Laney VC30 very low output

The most likely cause of intermittent changes in tone and volume in all amps is oxidation in the pots. Deoxit 5 is what I use, just squirt some in, wiggle it around for awhile and squirt some more to flush. Non-conductive, can be used on all contacts.
 
That dark gunky looking stuff looks like something that dripped out of a capacitor or flew out of one. It came from somewhere and doesn't belong. As RetiredUnit1 said, use non-conductive cleaner. Especially around high voltage. That capacitor appears normal, but is it? The 6.5 ohm reading on the speaker is perfectly normal when measured with a VOM. Remember, speakers are rated with an impedance, not resistance. I think impedance is typically measured at 1KHz(1000 hertz).
 
I replace power tubes and changue cap +two resistor, now just sound if I play very hard and its sound like someone is farting.

If I play normal or low it´s sound very very low (same happens on second channel)

some ideas?
 
I’d try some new (or known working) preamp tubes in it as well, before testing the transformer. But I hope someone knowledgeable answers your how to test OPT question, it’s something I’ve never done. I’d imagine the first test would be a simple conductivity for each coil. That cap juice looks like it could’ve gotten really messy. I’d look at everything in that area through a loupe, just to make sure it’s all okay, and cleaned up.
 
Travis, do you have a volt meter? You need one. As the schematic shows the plate voltage for the power tubes(EL84's) is around 300 volts and the voltage on the pre-amp tubes(ECC83's) is around 150 volts. Those voltages are typical for those tubes. As always, be careful around high voltage circuits. Be especially careful when measuring around the power transformer, the primary and the secondary. Do you have European voltage? That's more dangerous than what's in the US.
 
Does it have Effects Send & Return jacks?
These can Cut the sound in a lot of Amps by creating a dirty connection as it is closed when not in use!
Try putting a Jack Lead In & Out half a dozen times to see if it changes the response of the Amp.???
 
Travis, do you have a volt meter? You need one. As the schematic shows the plate voltage for the power tubes(EL84's) is around 300 volts and the voltage on the pre-amp tubes(ECC83's) is around 150 volts. Those voltages are typical for those tubes. As always, be careful around high voltage circuits. Be especially careful when measuring around the power transformer, the primary and the secondary. Do you have European voltage? That's more dangerous than what's in the US.


Preamp tubes, from left to right (right preamp tube is the one Next to the Power tubes)

Pin 6:

V1: 155 volts
V2: 199 vols
V3: 218 volts

El84s on pin 7 344 volts

I changue the volume clean knob and now doesnt make weird noise but the channel is distorted and weird...

some ideas?

fx loop doesnt affect when i plug a jack
 
Last edited:
I just had this same issue with a friend's bass amp. Signal drop and nasty fuzz sound especially when I dig in. Then when I went to diddle the master volume knob I found that pressure on the pot shaft in certain directions was cleaning the sound up and in other directions It was causing the drop/fuzz. I haven't gone in and replaced it yet, but I do think flipping it out and making sure those joints are solid may be a good look to fix the issue on his.

I saw mention that the volume knob on yours is maybe doing something similar. Could be an avenue worth investigating. God luck and good speed.
 
Back
Top