Xenon 100.4 bias pots

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Killerwatt
Posts: 12
Joined: Tue Aug 21, 2012 1:24 am

Xenon 100.4 bias pots

Post by Killerwatt »

Hey guys.

I have 2 100.4's running my system, used to run the sub and midbass off one amp and the tweeters and midrange off the other.
But recently i swaped the sub and midrange connections so that the midbass and midrange are on the same amp.

I noticed that this amp sounds a bit scratchy on strong transients. I checked all my wiring and settings and all seems well.
What i did notice is that all the 4 yellow/blue pots on this amp are set to the minimum value. The other amp has the pots turned approx half way.

Are these pots used to set the DC offset on the xenons? It looks that way but just wanted to confirm.
How do i check the DC offset?
I'm thinking to let the amp warm up for a while, set gain to minimum, remove the rca connections and then measure voltage accross the speaker terminals?
Is this the right way to do it?

Would i then just adjust the pots untill the dc offset is at its lowest value?
ttocs
the Floor Sweeping Hack with Golden Ears
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Re: Xenon 100.4 bias pots

Post by ttocs »

offset pots probablably are not causing scratchy sounds and are not something that the average DIY'er can/should mess with as there is a lot more of a chance of doing harm then good.

is the sound limited to a specific pair of speakers on a specific set of freqs?
what else can I say I am a grumpy asshole most of the time.
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stipud
Voltage Ohms
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Re: Xenon 100.4 bias pots

Post by stipud »

http://www.phoenixphorum.com/viewtopic.php?f=6&t=3428

Measure it first. Odds are you probably shouldn't mess with those pots, unless you bumped them by accident.
Killerwatt
Posts: 12
Joined: Tue Aug 21, 2012 1:24 am

Re: Xenon 100.4 bias pots

Post by Killerwatt »

Thanks guys. Got a chance to measure the amp today, all 4channels come out between 11 and 12.5mv. Not too bad at all. I just found it odd that all he pots were set to the minimum value.

I noticed the sound on my midranges but seems like my midbasses are doing it as well. Just not as much. I'm thinking it might just be that rca cable or headunit. Will do some fault finding later on. Just happy to know the dc offset is fine.
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