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AUDIO FORUMS >> General Discussion and Support >> Dancing Meter Needles
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Message started by GroovySauce on 05/01/21 at 23:27:07

Title: Dancing Meter Needles
Post by GroovySauce on 05/01/21 at 23:27:07

What does it mean when the needles on the meters start dancing when you turn up the amp?

On the ZMA I’m burning in some drivers and really turning it up. The needles start to dance at about the same time I can see the drivers moving a lot.

When the needles start dancing is this shortening the life of the tubes? is it stressing the amp in a way that will harm it? Is it okay to have a little bump on the needles? what about a big swing?

For context:

I’m currently burning in my new PAP quintet 15 drivers and XO, baffles should be here this coming week!

I have them setup so I can listen to music as they are playing, sounds off, yet better than I expected. I have about 100 hours on them right now.

I’ve experienced that after a speaker has hundreds of hours on them “having a party” can significantly improve the sound.

Many years ago I had Watt Puppy 8’s driven by VTL MB-450’s I had had them for many months maybe a year. I had a party and it was cranking, dance club levels! I blew 2 tubes and the police were called…. it was loud!

Side note, from a teenager I’ve worn and carried earplugs and yes I was wearing ear plugs that night.

A few days later after I was fully recovered from my hangover I had a listening session. It was very memorable! I couldn’t believe how good my system sounded! Having 16 6550’s total and they weren’t matched I don’t think the 2 new tubes made the significant difference. It was the driver mechanical bits that got a good workout.

Ever since, after I have some time on a pair of speakers I play them loud for a few hours. I’ve consistently found improvements doing this.

Today I popped in my ear plugs and turned up the ZMA and the needles started to bump with the music. turned it up a little more and they started to really dance with the music, turned it up even more and they started to go crazy flopping around not related to the music.

Is it okay to let the needles “dance” a little? or should I find a 200w+ amp to borrow for a day?

Title: Re: Dancing Meter Needles
Post by Archie on 05/01/21 at 23:43:05

I think Steve addresses this in either the ZMA or Mono product description. Anyway, he once said that when the meters start to move, you are pushing to the top of the specs and when they really move, you are starting to clip.

I never mind a little bouncing around but I avoid the big swings.

Oh, and I think if just one needle is moving it can indicate a weak power tube.

Title: Re: Dancing Meter Needles
Post by GroovySauce on 05/02/21 at 00:12:45

Is there any downside to running the amp for a few hours with the needles happily dancing? If it's hard on the tubes I can live with that. I'm not talking the airdancer movement you see in front of a used car lot.

Title: Re: Dancing Meter Needles
Post by Archie on 05/02/21 at 00:28:57

I'm not sure but do you have a quad of tubes that you don't care about that you could use?

Title: Re: Dancing Meter Needles
Post by GroovySauce on 05/02/21 at 01:48:13

I have a new quad of KT66's on the way so I'm not worried about stressing the tubes. I'll turn my room into a disco tomorrow 8-)

I do wonder if it's stressing the input tubes though.

Title: Re: Dancing Meter Needles
Post by Archie on 05/02/21 at 03:24:27

My guess is that it does. I was biasing some tubes on the high side and I think that shortened their life. So "pulsing" would seem to do a similar thing since the voltage keeps spiking.

Title: Re: Dancing Meter Needles
Post by GroovySauce on 05/03/21 at 01:00:07

I let it rip for 45 minutes or so... Now the channel balance is off... I guess one or more of the tubes had enough and is getting tired!

2-3db to the left and it's all balanced again.

Title: Re: Dancing Meter Needles
Post by GroovySauce on 05/04/21 at 03:07:31

My Brother brought over his UFO25TH for the night. When it starts to clip you see the OA3's start to blink. 92db peaks at 8feet on PAP quintet 15's at 8 feet.

I normally listen below 80dB peaks usually 70-75dB peaks. Some times a song just call for rocking out volume.

Here is what the UFO25th looks like when it starts to clip.

https://vimeo.com/544827627