(Lonestar Special, LSS): 5W: no sound

[kmr]

As previously posted, I added a second Mesa/Boogie (Stiletto Ace) to my Lonestar Special creating a Stereo System with a G-Force and GCX Audio Switcher. However, after adding to the Lone Star Special I noticed the 5 watt setting on Ch. 1 and 2 no longer works (it is silent) whereas the 15 and 30W still work normally. I have a few days to return it to the local dealer for credit and it may be months before they get a new LSS.

Does any one know what might be the culprit of the 5W setting becoming inoperable (while 15 and 30W work normally) ? If its just a tube, I'd rather have Mesa/Boogie ship a replacement rather that me returning the amp to dealer's service or returning the amp to Mesa/Boogie. It's late Thursday, so Mesa won''t have service personnel available until Monday.

Thanks in advance,

 

[simonich]

Holy cow, this is the 2nd post about this 5W issue in the last week. Here is the other thread...

http://forum.grailtone.com/viewtopic.php?t=26848&start=0&postdays=0&postorder=asc&highlight=

I don't know what the fix might be. My suggestion on the other thread was to swap the two outer power tubes (move right one to the left, left one to the right). If that fixes it you know it was a power tube. If not, I think most of us are stumped as to what it might be.

 

[Ducky]

I'm with Simon here. If it was a preamp tube, you would see the symptoms in either ch1/2. (since only v1A isn't shared throughout the signal chain)

Do you notice any Vol differences when you are in 15/30W since the 5W hasn't been working?

Basically what happens when you are in 5W mode is that the pair of power tubes being used, only 1/2 of the signal is being sent to the OT. (i.e only one tube is used) So maybe you have a bad power tube.

If you switch the power tubes, and it doesn't help, time to get Mesa involved. Good luck

 

[kmr]

Thanks for the link, Simon. Yes, the problem is the same as on that link including the random, soft scratching sound (which sounded a bit like a bad guitar cable, but I couldn't reproduce the sound with flexing my instrument cable).

Ducky, I don't notice any change in volume or tone in the 15/30W modes.

I'll try the tube swap and contact my dealer today -- bad timing with Mesa gone for a long weekend. Thanks for the thoughts guys!

 

[pjlcc14]

Thanks for the link, Simon. Yes, the problem is the same as on that link including the random, soft scratching sound (which sounded a bit like a bad guitar cable, but I couldn't reproduce the sound with flexing my instrument cable).

Ducky, I don't notice any change in volume or tone in the 15/30W modes.

I'll try the tube swap and contact my dealer today -- bad timing with Mesa gone for a long weekend. Thanks for the thoughts guys!

kmr....thats amazing.....(I am the one who started the other thread).....I thought the exact same thing when the noises started.....I was positive I had a bad guitar cable.......but like you.....I could not get it to repeat when wiggling every inch of the cable.......plus I switched to another cable with no results....then a day or 2 later....and the 5Watt selection is gone on both channels.......I haven't had time to switch tube locations yet.....hopefully tonight!

 

[kmr]

Thanks for the input, pjlcc14. How long had your LSS been used before you had the problem? I got mine new in a box from the dealer and had played about 10 hours over 4 days with it before I lost the 5W output. My dealer has another LSS and will swap amps, but with two reports of the same problem I might see if he can order a LSC for me as a replacement. I'll wait until Monday to make a decision after I talk with Mesa Boogie and see if they can confirm it's just a tube issue. Did you call Mesa Boogie during the week to get their opinion? I'll try the tube swap this weekend and report. I'll look forward to hearing your your swap goes.

 

[pjlcc14]

I've had mine for almost 2 years......and I would ssay I play it about 2 hours a night @ low volumes, about 3 times a week normally. I've been playiing about everynight during the summer......but again at low volumes....never really thought I was putting much stress on it. When I want to play loud, I use my LSC or my H&K TriAmp.
No I never did call Mesa......I find better and faster answers here actually. But if the Tube swap doesn't fix it tonight, I will call them Monday to see if it's a known problem!

Cheers

 

[kmr]

Thanks for the additional information, pjlcc14. I hope the tube swap works out well. If so, I'll probably order a replacement set for the LSS and Stiletto Ace to keep on the shelf for future failures. I've seen a few posts about suggested tubes that people like better than the Mesa Boogie tubes.

 

[MikeK]

Does Boogie use LDRs to do the switching on these? It might be the one doing the switching for the 5 watt circuit.

 

[kmr]

Sorry, Mike, what do you mean by LDR?

 

[pjlcc14]

Does Boogie use LDRs to do the switching on these? It might be the one doing the switching for the 5 watt circuit.

But that would mean that not one, but 2 switches failed at the same time......for each channel has its own watt selector switch!

Not that it couldn't happen....but I think it is something further down the line.....I think....you could be right.....I don't know

 

[MikeK]

Sorry, Mike, what do you mean by LDR?

LDR = light-dependent resistor
They're used to soften the blow of switching channels and the various modes so there isn't as much of a 'pop' when the other channel slams in.

pjlcc14: I see what you mean, but I couldn't tell you anything further. I'd be curious to hear what The Factory says to you guys about this.

 

[pjlcc14]

GOOD NEWS KMR!!!! Because I am not a LSS expert, and I don't really know what tube does what......I took both outsides and swapped them over with both insides.......(1234 swapped to 2143).......must have been a bad tube driving the 5Watt selection.....cause it works GREAT now!!!! Which means I got a bad tube in the 15Watt series of tubes......but at least I know now, it's nothing major.....I just need to go get a new set of tubes.........after 2 years....it's probably time I believe. Anyway.....sounds like we both had the same problem......hope this fixes yours!
Cheers!

 

[kmr]

Thanks for the information, Mike. I did consider than LDR meant light dependent resistor but was unsure how they'd be used for switching inside the amp. Does the amp have internal LEDs that shine and open-up the LDR?

 

[kmr]

...cause it works GREAT now!!!!

That's great news!! My dealer has a new LSS in stock and offered to swap, so I'll go and do that -- but I'll keep this in mind in case I have a problem like it in the future. In fact, I'm planning on doing a tube swap on both the LSS and Ace and I'll keep the original Mesa Boogie tubes around in case of a sudden failure like this.

 

[kmr]

I exchanged the LSS for a new LSS - it works quite well. When I was there, the dealer had some LSC combo's in stock as well. I really liked the LSC sound as well and strongly considered getting it instead of the LSS. But, in the end, they both sounded great and the LSS combo is more portable -- especially since I'll likely leave the Ace combo in the studio most of the time and gig with the LSS. Now, if they had a LSC head, that would have been very tempting!

 

[MikeK]

pjlcc14: Did you consider switching the outside pair only? ( 1234 to 4231) to narrow it down to a specific tube gone bad? Then switching back to the original 1-2-3-4 sequence to recreate the problem would confirm your findings. It's interesting how a 6L6 would not work single ended but still work as push-pull. Makes me curious to find out why.

kmr: I believe these are self contained and don't rely on any external source. Fender used something similar to initiate the vibrato on their blackface amps.

 

[kmr]

I believe these are self contained and don't rely on any external source.

Very cool, seems like a nice way to implement a softly opening/closing switch.

 

[drunkdolphin]

Hey, is it only in the 5 or 5 and 15w section?
if its both it is the 5y3 recto.

 

[kmr]

Hey, is it only in the 5 or 5 and 15w section?

Only in 5W setting, both channels.