Small beginner amplifier and hello :)

[SY]

Whoa, just looked at that schematic- DEADLY dangerous!!!!

At minimum, use an isolation transformer. This was the kind of thing that was banned decades ago after enough people got fried.

[planet10]

Morse's 6BM8 SE

Pics of my 6BM8 - The Gnat....



No bang, no flash, just music!

dave

[DigitalJunkie]

Originally posted by SY
Whoa, just looked at that schematic- DEADLY dangerous!!!!

At minimum, use an isolation transformer. This was the kind of thing that was banned decades ago after enough people got fried.

Dang,I glazed right over that the first time I looked at it.. My "minds eye" saw a separate HV secondary.

[MadsKaizer]

Thanks for all the warnings and links

As im "used" to work with live wires through my job as electrician and my latest tesla coil was fed by 2300Vac/500mA I am very careful around it.

I will look at the other schematics when I get home from work.

I just wanted to show you that I build the dangerous version without isolation from mains.

Picture here: http://gratisupload.dk/download/18027/view/

And that it acutally works, as I talked about earlier I thought the power trafo was the wrong way around as I missed 300V but had 180V instead, I will have to turn it back to 180V as I were feeding this poor little tube 380VDC last night and had red plates in short run times.

So remaking it with some fuses on my just ad dangerous power transformer as its just that old, lowering plate voltage and enclosure it in something

[MadsKaizer]

A note on isolation transformers

Secondary neutral can be grounded to avoid floating potentials

Shortcircuit current is lower as its determined by the secondary sides impedance, in difference to the 6kA shortcircuit current we have on mains in households, in Denmark.

Using a isolation transformer is not removing any dangerous parts as the secondary side of a 1:1 transformer will still kill you, but you can avoid having potential difference from your amp to other conducting objects in your home, which is why all old electronics mostly were in non conducting enclosures.

If you know what you are doing, using old transformers isnt DANGEROUS, but its a unsafe choice when there is better options

[MadsKaizer]

Just wanted to show the final product, the chassis is grounded and measurements from audio in to ground is no more than 20V+

Whatever is plugged to this amplifier is something that I could live on without, knowing there is no isolation or fuses.

Unfortunately youtube muted my video, but then again, listening to a tube amplifier recorded by a compact camera, compressed, uploaded to youtube and then played on computer speakers.. not a huge loss

http://www.disorder.dk/?page_id=469