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POD HD 400 volume level fluctuation while playing.
by indigobjn on 2012-06-14 19:42:56.9330

Hi all,

I have been using my HD400 for 8 months with all the latest updates loaded. After those months I have experienced a problem with the volume level fluctuation for the first time. The problem is while I'm playing, HD400 unit's screen enters to amp-parameters (Gain, Bass, Mid, Treble, Volume) screen and the volume level switches to the current position of the volume knob on HD400 unit from the volume level saved on that particular patch i'm playing. Actually, the HD400 enters and exits to amp-parameter screen and volume level switches between current volume knob position and saved volume level on that patch. This problem occured yesterday but it seems to work just fine now after I power OFF/ON the unit. I was very afraid when this occured. Will this problem repeat again? What do you think caused this problem?

Thank You,


Re: POD HD 400 volume level fluctuation while playing.
by indigobjn on 2012-06-16 03:11:20.8080

Still waiting for the response....

Re: POD HD 400 volume level fluctuation while playing.
by spaceatl on 2012-06-16 08:32:50.3450

It's not surprising to me...This is called jitter...Use any Line 6 modeler long enough and likely you will come upon it...The causes are many and it is inherent with what is going on...

Basically, the analog pots are diced up into digital values...say 0 to 100...each it a specific voltage...When you move the pot, that setting is sent to the modeler, when you recall a patch, the knob might be in a different spot than how you saved it...A little vibration, slight variance in input voltage and the voltage varies enough that the pot sends its position...

This is something as a longtime Line 6 combo amplifier user that I have had to deal with...Much more rare that it happens to a POD, but it has happened to me...More on that in a minute...Anyway, the vibration in the combo amps causes this more readily...What a lot of us have found is that during a performance, park all the knobs to zero or max...I have never had jitter happen to me and it is basically a habit for me now most of the time...

with the POD I tend to leave the knobs...but I have had my HD400 jitter on a stage that had a lot of vibration...Even saw a voltage drop from a kick drum hit severe enough to make the HD400 reset...That was an intentional test I did during a sound check...I always using an AVR on my power supply, so I don't have to worry about that too much...

If this gets to where it isn't usable, it might be that you have a dirty pot or a pot that needs replacing...Hard to say...This is one of those things that can happen just because it is in the nature of the design...keep an eye on it...One thing you can do is hook up to Edit and that can help narrow down the culprit...

Re: POD HD 400 volume level fluctuation while playing.
by Crusty_Old_Rocker on 2012-06-16 15:44:42.6770

Sometimes a little condensation can make its way into the pots and mess with the contacts.  As Space mentioned, the digital values that result from the pot position can "jitter" as a result.

Try this, rotate all your pots fully a dozen times, do this every now and then to keep them clear of any muck that might be getting in there.  You will also notice that there is like a null area on each pot near zero and 100 percent.  Once you have your settings assigned to your patches and don't need to make any adjustments while playing, you can "park" the knobs in that null area where they won't deliver a value change due to vibration.

Give that a go and let us know how you get on.  As Space said, if a pot is damaged it will need to be replaced.  However, quite often just giving the pots a workout and parking them in the null zone usually stops the jitters.



Re: POD HD 400 volume level fluctuation while playing.
by indigobjn on 2012-06-16 23:47:33.6620

Hi spaceatl,

Thank You for your reply. I agree with you. The input voltage fluctuation might be the cause. As I'm from Nepal, we face like 18 hours Loadshedding a day during dry seasons and power fluctuation is there. I have not tried turning all the knobs to null position while playing. I will try this and reply.

Thank You,


Re: POD HD 400 volume level fluctuation while playing.
by indigobjn on 2012-06-16 23:52:37.9950

Hi Crusty,

I haven't tried rotating pots to clear dirt from it. I usually create patches using HD400 Edit and I use those pots only if i need more volume or change other amp-parameters. I like the idea of yours to set the knobs to null position near 0 and 100%. MY POD seems okay now but will set the knobs to null position while playing now onwards.

Thank You guys. You guys are awesome.


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