OMG!!! New MC1.25KW !!!

[4-2-7]

Superfluous meters remain silly.

So if anyone reads you post on the open forum they would know your disdain for McIntosh.

So it begs the question..... Why would you go into the McIntosh specific forum?

I know I have never made any comments in sub forums I have no interest or like the equipment, why would I?

 

[E-Stat]

So it begs the question..... Why would you go into the McIntosh specific forum?

Quite simple - read my first post!

The text you quoted was a response to this post by Techguy who introduced the concept.

I have previously stated that I enjoy the sound of 2301s.

 

[ron-c]

Those are some huge meters! Looks like they are the size of a laptop display or small TV

They are a bit smaller than my new 55" TV....
Ron-C

 

[ron-c]

I understand the value of soft clipping circuits with pro amp where they are often run at the limit. I have a Crown amp with that feature, but never used it.

Correct me if I'm mistaken, but Powerguard is always enabled.

Power Guard is NOT soft clipping, it is no clipping unless you severely overdrive the amp. The PG indicator light will trigger at about 1% distortion and activate at 2% to limit the peak signal only. If you continue to increase the volume PG will act as a peak compressor. Peak compression is preferable to blown speakers but the larger amplifiers can torch many speakers with shear power so be aware that the amplifier will make much more power than rated when playing dynamic music.

Ron-C

 

[techguy0192]

I understand the value of soft clipping circuits with pro amp where they are often run at the limit. I have a Crown amp with that feature, but never used it.

Correct me if I'm mistaken, but Powerguard is always enabled.

You're correct, PG is always on. It's designed to not be audible.

 

[E-Stat]

You're correct, PG is always on. It's designed to not be audible.

Thanks.

While the intent is to be not audible...

"Unfortunately, at lower levels there will still be some distortion. For any circuit to clip 'softly', it must start to introduce distortion well below the clipping voltage (set by the power amp's supply rail voltage). As discussed in greater detail below, you will end up with 1-2% distortion at around half power (sometimes even less), with the distortion climbing rapidly as the amp delivers more power. This is not hi-fi!"

 

[4-2-7]

Thanks.

While the intent is to be not audible...

"Unfortunately, at lower levels there will still be some distortion. For any circuit to clip 'softly', it must start to introduce distortion well below the clipping voltage (set by the power amp's supply rail voltage). As discussed in greater detail below, you will end up with 1-2% distortion at around half power (sometimes even less), with the distortion climbing rapidly as the amp delivers more power. This is not hi-fi!"

But that’s wrong, I peg my meters before any pg starts to flash. It’s how you match the speakers and source. Digital CD being so compressed, over blown bass and loudness will trip the pg sooner than say a very nice vinyl rig. But that’s the source that’s the problem not the amps.

 

[E-Stat]

But that’s wrong, I peg my meters before any pg starts to flash.

What does that tell you? Either:

1. The meters aren't 100% accurate
2. Powerguard fails if #1 is true

 

[TSmith8605]

Thanks.

While the intent is to be not audible...

"Unfortunately, at lower levels there will still be some distortion. For any circuit to clip 'softly', it must start to introduce distortion well below the clipping voltage (set by the power amp's supply rail voltage). As discussed in greater detail below, you will end up with 1-2% distortion at around half power (sometimes even less), with the distortion climbing rapidly as the amp delivers more power. This is not hi-fi!"

Which McIntosh amp exhibits "1-2% distortion at around half power (sometimes even less), with the distortion climbing rapidly as the amp delivers more power"?

Which McIntosh amp does not measure with a fraction of a percent of distortion at any audio frequency when running above rated output power?

 

[E-Stat]

You'll have to ask Rod Elliott about his take on how soft clipping circuitry works.

 

[4-2-7]

What does that tell you? Either:

1. The meters aren't 100% accurate
2. Powerguard fails if #1 is true

No it detects crappy mastering.

 

[TSmith8605]

You'll have to ask Rod Elliott about his take on how soft clipping circuitry works.

