New Project -> Hammond AO-63 to Modded 5F6 Bassman

[turbofeedus]

They do look new. I'm surprised you found new ones that fit the original holes. Cleaning terminal strips and tube sockets is a very tedious job. I've done it before but always have to get in a certain frame of mind!

Yep keystone still makes them.

I compromise with my lazy side, I clean and reuse the sockets (assuming no broken lugs which these novals had, hence the beltons), but replace terminal strips. I do keep the old terminal strips just in case.

[turbofeedus]

Just a small update, I moved my entire shop this week so I haven't had much time to build.
Wired up all the primary power stuff, as well as B+ routing.

ao63-4.JPG

[turbofeedus]

Finished the preamp and some power supply.
It got a little hairy in there, but it'r rock solid.
Waiting on the right value presence pot.

ao63-6.JPG

[maxkracht]

Looking good!

[sluckey]

Does look good. Try to keep some of that vintage smell in it though!

[turbofeedus]

Thanks y'all, yep it's still got the musk
Waiting on a couple parts so won't be an update today, hopefully tomorrow.

[turbofeedus]

It lives. The 7591 Bassman lives.

Switchable cathode/fixed bias, channel jump switch, defeatable NFB, mostly defeatable tone control via "raw" control, Frondelli MV.
Fixed bias circuit still need a quick mod (reducing tail resistor; can only achieve about 50% diss. when pot is maxed out)
Cathode bias resistor is perfect, tubes sit at a comfortable 85% diss.

Overall really happy with this build, always a treat when it just works, 1st try.
A bit more congested than I like in some spots, but I have no doubt it's rugged.

Much thanks to Sluckey for trailblazing with his AO-63 conversion, and the others here for advice and such.
I'd like to make some sound recordings to share, if I do so I'll post here.

ao-63-7.JPG

ao-63-8.JPG

[martin manning]

Congrats, looks great!

[Colossal]

What a beautiful build! How do you like the Frondelli MV? Do you prefer fixed or cathode bias? How is the tone?

[turbofeedus]

What a beautiful build! How do you like the Frondelli MV? Do you prefer fixed or cathode bias? How is the tone?

Thanks y'all. One thing I like about this MV is it feels like the sweep is more even? This amp is quite loud so I haven't been able to really wind it up yet.
I wish I had more experience with a regular bassman, but I'm really liking this so far. It really gets dirty, I wasn't expecting that but I like it.
Like I said I'm going to try and make some samples to share.

[Luthierwnc]

Getting in late - hope someone sees this. Would there be any problem throwing in a pair of EL34s and using the OT secondary for four ohms? I figure I'd need to change the NFB resistor and make sure the bias supply can handle the voltage. Uhmmm ... screen resistors too. I'd do this with 7591s but I already have a Bassman variant using those tubes. This would be more Plexi territory. Thanks for ideas, Skip

edit: OT has two secondary taps: green-to-black shows a 776 impedance ratio so 8-ish ohms for a pair of 7591s and 4-ish for EL34s
yellow-to-black shows 3086 so 2-ish for 7591s - unusable for 4k octals