Blue voodoo problem... unbelievable!!

[warlok]

Well, I just got home, hooked up the head (BV120H), played for about 1-2 minutes, then it happened.... Heres what i did, you tell me what I did wrong.... DON"T SAY "YOU BOUGHT A CRATE HAHAHA" Im pissed enough already.
plugged in power
metered cab (8 ohms)
switch on head on 8 ohms
plugged in cab
power on
about 2 mins later, standby on
plug input to guitar and amp
woohoo... plays great on both channels for 2 minutes
then I see the lights go out behind the tubes and over the next 10-15 seconds, all sound fades out to nothing.
turned standby off and on every few minutes and nothing. disconnected everything, checked fuse (good), tried everything again twice, still nothing.

Guy said he bought it around 2003, sat in studio, hardly used, never above 50% vol, never even opened back, original tubes (GT 6l6).... I believe him. It came with a padded cover and it is immaculate like it just came out of the box.

Anyone got any ideas? Cant contact Crate till monday...

[rjohnstone]

Best case, you blew one or more tubes.
Worst case, the transformer is toast.
Both fixable, one just a tad more pricey.

[Newc]

Or you've found a heat-related issue - maybe a cracked resistor or loose solder connection.

My old (5-years) TV does that - 15 minutes into a video game and it blinks out. Let it sit for a few minutes and it's good - for another 15 minutes until it heats up again, then blink.


Could be something as simple as a bad/dirty power switch, too.


Did he run it 4 Ohms or 8 Ohms? Could have shorted something when you flipped the switch.

[Hellbat]

Metering a cab will NOT tell you the impedance unless you are using an LCR meter. Impedance while measured in ohms is not the same as resistance. The cabinet should be marked with its correct impedance rating.

[Spivonious]

If the amp is getting no power whatsoever, I'd check all of the fuses, then the power cord, then take it in to a tech. It's probably the transformer.

[warlok]

It's getting power. Power switch lights up, channel led lights up. Just not the tubes (each has a light behind it, cool factor i guess) and nothing happens when i hit the standby switch (lighted switch doesn't light either). I was playing it when it happened. When i first switched power on, everything lit up like it was supposed to. Hit standby and everything worked like it was supposed to and sounded great. I was playing when it happened, First the lights behind the tubes went out, then the sound faded. Even as it was fading, sound was still playing what I was playing till it faded to zero. Like maybe it was draining the capacitors or something? Is there another fuse other than the one on the back of the amp?

I thought you could tell what ohm a can was by checking the resistance with a cable in the cab and meter (ohm meter) the end of the connector? I did that and it was 7.9 ohms. That's not right? This cab is not the original speakers and i doubt it's the original wiring either. Speakers are OLD eminence legends with no sticker so I don't know what load it is without testing.

[toejam]

Are you using a speaker cable from the head to cab and not a guitar instrument cable?

[Cygnus X1]

Yes, you can get an idea of the cab ohms with a meter.
Not the ohms of the output of the amp.

There is not enough of a difference in load to fry the output transformer that quickly though, even if you got it wrong.

It could be a fried output transformer, but I would swap out power tubes before doing anything else.
If you did and I missed it, sorry.

How does it smell?

And, good point Joe.
Can't believe how many people don't know not to use a shielded cable instead of even a cheap speaker cable.
The imbalance can be devastating even though "it sounds fine".

[Jayster]

woohoo... plays great on both channels for 2 minutes
then I see the lights go out behind the tubes and over the next 10-15 seconds, all sound fades out to nothing.
turned standby off and on every few minutes and nothing. disconnected everything, checked fuse (good), tried everything again twice, still nothing.

Guy said he bought it around 2003, sat in studio, hardly used, never above 50% vol, never even opened back, original tubes (GT 6l6).... I believe him. It came with a padded cover and it is immaculate like it just came out of the box.

Anyone got any ideas? Cant contact Crate till monday...

Did you make sure all of the tubes are properly seated?
Is your wall outlet a gfci type?

[warlok]

Definitely a HUGE peavey speaker cable with huge wire and huge connector ends. I plugged the SPEAKER cable into the cab and measured the resistance at the end of the cable. 7.9 ohms.

Didn't/doesn't smell at all like anything burned. I can see the tubes and 2 big transformers just with the back cover off and nothing visibly burnt. Are we thinking power tubes? Any way to test? This is the first time I've touched a tube amp but I know they need to be biased when you replace any. Any way for me to tell before I spend more fucking money at a shop?

[Cygnus X1]

You would be ok swapping out some tubes.
Power tubes, yes they would need to be biased.
But it's ok to put them in there long enough to determine if that is where the problem lies.
Could be loose/bad preamp tubes also.

Kind of like owning the next step of a car...a race car rather than a daily driver. Buying extra tubes is part of the deal. Even if you don't need them NOW, you will need them eventually.
I snag tubes every chance I get.

[Cygnus X1]

Did you make sure all of the tubes are properly seated?
Is your wall outlet a gfci type?

Wondering why a GFCI would be a problem.
I plug my amp(s) into a 15 amp GFCI on my deck frequently, and it never pops it.

Until I decide to step into the pool while noodling with
:idea: the 'ole Jackson plugged in.

[warlok]

I haven't touched anything yet. Just pulled the back cover to look. They look seated though. Yes on the GFI but it's still getting power. Switch and channel LED still lights up when I turn the power on. Just not the standby switch or tubes or the lights behind the tubes.

I thought I remembered somewhere that you could remove tubes and make it 1/2 the wattage. Like this is 100 watts with 4 6l6's, if i took 2 out, it'd be 50 watts. Can I take certain ones out and swap around to test which are bad? Like if I take the right 2 out and it works, one of them is bad?

[DrDestruction]

Yeah. It's the transformer. They're the weakest link in the Blue Voodoo amp line- push 'em just a wee little bit and they'll fall down on you all the time.

I've got a Blue Voodoo 60-watt combo that is borked enough that it won't even power up. Even worse is the fact that trying to find a replacement on the cheap is a no-go, as they quit making those amps a while back.

You'd have to upgrade to a Mercury Magnetics transformer in order to get it working again, and that can be a wee bit pricey.

[warlok]

Really? It wasn't pushed at all. I had the volume at 1.5. You don't think it's tubes? Anyway to test that instead of just jumping to the replacing the transformer?

And yes, the tubes are seated.