Tube snobbery?

Casey · 05-24-2004, 10:24 PM

That's understood, but I was kind of joking because you said you'd liketo break it out, and then followed by saying that it isn't the tone you want.

Case

**thesteve** · 05-24-2004, 11:10 PM

Quote:

Originally Posted by Casey

That's understood, but I was kind of joking because you said you'd liketo break it out, and then followed by saying that it isn't the tone you want.

Case

gotcha, ah, it's not really the tone i want, but sometimes i just want to hear something different. it's like when I break out my project 86 cd. i don't really like the music, but occassionally i need something different.

as far as acoustic amps go, I've been under the impression that they were SS, but I could be wrong. i know Albert King used an Acoustic 270 head, and that it was a solid state amp.

Casey · 05-25-2004, 10:31 AM

MY uber-wealthy friend just bought one of the new Marshall Acoustic Amps, and with his Taylor Doyle Dykes... :drool: He says it's tube, but I'm not sure. That on-board PA is awesome.

Case

**thesteve** · 05-25-2004, 08:55 PM

Quote:

Originally Posted by Casey

MY uber-wealthy friend just bought one of the new Marshall Acoustic Amps, and with his Taylor Doyle Dykes... :drool: He says it's tube, but I'm not sure. That on-board PA is awesome.

Case

the Marshall acoustic isn't a tube amp. very few if any acoustic amps have tubes in them.

someone13 · 06-06-2004, 06:53 PM

Quote:

Oh, one downside to tubes.... They'll kill ya! I'm sure a solid state amp can shock you pretty bad, probably kill you also, but it doesn't have the exposed parts that a tube amp does. You fiddle around back there, and you could recieve a fatal shock.

well ya sure they'll kill ya if their plugged in now what kind of an idiot is gonna mess around back there when it's plugged in

*here's your sign* (that to whoever messes with tubes plugged in)

spmantar · 06-06-2004, 07:07 PM

Well, the big capacitors inside tube amps store a lot of voltage even after they are turned off. If they aren't drained properly before working on the amp, they can shock you and possibly kill you.

Major Tom · 06-06-2004, 08:08 PM

Quote:

Well, the big capacitors inside tube amps store a lot of voltage even after they are turned off. If they aren't drained properly before working on the amp, they can shock you and possibly kill you.

First off I am not recommending that non-electronic techs go messin' around the inside of any amp, tube or otherwise. Disclaimer and Caveat aside, that is actually kind of a myth that probably goes back to the old tube-rectified amps. Amps with diode (SS) rectifiers bleed off the high voltage on the caps very quickly since the they are in parallel with each other. I purposely measured one the other day - the 400 volt power supply voltage on the caps dropped down to 40 volts in like 4 or 5 seconds.

I am not familiar with tube rec's but I assume that when power is turned off, the circuit is broken, and the caps don't have anything across them to bleed it off. I would guess that in our litigious and safety-conscious society that modern amps with tube rec's are designd with a bleed-off circuit (like a 4 cent 500k resistor) to prevent such unpleasantness, but don't hold me to that! I have never gotten zapped with a cap holding a hi-voltage charge by itself, but the fatality thing might be a little overblown. I don't think those caps can store enuf current to cause that unless there is an underlying medical condition, or the tech is working on a steel beam on the 12th floor of a hi-rise construction site. I would venture to say however, that it would cause at least some degree of discomfort, more than I would be willing to endure for the purpose of testing that theory.

LWatford · 06-06-2004, 09:14 PM

Quote:

Originally Posted by Major Tom

First off I am not recommending that non-electronic techs go messin' around the inside of any amp, tube or otherwise. Disclaimer and Caveat aside, that is actually kind of a myth that probably goes back to the old tube-rectified amps. Amps with diode (SS) rectifiers bleed off the high voltage on the caps very quickly since the they are in parallel with each other. I purposely measured one the other day - the 400 volt power supply voltage on the caps dropped down to 40 volts in like 4 or 5 seconds.

I am not familiar with tube rec's but I assume that when power is turned off, the circuit is broken, and the caps don't have anything across them to bleed it off. I would guess that in our litigious and safety-conscious society that modern amps with tube rec's are designd with a bleed-off circuit (like a 4 cent 500k resistor) to prevent such unpleasantness, but don't hold me to that! I have never gotten zapped with a cap holding a hi-voltage charge by itself, but the fatality thing might be a little overblown. I don't think those caps can store enuf current to cause that unless there is an underlying medical condition, or the tech is working on a steel beam on the 12th floor of a hi-rise construction site. I would venture to say however, that it would cause at least some degree of discomfort, more than I would be willing to endure for the purpose of testing that theory.

I don't know either...but still, why take the chance? Discharge the filter caps if you're going to be messing around in there, it's simple, and I'd rather know before poking around in there!

And talking to people online (2nd/3rd/4th hand knowledge I know), I read from one guy that said he got a nice shock from a Champ...like enough to leave a slight burn...

Nothing wrong with being a little careful!

Major Tom · 06-06-2004, 10:46 PM

Quote:

I don't know either...but still, why take the chance? Discharge the filter caps if you're going to be messing around in there, it's simple, and I'd rather know before poking around in there!

Better yet- if anyone wants to find out about the legendary Fatal Caps of Death for themselves; measure the voltage, or lack thereof across them with your multimeter. If you do not have a multimeter and know how use it - get outta there now, you have no business in there !!! If you don't know what a cap looks like, put it back together!!! If you don't know whether your amp has a tube or diode rectifier - don't even open it up, you are not qualified!!!

LWatford · 06-06-2004, 10:56 PM

Quote:

Originally Posted by Major Tom

Better yet- if anyone wants to find out about the legendary Fatal Caps of Death for themselves; measure the voltage, or lack thereof across them with your multimeter. If you do not have a multimeter and know how use it - get outta there now, you have no business in there !!! If you don't know what a cap looks like, put it back together!!! If you don't know whether your amp has a tube or diode rectifier - don't even open it up, you are not qualified!!!

"Fatal Caps of Death" love it...good post. But like you've said in other posts, a little knowledge can go a long way, and amps are not some mystery, whose secrets are avalible only to a select few. So if you want to work on these things, start reading! Therea are lots of good sites online with lots of great info.

And it's kinda fun...
L.

Major Tom · 06-07-2004, 12:29 AM

Well us electric guitarists are quite dependent on electronic gear, and having a working knowledge of electronics really comes in handy - saving trips to and $$ at the repair shop, and just having a better understanding of the components of the final tone that comes forth from the speakers. I would strongly suggest that anyone who is serious about electric guitar learn at least some basic electronics and sound reproduction physics. Every elec guitarist should have a multimeter and know how to use it IMHO. Oh yeah, and how to make a good solder joint too.

**Rainer.** · 06-07-2004, 06:29 PM

Quote:

Originally Posted by Major Tom

Well us electric guitarists are quite dependent on electronic gear, and having a working knowledge of electronics really comes in handy - saving trips to and $$ at the repair shop, and just having a better understanding of the components of the final tone that comes forth from the speakers. I would strongly suggest that anyone who is serious about electric guitar learn at least some basic electronics and sound reproduction physics. Every elec guitarist should have a multimeter and know how to use it IMHO. Oh yeah, and how to make a good solder joint too.

And who knows, you might just end up obsessed and start building guitars and amps all just for the heck of it...