LSC problems! Help/Advice needed and much appreciated!

[ama_kid]

Okay, so I just bought a sweet looking Blonde Tolex/Chocolate Grill 50/100 Lonestar Classic from GC a few hours ago and I am already having problems with it! The sound is amazing, but I have two problems and I am starting to get really frustrated!!

1 - Switching issues - My solo button doesn't work. Channel works no problem, but when I click on the solo button...nothing, no lights either. Additionally, if I plug the cord into the FW jack on the front all the way, neither works. I have to pull the cord out of the jack about an 1/8 of an inch for it to work. Tried a single button footswitch into the back of the amp in both the solo and channel and neither worked.

2 - Random volume drops on the gain channel. It doesn't cut completely out, but it it goes about 1/2 output in then back in. It happens everytime when I just switch channels and intermittently when playing on Channel 2.

I have tried multiple cables and guitars and am experiencing it with any configuration. I really should have tested it in the store, but just took for granted that it would work how it should.

All of this is when the loop is enabled and set at 1:00. I haven't tried it when it is in Hard Bypass as I just started getting frustrated after spending all this money on what I know is a sweet amp! Any suggestions? Could it be a tube issue in V3 (controls the loop I believe)? What about bridging the Effects Loop's Send and Receive? I've seen that be a fix on a LSS on these boards along with spraying some contact cleaner in the jacks. You all convinced my on the LSC and I absolutely love the tone and I know you'll point me in the right direction! The LSC is the amp for me, just a little growing pains in the beginning

Thanks so much in advance!
Jasun Krebs

 

[vibrocaster]

Are you using a stereo cable for your footswitch?

 

[vibrocaster]

Is this a brand new amp? Contact cleaner along with plugging a jack in and out of both loop jacks a few times might take care of a possible oxidization problem causing your volume drop situation. It worked for me.

 

[BobL]

As mentioned above the cable MUST be TRS (tip/ring/sleeve) on both ends, and based on your description I'll bet your using a standard 1/4" guitar cable.

Changing this cable may also cure the volume drop, believe it or not, so start with this. If the volume drop won't go away there are a number of issues that could cause this problem, not the least of all a tube. One problem that's easy to check for is possible insulating material (mica) caught up in the tube itself. The mica used to insulate the tube elements, collector, grid, plate, will on rare occasions flake off. Take out each tube one at a time and snap it a few times with your finger holding it in different positions, up, down, sideways, etc. as you snap. Then hold the tube down as it would be in the amp and look to see if there is some crap in the top of the tube. Do this to each tube one at a time.

If all this fails take it back to GC for another amp and make it their problem. If you take it back have them give you one that's still in the box.

 

[Monsta-Tone]

Hey Jason,

I just bought an LSC the other day. When I got it, I had the same problem, sort of.

I could not get the Solo to turn on.



Unscrew the cover on the ends of your footswitch cord. Mine had a broken wire on one end. As soon as I re-soldered it, the amp worked beautifully.




As for the loss in volume...
You might try changing V1. V1A is the only gain stage that is not shared with the Clean channel, and this is only when the Drive is engaged.

If that does not help, see what the Power Amp setting is on.
If you are using "Rectifier Tracking," and the Lead channel is set to 50 watts, then try changing your rectifier tube.
If you have it set to 100 watts, then try changing your power tubes.


No matter what you find, the store should be obligated to repair it for you. Hopefully it is a simple fix and you can do it yourself and just get some free tubes from them. If not, take it back and politely demand that they fix it.


Hope this helps.

 

[ama_kid]

Thanks for the suggestions! Here's an update...

I attempted to tackle the volume issue first. Unplugged the footswitch to eliminate that as a possible cause. Strayed contact cleaner on an instrument cable and worked it in and out of the effects loop send and receive jacks (did it on all jacks just for good measure). After I let the contact cleaner evaporate, I played the amp for about 15-20 minutes and only experienced the volume loss once. Repeated using the contact cleaner again, let dry and played for about 30 minutes without it happening. As an FYI, it was also happening on the clean channel as well, just didn't notice it before. I then checked all the tubes one by one using the method BobL suggested, but didn't see anything in the bottom of the tubes. Performed the contact cleaner process once more and played for about 45 minutes on Channel 2 and another 20 on Channel 1 with no volume drops. During the last few minutes of the 45 minutes on Channel 2, I tested manually switching back and forth from channel to channel to see if switching channels had an impact. It didn't and I had no volume drops. I think we are good on this one.

The cable provided to me was a not TRS on both ends, so I suspect that is the issue with the solo and channel issues. I couldn't get over to GC today, but heading that way tomorrow and will pick one up and report back.

Now the bad news...there is a bigtime hum on both channels, more prevalent on Channel 2 on the bridge pickup of both my telecaster and my SG. Additionally, as I have been playing this for about 3 hours today, I noticed a lot of pick scrape coming through the amp. I do a lot of trem picking in my band and changing my picking location the pitch of the pick scrapes changes as well. Depending on how much I dig into the guitar, the scrapes actually start coming out louder than the notes. I know this amp is very touch sensitive, but has anyone experienced this? I wish I was at the studio so I could record both of these issues for examples.

Any thoughts on these, now 3rd and 4th, issues would be appreciated!

Thanks
JK

 

[cb101]

I know you probably have already done this but:

1A. As mentioned above check those tubes.

1. Make sure the tube bias switch on the rear was not set to the EL34 position by mistake. (assuming you have 6L6's in there)

2. Turn the reverb knobs down completely and see if that is where the hum is coming from.

3. Bypass the loop and/or turn the loop completely down to see if that affects the hum.

These amps are very sensitive. I notice on mine that just scraping my finger lightly on the strings while picking will come through the amp. I actually find myself being more conscious of how I pick and how I hold my fingers.

