AC50

[Blackburn]

Anyone built one from the 1965 schem? I'm thinking about one of these for a project in the near future and I'm curious just how 'clean' they are. A few designs that stray from the normal run of things on the schem and I'm interested to see how this translates in tone.

David

[Roe]

they have plenty of breakup with an ecc83 in the first gainstages

[randalp3000]

I picked up one of those last summer but I haven't had a chance to bring it out yet.

One thing I learned from this amp is that the bias circuit acts like a charge pump for the b+ until it warms up which I find kinda scary. The B+ voltage on mine shoots up close to 600 volts for a few seconds until it settles back down to the 450 range.

I would highly recommend using a center tapped PT for one of these so you can use a standard bias supply. But if I'm wrong please correct me because I'm no expert for sure.

I have all the parts to build a single channel version of this amp on a Express chassis but been too busy with the ac30's.

and yes it breaks up pretty early.

[Blackburn]

Good to know about the early clipping. I'll be using a PT with a CT and a bias tap so no worries. This may be a rebuild of an amp that just isn't working out and I'm trying to figure out what to do. Interesting to note on the schem polystyrene caps are stated. Never used em. I'm sure polyester will be a fantastic cap in there anyway. Maybe even put a 5ar4 in just to taste or the SS cap instead. Since it's wired in anyway I'll probably just use it so I don't have to mount a diode board in there leaving room for the bias circuit.

I read an article where Ken was talking about these in very high regard and apparently had one himself. Sounds good to me!

[lumox0013]

a link to that article if you can dig it up would be great. thanxxx

[oj]

Anyone built one from the 1965 schem? I'm thinking about one of these for a project in the near future and I'm curious just how 'clean' they are. A few designs that stray from the normal run of things on the schem and I'm interested to see how this translates in tone.

David

http://www.backfromthesixties.co.uk/Pages/Vox_AC50.aspx

[Mant]

I have a small box AC50 that is single channel with 4 inputs.
Kinda looks like its in an AC100 head.
It sounds like neil young and crazy horse.
Pretty vicious.
Volume Treble Bass Cut.

[Turret]

I picked up one of those last summer but I haven't had a chance to bring it out yet.

Are you able to take good quality picts, and answer few questions? I'm happy to make replica layout for one if you just give me a hand

[randalp3000]

I picked up one of those last summer but I haven't had a chance to bring it out yet.

Are you able to take good quality picts, and answer few questions? I'm happy to make replica layout for one if you just give me a hand

I think this might be more helpful, compared it to mine when I was working on it and seemed pretty accurate. Much easier to follow than pictures.

I'm in the middle of a build at the moment so the bench is a bit full and messy.

[Roe]

I services two ac50s at the same time last year. there were small differences between the amps. one had a bigger screen resistor than the other. and the voltages varied a little (though both were around 460v)