Hooked up an old realistic power meter


Not sure if anyone remembers the Realistic APM-300 and I've  had one from years ago and decided to hook it back up for fun. According to it, for most music and volume I listen to, it says I'm using barely a watt.

My speakers are 87db for one watt, amp pushes 225. My sounds level meter confirms the approx. 88 decibels I listen to and I did crank it up to around 90+ decibels and was still only using a few watts.

For some reason I though I would be using way more power than that and wonder why if everything is correct, why I need such a big amp?

norton

You don't need such a big amp.  I am currently listening to a 2 wpc amp, probably most of the time at closer to 1/4 watt.  Now my speakers are 96 dB so that helps.  

photo of my system as currently configured.  amp looks tiny on top of the system.

https://photos.app.goo.gl/vAMi1ejqXZDaLVNNA

Your meter is probably reasonably close to correct. :)

You really don’t need a big amp unless your speakers are hard to drive, and you don’t need watts so much as current.

Current sometimes, and often not, comes with bigger amps.

You might want to look at an online power / dB calculator. For 10dB louder you need 10x more power, so to go from 87 to 97 you would need 10 watts, from 97 to 107 you’d need 100.

Of course it is important to note that those meters are slow responding.  Instantaneous transients will peak at higher outputs. 

My speakers are PMC and always read that they are hard to drive and need lot's of juice but am now rethinking it. All my amps are getting really up there age wise and have been looking at replacing the main one just to be spending some of the grandkids money and something to look forward to. lol

At this age I don't have a lot I enjoy but have always had a great love for listening to music and buying all kinds of different equipment.

@norton

Your findings aren’t that surprising to me. I do believe that the often stated need for reasonable amplifier “headroom “ is logical but can be overstated. I find myself generally in the same camp as @carlsbad2 . If possible borrow a high quality modest power rated amplifier (Tube or transistor) and compare with your current amplifiers. Could be a case of quality amplifier wins out versus the quantity of available/stated watts.

Charles

I was always amazed when I got my Macintosh amps $100,000 and I could watch the meters. Most times I am listening at half of watt. When I really wanna listen it’s pushing 6 W the biggest transient I’ve ever seen made the meter go up to approximately 600 W. I also asked myself the same question.

Totally believable and consistent with my experience.  I've gone from 255 wpc to 12wpc, and get much better sound from a better sounding amp.  If that first 1/4 watt is good, the system should sound good.

@knotscott 

Totally believable and consistent with my experience.  I've gone from 255 wpc to 12wpc, and get much better sound from a better sounding amp. 

That must have been quite the revelation for you. Granted, it won’t be the outcome in every scenario. Some speaker designs will demand/require more amplifier power/current. I suspect that the 12 watt amplifier is very high quality with a well thought out power supply.

Charles

@knotscott

Totally believable and consistent with my experience. I’ve gone from 255 wpc to 12wpc, and get much better sound from a better sounding amp.

That must have been quite the revelation for you. Granted, it won’t be the outcome in every scenario. Some speaker designs will demand/require more amplifier power/current. I suspect that the 12 watt amplifier is very high quality with a well thought out power supply.

Charles

That’s true on all accounts. The 255 wpc was a Hafler DH-500. The 12 wpc amp is a pair of modified Dyna 70s being used as monoblocks, each with a pair of Gold Lion KT-66 output tubes...certainly not a "holy grail" amplifier, but a very nice sounding setup that’s been optimized to my liking.