MMG - help to stop this issue...

jk@home · « **Reply #40 on:** 13 Jan 2012, 01:09 pm »

Quote from: Davey on 13 Jan 2012, 05:41 am

Does amplification 'add' information?

Dave.

Only if it's a good one

Another thing the op can try is the choke tweak, fairly inexpensive experiment that's easy to implement:

http://www.integracoustics.com/MUG/MUG/tweaks/Al_Sekela.html

Curiously when I added chokes to my series crossovers, didn't work from me. But some folks swear by it. And if that's not enough, here's more tweaks:

http://www.integracoustics.com/MUG/MUG/tweaks/index.html

My limited experiences with pro amps on my Maggies have not been good, tried a low cost Mackie (FR1400), and a slightly better Yamaha (PS3500S) on my MMGs, didn't hold a candle to my almost 20 yo Aragon 8008. Maybe that's where the brightness is coming from, but that was not the results from my pro amps. More of a fuzzing flat soundstage, with less detail and articulate bass compared to the Aragon.

Davey · « **Reply #41 on:** 13 Jan 2012, 04:35 pm »

With all this "adding" and "removing" of information maybe we could put the local high school band in and get the Boston Symphony out?

Or maybe Justin Bieber in and Frank Sinatra out?

The reason the "choke tweak" doesn't work on your series crossover is because the capacitor shunts the woofer at high frequencies. The woofer is a much bigger transducer ("antenna") than the tweeter.
And maybe your amplifier is not bothered by high frequency information at its outputs.....or maybe you live in an area where there isn't much RFI.

Cheers,

Dave.

Berndt · « **Reply #42 on:** 13 Jan 2012, 05:52 pm »

Is distortion information?

Crimson · « **Reply #43 on:** 13 Jan 2012, 06:48 pm »

Absolutely. Just ask Trent Reznor.

Æ · « **Reply #44 on:** 13 Jan 2012, 07:23 pm »

Quote from: jk@home on 13 Jan 2012, 01:09 pm

Curiously when I added chokes to my series crossovers, didn't work from me.

I went and looked at the value of inductance. Microhenries! Not even applicable to the audio band.

I could tell you some interesting stuff about Al, I saw his big pair of Maggies up close. But I won't, out of respect for his still living widow. He passed away last year.

jk@home · « **Reply #45 on:** 13 Jan 2012, 07:43 pm »

Quote from: Davey on 13 Jan 2012, 04:35 pm

....or maybe you live in an area where there isn't much RFI....

LOL. I live in military land central (Hampton Roads VA). Imagine there's a little bit of that stuff floating around here.

jk@home · « **Reply #46 on:** 13 Jan 2012, 07:44 pm »

Quote from: Æ on 13 Jan 2012, 07:23 pm

I went and looked at the value of inductance. Microhenries! Not even applicable to the audio band.

I could tell you some interesting stuff about Al, I saw his big pair of Maggies up close. But I won't, out of respect for his still living widow. He passed away last year.

Yes that was a shame about Al. He was a good guy.

Davey · « **Reply #47 on:** 13 Jan 2012, 07:49 pm »

Quote from: Æ on 13 Jan 2012, 07:23 pm

I went and looked at the value of inductance. Microhenries! Not even applicable to the audio band.

My goodness, that was the whole point! To block higher-than-audio frequencies from returning to the amplifier outputs and interacting with the feedback gain while and having zero impact on the audio frequencies passing through.

Dave.

Æ · « **Reply #48 on:** 13 Jan 2012, 08:01 pm »

Quote from: Davey on 13 Jan 2012, 07:49 pm

My goodness, that was the whole point! To block higher-than-audio frequencies from returning to the amplifier outputs and interacting with the feedback gain while and having zero impact on the audio frequencies passing through.

Dave.

Many amplifiers already have a small output inductor, factory installed.

I.Greyhound Fan · « **Reply #49 on:** 13 Jan 2012, 08:16 pm »

Quote from: Crimson on 11 Jan 2012, 11:15 pm

You said it. Attenuation of high frequency energy is removing info. Air, space, an instruments' HF attack, etc. are all affected by this attenuation. Either way, seems the OP made some changes and all is good.

I guess you really don't understand how they work. All the resistor is doing is turning down the volume on the HF's like turning down the volume control.

Davey · « **Reply #50 on:** 13 Jan 2012, 08:23 pm »

Quote from: Æ on 13 Jan 2012, 08:01 pm

Many amplifiers already have a small output inductor, factory installed.

Many? Some do, some don't. There are a variety of potentially unstable amplifier designs in the audio world.

Regardless, many/some of the inmates on that other crazy forum noticed audible improvements when installing the small value inductor in series with their speakers. I suppose we could conclude a number of things from that.
Maybe there was no change but the audiophile ego made them hear a difference?
Maybe they were using an "inductor-less" amplifier and the choke did stop RFI from contaminating a conditionally stable operation?
Maybe some other "issue" was created (or alleviated) by installing the series inductor?

