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Loss Of Distortion


StuGT8
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Hi everyone,  i am in desperate need of a quick `fix` here as i have several gigs coming up, i will explain best i can as to the problem and hope someone can help as Line 6 themselves cant!

 

This has happened 3 times now in the last 3-4 months : ( usually at the worst possible times) I have the SV 212 Mk2 40w Combo and use the FBV shortboard Mk2 .

 

 I have ABCD patches set up as Clean/Crunch/Distortion/Lead ,(i have several banks setup in a similar way with different sounds and it affects them all),  the problem is sometimes the Distortion channel loses its sound, not totally, just the distortion, i am left with basically a `bare` sound ( slightly crunch) and i think there is a loss in volume too,  the  distortion sound just disappears, and the other channels suffer too although the clean channel not so much ( but does lose clarity) ........ hard to say how i manage to get it back, as i shut alll down, unplug everything, restart, the usual routine when theres a problem,.....this dosent `fix` the issue though as it can takes several attempts and sometimes not at all. Strangely if its left alone for a while and i fire it up it seems to be ok. The issue isn`t always there as i have done several 2 hr gigs since the problem started without issue and other times it has happened before ive even really started to play anything.

 

I have a new CAT cable so thats not the problem.

 

The problem seems to appear even at lowish volumes

 

I have seen another user in the forums whos problem was like mine, ( who i have tried to contact), and there was a reply that it may be the valves ( valve!?) Could this be the case?

 

Its very erratic therefore i am reluctant to send to Line 6 as it could spend weeks on a test bench without the problem arrising

 

Any suggestions would be greatly appreciated, thank you.

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Hi toneman, the problem arrises wether the foot controller is used or not,........ i was testing that last night straight into amp and again the distortion just `cut` :(

 I am reading many things as to what the source of the issue may ( or not ) be and again returning to the valves i have noticed there is some slight `blueing` at the top of my 12AX7`s? ( i am new to valves,..the two in the cage at the back), apparently this could indicate the valves are suspect? is that correct? ( both have the same bluey hue........again,,its not much but its there).

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i've read good and bad. i couldn't decide one way or the other. if you change tubes change them all. that way you eliminate tubes being the culprit. if the problem persists you have a spare set. also read up on various factors concerning the same type tube. the page i have talks about 12ax7 and the like. other tubes are also discussed. check around the site.

 

http://www.thetubestore.com/Resources/Guitar-Amp-Info/Gain-Factor   :o

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Thnx ,... i will look into changing the tubes, all of them, having browsed over the site you linked and several forums/websites i will need to study further as their is some terminology i am not familiar with,.....balanced, phase inverter, bias setup, i understand this amp is lethal so need to be sure im doing it correct,...... just out of interest, for the SV 212 without being `too` exspensive do you have any suggestions as to what different types of valves are better, i find the stock valves somewhat harsh. Appreciate your replys, thnx.

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Hi napynap,. i doubt it is the guitar as i have have several amps i use for home use and spend longer playing through them per week than i do with the SV 212, without any issue at all,.........BUT! yes,, as and when the problem reoccurs with the the SV ( which as stated is erratic) i will plug a different guitar in and check,.....thanks for your reply,......  i have spoken to someone who knows his stuff with regrads to valves and i am having them all checked out just to eliminate that, ( think i got the valves mixed up on previous post,, its the 6L6`s which have a slight blue hue at the top,, which i am told is normal), i have reloaded firmware V2.00 too, but had same problem so it aint that,..next on my hit list is a factory reset, as stated i need to sort this quick as i just cannot trust the amp to deliver at gigs and have several creeping up on me.......eeek!

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OK,...it seems i have found the problem,.......i need to crank the amp up tomorrow to be 100% sure but at the time of writing this i am 99%!! 

 

  If the amp model dial is physically turned to clean and left there while using channel presets there seems to be a clash, even though the LED`s display the correct position when switching patches, Crunch, Metal etc etc,, i am sure the amp presumes it should be a`clean` sound regardless, thus causing the selected patch to lose its preset sound after just a few seconds...........physically turning the amp model dial to say 12 o`clock maintains any sound selected on any of the presets....hurrah!

 

  maybe this is common knowledge i dunno but i am happy now again :))

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  • 2 months later...

OK,...it seems i have found the problem,.......i need to crank the amp up tomorrow to be 100% sure but at the time of writing this i am 99%!! 

 

  If the amp model dial is physically turned to clean and left there while using channel presets there seems to be a clash, even though the LED`s display the correct position when switching patches, Crunch, Metal etc etc,, i am sure the amp presumes it should be a`clean` sound regardless, thus causing the selected patch to lose its preset sound after just a few seconds...........physically turning the amp model dial to say 12 o`clock maintains any sound selected on any of the presets....hurrah!

 

  maybe this is common knowledge i dunno but i am happy now again :))

 

It's the firmware upgrade that's causing your problems, I had to return 4 spiders valves all which I had made the mistake upgrading to V2.0 which ruin the distortion character modes.

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  • 4 weeks later...

OK,...it seems i have found the problem,.......i need to crank the amp up tomorrow to be 100% sure but at the time of writing this i am 99%!! 

 

  If the amp model dial is physically turned to clean and left there while using channel presets there seems to be a clash, even though the LED`s display the correct position when switching patches, Crunch, Metal etc etc,, i am sure the amp presumes it should be a`clean` sound regardless, thus causing the selected patch to lose its preset sound after just a few seconds...........physically turning the amp model dial to say 12 o`clock maintains any sound selected on any of the presets....hurrah!

 

  maybe this is common knowledge i dunno but i am happy now again :))

 

I just posted about my issue here http://line6.com/support/topic/3514-spider-valve-mkii-randomly-going-to-manual-mode-and-other-odd-issues/ which after reading your posts seems like it could be related. I am going to try what you said. Thanks for updating the post with the fix you found! 

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Hi,  i read your post with great interest because i have the same type of problem.  I have used the following amps all with the same problem:  Vox AC15, Marshall JVM, Mesa Boogie Express, Laney Vc15, Marshall AVT 50 watt amp,  Same problem -- after two or three hours the distortion just disappears.  Does not matter what guitar, what pedals, etc.  In frustration I took my Mesa Boogie to a really superb tech who tested it, turned it on with a load for 5 hours, etc.  He said that the tubes did not malfunction and there is no other internal problem in the amp.  Don't need to change tubes, they are ok.  So what in the hell happens???   I think it is simply that the tubes overheat and get "tired" and somehow lose their punch.  If the amps are turned off and allowed to cool down completely then they are fine,   The problem appears when you run the amp for a couple hours with high distortion/overdrive.  Maybe the answer is to take the Mesa and the Marshall to the same gig and alternate between them changing amps after every set?  Anybody got any other ideas?

 

This is such a common problem it is strange there is not more info out there about it.

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