Variac?

[dnsey]

Find a couple of multi-tapped mains transformers and connect them back-to-back with provision for switching between windings.
Doesn't matter what the secondary voltages actually are as long as they are similar ranges, and the overall rating of the txs is adequate for what you want to power plus a bit for losses.

eg - HT in > 6V sec >12V sec > approx 0.5 HT out:

HT 6V 12V 0.5HT
---II------.------II---
---II------.------II---

[dnsey]

Well, the formatting changed a bit between the preview screen and my published post, but I hope you get the idea!

[D3]

Hi Cr3ator..........
Yup got mine on ebay....for £65..........it's an 8amp jobby.........
once I've used it I will selll it on....................cheap deal really...
should get money back!

I recommend that all you guys do this...............

D3 Bolton uk

[Frazzled]

I purchased a 20A variac new for US$110 and there is no way I will be selling it, it is just way too useful!

[D3]

Hi Fraz.............
Thats a great deal........you've had........could you post where you got it............or a link.....I think the guys on this site would find it usefull.


Richard Bolton Uk

[anatech]

For small projects & "normal" amplifiers, a 2 amp variac is fine. I use that most of the time and go to the 10A model for big tube amps .... or one of Nelson's designs.
Very useful device.
-Chris

[Variac]

Variacs are very good things. They are clever in design, and come in a multitude of forms and shapes. They had been around a long time so there are vintage models too. One should start a collection immedietly. I have one as a doorstop and one to dim my tracklights, and a couple for makin' amps... You can adjust the output of your Son o Zen to just a cople of watts when you just need background music...Plus the name is super-cool

As they say about oil wells in Texas: "If you ain't got one-get one"