rats - found a bugaboo with my carvin amp

[DankStar]

I heard a crackling today in between riffs and then gave a little knock with my knuckle on the front panel of my carvin power amp. Sure enough I got another crackle. If I push on it, it crackles as well. I can live with it, but I'm hoping it doesn't get worse or mess up my speakers. It's not a loud thing right now (and doesn't really happen unless I touch it), but a bummer nonetheless.

There's two volume pots and two switches (standby & power) mounted to the front panel. I think the volume pots are PCB-mounted so maybe a connection there is bad.

 

[HALENisking]

Re: rats - found a bugaboo with my carvin amp

That doesn't sound like the sort of thing you hope goes away :\
but it's good news if it's only a pot or connection

 

[ehdwuld]

Re: rats - found a bugaboo with my carvin amp

Sounds like a loose ground connection somewhere

*(Sent from my durned phone!)*

 

[Darg1911]

Re: rats - found a bugaboo with my carvin amp

Check the tubes and sockets. I have had more than one intermittent crackle that was caused by a bad tube. Most recently a power tube in an OTL amp but also a preamp tube in the past. You should have spare tubes. Try swapping out the preamp tubes one at a time. It's the easiest test. You can also clean a tube socket and tube pins fairly well, at least temporarily, but pulling and reinserting the tube 3 or 4 times.

 

[DankStar]

Re: rats - found a bugaboo with my carvin amp

Sounds like a loose ground connection somewhere

*(Sent from my durned phone!)*

I ought to loosen your ground wire! Oh, you meant the amp. Thx

 

[ehdwuld]

Re: rats - found a bugaboo with my carvin amp

Oh wait I just remembered
Carvin uses the ribbon cables between boards
These are notorious for coming loose

Check to ensure good connections

*(Sent from my durned phone!)*

 

[DankStar]

Re: rats - found a bugaboo with my carvin amp

Yes, lots of ribbons and those silver colored push-on/crimp connectors. I'll check em.

 

[Gearjoneser]

Re: rats - found a bugaboo with my carvin amp

Bugaboos only come in Bugera amps.

Cracklins come in Carvins.

 

[DankStar]

Re: rats - found a bugaboo with my carvin amp

update: took it to a great local tech when channel 2 started really cutting out. he found some bad solder connections on the tube filaments. kinda negates the deal I got on it, but it should be good to go for awhile now. and the process resulted in me finding a tech I can trust. dude took it in, diagnosed it, and fixed it within a day's time.

 

[ehdwuld]

Re: rats - found a bugaboo with my carvin amp

My Belair had some cracked solder joints on the tube sockets

pulled the pan
touched them with iron
all was well

those Carvin amps sound great when they are working:1:

 

[DankStar]

Re: rats - found a bugaboo with my carvin amp

I was pretty close to pulling the trigger on a rocktron velocity 300 and then selling the carvin, but I love how the carvin sounds and I know that I'd really take a hit trying to sell an amp with an issue.

 

[Darg1911]

Re: rats - found a bugaboo with my carvin amp

Does Carvin get their boards pre-assembled from China? I know they state "Made in the USA" but that doesn't mean that the amp is 100% USA made. I've played some of the Vintage series and a V3 Micro recently. I like them. But for the prices, I wouldn't be surprised if the boards came over from Asia, already assembled. I'd probably be surprised if they weren't.

 

[ehdwuld]

Re: rats - found a bugaboo with my carvin amp

according to the YouTube video
they do it with a machine at the factory

but this may be wrong

 

[Darg1911]

Re: rats - found a bugaboo with my carvin amp

according to the YouTube video
they do it with a machine at the factory

but this may be wrong

Thanks, I just watched it. Interesting. The two employees who's faces were shown were both Asian. But the computer screen was in English. I'll trust them that they are made here. They are wave soldering the SMT components. I'd bet that they hand solder the tube sockets and some of the other components. Just thinking out loud because of the two above posts stating that the tube sockets of their amps had cold solder joints.

 

[DankStar]

Re: rats - found a bugaboo with my carvin amp

The tube 100 is from an earlier time period as well, construction may have differed then versus now, I'm not sure. Mine could have been through a lot being used. I need to stop buying amps before trying them, unless it's through a place with a nice warranty.

 

[Demanic]

Re: rats - found a bugaboo with my carvin amp

One of these days, if I get ambitious enough, I could consider rewiring my Carvin X amp onto breadboard. I will have to get quite ambitious though...

 

[DrNewcenstein]

Re: rats - found a bugaboo with my carvin amp

Wave soldering is no guarantee. The first run of Xbox 360s were wave soldered, and last I saw about 30% of them were returned for a second rinse on Microsoft's dime.

 

[Demanic]

Re: rats - found a bugaboo with my carvin amp

I used to work at a recycling operation. You have no idea how many faulty 360's we processed.

 

[Darg1911]

Re: rats - found a bugaboo with my carvin amp

Wave soldering is no guarantee. The first run of Xbox 360s were wave soldered, and last I saw about 30% of them were returned for a second rinse on Microsoft's dime.

I know but they showed machine fluxing, SMT placement and then mentioned and showed the wave soldering after placement of the SMT components. That just got me thinking that they may be soldering some of the larger components, like tube sockets, by hand. I could be wrong, it was just a thought based on both posts mentioning cold solder joints on the tube sockets.

 

[DankStar]

Re: rats - found a bugaboo with my carvin amp

OK, when I picked it up he described it better to me. It was the soldering at the big (concrete type) resistors for the tubes. He was saying it's not necessarily carvin's fault (or the previous owner). Companies were mandated around the time of this amp's production to use lead-free solder and as a result it just wasn't as strong. He's seen a lot of equipment with issues like that due to the use of lead-free/low-lead solder.