LSC Solo - What does it actually do?

[ellem52]

I am a little fuzzy on what the Solo "button" does on my LSC. I understand that I can set it to a louder volume setting and stomp on it to "Go to 11" but it changes the sound by more than volume. It almost "clears" the sound up some.

Sometimes I just run the amp on Solo because it sounds a little better to me for a lot of applications.

Why yes, I could be crazy... but that do you think anyway?

 

[djw]

No you're not crazy. Have you noticed that the same effect -- an apparent increase in tonal clarity -- occurs if you disengage the loop? Not only will it probably be lots louder, but it seems clearer altogether.

The same thing happens as you increase the loop's Send level (with the loop engaged, obviously)... conversely, and more noticeably, the tone degrades a little when the loop is engaged. This is because the loop adds a stage to the signal path, and adds an attenuator to boot (the Send control). I can't tell you technically why this degrades the signal, but it's pretty universally observed that it does, and Mesa discusses this in the manual (e.g., turn the loop off to satisfy the tone purist in you). I always visualize it as adding distance and clutter between the signal's origin (input) and the target (power stage), which incrementally dilutes or muddies the pure tone of the guitar.

Anyway, I think what this means is that the Solo boost basically controls the Return level in the loop, which is also why the Solo function is inoperative when the loop is disengaged. So it comes down to whether it's more important to have the footswitchable Solo capability and possibly use effects in the loop, or to have the tone just how you like it... but with no boost.

Personally, I use the amp with the loop engaged but nothing in it, just so I can use the Solo function. I keep the Send level at about 1:30, and often use it to fine-tune my volume depending on the venue's requirements. In anything larger than a power trio, this is probably how I'll always do it: I hate having to strain to hear myself during a solo. Otherwise, I'd just stick with the pure tone.

 

[ellem52]

I must try this loop disengagement you speak of - as I have no effects with which to loop anyway. (No one puts their CryBaby in a loop; right?)

 

[djw]

I must try this loop disengagement you speak of - as I have no effects with which to loop anyway. (No one puts their CryBaby in a loop; right?)

Right.

 

[plan-x]

I have been tempted, and have left the solo on for a time. The amp sounds bigger and fuller. but the boost function is to valuable to lose, especially for certain song sections, like solos etc. It's like a turbo charger.

 

[attikawarren]

I run my lonestar in true by pass (loop disengaged) and feel the tone is noticeably better.

The tone feels a little more dynamic and certainly clearer.

To get round the solo boost I run an xotic rc booster which ultimately gives that third solo channel.

 

[Telemaster]

Hmmmmm....I've been using a Lonestar 2 x 12 for about 3.5 years for gigs and haven't had any issue or confusion at all with the solo option.
I usually set my solo volume control to a level just a little higher than the
master volume...maybe 10-15 db hotter...and it works great. For indoor club gigs I have the master set at about 9 oclock...which would be on something around 2...and the solo gain up to about 2.5 or just shy of 10 oclock. It does't take much to over do the solo level.

 

[djw]

Hmmmmm....I've been using a Lonestar 2 x 12 for about 3.5 years for gigs and haven't had any issue or confusion at all with the solo option.
I usually set my solo volume control to a level just a little higher than the
master volume...maybe 10-15 db hotter...and it works great. For indoor club gigs I have the master set at about 9 oclock...which would be on something around 2...and the solo gain up to about 2.5 or just shy of 10 oclock. It does't take much to over do the solo level.

Yeah, I usually set my solo control just about right at the same setting as the output, sometimes even a hair lower -- which still gives me just enough of a boost. More than that and it's a huge jump in volume.

I believe the relative positions and differences between the solo and output also work in conjunction with the positions of the channel masters and the loop send level. So I'll bet one could probably get a relatively slight bump out of a larger gap if the other levels were tweaked a particular way.

