PL400 Meter Sensitivity

[gmonstah]

Hi all,

New to site, and not sure if this is in the right place, but...

Have just resurrected a 400 from a case of bad PS cap. Now on to testing.

When she outputs about 100 watts the meters are pegged. 50 watts indicates 100 on the meters. Yes, they are zeroed at rest.

Maybe not a big deal, I can disconnect the meters rather than risk damage, but i would like to know if this is normal? Or adjustable?

Thanks

 

[laatsch55]

Pegged at 50 watts is NOT normal. Good idea to unhook them. Look up White Oaks new LED light board. It also drives the meters. Check to store link and peruse light boards for 400s.

 

[gmonstah]

Thanks for the reply.

They peg at 100, but read at twice the actual value.

I can't believe that a board with, iirc, two resistors and two diodes, none of which check as shorted, needs to be replaced. There has got to be a better way.

 

[laatsch55]

When you find it, let us know....

 

[Gepetto]

Thanks for the reply.

They peg at 100, but read at twice the actual value.

I can't believe that a board with, iirc, two resistors and two diodes, none of which check as shorted, needs to be replaced. There has got to be a better way.

OK what is the value of the 2 resistors that check out OK?

 

[oblivion321]

Yup. Mine has a lazy eye, but I find her sexy anyway.

 

[gmonstah]

OK what is the value of the 2 resistors that check out OK?

both resisters are between 12.6 and 12.9k.

 

[Gepetto]

both resisters are between 12.6 and 12.9k.

That is the correct resistor value you are measuring. The nominal is 13k

 

[gmonstah]

That is the correct resistor value you are measuring. The nominal is 13k

So OK. I'm back to my original question.

Is indicating twice the actual power value normal behavior for the 400?

 

[laatsch55]

Look for a thread called " Some PL 400 Meter Data" in the WOPL archives...

 

[NavLinear]

What are you using for a load? Here's some info about the meters. BTW - welcome to Phoenix.

 

[Gepetto]

So OK. I'm back to my original question.

Is indicating twice the actual power value normal behavior for the 400?

Doubt that they are. The meters are calibrated with the 13K resistor to indicate 0dB VU at 50W RMS. Every 400 was built that way

 

[gmonstah]

to indicate 0dB VU at 50W RMS.


Now that I look closely at the meter, and read the manual, I see that the lower set of numbers do not mean watts. If 0db is 50 watts, not 100...

DUH
Sorry to waste everyone's time
Dumb*ss
If in doubt, read the manual
NEVER MIND

 

[laatsch55]

We have an acronym for that around here ....RTFM..... yeah, those meters are just an approximation only, eye candy....

 

[BlueCrab]

So, essentially for a PL400, it's okay to peg the shit out of the meter when you're playing music over 100W?

 

[Northwinds]

So, essentially for a PL400, it's okay to peg the shit out of the meter when you're playing music over 100W?

I have a rather well known vid of the meters laying flat on one of my 400s, no distortion at all

 

[BlueCrab]

Meters were not happy with you. At what point do they give up the ghost?

 

[Northwinds]

Meters were not happy with you. At what point do they give up the ghost?

The meters loved it and so did everyone else that has seen that vid. The meters never failed ever, the amp belongs to a nice ladyfriend up in Maine now, she has had it for a few years

 

[laatsch55]

Jim,I've pegged 400 meters myself, doesnt seem to hurt em..

 

[BlueCrab]

I thought of putting some 30v zeners across them, but if you guys say it’s alright then it must be alright. I trust you guys... well sometimes.