Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Hellawatt on June 24, 2017, 12:01:55 am

Title: AO-35 OT for a plexi 6V6?
Post by: Hellawatt on June 24, 2017, 12:01:55 am
Hi. Im building a plexi 6V6, and I had been planning on using the iron from a Hammond AO-35 that I have, but now I am thinking about upgrading the OT. How much difference would it make in terms of tone, power, headroom, compression, etc. if I went with a heyboer or classictone or something like that instead? Also I don't want sag. Thanks
Title: Re: AO-35 OT for a plexi 6V6?
Post by: sluckey on June 24, 2017, 12:51:58 am
That AO-35 OT is just as good, maybe even better, than the iron you mentioned. I'm not fond of the laydown style though. That's the only reason I have not converted any AO-35s.
Title: Re: AO-35 OT for a plexi 6V6?
Post by: dude on June 24, 2017, 11:49:56 am
The AO-35 Hammond reverb chassis is set up for EL84's. You'd have to drill out the chassis for 6V6s which the plexi's "usually have", although you could build a plexi with EL84's. Also, this is a small chassis and you'd have to add a 12AX7 socket, although you could do a Lite Plexi.  All these changes would not be a true plexi you see all around and would sound different.


My substitution suggestion would be something in the 18 Watt lite II, range. I have done a AO-35 conversion to a 18 watt style amp with the AO's transformers, plays well. I don't like the lay down OT either, I though it sounded a little sterile, I used a bigger 18 watt style OT mounted upright. Also the bd. is vertical, I took mine out, stripped it, loaded it and used it, some just use a new bd., all preference.


Here is a nice sounding layout for that chassis, a little tight but has a full tone stack and master volume. The Hammond has a 5Y3 rectifier, the layout here has diodes, you could easily just use the tube instead.
One other thing, you could just make a few changes to the chassis, as is and make it a guitar amp. 

Any help you need is here for the asking.
al   


   
Title: Re: AO-35 OT for a plexi 6V6?
Post by: jojokeo on June 26, 2017, 02:32:14 pm
That AO-35 OT is just as good, maybe even better, than the iron you mentioned. I'm not fond of the laydown style though. That's the only reason I have not converted any AO-35s.
I've tested lay down PTs as being quieter regarding magnetic coupling over stand up types as far as with the proximity of OT placements. But haven't messed with lay down OTs.


+1 on Hammond iron. You've inspired me to put ao-44 iron and tubes into a Vox SS Pathfinder donor cab & chassis for a fun test project and make another grab n go amp. It's at the final assembly stage... have you tried replacing the 8" for a ten yet?
Title: Re: AO-35 OT for a plexi 6V6?
Post by: Hellawatt on June 26, 2017, 04:19:27 pm
Thanks guys. I've put the transformers up on standoffs to try to make space for a turret board.
Title: Re: AO-35 OT for a plexi 6V6?
Post by: purpletele on June 26, 2017, 05:38:20 pm
^^^Crafty!!

 :bravo1:
Title: Re: AO-35 OT for a plexi 6V6?
Post by: PRR on June 26, 2017, 06:49:25 pm
> I've put the transformers up on standoffs

Space-efficient; but I would not take that on the road. Any hard side-impact (slinging it in or out of the Econoline) will deform things.

As a hand-carried mostly-home amp it's fine.