I think I cooked my Black Cat

A

Aelred

Roadie
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129
No, not a tale of anaimal cruelty but of unprecedented negligence towards my cherished amplifier.

I left in on over Easter in Standby. The Black Cat didn't hiss like this previously. I have never done this to an amp before, so naturally I did it to my favourite. :bonk

Maybe Warranty covers it, but I have doubts. I hope I can fix the thing though.
 
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Sucks man.
How's it behave? Does it power on still? Maybe one of the fuses is blown...?
 
2dor said:
Sucks man.
How's it behave? Does it power on still? Maybe one of the fuses is blown...?
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It powers on, and if I play I can swamp the static hiss. But as soon as I rest...

Hopefully it won;t cost too much or be too hard to fix. I'm just bummed I did it when I never have before and had to vent somewhere.

I still have a couple of working Orange Terrors, etc.

Thanks for the mojo everyone. I better call the store and arrange for the fix - the only real cure.
 
Aelred said:
It powers on, and if I play I can swamp the static hiss. But as soon as I rest...
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If everything on the amp WORKS and the only real issue is the noise then it's 99.9% a tube. Most likely pre-amp. Output tubes usually blow fuses or start having weird volume jumps and dips before you know they're bad.

Swap out the pre-amp tubes one at a time until the hiss is gone. Do you have a tube chart? One tube might be dedicated to the loop and if that's not part of the problem you can cross that tube initially off the list as being the bad one. 9 times out of 10 it's gonna be V1 or V2.

Good luck! Which Black Cat?
 
Achilles said:
Which Black Cat?
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Bad Cat Black Cat Player Series II 1x12 Combo 20w.

Not knowing how to fix amps, but vaguely knowing something about electricity, Capacitors and Australia having dealy voltage... I have no intention of touching it myself.
 
Aelred said:
Bad Cat Black Cat Player Series II 1x12 Combo 20w.

Not knowing how to fix amps, but vaguely knowing something about electricity, Capacitors and Australia having dealy voltage... I have no intention of touching it myself.
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No need to deal with caps or any sort of electricity.

You don't even need to open the amp up. It's honestly super easy and could save you a good chunk of change

Assuming preamp tube
 
Mongillo19 said:
No need to deal with caps or any sort of electricity.

You don't even need to open the amp up. It's honestly super easy and could save you a good chunk of change

Assuming preamp tube
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Well, in that case I am just clueless. Not the first time, nor the last.

Not open the amp up? That seems like a Magicians trick to me.

How do I test and replace a Tube (which I will need to buy from the same store I bought the amp) inside the amp without opening it?

I can get to the speaker at the back.
 
Aelred said:
How do I test and replace a Tube (which I will need to buy from the same store I bought the amp) inside the amp without opening it?
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Does not have to be from the same store. Is it a certain channel that has the hiss? I'll look up your amp real quick

If this diagram is correct, you'd just want to do trial and error. Pull one of the 12AX7s preamp tubes and put in the new one. You can buy 12AX7s essentially anywhere.

Combos are tricker but imo this is totally doable. If you don't feel comfortable that makes sense but it might save you some $$$. I doubt an amp tech would charge much to replace some preamp tubes

1000002577.png
 
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Aelred said:
Not open the amp up? That seems like a Magicians trick to me.
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Let's be clear on terminology.

Opening the amp up = exposing the circuit board and components and the scary stuff.
Removing a cover = super simple and super safe. Only issue is burning yourself if you grab a hot tube.

You just need to remove a cover.

Your amp has 2 back covers. One on top and one on the bottom. You need to remove the top one.
It has 4 screws. 2 on the left side and 2 on the right. Easy peasy.

image.jpg
 
Mongillo19 said:
Does not have to be from the same store. Is it a certain channel that has the hiss? I'll look up your amp real quick
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Thank you for this! Both channels.

I guess I could buy a few 12AX7 tubes, a tube tester and such Online. Maybe it's one of those things I need to learn if I intend to keep using Tube amps.
 
Aelred said:
Ok, that makes sense.

I still need the Tester and Tube...

Thanks again.
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Don't need a tube tester. Trial and error can be your friend. Change one out, see if that resolves the issue....if not, try the next one.

People also say you can take the eraser end of a pencil and tap on the preamp tubes in question and the potential issue tube will sound different
 
Mongillo19 said:
Don't need a tube tester. Trial and error can be your friend. Change one out, see if that resolves the issue....if not, try the next one.

People also say you can take the eraser end of a pencil and tap on the preamp tubes in question and the potential issue tube will sound different
Click to expand...

You don't have to use the eraser end.



It's so easy to hear the bad one when doing this - BUT, it doesn't always work unless the tube's pretty bad.
Like Mong said - simple trial and error.

Think of the tubes as light-bulbs that make sound. You got a bad light-bulb.
Get a good one and use trial and error to find the dud.

Just don't touch the tubes until they're cooled and you'll be fine. (just like with light-bulbs)

NEVER REMOVE A TUBE WITH THE AMP ON OR IN STANDBY. IT MUST BE FULLY OFF AND UNPLUGGED.

not really unplugged but better safe than sorry.
 
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Aelred said:
No, not a tale of anaimal cruelty but of unprecedented negligence towards my cherished amplifier.

I left in on over Easter in Standby. The Black Cat didn't hiss like this previously. I have never done this to an amp before, so naturally I did it to my favourite. :bonk

Maybe Warranty covers it, but I have doubts. I hope I can fix the thing though.
Click to expand...
Aelred said:
No, not a tale of anaimal cruelty but of unprecedented negligence towards my cherished amplifier.

I left in on over Easter in Standby. The Black Cat didn't hiss like this previously. I have never done this to an amp before, so naturally I did it to my favourite. :bonk

Maybe Warranty covers it, but I have doubts. I hope I can fix the thing though.
Click to expand...
You should always have a spare set of known good tubes. With preamp tubes, you can swap one at a time out. Replace the V1 first with a known good 12AX7. No fix? Put the original V1 back in and put the good tube in V2. No fix? Replace with original V2. Etc.

Careful with the phase inverter tube which will look almost exactly like a 12AX7. Usually they are 12AU7s.

Most amps are Class AB, meaning power tubes should be swapped out as a pair. Usually they are 6L6s, 6V6s, or EL34s.
 
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