Roadster lag fix

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Purist
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Re: Roadster lag fix

Post by Purist » Thu Aug 12, 2010 10:43 am

I always have my reverb switched on, and didn't realize it was off the other night at band practice. We were playing LOUD.. all of a sudden I had these 2-4 second lags of pure silence in between channel switches. I just about lost my mind thinking I had pushed my MESA roadster too hard.

I hope this really fixes the problem, cause I've got a gig this weekend. Haven't tested it out yet. :?
Mesa Dual Rec Roadster
Mesa 4x12 cab
LTD Eclipse EC-1000
Jackson Kelly KE-3 Pro
Crybaby, Boss Chorus Ensemble, Boss Noise Gate, Digitech Delay.

bumble bee
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Re: Roadster lag fix

Post by bumble bee » Sun Oct 24, 2010 12:18 pm

I've got the same problem on a Rect-o-verb...The reverb switching always have a 2 second delay...it's lake a fade in effect.

Do you know if its normal on this particular model?

starrsound
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Re: Roadster lag fix

Post by starrsound » Sat May 28, 2011 1:55 am

If anyone can help me confirm or deny what I'm about to tell you I would be grateful. So would a lot of other owners, I suspect.

My Roadster lags badly when it's hot. I played what amounted to an outdoor gig in Texas last weekend & got 3-5 second lag after the first set.
So I bought a heat gun.

If I point the heat gun at the mute circuit bits I can get the collector voltage of the driving transistor (6426P) to drop from 11-12V down to 1V even while the base of the transistor is pulled down with the 10K resistor. Somewhere around 4-5V the muting will kick in. I pulled all the pieces around the transistor & tested them for heat stability. They are all good so I'm left with the transistor.

What I think is happening is that as the transistor gets hot it pulls more collector current & gets the collector voltage dangerously close to the 5V threshold. Once the mute is triggered & then released back to "cutoff" there is not enough voltage available on the collector to release the jfets until one or more of the caps in the muting circuit charge back up. Interestingly, there is a 2uf2 cap charging through a 2M2 resistor that should take about 4.8 seconds to charge. This corresponds nicely with how long my mute lag lasts.

Is there a better transistor to use? (I am not an EE...)

I'm going to find a heatsink to fit onto the transistor & see if that will be enough to stabilize it. Failing that, I'm going to devise some kind of venting. Maybe a grill in the bottom of the case or something.


Anyway, if anyone wants to help me out in establishing the root cause that would be great.
thanks.
Dave

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c.t.d-nicke
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Re: Roadster lag fix

Post by c.t.d-nicke » Sat May 28, 2011 7:46 am

starrsound wrote:If anyone can help me confirm or deny what I'm about to tell you I would be grateful. So would a lot of other owners, I suspect.

My Roadster lags badly when it's hot. I played what amounted to an outdoor gig in Texas last weekend & got 3-5 second lag after the first set.
So I bought a heat gun.

If I point the heat gun at the mute circuit bits I can get the collector voltage of the driving transistor (6426P) to drop from 11-12V down to 1V even while the base of the transistor is pulled down with the 10K resistor. Somewhere around 4-5V the muting will kick in. I pulled all the pieces around the transistor & tested them for heat stability. They are all good so I'm left with the transistor.

What I think is happening is that as the transistor gets hot it pulls more collector current & gets the collector voltage dangerously close to the 5V threshold. Once the mute is triggered & then released back to "cutoff" there is not enough voltage available on the collector to release the jfets until one or more of the caps in the muting circuit charge back up. Interestingly, there is a 2uf2 cap charging through a 2M2 resistor that should take about 4.8 seconds to charge. This corresponds nicely with how long my mute lag lasts.

Is there a better transistor to use? (I am not an EE...)

I'm going to find a heatsink to fit onto the transistor & see if that will be enough to stabilize it. Failing that, I'm going to devise some kind of venting. Maybe a grill in the bottom of the case or something.


Anyway, if anyone wants to help me out in establishing the root cause that would be great.
thanks.
Dave
Hi Dave

Read this:
http://forum.grailtone.com/viewtopic.ph ... 4&start=45
scroll down to my update post. I think you're on to something!

