Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Misc Schematics and Layouts => Topic started by: tubeswell on August 27, 2014, 03:06:57 pm

Title: Odd schematics - Jansen tube amps from NZ
Post by: tubeswell on August 27, 2014, 03:06:57 pm

Local manufacturer, Beverley Bruce and Goldie, did this with their  'Jansen' brand 'copies' of Fender amps (http://"http://www.nzguitars.com/forum/viewtopic.php?f=6&t=10197") in the 1960s. In the heyday of good old trade protectionism, when you couldn't buy Fender tube amps in NZ, local people started making their own versions.


'Blackface' (hehe)
(http://www.retrotronics.co.nz/images/forsale/147.jpg)


'Silverface' (hehe)
(http://i454.photobucket.com/albums/qq267/yo_burger/DSC06450.jpg)


Note that some of the stuff he says about Fender's amps typology in that blog I linked to above, is just plain wrong, but that main message is that Jansen 'Bassman' amps used a 12AU7 post PI gain stage on each side of the inverter (which often was also a 12AU7) to increase the drive to the output tubes.


(http://www.ozvalveamps.org/jansen/bass50n1.jpg)


They also used a separate PT winding for the screen supply (as he says in that blog article)


(http://www.ozvalveamps.org/jansen/bass50n2.jpg)

Title: Re: Odd schematics - Jansen tube amps from NZ
Post by: DummyLoad on August 27, 2014, 10:31:28 pm

cool stuff. thanks for sharing.


--pete

Title: Re: Odd schematics - Jansen tube amps from NZ
Post by: EL34 on August 29, 2014, 05:52:41 am

Got em
Just happened to pop in


PM me when you guys have schematics to add to the library
I get busy and may not see your post

Title: Re: Odd schematics - Jansen tube amps from NZ
Post by: tubeswell on January 11, 2015, 01:06:11 pm

Here's the schematics for the power supplies of their '60s tube amps. (Sorry its clipped at the top but its the only one I could find)