 

[ellem52]

Hmmmmm....I've been using a Lonestar 2 x 12 for about 3.5 years for gigs and haven't had any issue or confusion at all with the solo option.
I usually set my solo volume control to a level just a little higher than the
master volume...maybe 10-15 db hotter...and it works great. For indoor club gigs I have the master set at about 9 oclock...which would be on something around 2...and the solo gain up to about 2.5 or just shy of 10 oclock. It does't take much to over do the solo level.

no, it's not that I don't understand its function... it's that I don't understand how it achieves it! If all it did was make the volume louder then it wouldn't be a mystery. However, as discussed above it does more than that.

 

[Telemaster]

I've always kept the effects loop switched to hard bypass and use my pedal board inline. As for a cleaner sound I've never noticed a change in tone when I hit the solo button - (probably since I usually have the Toadworks John Bull Mk2 engaged when I go to solo mode).

 

[ellem52]

I've always kept the effects loop switched to hard bypass and use my pedal board inline. As for a cleaner sound I've never noticed a change in tone when I hit the solo button - (probably since I usually have the Toadworks John Bull Mk2 engaged when I go to solo mode).

if you have the Lonestar in Hard Bypass the Solo button doesn't work so it isn't surprising you don't hear a tone difference when you engage it

 

[plan-x]

I've always kept the effects loop switched to hard bypass and use my pedal board inline. As for a cleaner sound I've never noticed a change in tone when I hit the solo button - (probably since I usually have the Toadworks John Bull Mk2 engaged when I go to solo mode).

Me thinks somebody didn't read their manuel. :shock:

 

[plan-x]

no, it's not that I don't understand its function... it's that I don't understand how it achieves it! If all it did was make the volume louder then it wouldn't be a mystery. However, as discussed above it does more than that.

I guess that's what this thread is about and honestly I wish the solo was not an integrated circuit with the loop. This must of saved some space and money. I really don't like interactive stuff, like EQ. Thats like a car's windshield wipers integrated with the radio or something.

 

[MrMarkIII]

Dude, the universe is interactive.

 

[agefender]

I am with warren... disengaging the Loop makes a big difference IMHO ..not just for tone freaks. rc booster here also. Do miss the solo function but wont sacrifice tone ATM

 

[BobL]

I am with warren... disengaging the Loop makes a big difference IMHO ..not just for tone freaks. rc booster here also. Do miss the solo function but wont sacrifice tone ATM

You can have both if you want. First set the loop knob to about 1 o'clock, then use a short 1/4" cable between the send and return. This tends to cure the tone lost issue.

The solo button does not make the volume louder, it simply bypasses the effects loop, which is an attenuator. The problem is that Mesa set up the Lonestar to work without the effects loop but the circuit then bypasses the master volume. The master volume is very useful when matching channels. I.e. In the middle of the set as the overall volume creeps up your not spinning the volume on two channels that have already been matched. The solo is nice for that 6db jump in volume needed for a solo.

What Mesa should have done is make the loop an option via a switch, but left the master volume available as well.

 

[xarkon]

See page 5 of the following Acrobat document:

http://www.schematicheaven.com/boogieamps/boogie_lonestar.pdf

For our purposes, I think this part of the schematic is similar, if not identical, for both the LSC and LSS.

Solo is a pot wired as a variable resistor (i.e. only the wiper (center) and one side are used). When Hard Bypass is off, Output is driven by the network off V3B (12AX7 tube in the effects return loop). There is a 100k resistor followed by a .68 uF cap, followed by another 220k resistor. This 220k ties to the top of the master output pot which ties to the top of the Solo pot.

If I'm reading this right (corrections welcome), then when Solo is off (normal condition), then the bottom end of the Output pot is tied to ground. If you turn Output all the way up, then the signal is effectively the output of V3B split between the 100k/.68uF/220k and the 1 meg pot. The 1 meg wins, so you get lots of signal. Turn Output all the way down, and it's at ground, so no signal to out.

