Changing tubes for an ENGL SCREAMER COMBO

[Yamhammer]

I want to replace ALL the stock ENGL tubes
for new and fresh JJ Tubes.

1). How many tubes do I have to change?

2). Which JJ Tubes do I need?


Thanks in advance.

[MDV]

you need 4 12AX7s and 2 6L6's

And a biasrite or similar and a multimeter, and an insulated screwdriver, a steady hand and COMPLETE AND TOTAL CERTAINTY THAT IF YOU TOUCH A SINGLE THING IN THERE WITH YOUR FINGERS YOU WILL DIE.

Cant stress that enough. Be hyper-carefull. 50mA (roughly the screamers cathode current, I seem to recall from when I biased mine. Probably horribly wrong though, the memory isnt exactly clear) is you-need-a-paramedic-on-the-scene levels. 6mA is lethal.

[Yamhammer]

Thanks very, very much for your info.

I'll leave the job to a specialized tech.

[MDV]

Well, dont be too scared, not everything in there will kill you. You just have to assume it all will, because a lot of it will.

But yeah, if youre in the least unsure, take it and the valves to a tech.

[noodleplugerine]

Not to question your far superior knowledge about amps MDV, but will 50mA really kill you? Wiki tells me the minimum a human can even feel is 1mA

[MDV]

You mean mythbusters lied to me!?!?!

I think thats the value for accross the heart, which is quite possible, holding a chassis or any other form of ground with one hand, and you fumble onto the circuitry with the other.

Mayhaps I'm wrong though. If anyone can confirm or deny, shout up.

[Antag]

If anyone can confirm or deny, shout up.

Shut up MDV, you're talking nonsense.

He should test ever connection with his tongue, while standing barefoot in a metal tray of salt water...



(then the HD-loaded silverburst LP will be MIIIIINNNNNEEEEE mwahahaha!) :)

[MDV]

If anyone can confirm or deny, shout up.

Shut up MDV, you're talking nonsense.

He should test ever connection with his tongue, while standing barefoot in a metal tray of salt water...



(then the HD-loaded silverburst LP will be MIIIIINNNNNEEEEE mwahahaha!) :)

:lol:

[dave_mc]

http://en.wikipedia.org/wiki/Electric_shock#Lethality_of_a_shock

i know that the current, especially if it goes through the heart, doesn't have to be very much to be lethal. i'd stick with mark's advice, assume it's lethal unless you're 100% sure it won't be.

[Johnny Mac]

Does 50mA stand for 50 mini amps? Micro amps?

I was thinking mains electricity is 13A which is lethal but i've had a few jolts over the years and it hasn't done me any harm :crzy: Plus car ignitions at the spark plug can be very powerful not sure is it 3 amps?
Each year the Darwin Awards have people who have died putting 9v batterys on their tongue.
My brother had a shock from a 3 phase circuit and lived which is seriously lethal. So perhaps its like the lottery.

I'd use a insulated screw driver like Mark says, those transformers are putting out some big voltages.

[MDV]

Voltage doesnt actually hurt you though. Current does.

But yeah, the screamers plate voltage is about 500V, so if it in fact does, then thats more than twice mains.

[CJ]

am i missing something... or can't you just unplug the amp before working on it, thus taking away the dangers?

[FELINEGUITARS]

Does 50mA stand for 50 mini amps? Micro amps?

I was thinking mains electricity is 13A which is lethal but i've had a few jolts over the years and it hasn't done me any harm :crzy: Plus car ignitions at the spark plug can be very powerful not sure is it 3 amps?
Each year the Darwin Awards have people who have died putting 9v batterys on their tongue.
My brother had a shock from a 3 phase circuit and lived which is seriously lethal. So perhaps its like the lottery.

I'd use a insulated screw driver like Mark says, those transformers are putting out some big voltages.

Wear latex gloves too - or washing up gloves

[noodleplugerine]

am i missing something... or can't you just unplug the amp before working on it, thus taking away the dangers?

You need to be getting a reading from it to bias it.

[CJ]

am i missing something... or can't you just unplug the amp before working on it, thus taking away the dangers?

You need to be getting a reading from it to bias it.

ahh... biasing. forgot about that. my amp is fixed bias, which would explain why i forgot about that.