Biasing an amp yourself: How dangerous is it really?

[Bengal65]

When I manuver the chassis around, I do use thick rubber gloves as a precaution to anything that might have come loose during transit. Always, an extra good idea.

[jacksonaxes]

I was screwing around with a camera flash unit once, and did some googleing, and read that a watch battery 1.5 volts can charge the capacitors to lethal voltage, so BEWARE!

[emperor_black]

I was screwing around with a camera flash unit once, and did some googleing, and read that a watch battery 1.5 volts can charge the capacitors to lethal voltage, so BEWARE!

yeah DC voltage is much more deadly than AC. You can get a great big spark, burn your finger real bad with just a 1.5 V battery.

[Aaronharmon]

You're right. The discharging was while changing the tubes. Not for biasing them. Double And while I have got some attention on this thread, the ebay biasing tool has the 8 pin base on which a power tube sits so it can be biased. However, the thing with the carvin is that the back plate gives just enough room for the last two power tubes to sit. I dont think there is any extra space between the top of the power tube and the back plate. In that case, can I bias the first two tubes using the ebay tool and then turn the pot to approx the same position for the last two without actually seating them over the base and biasing them?

The smallest variance can make a huge jump in the numbers. They could appear to be positioned perfectly and off by a huge amount.

[Rsmacker]

if I were to wear thick plastic gloves, it should act as a very good inductor right?

I hope you mean "rubber gloves.......very good insulator" !!!

[phill_up]

you did "click" and watch a video didnt you?
this one is for the "HotRod Deluxe" its way easy.

[emperor_black]

I hope you mean "rubber gloves.......very good insulator" !!!

Yeah. I did mean rubber gloves.

you did "click" and watch a video didnt you?
this one is for the "HotRod Deluxe" its way easy.

Yes I did. I read Bob's comments on the page and they were very encouraging. I watched the carvin V3 video hoping the pot would be buried deep similar to the TS100, but the pot was positioned well out of reach of other wires and leads making it a breeze to reach. I guess if I keep clear of the caps and the power section, I should be good to go.

[Bengal65]

Also, don't be afraid to call Eurotubes. Jay, Ed and Bob have all been of great help for me. Their help and knowledge of the different amps is of great support. I just re-tubed 2 amps with their products and I am working over the restoration of a '65 Fender Showman right now. It even has the old 2 prong plug with the "Death Cap" on the Ground Switch. That is getting changed out pronto.

[Spivonious]

I touched the top of the big capacitor in my VCR once. Holy cow that burned. Just be careful and you should be fine. Give electricity the respect it deserves.

[phill_up]

I have to agree with you Bengal65, When you call Bob @ Eurotubes, its like you have known him forever. I really like the JJs also so I will probably never use anybody else. Bad ass tubes from a kick ass guy. Why change?

[emperor_black]

I just got an email from THE man himself. Very nice guy, that Bob.

One other question...when biasing a quad, can I start with two first and then do the other two or do I need to read the digital multimeters simultaneously for both pairs? I have only one multimeter and was thinking of getting one of those probes with just one base.

[phill_up]

You better talk to Bob mine was easier than yours, I only have 2 powertubes to bias so I just divided it. All I had was one meter. He will have some advice on how to do it. "clicky"
One thing for sure when you do it you will get a really good feeling because you did it yourself. You may want to try different tube brands, as well as sizes and you can do it yourself for a small fraction. Nothing like tinkering with things

[Bengal65]

If you have a matched up set (duals, quads, etc.), one socket is only needed to be tested. You can test the others to see if there is any difference, but if any it will be small if any. It's very easy. If you want to test 2, or all 4, Weber has a quad test lead setup to test a 4. and with a flick of a switch, you can move from one tube to the other. I think Bob has some Webers, so you don't have to wait the standard 2-4 weeks for Weber to build them.

On the JJ's, I have been very happy with. I have run the whole gamit to Groove tubes, through RCA Blackplates, Greyplates etc. I have spent a small fortune on NOS, RCA, Sylvania, Mullards and GE, and have since stopped using NOS and instead, buy the new JJ's from Bob. On occasion, I'll use TAD's imported from the Amp Doctor in Germany, but the majority of changes I perform now are the JJ's. I use the standard ones, or you can use the "Goldpins" if you are an audiophile.

[emperor_black]

Got it. I was planning on getting them JJ's anyway. I guess I will stick with regulars. Thanks. Bob did reply about biasing a pair at a time and he says it should be ok.

[phill_up]

Bengal65, has everything got back to normal since the hurricane?