Building a Aikido preamplifier

[ollebolle]

Me: -But after the transformer I am separated from earth, and it's less dangerous
Renron -Not only the A/C but how about the B+???

If the B+ gets in contact with my chassis the fuse will blow immideatly.
But: Let's say I made a bad connection (no contact) between ground and chassiss.
The B+ gets in contact with the chassis and I touch the amp. Still nothing happens!

A couple of minutes ago I touched my B+ just to be sure I was right. I was, cause nothing happened I didn't feel anything!

Example:

It's dangerous to touch phase, because the current will flow through your body down to ground. Not recommended!
The neutral should not be dangerous, but don't try!

But after the transformer we are separated from earth! You can touch tap 1, or tap 2 and nothing will happen!
Do not touch both though!!! If you touch both you will of course have an electrical shock!
In other words: It should not be dangerous to touch the B+ if you use a transformer

I do not recommend anyone to try the thing I tried, but I thought I had to know the truth...

[ollebolle]

The last post was not an argument not to ground the chassis!

I totally agree with all you people saying you should ground the chassis for safety!
Grounded chassis is safe! I will do it, I promise

[Renron]

Originally posted by ollebolle
The last post was not an argument not to ground the chassis!

I totally agree with all you people saying you should ground the chassis for safety!
Grounded chassis is safe! I will do it, I promise

You are correct the B+ is NOT the same as the A/C, it's a second order insulated circuit. However if you touch the case and the B+ at the same time, you're gonna glow in the dark.

Transformers only separate the Primary from the Secondary.....
the Secondary B+ voltage is MORE dangerous than the A/C.

Merck states that 60HZ AC is "3 to 5 times more dangerous than DC of the same voltage and amperage. Low-frequency AC produces extended muscle contraction (tetany), which may freeze the hand to the current's source, prolonging exposure. DC is most likely to cause a single convulsive contraction, which often forces the victim away from the current's source."link to AC vs DC

Please don't test like this anymore. You may be safe but it may also give others ideas it would be safe for them too.

Ron

[ollebolle]

Originally posted by Renron
You are correct the B+ is NOT the same as the A/C, it's a second order insulated circuit. However if you touch the case and the B+ at the same time, you're gonna glow in the dark.

I totally agree

Originally posted by Renron Please don't test like this anymore. You may be safe but it may also give others ideas it would be safe for them too.

I thought I had to try it to know I was right...
I also wrote in bold letters that I don't want anyone else to try...

[Renron]

OLLE,

"I also wrote in bold letters that I don't want anyone else to try..."

You sure did, and I agree. I was emphasizing your point.

BTW, I've had my Aikido sitting on my workbench for about 1 1/2 years now, LOL. I'm jealous, and very happy you got your's working.
Congratulations,
Ron

[ollebolle]

Yes, it's nice to be up an running. I think I will get time this weekend to look into the hum-problem

[Brit01]

Hi,

Just got my custom built transformers. Very happy with them indeed.
Take a look.
1st tranny:
0-275 200 mA
2nd tranny:
0-12.6 V 4 amps (6N1P,5687 heaters)
0-6.3 V 1.5 amps (for 6X5 heater)

[ollebolle]

Nice transformers! Much larger than mine

[Brit01]

Thanks. (just 45 bucks for the 2 )

Yes they are rather big, no problems as I planned to place them externally on the top anyway. I like to see them.

I guess they will dissipate the heat very well. Also the heater tranny has lots of headroom with 4 amps for the 6N1P and 5687 tubes.

[ollebolle]

Yes, black things dissipate heat very good!
But I don't think they will get very warm, because they are properly dimensioned