What's Wrong with this Amp?

[Unicorn Warrior]

Just bought this JC-120 off Reverb, in "excellent" condition. Paid quite a bit because of that too. Low output channel of chorus sounded great. Then, I changed to high output of the same channel and became alarmed when I heard some volume loss and static. It eventually leveled out and didn't do it anymore on that channel.

Then I tried the normal channel. Here is an example of what I'm experiencing. I'm afraid I'm going to have to send it back, unless I get a hefty refund and it's also an easy fix. Inconvenient as heck but I can't have a lemon.


What do you guys think? Is it serious?

https://youtu.be/ZWvxhvugUyc

[Domm]

Watch out power transformer! I blew 2 Jc 120's

[Unicorn Warrior]

Watch out power transformer! I blew 2 Jc 120's

Aww man really? I'll definitely be seeking a refund.

[Witchburner]

Holy shit I just looked up the schematic on that thing

How are these so desirable? haha

Could be a lot of things that actually happened in shipping, a broken solder joint? did you try banging the amp while on a couple of times, a loose connection, really a lot of issues, could be a cap, since it's not SQUEALING.

I'd recommend getting your money back if you already think it's a problem, or speak to the seller maybe they'll cover the repair cost at the shop so they won't loose THAT much money.

Really depends on what the vibe you got was, the seller was a genuine person, or they tried to show it off as mint and wanted to sell it and not say anything hoping you wouldn't say anything, or it actually got fucked up in shipping.

[Unicorn Warrior]

I think the guy genuinely may not have known. He's supposed to be refunding me. Hoping for a smooth transaction so I won't be ampless. Have a show next weekend

[Unicorn Warrior]

Also, anyone ever return on item on Reverb?? How do I recoup shipping fee? I'll be getting what I paid for it back, but I'm also going to have to pay to ship it back now.

[oid]

Unless you can prove the buyer misrepresented the amp or the carrier service damaged it in shipping, you don't. This is the cost buying online.

[Unicorn Warrior]

That would not be cool.

I believe it was misrepresented when he stated it was in "excellent" condition. And I received it this way.

He sent me a video of the amp after I had already received it. The vid was never on the listing to begin with.

[Fiddy]

Fuck man, what's up with all these idiots selling amps with issues?

[oid]

I think the guy genuinely may not have known

I believe it was misrepresented when he stated it was in "excellent" condition. And I received it this way.

which is it? It is on you to prove it if you want your shipping funds back. Otherwise you are at the seller's mercy.

This could be shipping damage, could be a less than honest seller, hell it could even be the difference in local mains voltages, it may run perfectly at the sellers house.

Good luck, I would not hold my breath though, experience tells me you will get refunded shipping one way at best, Reverb is not Amazon.

[Witchburner]

A foul rating really changes the mood of things

You seem to easily be in a position to dispute the cost of shipping, one side sure, the other way don't hold you breath.

[BlueSparkle]

As a JC owner ( a much older version than yours) it is hard to see from the vid if that is you playing with chorus or not.

bear in mind this is a stereo amp, so if the sound is intermittently coming from both speakers at the same volume then your amp likely has an output stage issue.

if the amp is preferring one speaker over the other, then you could have a dodgy preamp channel.

try the following:

1. channel 1, vib/chorus set to off. listen to both speakers, are they both doing the same or is the sound from only one speaker constant?

2. channel 2, same as above.

3. vibrato on, channel 2, turn the volume up to about 5. hit an open G as hard as you can. Are both speakers blowing your hair off?
4. chorus on, channel 2, same open G. You should get a clean sound from one speaker and the phase modulation from the other.

It's commpn for the preamp stages to fail on the early BJT/FET versions, but the later ones often have issues with caps and the FETs. / TA7122's.

If you have some skills, I can send you the service manual and schamtics for your particular serial number - it looks like a unit made in the early 1980s, with the bright switches and the plastic corner protectors.

[Unicorn Warrior]

which is it? It is on you to prove it if you want your shipping funds back. Otherwise you are at the seller's mercy.

This could be shipping damage, could be a less than honest seller, hell it could even be the difference in local mains voltages, it may run perfectly at the sellers house.

Good luck, I would not hold my breath though, experience tells me you will get refunded shipping one way at best, Reverb is not Amazon.

I'm giving him the benefit of the doubt and assuming it's both. This guy had a bunch of amps on his Reverb store which leads me to believe he flipped it for a profit and it wasn't a personal amp of his. In saying that, he really may not have seen the problem when he tested for himself. That doesn't mean the problem didn't exist. I shot another video where I played the amp for nearly 3 minutes and at a higher volume until the problem occurred.

[filthypit]

Been playing them since early 80's - They're awesome amps - but can be VERY finicky.
Also, its a BIG fragile piece of equipment so I'd worry abt inadequate or improper packing. My current JC120 doesn't leave the house because I don't wanna replace it (again). All the diff elec components make it a nightmare to work on.
Reverb is good abt backing up 'item not as described' claims... not so much 'shipping damage' claims.
Sorry to hear abt your probs - good luck w/ it

[Unicorn Warrior]

Been playing them since early 80's - They're awesome amps - but can be VERY finicky.
Also, its a BIG fragile piece of equipment so I'd worry abt inadequate or improper packing. My current JC120 doesn't leave the house because I don't wanna replace it (again). All the diff elec components make it a nightmare to work on.

I still plan to source another one. I'm just very fond of their sound. What sort of problems have you had over the years?