 

[ama_kid]

Tube bias is set at 6L6 (I am using the stock Mesa 6L6s). Hum is present with reverb down on both channels (tried both warm and bright just to make sure it wasn't the switch either). Hum is much more prevalent when loop is set to Hard Bypass (almost deafening). Stranger now, I have unplugged everything and set the amp to "On" with it on Standby. If the switch is set to channel 2s, when I switch the amp off of Standby, I get all kinds of popping and noise. Noises that sound like they are hurting the amp.

Man, I am really bummed now...I've been researching gear for my live sound almost 4 months now (since I sold my Rectoverb) and I'm so sick of looking at gear...I just want to play!!!

Any thoughts? I'm thinking tubes...maybe V1? Loop and Reverb have been ruled out, so V3 and V4 should be fine. I just don't have any extra pre-amp tubes laying around to check. I think I'm just going to bring it into GC tomorrow and show them what's up. That way we can break open a new set of tubes and replace them one by one. At the same time, they can provide me with the correct footswitch cable.

 

[ama_kid]

Upon further testing, all this hum, popping and noise is only present when the Drive is engaged on Channel 2. If I turn it off, no noise, hum or popping. Also, if I have it on, this is when my volume issues return. I found a few Mesa stock 12AX7s I had left over from my retube of my Rectoverb (Doug's Tubes swap with JJ ECC83s) and swapped out each tube one by one. Same noise is present throughout the tubes swaps. I am fairly certain it is the Drive circut. Is there a certain tube that drives this circut? I checked the manual and I didn't find anything that refers to it being based on a tube. This issue exists with Silicon Diodes engaged as well and with it at 100 watt, so I don't think the rectifier (5U4) tube isn't the culprit.

I'm just going to bring the whole setup into GC later this morning and show them what is up. Hopefully they will just send this back to Mesa and loan me another one until it returns.

 

[Monsta-Tone]

V1A is the only part of the preamp that is not shared. It is the Drive circuit.

Have you tried the amp in channel 2 with the drive off?



GC should make things right for you. If not, explode and say things VERY loud, like "I just bought this thing, what do you mean you won't fix it?"

As long as you are not beligerent or spouting cuss words out like a Turret's patient, they will politely usher you into the Manager's office and give you anything you want. Usually.

 

[Tubegear Junkie]

You have probably already gone to GC by the
time you read this thread...which is the best thing to do.
Reading all the posted threads on your problematic amp,
I'm only guessing, but it sounds (no pun intended) that there's
a connection that is desoldering itself in that particular drive channel.

If the amp is new I would ask for an exchange.

Good luck & let us know the outcome...

 

[zappaslaughter]

My LSC hums very loud when I plug it into a non grounded outlet.

 

[ja22y]

Upon further testing, all this hum, popping and noise is only present when the Drive is engaged on Channel 2. If I turn it off, no noise, hum or popping. Also, if I have it on, this is when my volume issues return. I found a few Mesa stock 12AX7s I had left over from my retube of my Rectoverb (Doug's Tubes swap with JJ ECC83s) and swapped out each tube one by one. Same noise is present throughout the tubes swaps. I am fairly certain it is the Drive circut. Is there a certain tube that drives this circut? I checked the manual and I didn't find anything that refers to it being based on a tube. This issue exists with Silicon Diodes engaged as well and with it at 100 watt, so I don't think the rectifier (5U4) tube isn't the culprit.

I'm just going to bring the whole setup into GC later this morning and show them what is up. Hopefully they will just send this back to Mesa and loan me another one until it returns.

Tube V1A is the drive tube. Try swapping this tube. But since you just bought the amp, GC should do you right.. I always power up and check out at the store before taking it home.

 

[ama_kid]

Sorry for the delay guys! I took it into GC today (the guy I dealt with was off for 3 days) and we got everything all figured out on this. The drive on channel 2 issue due to a combo of a bad power tube and fuse. I guessed I missed this somehow. Once we swapped the tubes, the 4A 120v fuse blew. Swapped the 2 outside 6L6s and replaced the fuse and no more hum, crackles, pops and no more volume drops. Played the amp cranked in GC for about 45 minutes with no issues.

Now to the footswitch issue. Tried two separate cords and two different foootswitches. Same issue and most likely due to the jack. The channel switch is usable for now if I pull the cable about 1/8 inch out, but the Solo is not. Since I have a gig on Friday, I'll deal with no Solo and use my Katana as a boost then going to take it into the Mesa Warranty Service shop we have here in San Diego on Saturday and have them swap out this jack and do a once over on this amp. Jeff Snider (Snider Amps) is the tech there and has been my tech for about 6 years. I talked with him and he said he could have it back to me by Thursday next week and I am okay with that.

You might be asking why I just didn't swap out the amp with another. The reason is one, because of the custom Cream Tolex / Black Grill, two, because it sounded so much better than the other 50/100 they had in stock (it was also in the Blue Tolex / Silver Grill which looks great, but hasn't quite grown on me).

Just wanted to give you all an update and thank you all again for your help!

jasun

 

[BobL]

Glad everything is working out. Have the tech change all the power tubes with a matched set. Mesa will re-imburse him and it shouldn't cost you a dime. You didn't say if you finally got the correct TRS cable for the foot pedal or not, and I apologize for not having you thump the power tubes while in the amp while the volume was lost. Good luck, and I understand the hesitation to return the amp. One of my Lonestars is the same custom color, really nice comb, but it took 3 1/2 months to get to Boston.

 

[ama_kid]

Thanks and no problem about that I think I was about 9 hours into looking at this on Saturday and was a little loopy

I received the correct cable and was still having issues with the footswitch and I believe it is the jack. I'll know a little more by saturday.

Take Care!
jasun