P20 limitations? Empirical data please

Agree. That’s the explanation I get from my dealer and also from Pass.

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Hey George_P…

Agreeing with Paul and his engineers on powering the amps with
the regenerators…

In my .02 experience with my Parsound JC5 powered by my P15 results
in a cleaner more dynamic soundstage.

The JC5 is a 400 watt/ channel 8 ohm that on power on from standby from
time to time shut down the P15 while the power caps charge up. The power
watt meter will swing all the way over to the right and hang there…if for more
than a few seconds the P15 will auto shut down…next all needs to be done
is to press the power on on the remote or on the P15 itself…and voila…back
in business…

During normal play with heavy bass and percussion hitting 95 dbs roughly the
power watt meter rarely budges beyond 300-330 watts.

All this just to show that that even with large amps like the JC5 my P15
does not restrict my normal listening which rarely gets into the low 80db
sound level.

Again this is my own .02 experience and ymmv.

Best wishes everyone

I think it all boils down to listening levels. McIntosh owner manuals back when they were for industrial and sound reinforcement use actually included real performance info snd measurements. Here is excerpt for my MC2500.

The newer manuals just give numbers.
But note the highlights. It is about rated power and what was needed and why. My MC1000s though later still had decent real engineering documentation. Try to find that anywhere these days on any HiFi equipment. Everyone is afraid to disclose.

The MC 2500 is designed to operate on 120 volts 50/60 Hz. Plug the AC power cord directly into a wall outlet. Make certain that the AC power outlet has at
Figure 4
least 15 ampere capacity with nothing else connec- ted to the circuit. Do not plug the MC 2500 into an auxiliary AC power outlet on a preamplifier or other source equipment unless it is known there is ade- quate current capacity. If remote power operation is required, an external relay arrangement must be made. If an extension cord is used make certain that it has 15 ampere current capacity.
The MC 2500 draws 15 amperes AC line current when amplifying music or speech at rated output on program peaks. The amplifier uses only 0.7 ampere while idling at no output. If the amplifier is driven to rated output using sine wave signals it will draw 22 amperes. The MC 2500 is designed for continuous and reliable operation at any power level to its rated 500 watts continuous average power output per channel or 1000 watts as a mono amplifier. For con- tinuous sine wave operation the AC source must be capable of supplying the required 22 amperes.

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The real thing is continuous sine wave operation. Most music unless test tone never comes close. The MC2500 drrove sub sonar and shaker tables plus music. So a P20 under normal listening no sweat. At concert music levels. Go to the wall.

McIntosh is an excellent brand …with great products.

Yet there are still other companies such as Parasound do give a quite bit of information on their amps perhaps not the graphs…

JC 5

Features Specs Reviews Support

  • 400 watts x 2 @ 8 Ω RMS, both channels driven
  • 600 watts x 2 @ 4 Ω RMS, both channels driven
  • 1200 watts x 1@ 8 Ω, in bridged mode
  • Circuitry designed by legendary John Curl
  • Ultra-high bias Class A/AB operation
  • 12 watts per channel of pure Class A power
  • 90 amperes peak current per channel
  • Stable with speaker impedance dips to 1.5 Ω
  • Balanced inputs with discrete circuits
  • CHK Infinium, custom 5-way speaker binding posts
  • Neutrik locking XLR input connectors
  • Vampire gold-plated RCA input & loop output jacks
  • Direct-coupled signal path, no capacitors or inductors
  • DC Servo and relay protection circuits
  • AC turn-on inrush surge protection with relay bypass
  • Dual-mono input stages with ±110 volt DC rails
  • JFET input stage, MOSFET driver stage
  • 24 beta-matched 15 ampere, 60 MHz bipolar output transistors
  • 1.7 kVA shielded toroid power transformer with independent windings for each channel
  • Independent power supplies for left & right channel input stages, driver stages, output stages
  • 8,880 µF Nichicon Gold Tune filter capacitors for input stages
  • 132,000 µF Rubycon filter capacitors for output stages
  • Full power is rated all the way down to 5Hz for unrestricted low-end bass
  • Harris hyper-fast soft-recovery bridge diode rectifiers
  • Automatic turn-on by 12 V trigger or audio sensing
  • 4 rack space chassis with rear carry handles
  • Rack mount hardware is included
  • Available in silver or black

There are still a few that do show their amp details

Best wishes everyone…

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So going back to powering your power amp with a regenerator
My P15 is doing a wonderful job powering this big baby…

I have tried direct to wall vs P15…P15 is the verdict for my system.
Again just my .02 and more importantly ymmv!!

Thanks for putting up with me Vmax…

Getting back to empirical…

Best wishes everyone!!!

Best wishes

132,000 µF Rubycon

That must be four combined for both channels. But still impressive having 90 amps at the ready for peaks though. I think they likely combined peak amps for two channels too. That is a only feasible way to equate everything to capacitor quotes. Half truths so to say in their specs if you try to call them out on it.

Edit: okay I see it is a bridgeable amp. Th dpecs make better sense

Somehow this picture of JC5 wouldn’t post

Here is a retry

Best wishes all

Opinions from people who live here, don’t live here, are audiophiles, don’t know what an audiophile is:
“The wall sounds louder” (it’s not)
“The wall sounds brighter” (not to me)
“The wall sounds bigger, more dense” (I’m closest to this opinion) (audiophile)
“The P20 sounds more detailed” (audiophile #2)
“The wall sounds more lively” (non-audiophile)
I’m going to leave the amps plugged into the wall for a while because I don’t hear a difference worth bending over for; plug into the P20 on some rainy day a month from now.


Yesiree boss dat fer sure be an audidiofile yep :grin:


Try the P20 3M AB7050HF absorber mod. I got two converts one of them Al.ore are ordering Then tell us what is better P20 or wall for Amps

So has anyone attempted to apply the 3M AB7050HF to their power cords?

I wrapped mine to P20 and amps at p20 Had zero affect to sound but was loosely applied.

Going to try my streamer, matrix and ulrarendu next. Perhaps my LPS’s after that.

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I played around a little more yesterday and this morning and I consistently hear added richness from the P20. So, the better sound plus the security and the P20 wins.
Happily, my dealer is wrong and the amps are staying connected to the P20. Another life-critical question answered.

Oh—and my friend Larry, The Audioslut has offered to lend me his Niagara 7000 to try. Not sure I want to bother.


The experiment could be fun, and what may result. Is Larry willing to change?

2 posts were merged into an existing topic: P20 Performance Tweaks and Performance Enhancements

I plugged my puny 150 watt Class A amp into my P20 and I was surprised to see at full power my whole system was using 800 watts.

Try it. The P20, the amps, and the wall will all protect themselves.

Al your amp is not puny at all…it is a great amp!!

That’s great to read that indeed power amps do benefit from power regenerators
in sound quality as well as well as protection.

Seems as ole uncle Paul was right after all…recommending power amps be plugged
into regenerators…

I run my whole system on my P15 …my JC5 amp sound quality benefits greatly
as well as my whole system…when I did try running my JC5 direct to wall…
the result was a diminished sq. So again P15 wins and by no small factor!!!

Hopefully others will see their way to acquiring a new regenerator…it will be a
revelation for them as it has been for us…

As my P15 sits a good 5’ from my JC5 amp and my preamp 3’ away from my P15
noise from P15 does not appear to affect my system…thankfully!!

Best wishes to all you guys!!


Moments ago I plugged my amp back into the P20. I powered it up and set it to full blast and I got the hum again. So back into the wall it’s two power cables go. Bah.