LSS Channel 1 30-15-5 weirdness

[scienceguy]

Greetings all,
I'm new to this forum so please be gentle... I have a 4-yr old LS Special that I love dearly. I use it primarily in a blues band and leave it on channel 2 and work with my guitar volume control. The few times I tried Channel 1 I wasn't real happy with it - early this evening I experimented a little and it seems like the 30-15-5 switch has no effect on Channel 1. It works fine on Channel 2. Feels like it's stuck on 15 watts. I've replaced the power tubes but no change.
If this was a rectifier tube issue, wouldn't I have the same problem with both channels?
Anybody got any ideas (before I call the guys in Petaluma)?
Thanks!

 

[bduersch]

When messing with my LSS today I noticed minimal difference between the 5 & 15 & 30 watt settings on C1. On C2, there's a bigger difference going from 5 to 15 than from 15 to 30.

I never paid much attention to it until I read your post, but now you've got me paranoid that something's not working. Thanks!

--B

 

[bduersch]

Ok... I had a chance to mess around with this a bit more later last night...

When I switch wattages on the LSS, there's more of a "fade" from one level to the next. In some cases it can take 3-5 seconds for the output to reach its final level. It's less obvious, say, than on a Mark V or Roadster where you flip the wattage switch and the increase/decrease is immediate.

Don't know if this is a glitch or just a function of how the class A design works.

--B

 

[scienceguy]

I'd be happy if I got that - as it is I can't tell the difference from one wattage setting to the next. You'd think there would be an obvious difference between 5 W and 30 W in C1.

 

[thom]

Hi

I just checked out my LSS. I have to play at low volume in the house to keep the neighbours happy btw. Anyway on channel 1 on my amp there is a very very obvious difference when switching form 5 watts to 15 and a slightly less obvious difference when changing to 30 watts. It is very apparent and you should be able to easily hear the difference. Have you tried at low and high volumes?

Regards

 

[scienceguy]

I've tried it at all ranges of volumes and tones.
I talked with the Chris at M/B and he suggested I pull the rectifier tube and see which wattage settings produce sound (it should be just the 30W setting).
We'll see what happens tonight...

 

[scienceguy]

Well - crap.
I pulled the rectifier tube and got no sound at all out of C1. Still got my sound out of C2 at 30W, but that means there is something significantly wrong with the amp.
Not happy.

 

[Octavarius]

There will always be a thump/pop when switching between the wattages, atleast it's very audible when going from Class AB to Class A on the Lonestar Classic.

It's easy to tell visually too: the power tubes always have a degree of blue-ish glow on the top and bottom of the plates (the biggest metal structures inside the tube glass). This is normal and comes from the cobalt inpurities in the plates. However, these inpurities only light up when the plates get voltage, so it's a good way of telling which tubes are "on" (when they are off, when the amp is in standby, only the heaters are on (the orange glowing wire inside the plates)). When I am going from 100W to 50W on my LSC, I can easily hear a small pop and see the two inner tube's blue glow going away (50W uses the two outer tubes, 100W uses all four, and 10W uses a combo of three, with the two left 6L6s running in parallel for single ended Class A and the third is just on to provide proper balance for the output transformer (but no signal gets to it)).

I'm not exactly sure, but I guess that the LSS works in a similar fashion. In any case, I hope this info helps your future diagnosis/troubleshooting.

I'm really sorry to hear something is wrong with your amp. But on the bright side: people usually rave about Channel 1 and say that Channel 2 is lacking the same magic that the first one has (including me as well, though today I found exactly the tone I've been searching for in Channel 2, so I officially love the entire amp now...). Perhaps, since there obviously has been something wrong with that channel for a while, maybe the tone's been poor because of that as well. Hopefully you'll get a positive suprise when you fire it up after it's all fixed. :wink:

 

[zm4]

I am only throwing this out as an idea. Could your switch be the problem? Mabey the contacts are not moving inside the toggle? I can hear a defined diffrence on all three settings even more so with the ev sro vs. the stock speaker.

z

 

[scienceguy]

I'm a happy guy now! I'm been waiting for M/B to call ever since I did the rectifier tube pull test yesterday, so this afternoon I decided to pop the hood and see if anything looks out of place.
When's the last time you looked at your car engine thinking there's something there you might recognize is wrong? Maybe if the cables aren't connected to the battery - I might catch that...
Lo and behold, the wire going to the middle terminal of the C1 wattage switch had never been soldered!
A quick touch with the iron and we're in business. I've been missing the full wattage C1 all this time!
Thanks for all your suggestions, advice and help!
bp

 

[zm4]

Glad to hear its back up and running! Its a bummer when amps, cars and the like dont work right. But, it feels good when you fix it yourself!

z

 

[bduersch]

Cool... glad to hear it was a simple fix.

--B