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Is It A Tube Problem?


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#1 cw0401

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Posted 01 October 2013 - 01:11 AM

Hi.

Every time I try to use external analog OD pedals with the DT, it get a high pitched whine at the same time as the pedal sound. The higher the gain the woes it gets.

Doesn't make any difference changing the cables or which pedal is used but it is worse on higher gain pedals. It is there whether going direct such as JTV59 - OD - DT25 or JTV59 - OD pedals - POD500 - L6 Link.

Changing the voicings on the DT again makes it worse the higher the gain.

Interestingly, when I just use the Dream Rig with no OD Analog pedals, there is no problem.

Could it be the tubes?

Thanks for any help.
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#2 shaker

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Posted 01 October 2013 - 03:04 AM

Could be the power supply to the OD causing it to whine, can you run it on a battery or another power supply to see if this alleviates the problem?


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#3 psarkissian

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Posted 01 October 2013 - 07:46 AM

Does it sound like a fax machine over a phone line, or a whistling kind of whine?


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#4 cw0401

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Posted 04 October 2013 - 02:18 AM

Does it sound like a fax machine over a phone line, or a whistling kind of whine?



Ummmmm.....more of a whistling whine perhaps like a TV when theres only the test pattern on or perhaps the sound of a hearing testing machine if you know what I mean.

I put my ODs on separate power cords instead of daisy chain and it was slightly better but still there on higher level gain
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#5 psarkissian

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Posted 04 October 2013 - 07:48 AM

Could be a slight ring,... do you use a high level of Reverb? Noise floor and a lot of Reverb, at high amplitude can do this.

 

Could be a tube going microphonic at high gains. The tubes in the DT Series of amps are chosen to be "low microphonic",

so that this won't happen. But maybe one is on the edge.

 

 


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#6 cw0401

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Posted 05 October 2013 - 01:16 AM

Could be a slight ring,... do you use a high level of Reverb? Noise floor and a lot of Reverb, at high amplitude can do this.

 

Could be a tube going microphonic at high gains. The tubes in the DT Series of amps are chosen to be "low microphonic",

so that this won't happen. But maybe one is on the edge.

No I wouldn't say I use a lot of reverb.  I like having some but not a great deal from the POD HD500.   With reverb in the amp, I just use the settings that are listed on the bit of cardboard on the top that comes with it.   Mainly use the British Crunch or Class A Chime.

 

I do have replacement tubes but I might try to test the old ones first before bunging them in.

 

Thanks for the advice


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#7 psarkissian

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Posted 07 October 2013 - 08:34 AM

Be sure that these tubes are Line 6 authorized Electro-Harmonix power tubes (and the pre-amp tubes as well),

and that the power tubes are matched pairs.

 

Have a Line 6 authorized service center install them, they will have to be properly biased and the unit signal tested.

There is a proper biased and signal test that always has to be done on a tube amp, it's not a swap-n-play sort of thing.

Incorrect bias leads to distortions, distortions lead to stressed tubes, stressed tubes lead to a failing amp and a trip

to a service tech.

 

The Electro-Harmonix power tubes are scrutinized more so for Line 6, than what you would get from a store.

 

These are Bogner designed tube amp stages and not very forgiving with anything other than the specified tube brand,

so don't try to hot rod these hot rods with Mesa or Groove Tube versions.

 

The characteristic curves of the Mesa or Groove Tube versions are different enough to make a difference in performance

and can stress the amp. After which, at that point, it might end up on my bench, or one of my lab mate's benches,... and we

don't want that, we want it to run well for you.

 

Depending on how much you play, a tube swap (the amp equivalent of a car tune-up and oil change) should be done

every 12 to 18 months if you're a gigging musician,... every 24-months if you play less.

 

Take good care of the amp and it will take care of you. Always take it to Line 6 authorized service center for checking out

and servicing.

 

In the meantime, lock-n-load the rock-n-roll!


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#8 stumblinman

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Posted 07 October 2013 - 08:57 AM

Be sure that these tubes are Line 6 authorized Electro-Harmonix power tubes (and the pre-amp tubes as well),
and that the power tubes are matched pairs.

Have a Line 6 authorized service center install them, they will have to be properly biased and the unit signal tested.
There is a proper biased and signal test that always has to be done on a tube amp, it's not a swap-n-play sort of thing.
Incorrect bias leads to distortions, distortions lead to stressed tubes, stressed tubes lead to a failing amp and a trip
to a service tech.

The Electro-Harmonix power tubes are scrutinized more so for Line 6, than what you would get from a store.

These are Bogner designed tube amp stages and not very forgiving with anything other than the specified tube brand,
so don't try to hot rod these hot rods with Mesa or Groove Tube versions.

The characteristic curves of the Mesa or Groove Tube versions are different enough to make a difference in performance
and can stress the amp. After which, at that point, it might end up on my bench, or one of my lab mate's benches,... and we
don't want that, we want it to run well for you.