No, I asked you since you brought it up in relation to McIntosh PG. How does that article relate to the PG subject?

 

[62caddy]

You'll have to ask Rod Elliott about his take on how soft clipping circuitry works.

PG is NOT a soft clipping circuit. The system uses a comparator to measure the original input signal against that of the output. When the disparity between the two reaches 1% (ie 1% THD) the system limits the input to the point that THD cannot exceed 2% THD, further overdriving will simply limit output signal to the maximum capable without exceeding 2% as RonC says. A McIntosh PG amplifier does not produce "soft clipping"; it is NO clipping.

PG took the Laboratory many years to perfect.

 

[damacman]

Thanks.

While the intent is to be not audible...

"Unfortunately, at lower levels there will still be some distortion. For any circuit to clip 'softly', it must start to introduce distortion well below the clipping voltage (set by the power amp's supply rail voltage). As discussed in greater detail below, you will end up with 1-2% distortion at around half power (sometimes even less), with the distortion climbing rapidly as the amp delivers more power. This is not hi-fi!"

Does not apply here.

 

[kevzep]

I understand the value of soft clipping circuits with pro amp where they are often run at the limit. I have a Crown amp with that feature, but never used it.

Correct me if I'm mistaken, but Powerguard is always enabled.

In the pro world, anti-clipping management happens in the front end with the active crossover processing, some of our amplifiers have those soft clipping circuits, but we don't use them, its not normal practice to do so.

The MC452 has the powerguard in all the time, however it can be turned off on the MC2205 I have here which is good, because I have it, OFF...

Powerguard is actually not a soft clipping circuit whilst we are at it.

 

[4-2-7]

PG is NOT a soft clipping circuit. The system uses a comparator to measure the original input signal against that of the output. When the disparity between the two reaches 1% (ie 1% THD) the system limits the input to the point that THD cannot exceed 2% THD, further overdriving will simply limit output signal to the maximum capable without exceeding 2% as RonC says. A McIntosh PG amplifier does not produce "soft clipping"; it is NO clipping.

PG took the Laboratory many years to perfect.

And this is why the pg detects and treats the digital copy of a song different than the same song mastered with RIAA EQ curve for vinyl.

 

[E-Stat]

The MC452 has the powerguard in all the time, however it can be turned off on the MC2205 I have here which is good, because I have it, OFF...Powerguard is actually not a soft clipping circuit whilst we are at it.

Whatever you want to call it, I share your view in not wanting to incorporate a compressor into high fidelity gear!

Isn't that what we're trying to avoid?

 

[62caddy]

Whatever you want to call it, I share your view in not wanting to incorporate a compressor into high fidelity gear!

Isn't that what we're trying to avoid?

Not if doing so results in clipping.

 

[kevzep]

@4-2-7 The reason you are experiencing this is simply because CD's have a much greater dynamic range than Vinyl.
Its not "overblown bass" and compression with digital music, that is an old wives tale. Compression reduces dynamic range and increases average power output.
The peaks in digital recordings are far greater than vinyl, simply because vinyl has a limited bandwidth and needs to be mastered/limited in a particular way to stop the stylus jumping out of the grooves, this includes the RIAA curve which is the Achilles heal of vinyl, NOT that I am saying it cant sound good.. .....

 

[kevzep]

Whatever you want to call it, I share your view in not wanting to incorporate a compressor into high fidelity gear!

Isn't that what we're trying to avoid?

Of course, which is why having an amplifier which is powerful enough to provide the necessary headroom is the way to go.
However, I am not against having something which acts as protection against speaker damage.

I must admit, I could have got the MC302, but I remember thinking, the MC452 is what "they're" all talking about and with the extra 150 per channel, I will never hit the powergaurd.

I actually believe PG is not supposed to be an area of normal operation for these amplifiers, it is purely a protection device, I believe your well informed McIntosh dealer would say if you were constantly driving into PG, "you sir, need a more powerful amplifier".