The VU meter and how it got that way

[Capt.Willard]

I figured since the big beautiful blue VU meters are such an iconic part of the McIntosh esthetic, you fellow mac heads might find this interesting:
https://hackaday.com/2018/08/09/the-vu-meter-and-how-it-got-that-way/

 

[Mike Gibson]

Thanks, that was very interesting to read.

 

[twiiii]

Until Mcintosh and Accuphase decided to change circuits to correct for mechanical ballistics and the way the eye perceives movement. Once Mac got the acceleration and deceleration improved they had to slow the meters down so the brain could better interpret what it was seeing. Personally I prefer the electronic columns on a MPI-4. Or watching the dual trace of my oscilloscope. When you see flattened or tilted wave forms its time to take action. Back in the day I would use the differential mode on my HP scope to compare the wave form change between the input to the amp and the output. It. was a contest to see at what point yo could here the distortion the scope was showing.

 

[sKiZo]

Point of order ...

Technically, we're talking "peak program meters", on the big macs, right? A VU meter is more of a subjective scale intended to mimic the human ear and indicate the potential for distortion. Even the db scales on these are strictly an approximation based on the actual wattage output and not a true measurement.

** I do know if you peak mine at 400 watts instantaneous, it's probably the last thing you'll ever hear. <G>

 

[Capt.Willard]

Personally I prefer the electronic columns on a MPI-4. Or watching the dual trace of my oscilloscope. When you see flattened or tilted wave forms its time to take action. Back in the day I would use the differential mode on my HP scope to compare the wave form change between the input to the amp and the output. It. was a contest to see at what point yo could here the distortion the scope was showing.

What if McIntosh started putting scopes on their amps? That would be pretty cool, actually.

 

[damacman]

Personally, I've always preferred the VU meters of the older Mc amps vs the Watt meters of the later models. I get more utility from them. I also don't like the time stretch circuits that slow the movements on the Watt meters. Some amps - MC2125 / MC2205 / MC2155 / MC2255 / MC2500 - give the user the ability to choose either, which is a major plus.