Depending on how much you play, a tube swap (the amp equivalent of a car tune-up and oil change) should be done
every 12 to 18 months if you're a gigging musician,... every 24-months if you play less.

Take good care of the amp and it will take care of you. Always take it to Line 6 authorized service center for checking out
and servicing.

In the meantime, lock-n-load the rock-n-roll!


Holy crap, an actual Line 6 employee?
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#9 psarkissian

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Posted 07 October 2013 - 12:51 PM

Shhh,... don't let get around.

 

And I'm a forum moderator. Trolling the forums is okay with my bosses,

so long as it doesn't take too much time away from me fixing stuff. A two

cents here, a two cents there,...

 

... oh, and being a moderator, maybe c#%*p would be a more netiquette way of saying it,

though it's probably okay here for now. I typically use "holy moly" or "mola mola". ;)

 

Rock on!


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#10 geppert

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Posted 07 October 2013 - 01:25 PM

Shhh,... don't let get around.

 

 

You participation here is greatly appreciated.

 

Now .... I want to do some mods on my DT25 (tech humour) ...


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#11 psarkissian

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Posted 07 October 2013 - 01:31 PM

I grok.   :)


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#12 geppert

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Posted 07 October 2013 - 01:43 PM

I grok.   :)

 

Ah good ... we grok each other ... this is a good beginning ....


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#13 stumblinman

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Posted 08 October 2013 - 07:13 AM

Shhh,... don't let get around.

And I'm a forum moderator. Trolling the forums is okay with my bosses,
so long as it doesn't take too much time away from me fixing stuff. A two
cents here, a two cents there,...

... oh, and being a moderator, maybe c#%*p would be a more netiquette way of saying it,
though it's probably okay here for now. It typically use "holy moly" or "mola mola". ;)

Rock on!


I figured crap was ok since it didn't get changed to lollipop.
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#14 toneman2121

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Posted 08 October 2013 - 04:16 PM

Be sure that these tubes are Line 6 authorized Electro-Harmonix power tubes (and the pre-amp tubes as well),

 

why?


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I'M SO HAPPY!


#15 stumblinman

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Posted 09 October 2013 - 08:04 AM

Be sure that these tubes are Line 6 authorized Electro-Harmonix power tubes (and the pre-amp tubes as well),

why?


Because L6 must get a cut of them or something. EH tubes are about my last resort.
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#16 psarkissian

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Posted 09 October 2013 - 08:49 AM

No extra cut that I'm aware of.

 

The Electro-Harmonix (EH) power tubes get extra scrutiny for Line 6, than what you would get from a store,

as far as I'm aware. Had a chat with Mike Matthews (the founder/owner of EH) about their tubes at NAMM

earlier this year.

 

EH bought a tube factory in Russia, it's theirs, they scrutinize the tubes really well. From others there can

be inconsistent batches of tubes.

 

Some of these inconsistencies go to the characteristic curves on the data spec sheets. These differences

can have an effect on performance or lifespan of the tube, as does correct biasing of the tube. And it's

even more crucial when it comes to Matched Pairs.

 

I know people like to use tubes versions from other tube companies in Line 6 amps. Not a good idea. I see

too many come back for problems, with these other tubes inside.

 

These other tubes are fine,... just don't put them in Line 6 tube amps. Bogner designed the tube stages of

our amps to use what we use, biased to what they're biased to,.... and these amps are not forgiving of

alterations, deviations or modifications.

 

It's like trying to over hot rod a hot rod, give it too much and you throw a rod or blow an engine,... and that's

never a pretty sight.

 

We recommend coming to us for tubes for Line 6, Bogner designed Spider Valve, Alchemist and DT Series

tube amps because, we can't vouch for other tube sources. Besides,... we have a 90 day warranty on our

tubes when you go to an authorized service center for amp servicing our tube amps.

 

 

Enjoy the tube sound. Rock-On!


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#17 daddydoodles

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Posted 14 October 2013 - 10:12 AM

I too have a HD500 running into a DT25. Intermittantly, there will suddenly be NO sound except a low volume high pitched squeal. The only way to resolve it to shut the amp off and turn it back on (presumably rebooting the amp). This is unacceptable since I might be playing along live and suddenly have no sound. Advice? Suggestions? I have only had the amp about 4 months. I have retubed it thinking that it might fix the problem. It does it even with the new tubes.


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#18 psarkissian

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Posted 15 October 2013 - 07:16 AM

Microphonics in the tubes,... but since you've swapped them out, that's not the case.

 

Digital clock bleeding into the audio from either the HD500 or the DT25 digital board.

 

Are you using the Line6 Link?

If so, are you using "Link 6 Link Cable" or a standard XLR mic cable?

 

 


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