Plus I have the reverb on all the time so the lag is totally gone!

nicke
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Purist
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Re: Roadster lag fix

Post by Purist » Sat May 28, 2011 9:40 am

This is good to know for sure. I've still been struggling with "is my amp going to die" stress during gigs and practices since last summer! Guess I need to take it into my local MESA tech and tell him the specifics I've read here and on the other topic here: http://forum.grailtone.com/viewtopic.ph ... 4&start=45

Thanks c.t.d-nicke and starrsound!
Mesa Dual Rec Roadster
Mesa 4x12 cab
LTD Eclipse EC-1000
Jackson Kelly KE-3 Pro
Crybaby, Boss Chorus Ensemble, Boss Noise Gate, Digitech Delay.

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Bisconne
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Re: Roadster lag fix

Post by Bisconne » Sat Sep 24, 2011 3:27 am

Hello!
New Roadster user here.
So far very happy. Was gonna buy Mark IV but turned out I was not a Mark guy…

Well, I must say that despite having reverb on I still experience lag while switching between channels and also an audible tone change (drop/suck) when switching loop on.
Does anyone have any idea what might be the problem?

Thanx.
DC-10 (head)
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khingpynn
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Re: Roadster lag fix

Post by khingpynn » Thu Nov 10, 2011 11:58 pm

New Road King owner here. and yes I had lag issues until idialed in the reverb on each channel and left it on!
Interesting...
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brianr0131
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Re: Roadster lag fix

Post by brianr0131 » Sun May 20, 2012 3:01 pm

Thanks for the great tip

themightyjay
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Re: Roadster lag fix

Post by themightyjay » Mon Sep 17, 2012 6:47 am

I'm experiencing a lag with switching as well. Unfortunately I don't have the footswitch and use a G-System to change channels.

Is there any way of keeping the reverb switched in or minimising the lag with this set up?
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ikhor
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Re: Roadster lag fix

Post by ikhor » Mon Oct 14, 2013 2:24 am

I Have a Roadster combo, sometimes got the lag sometimes dont, I will check this workaround.

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screamingdaisy
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Re: Roadster lag fix

Post by screamingdaisy » Mon Oct 14, 2013 11:52 am

themightyjay wrote:I'm experiencing a lag with switching as well. Unfortunately I don't have the footswitch and use a G-System to change channels.

Is there any way of keeping the reverb switched in or minimising the lag with this set up?
Kind of a late reply... But...

When the foot switch is disconnected the reverb is always on by default.

The lag when using the G-System is most likely from the relays in the G-System. I found that within the G-System some relays were faster than others and experimented using different ones until I achieved the fastest switching.
Ignore the hype and trust your ears. Play more, buy less = better tone.

bandit2013
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Re: Roadster lag fix

Post by bandit2013 » Sat Aug 02, 2014 7:25 pm

I have had my Roadster for a little over a month now. I was uncertain why such the big deal on 15 to 30 ms. I was unaware that most of you hare seeing 1 to 5 seconds of delay. That is not good. I have tried to run the amp with the Reverb off, I get only approximately 30ms of switching lag. With the Reverb on, it is much less but the ramp up on the reverb is more annoying. I will have to take watch and see what becomes of this for a longer duration of use. So far I do not have any switching issues like those reported.

barryswanson
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Re: Roadster lag fix

Post by barryswanson » Tue Jul 12, 2016 5:20 am

Has Mesa fixed this? They quickly corrected the JP-2C with its channel/loop issue.

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tzoranski
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Re: Roadster lag fix

Post by tzoranski » Fri Mar 10, 2017 6:11 pm

So I have a few questions about the pops that people say can be fix by cycling through the channels in stand by mode. I using my roadster with the G System in the 4 cable method with a RJM mini amp gizmo and the Mesa RRN cable. I tried turning my amp on, leaving it in stand by and cycling through the channels using the mini amp gizmo but I still get pops. When I turn on my amp it's in channel one and I cycle through the channels until I'm back at one then I take it out of stand by. Is that what i'm supposed to do? I don't see any difference.

I also notice a bigger pop when going from CH 2,3 or 4 to CH 1. In order to have CH 1 loud enough without it breaking up I'm engaging the solo on that channel. Giving it some additional volume to compete with the other channels. The popping sound is driving me crazy and I can't figure out how to get rid of it. Any input would be greatly appreciated.

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