Fender Bassman 50 with Master Volume

[xtian]

This is premature, because I just bought this amp a few hours ago, but...never to early to read up on new (old) gear. Here's everything I know. So it's a 1976-ish Bassman 50 with Master Volume.

So, anyone have experience with this model, or suggestions of best mods, etc?

[topbrent]

Convert the Master volume to LarMar, put the normal channel to AA864.
Now you will have 4 free triode sections to play with.

Try some of the well covered circuits on this site. Convert the bass channel to 5f6A/Plexi/2203 or Trainwreck Express or rocket specs or simplified Dumble ODS.

Pick the circuit of your choice and have fun

There is a lot you can do with that framework.

Not one hole will need to be drilled, either.

[dreric]

Check out:

https://tubeamparchive.com/viewtopic.php?t=11104

I really want someone to make this amp:

https://tubeamparchive.com/viewtopic.php?t=652

If you'd add a tube it could be cool.

Eric

[xtian]

Convert the Master volume to LarMar, put the normal channel to AA864. Now you will have 4 free triode sections to play with.

Try some of the well covered circuits on this site. Convert the bass channel to 5f6A/Plexi/2203 or Trainwreck Express or rocket specs or simplified Dumble ODS.

Pick the circuit of your choice and have fun

There is a lot you can do with that framework.

Not one hole will need to be drilled, either.

I like your advice. However, I have never played Marshall, TW, or Dumble type amps. How to decide?

[M Fowler]

This amp may not need a mod, crank it up and take a listen, toss some pedals in front of it and roar.

Mark

[dreric]

This amp may not need a mod, crank it up and take a listen, toss some pedals in front of it and roar.

Mark

+1

[xtian]

This amp may not need a mod, crank it up and take a listen, toss some pedals in front of it and roar.

True, dat. Will do. In the mean time, I like to read up on the options.

I got one good photo of the circuit of this Bassman from the seller, attached.

[NickC]

Here is a shot of my 1966 (AB165 circuit, with earlier version circuit label affixed to inside of head cab). I changed it to AA864 / AB165 hybrid.

[img1728]http://homepage.mac.com/swamptone/ModsBassmanDone.jpg[/img]


Here's a link, I followed much of the advice contained therein and it worked out well:

http://acruhl.freeshell.org/mga/main/AA ... AB165.html

[Firestorm]

It's a great mod platform: plenty of room for another tube or two. But even if you don't mod anything else, the Master should go (or be changed to one of the post PI styles). And the lead-dress on these is terrible; fixing that will really open it up.

[rdjones]

Is there a schematic for the 50 watt MV ?
I've found the schem for the UL 70W MV and the early '70s 50 watt non MV, but no 50W MV.

There's an unused triode at V2 just waiting to be implemented, maybe a cathode follower, or a gainstage on the 'bass' channel.
Look at the 6G6 series schematics for ideas.

I agree that the normal channel should go to AA864.

The AA864_vs_AB165.html page pretty much lays it out if you want to take a conservative approach, but there's still that pesky master volume.
If you want to make it usable the preceding stage needs to be made more overdrive friendly (or change to PPIMV).

rd

[Structo]

I have never seen a Bassman 50 with Master Volume.

I wonder how many of those things were built?

[topbrent]

Here are some modded bassman's.

[topbrent]

Here is a AA864+5F6A hybrid that Smolder built last year.

[xtian]

Thanks, guys. Amp doesn't arrive until 6/14.

[M Fowler]

Here is a schematic. I had to send this to Jeff Bober about 3 weeks ago he couldn't find it for his magazine article.