When Solo is on, then, the value of the Solo variable resistor gets added onto the bottom of the output pot, thus increasing the resistance for the bottom part of the network and increasing the proportion of output signal sent to the driver stage. If you turn the Output pot all the way down, you'll still get signal unless you also turn Solo all the way down. Bump Solo up even a little bit and you should get some signal out. (I haven't tried this on my LSS but it should work that way.)

Now, this output network has a capacitor in it. While this looks like a simple high-pass filter, from doing a couple quick calcs, it looks to me like the sole purpose of that cap is to keep DC from being passed to the output stage. Once Output is turned up much, the cutoff frequency is already pretty low...a few hertz at most. Adding Solo has little effect on that cutoff frequency. And - since it is a high-pass filter - we're really just talking about taking out really low-frequency signals - DC.

I suspect what you're hearing in terms of "clearing things up" is simply that the output tubes are being pushed more, giving a bit more of the power tube distortion and energy that we like.

Again, corrections welcome. 20+ years since I have used this knowledge on a regular basis.

Dave

 

[BobL]

See page 5 of the following Acrobat document:

http://www.schematicheaven.com/boogieamps/boogie_lonestar.pdf

For our purposes, I think this part of the schematic is similar, if not identical, for both the LSC and LSS.

Solo is a pot wired as a variable resistor (i.e. only the wiper (center) and one side are used). When Hard Bypass is off, Output is driven by the network off V3B (12AX7 tube in the effects return loop). There is a 100k resistor followed by a .68 uF cap, followed by another 220k resistor. This 220k ties to the top of the master output pot which ties to the top of the Solo pot.

If I'm reading this right (corrections welcome), then when Solo is off (normal condition), then the bottom end of the Output pot is tied to ground. If you turn Output all the way up, then the signal is effectively the output of V3B split between the 100k/.68uF/220k and the 1 meg pot. The 1 meg wins, so you get lots of signal. Turn Output all the way down, and it's at ground, so no signal to out.

When Solo is on, then, the value of the Solo variable resistor gets added onto the bottom of the output pot, thus increasing the resistance for the bottom part of the network and increasing the proportion of output signal sent to the driver stage. If you turn the Output pot all the way down, you'll still get signal unless you also turn Solo all the way down. Bump Solo up even a little bit and you should get some signal out. (I haven't tried this on my LSS but it should work that way.)

Now, this output network has a capacitor in it. While this looks like a simple high-pass filter, from doing a couple quick calcs, it looks to me like the sole purpose of that cap is to keep DC from being passed to the output stage. Once Output is turned up much, the cutoff frequency is already pretty low...a few hertz at most. Adding Solo has little effect on that cutoff frequency. And - since it is a high-pass filter - we're really just talking about taking out really low-frequency signals - DC.

I suspect what you're hearing in terms of "clearing things up" is simply that the output tubes are being pushed more, giving a bit more of the power tube distortion and energy that we like.

Again, corrections welcome. 20+ years since I have used this knowledge on a regular basis.

Dave

You are correct in your trace, the problem being that the effects loop can not be gracefully bypassed. According to the schematic my suggestion to use a jumper between the 1/4" jacks is invalid specifically because the is done internally by the jack. What tends to preserve the "tone" is the additional gain applied to VB3 when placing the effects pot above the 12 o'clock position.

 

[ja22y]

I am a little fuzzy on what the Solo "button" does on my LSC. I understand that I can set it to a louder volume setting and stomp on it to "Go to 11" but it changes the sound by more than volume. It almost "clears" the sound up some.

Sometimes I just run the amp on Solo because it sounds a little better to me for a lot of applications.

Why yes, I could be crazy... but that do you think anyway?

With an added gain circuit, it definitely changes tone and not just volume. For me initially a got a nasty ringing tone and after changing the V3 tube, it's now great. So that V3 plays a role in your tone also. With more gain, in my amp, the tone get brighter but not 'cleaner'