Lonestar Clean Channel Problem

[CudBucket]

Hey guys. Just picked up a used Lonestar 2x12 combo. I believe it's a 2004 model. Version 1. Anyway, the amp is pretty cool and has a popping and hissing on the clean channel only. Happens as soon as you switch to it and occurs every 10 seconds or so and does so, consistently. No issues on the lead channel.

The amp came with a mix of Mesa Russian-2 and EH preamp tubes. I pulled them all and put in a brand new set of JJs and it still happens.

The amp has 4 Mesa 6L6GC greens and a Mesa 5U4GB recto tube. The center pin on the rectifier tube is broken but I'm running in Diode recto mode so the tube isn't even in the circuit.

Any thoughts? I've emailed the seller. I bought it from a guy on The Gear Page. The amp is in mint condition and is in new condition. He claimed it was working fine but this is impossible to not notice. The amp was packed well and there's no sign of mis-handling or damage during shipping.

I'll see what he says he wants to do but it looks like I'm going to incur a repair cost that I don't think I should have to pay for.

Any help would be greatly appreciated.

Dave

 

[fishyfishfish]

To me it sounds like a pre amp tube, but you changed them out. Mine did the same thing on the dirty channel, and it was a dirty send/return effects jack. Does it make noise with the loop by passed?

 

[CudBucket]

To me it sounds like a pre amp tube, but you changed them out. Mine did the same thing on the dirty channel, and it was a dirty send/return effects jack. Does it make noise with the loop by passed?

I'll check. I don't think that changes anything but I'll check.

Dave

 

[cb101]

Just for the heck of it I would check and change out those preamp tubes again. I had the same problem on channel 2 and it turned out to be V2. If your channel 2 is working OK then it's probably not the power or rectifier tubes which only leaves the preamps. Just a thought.

 

[CudBucket]

I'll try the V2 again as well. I bypassed the loop and for a few minutes I thought that was the problem. But then the noises started up. I'm going to pop in a new Mesa tube in V2 just to see what happens.

It's such a beautiful clean channel and the gain channel is so under-rated. This amp has plenty of gain for metal and hard-rock. It's also tighter than a recto and much smoother.

The seller hasn't responded to my note so I'm getting a little put off but that's nother matter.

Thanks guys.


Dave

 

[CudBucket]

Just for the heck of it I would check and change out those preamp tubes again. I had the same problem on channel 2 and it turned out to be V2. If your channel 2 is working OK then it's probably not the power or rectifier tubes which only leaves the preamps. Just a thought.

I hope you're right. I had these same JJ tubes in a Studio Pre and they were fine there but you never know. There's less than 3 hours on these pres. I've got many more I can try.

Dave

 

[Octavarius]

If you have any spare power tubes/rectifier tubes, I'd try them as well, just to be sure. Make sure the sockets are clean and that all tubes are properly inserted. Follow the basic troubleshooting procedure by tapping each tube with a pencil or similar and check for response. I'd also open it up and check the input jack and look for any loose connections or faulty components.

 

[CudBucket]

Well, I swapped the JJs in V1 and V2, no change. That means both JJs were not good for V2. In other words, the noise didn't move to V1 (Lead channel). Then I put them back where they were except for the V2. I took a new Mesa 12AX7 and put that in V2. And I just played for about 5-10 minutes with no noises in the clean channel at all. Lead channel was fine too.

For the record, on Friday night, I pulled the chassis and all the tubes and coated each tube's pins with some De-oxit. The chassis is spotless so there was nothing to clean.

None the less. The amp seems to be working fine now. But isn't it odd that a preamp tube would cause popping in one slot but not the other? I just think that's wierd. I have to go out right now but I think when I get home, I'm going to replace all the JJs with Mesa pres. I had the JJ's in a Studio Pre and they sound great, quiet.

Are tube amps and tubes that finicky?

Dave

 

[cb101]

When I first got my lonestar it sounded great with the stock Mesa tubes. Well, I though if I got some cool NOS and new preamp tubes and added some new power tubes it would sound even better. As it turned out, all but one of the stock Mesa tubes are back in there. I was getting noise all over the place ranging from the effects loop to the reverb. For some reason the amp just didn't like the new tubes.

 

[MikeK]

Are tube amps and tubes that finicky?

Well it seems this amp might prefer a particular diet ... and perhaps we can conclude that a Mesa 12AX7 is more robust and you've shown us that the V2 position on the LS requires a tube that is.

It looks like the plate voltage on V2 is slightly higher than V1 and V2 feeds the reverb section and accepts that signal back in a slightly different way than some other Mesa's. But I'm really not the person who can comment too much about this. Hopefully someone who can will chime in?

 

[ja22y]

check the jacks and switches. I had a similar issue and I thought that it was tube but it was due to a loose jack/connector

 

[CudBucket]

Oddly enough, my clean channel noise is back. It was working fine for at least 2 weeks after the tube change in V1 and V2 but it just started again all of a sudden. I pulled the chassis and nothing seems loose or out of order. I guess it's time for a tech.

Dave

 

[Octavarius]

Oddly enough, my clean channel noise is back. It was working fine for at least 2 weeks after the tube change in V1 and V2 but it just started again all of a sudden. I pulled the chassis and nothing seems loose or out of order. I guess it's time for a tech.

Dave

If you have another amp around, try patching the Lonestar effects send into the power section of the second amp. That should verify that the problem lies in the preamp section. Also try moving knobs and switches, and check the solder joints on that standby switch.

 

[CudBucket]

I don't have another amp to test the preamp in yet. I did change all the preamp tubes again last night and I still have the noise. I have some SED Winged 6L6's that I can try just to rule out the power tubes.

 

[cb101]

I think maybe it's time for a Mesa tech. It's probably just a minor problem with a defective resistor or LDR.

 

[djw]

Are tube amps and tubes that finicky?

Shouldn't be. But they can be, and when they are they need to be fixed. There are definitely more "moving parts" (i.e., tubes) to worry about in a tube amp, but the benefits as far as tone goes are immeasurable. Once you're comfortable with it, you won't give solid state a moment's consideration. The majority of those haven't been built with the same level of care as a good tube amp anyway, let alone how few of them sound even halfway acceptable (though some do). But you probably know all this.

Seems like there's just a hump to get over with this amp (this is the one with the gap between the chassis and cabinet, yes?). It should still be under warrantee, so Mesa ought to deal with it. When all is done, it'll be solid as a rock.

 

[CudBucket]

I just found out that my LS was built in November of 2004 so if the original owner can give me a copy of the receipt, I could transfer the warranty and get it looked at. In that case, I'd consider sending the chassis back to CA for a look.

Dave

 

[djw]

I just found out that my LS was built in November of 2004

Hey, how did you find this out? I think mine was made that year, but I haven't found a good source for this info (nor have I called Mesa about it).

My LSC's serial number is L-0020XX (where XX is a number between 00 and 99). I only assume it's a 2004 because it came with a 2004 pro net price list.

 

[CudBucket]

I called Mesa. My serial is 0023XX.

 

[cb101]

Mine must have been among the first group. My number is 0006XX