Rick Campbell's Trem-o-drive, EU version

[mrsmash23]

Hello guys!

I would like to build Trem-o-drive by Rick Campbell. Have few questions about his schematics, because theyre made for US 120V mains voltage and I will use european 240V.

1) Changing mains transformer to 240V primary (+ identical secondary +pilot 240V pilot lamp). Is that only change I need to do?
2) Secondary for mains transformer, 12V - should I understand it as 6V-0V-6V, with middle lug being center tap.
3) Recommended amp ratings for both transformers?

Bonus question 4) Read about some improvements of this circuit, but nothing specific, any suggestions?

Orignal power section wiring layout:
http://i.imgur.com/WgPLqE4.jpg

Original circuit wiring layout:
http://i.imgur.com/4tpY1jr.jpg

Thank you in advance!

[PRR]

Usual WARNING that working with Mains Power can burn down your house or electrocute you.

Mistakes on the secondary side are unlikely to start a fire but are still an electrocution hazard.

Yes, for 240V walls the first transformer may be 240:12, second is still 12:120 (sold as 120:12).

You may find "split primary" "dual voltage" with four primary leads which can be connected for either 120 or 240. Be SURE you understand this connection! Get it wrong, it is a near-short, pulls near-infinite current from the wall, tries to burn-up your wall wires. I've done that (oops!) and with a small transformer it is not *sure* to blow the breaker in the cellar. In my case I was probably pulling 23A from 20A wires and it could take many minutes to pop the breaker; meanwhile the wall wires were cooking above their rated temperature.

Good that this plan shows a mains fuse. This protects things IF it is wired correctly. Fuse rating not noted. I should think that 1 Amp (even 630mA) would be ample.

A Lamp-Limiter is a VERY wise idea for initial smoke-test. (I'm not usually as dumb as I look, but see my "oops!" above.) 60 Watt *Incandescent* should barely-glow. Full-bright is bad. (250W incandescent may be easier to find in this day of fluorescent and LED lighting; 250W will protect your wall-wires but not your transformer.) Don't expect circuit voltages to be right while on the lamp-limiter; it is just for initial smoke-test.

> Read about some improvements

Where?

> any suggestions?

Schematic. Working-out function from a pictorial is  mind-numbing.

[PRR]

Green (green/yellow) wire in wall-cord should go to a DEDICATED screw and tooth-washer in the case.

This is so no matter what else is wrong in the grounding, the case WILL be at wall-outlet ground potential.

This is perhaps new, and mostly for sold-to-consumer goods, so I can see why this layout does what it does. However a SOLID fail-safe wall-ground on case is a VERY good idea, and certainly worth the extra screw/washer.

[samhay]

This looks to be it:
Might be a good candidate to power with a 12V AC power supply and a single transformer inside.

http://www.ricktone.com/tremodrive.shtml  and look for 'Electrical Schematic'

[PRR]

> power with a 12V AC power supply and a single transformer inside.

Very true. Good thought. Dodges a lot of concern about wall-power wiring mistakes.

As long as we can get pre-made Approved 12VAC power-lumps. These are traditionally "vampires", sucking power 24/7 even when the device is off. "Green" laws are discouraging such waste.

And there is the issue of ground for audio shielding. Most 12VAC lumps won't have the 3rd pin and conductor. Yes, in a complete effects+amp setup, the effect gets "audio ground" from the amplifier, which these days often does have good 3rd-pin connection, mainly for life safety but also for general electric-field shielding.

In hind-sight I would look for pre-made 12VAC warts in preference to DIY wall-power.

[mrsmash23]

Thank you for your input, guys!