Power meter question

[Cal Blacksmith]

The Mac that Mdeen has for sale prompted a question for me. I sure do love the looks of those meters, are/is there any add on meters on the market? Is the circuit hard to build and could a person make one if they wanted to? What do they REALLY measure? ......Voltage?

[pauln]

If they are power meters they should measure watts at some ohm load like 8 ohms. They may have an accompanying dB scale, too. Some built in meters, like in the Yamaha 2010 are super fast rise with a slow decay to measure the instantaneous peaks. In the Yamaha these same meters have a voltage scale that can be switched to measure the record-out level.

The famous RS SPL meter uses the old standard time integration value used from the days of voice radio - it measures about 13dB too low for true peak levels even when set to the 'fast' setting (per PWK).

I also would like to find some good outboard meters that could be placed between the amps and speakers just to see what is going on rather than using the RS SPL meter to infer same by reverse calculations.

[tigerwoodKhorns]

If they are power meters they should measure watts at some ohm load like 8 ohms. They may have an accompanying dB scale, too. Some built in meters, like in the Yamaha 2010 are super fast rise with a slow decay to measure the instantaneous peaks. In the Yamaha these same meters have a voltage scale that can be switched to measure the record-out level.

The famous RS SPL meter uses the old standard time integration value used from the days of voice radio - it measures about 13dB too low for true peak levels even when set to the 'fast' setting (per PWK).

I also would like to find some good outboard meters that could be placed between the amps and speakers just to see what is going on rather than using the RS SPL meter to infer same by reverse calculations.

Nice Yamaha. I just bought a C1020 to go with a mint pair of JBL L100's for my office. The guy that I bought the JBL's from had a Yamaha 1020 and I was not sure that I wanted it. It sold (local unit too) so I picked one up off of ebay because I decided that I really did want it. One just went for $300+ tonight. The old Yamaha's are beautiful and should look cool with the JBL's retro white woofers.

Chris

[pauln]

http://cgi.ebay.com/Classic-vintage-Yamaha-CA-2010-Power-Amplifier-Exellent_W0QQitemZ200018308222QQihZ010QQcategoryZ71550QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I don't have one yet, this one sold for under $200...

[Frzninvt]

Technics and Radio Shack made outboard power level indicators. However, I can tell you from experience of owning a number of amps with Analog and Digital power meters it is almost pointless with Klipsch speakers due to their efficiency.

I would hardly get any meter deflection at all unless I changed the sensitivity of the meter to like 0.01.

[Cal Blacksmith]

Perhaps I should just hook up my dual trace Oscope?[] []

It sure is fun to watch but is rather large being an old TekTronics TUBE scope[]

[Frzninvt]

I have seen something similar done and it was the coolest thing I have ever seen.

An electronics technician I knew took a regular television and somehow converted it to display incoming musical signals. When idling there was just a single line (flat) across the screen but once the music kicked in it would display all sorts of patterns in the form of jagged lines and such, the louder it got the further they would branch out. It was the wildest and most ingenious thing I have ever seen.

I would love to have something like that, you could find like a small 9" or 13" black and white TV and use it as a display of the musical energy.

[Guest " "]

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=320-222

power meters for amps, connects to speaker lines, 30 bucks per channel.

[BEC]

I have seen something similar done and it was the coolest thing I have ever seen.

An electronics technician I knew took a regular television and somehow converted it to display incoming musical signals.  When idling there was just a single line (flat) across the screen but once the music kicked in it would display all sorts of patterns in the form of jagged lines and such, the louder it got the further they would branch out.  It was the wildest and most ingenious thing I have ever seen. 

I would love to have something like that, you could find like a small 9" or 13" black and white TV and use it as a display of the musical energy.

 

 

itunes visualizer

[colterphoto1]

world's cheapest light show. Invented by stoned roadies on a break.

Rig up an old unused woofer to power, set it facing up and stretch some type of rubber sheet over the surface. Now glue a compact mirror to that rubber sheet. Aim a laser pointer across the mirror, point at non-human surface, turn on the tunes, turn off the lights- instant cheesy 'laser' light show!

M

[WMcD]

It is interesting. The blue meters are so pretty.

If you go to the McIntosh Labs site you'll see they sell blue meters for car applications. However, as pointed out by others above, they probably are not going to budge at levels at which our Klipsch work.

Gil

[pauln]

My room mate in college had a 19" B/W TV in which the tuner section when south. We turned it off, took off the back and disconnected the TV tuner and other stuff - left the electron gun on so the tube made a spot in the center of the screen.

Then we disconnect the stepper and flyback from the two pairs of coils at the base of the tube (one takes a signal that steps down the lines of the screen, the other takes a signal that swings across - then jerks back to make the next one).

Since the two coils are oriented 90 degrees apart, and each had two connections, we put one channel on one and the other channel to to other.

Put on a record and the spot wiggled around during the lead in groove. Bass sounds make large lissajou patterns (circles, ovals, ellipses. figues of eight...), higher sounds make more complicated figures, drums make fast explosive-edged figures.

By adjusting the brightness and contrast we could get very fine lines in the patterns, or set it to be over contrasted so the shapes would burn after traces in the screen.

This was in 1976 - beleive it not, we called it music TV.

[Cal Blacksmith]

Thanks for the options. I just remembered I have a DB meter (HP I think) It looks like an old VTVM. I picked it up for a few bucks at a large electronics store by me. I don't even know what it would be used for but is it somehow related to what I am talking about here? I will try to shoot a pic of it tonight and post it.

Those Mac meters are indeed cool and are what I was looking for but they need a 12v power source and are calibrated for 4 ohm speakers. I have the speakers hooked up to the 4 ohm taps and I am driving cornwalls with the amp. They are rated for 8 ohms but we all know that is a moving target. Would they be close in output readings?

[efzauner]

What do you want to measure? Do you want to watch meters move while listening to music and try to see what sort of peaks you get? Analog meters will never capture the very fast peaks that cause clipping unless you can already hear it, unless then have some sort of active cicruitry and leds.

Or do you want to measure power duing a constant tone?

[Cal Blacksmith]

Uh, well, to be honest, I would like to recapture my mis-spent youth. It is just fun to watch the meters move[:$] To really know what I am using power wise is a positive thing also.

I guess I could also hook up my Tandberg RtoR and watch the VU meters but it is not the same

I have also always loved those big blue meters that are on Macs but even the add on unit they sell is $500 retail. A bit steep to just watch for fun[:|]

[Me Loves Khorns]

I love those blue meters also.

I just bought a McIntosh MC 206 with 3 meters on it. Unfortunately, the glass was broken in shipping. It was insured at least...

OT: how hard is it to replace the glass on a Mac, I have not tried to dissect the thing yet, had to let Fed Ex see it first. I found out how much it is buy the replacement glass from McIntosh. Is it as simple as removing the old one, removing the sides, taking off the dials, and placing the new one on. Or is this something that only a tech or someone who does this kind of thing all the time can do?

Paul