gear. There's a lot of them in those.

But radio guys come across them all the time in 50's radios, and they have no good comments about them. Those guys are also all about practicality, and only get hung up on "special parts" when they are trying to have a beautiful cosmetic restoration. They'll cut caps open, restuff the bodies, and seal it back up to preserve cosmetics but have new, perfectly functioning guts.

[BarryW]

I've got one of these on the books as well.  Parts almost all here, but I have a few others in front of it for a customer.  And I'd agree, the 5e9a is a great circuit - I did one, it's awesome.