Who knows, but it certainly has the "possibility" of creating an audible difference. I hope you weren't dismissing it out-of-hand because of the small value of the inductor. I much prefer shunting with an RC combo vice a series inductor, but Al had developed a "following" so his experience had some weight.

Cheers,

Dave.

Æ · « **Reply #51 on:** 13 Jan 2012, 08:24 pm »

Quote from: I.Greyhound Fan on 13 Jan 2012, 08:16 pm

I guess you really don't understand how they work. All the resistor is doing is turning down the volume on the HF's like turning down the volume control.

Yeah, I'm glad you said it, I was thinking along the same lines as you, but I decided it probably wasn't worth my time trying to convince someone who apparently is lacking in basic electronics knowledge, theory.

Æ · « **Reply #52 on:** 13 Jan 2012, 08:28 pm »

Quote from: Davey on 13 Jan 2012, 08:23 pm

Many? Some do, some don't. There are a variety of potentially unstable amplifier designs in the audio world.

Regardless, many/some of the inmates on that other crazy forum noticed audible improvements when installing the small value inductor in series with their speakers. I suppose we could conclude a number of things from that.
Maybe there was no change but the audiophile ego made them hear a difference?
Maybe they were using an "inductor-less" amplifier and the choke did stop RFI from contaminating a conditionally stable operation?
Maybe some other "issue" was created (or alleviated) by installing the series inductor?

Who knows, but it certainly has the "possibility" of creating an audible difference. I hope you weren't dismissing it out-of-hand because of the small value of the inductor. I much prefer shunting with an RC combo vice a series inductor, but Al had developed a "following" so his experience had some weight.

Cheers,

Dave.

He's dead and so is his tweak. RIP.

Crimson · « **Reply #53 on:** 13 Jan 2012, 09:14 pm »

Quote from: I.Greyhound Fan on 13 Jan 2012, 08:16 pm

I guess you really don't understand how they work. All the resistor is doing is turning down the volume on the HF's like turning down the volume control.

Right. For half the speaker. Is that how your volume control works? Attenuates the amplitude of the signal to the tweeter and not the woofer? You guys should just get a graphic eq and have fun with your resistors.

Æ · « **Reply #54 on:** 13 Jan 2012, 09:29 pm »

Quote from: Crimson on 13 Jan 2012, 09:14 pm

Right. For half the speaker. Is that how your volume control works? Attenuates the amplitude of the signal to the tweeter and not the woofer? You guys should just get a graphic eq and have fun with your resistors.

How about if you ask Danny Richie how resistors work and if he uses them in loudspeakers or not? I'm sure he can explain it to you. Maybe you'll respect him enough to listen to what he has to say about it.

josh358 · « **Reply #55 on:** 13 Jan 2012, 10:56 pm »

I'd be more convinced about Al's tweak if someone put an RF analyzer on an amp to show that it was getting past the output inductor and the cap in the Zoebel network.

Æ · « **Reply #56 on:** 13 Jan 2012, 11:05 pm »

Quote from: josh358 on 13 Jan 2012, 10:56 pm

I'd be more convinced about Al's tweak if someone put an RF analyzer on an amp to show that it was getting past the output inductor and the cap in the Zoebel network.

So would I. It's not so subjective that it can't be measured.

Davey · « **Reply #57 on:** 13 Jan 2012, 11:11 pm »

Quote from: josh358 on 13 Jan 2012, 10:56 pm

I'd be more convinced about Al's tweak if someone put an RF analyzer on an amp to show that it was getting past the output inductor and the cap in the Zoebel network.

Yeah, if there was one....or both.

As I alluded to earlier, many amplifiers in use by audiophiles today may not have these type of stability-related components in their outputs. And they could, conceivably, be bothered by some outside "pick up" being fed back into their outputs.

I had a number of PM conversations with Al through the years regarding the benefits of bi-amping speaker systems. He wasn't convince-able and refused to even try it. He was an audiophile with a vivid imagination, but that didn't mean he couldn't understand some of the technical aspects.
However, to call this the "Al choke tweak" is not really accurate. This type of inductor "isolation" I first saw used many years ago by radio station and ham radio operators who were helping citizens located close to their transmitters.

Cheers,

Dave.

I.Greyhound Fan · « **Reply #58 on:** 14 Jan 2012, 12:06 am »

Quote from: Crimson on 13 Jan 2012, 09:14 pm

Right. For half the speaker. Is that how your volume control works? Attenuates the amplitude of the signal to the tweeter and not the woofer? You guys should just get a graphic eq and have fun with your resistors.

Tone controls and equalizer's work the the same way. But they don't leave out info. And I guess when I roll tubes in my tube preamp and DAC to tailor the sound to my liking that I am leaving out info too.

SteveFord · « **Reply #59 on:** 14 Jan 2012, 02:01 am »

Pick the right tubes and you'll retrieve a lot more info if you're lucky.