safety in old circuit designs

[guitarist28]

Hi,
This is my first post on this forum.
I am seriously thinking of builing an amp such as a Fender Deluxe from the collection of amp schematics that I have (from the cd from Aspen Pitman GT book). I am led to believe that earlier circuit designs were not necessarily built with the highiest level of user safety in mind.
Has anyone built an amp from older schemtics and if so, were any additional electrical safety measures added eg safety cut out etc?

Thanks

Rob

 

[Speedskater]

Old musical equipment did some strange and dangerous things with the AC power input circuit. Some times it was a capacitor from the power line to the chassis, sometimes it was strange switch arrangements.

 

[leadbelly]

Yes, nobody builds the very old (2 prong non-polarized AC plug) per the schematic anymore, and pro musicians have the vintage stuff modified if they want to use it for gigs. Just look at the difference between the original and a modern kit to see the difference:

http://ampwares.com/schematics/deluxe_5e3.pdf

https://taweber.powweb.com/store/5e3_schem.jpg

 

[guitarist28]

Hi Leadbelly,
Many thanks for this ant it makes me much happier to make a start on my project.

Rob

 

[Enzo]

Take any of those old schematics, and everything past the power transformer is fine. USA amps had two-wire mains cords, and a cap to chassis that was switchable from either side of the mains. The only conversion necessary is to eliminate the cap and switch, and install a three-wire mains cord with the earth lead to chassis. Exactly the way amps are made today. In the USA, all teh switches and fuses should be in the hot leg of the mains. I don;t recall if your 240 mains has a hot side. I was under the impression both sides were hot relative to earth.

Pittman's CD has a lot of drawings, here is a web site with plenty. The link is to the Fender section, but they cover numerous other brands.

Fender Amp Heaven Schematics - Tweed Blackface Brownface Silverface Bassman Champ Deluxe Princeton Super Vibroverb Reissue

 

[guitarist28]

Thanks Enzo,
I have added the link to my list of favorites

Rob