You have got to see this...

[trdlasvegas]

Please understand I am not bagging on Bob @ eurotubes because I'm sure he knows what he 's doing but to put out a video advising people to do this I think is just plain insane.

Many people on this forum will warn you about using the transformer shunt method for measuring bias current. And rightly so because you have B+ on the tip of your probe and can eaisly slip or touch the probe somewhere it's not supposed to be.

Well here's Bob doing a Carvin "Standby Switch Shunt Bias" with more than 400V of B+ on the tip of his probe. Notice how close to the chassis he gets the probe tip. Or how about the fact he using the "B+ charged" probe tip as a pointer to emphasis his video?

How many people are going to destroy some probes and or themselves following Bob's advice?

http://www.eurotubes.com/euro-CarvinV.htm

-Tony

[KLB]

Yeah, you have to be careful with electricity. No news there. :AOK

When doing a transformer shunt bias, the fuse will pop if you touch ground with the live B+ probe. It happens all the time. Also, the fuse will blow if you forgot to put the meter into amps mode.

A safer method is to put insulated alligator clips on the probe tips and attach them to the correct points before taking the amp off standby. Touching the hot probe tip with one hand while the other hand is touching ground (the chassis) will cause the electricity to flow through your body, and just may blow YOUR fuse! It hurts bad enough when B+ only hits one body part, but it isn't likely to cause anything more than intense momentary distress, a cuss word or two, and a big welt! Of course, you can hurt yourself as you are repelled away from that snarly B+...

Want dangerous? Here is something all of us do on a fairly regular basis:

We drive a car down a two lane road at 65mph. The car in the other lane is going the same speed, coming nearly straight at us. A quick flick of the wrist by either driver in the direction of the other car will cause a deadly, head-on collision. Wow. Think about that the next time you are driving down a road.

This reminds me of a funny scene in a Woody Allen film when he is taking a couple to the airport at night. He tells them that sometimes when he is driving down the road he gets the urge to swerve into the other lane and hit the other car head on... Their eyes get as big as saucers!

Cheers, and careful with that axe, Eugene.

[Trout]

I really had an entirely different take on that video.

Bob Biased the amp using the tradition bias probe method that most guys use. Then he explained " This is how CARVIN says to do it and the readings are the same"

My take on it was simply he showed the normal method to demonstrate that Carvins method was not necessary and the end result was the same.

I hardly think he was endorsing Carvins method and It clearly demonstrated that the probe system is easier than Carvins method.

This reminds me of a funny scene in a Woody Allen film when he is taking a couple to the airport at night. He tells them that sometimes when he is driving down the road he gets the urge to swerve into the other lane and hit the other car head on... Their eyes get as big as saucers!


My favorite is Steven Wright driving down the road and he asks his passengers to tighten their seatbelt, They ask " Why"
Steven Responds;Not to worry
" I saw this in a cartoon once, But I think I can Do It"

Trout

[boobtoob]

Also, our defensive driving instructor said that crashing your car at 65 mph is like falling off a 6 and 1/2 story building (1 story for every 10 mph). So, 2 cars colliding at 65 mph would be like falling off a 13 story building. Ouch.

[KissTone]

Also, our defensive driving instructor said that crashing your car at 65 mph is like falling off a 6 and 1/2 story building (1 story for every 10 mph). So, 2 cars colliding at 65 mph would be like falling off a 13 story building. Ouch.

Wait, what's the approximate terminal velocity of an "average" body in free fall"? It doesn't make a difference from how high you fall after about 15 or so seconds of descent, right? Once terminal velocity is reached, speed equalizes. (My physics background is limited: I'm really oversimplifying this . . . and really derailing this thread!):messedup

[Norse]

My guess is that he had the meter connected to the cold side of the circuit - looked as though he'd done that procedure a few times before.

[mcknigs]

Also, our defensive driving instructor said that crashing your car at 65 mph is like falling off a 6 and 1/2 story building (1 story for every 10 mph). So, 2 cars colliding at 65 mph would be like falling off a 13 story building. Ouch.

I think I heard that crashing at 30mph was like a 3 story building - which would go along with your theory, except that I also thought I heard that the increase in momentum was not linear, so that at 65 it would be a lot more than 6.5 stories. Maybe I'm getting this confused with stopping distances.:confused: