PMC EB1i impedance curve

[Jerome W]

Hello folks, and Ian especially,

Can we get a table of the impedance curve / frequency of the EB1i somewhere ?
If not, do you the minimal impedance of it ? for which frequency ?
Thanks a lot !

[jdandy]

Jérôme.......I hope you have better luck that I did with this request. I asked PMC in Great Britain for the EB1i's impedance/phase curve chart, and never got a response. I emailed them several times, but no information was ever sent to me. I asked Ian on this forum, and he saud he would find the information, but it never came.

[Jerome W]

Jérôme.......I hope you have better luck that I did with this request. I asked PMC in Great Britain for the EB1i's impedance/phase curve chart, and never got a response. I emailed them several times, but no information was ever sent to me. I asked Ian on this forum, and he saud he would find the information, but it never came.

Thanks Dan !

And you don't have the instruments to take the measures by yourself I guess...
too bad when one thinks about all the gear you have in the studio :D !

[jdandy]

Jérôme.......Those test instruments are sophisticated and very expensive to own for occasional use. I had hoped to see Stereophile put the PMC EB1i through a full review. They would have done those tests and published them.

[Jerome W]

Jérôme.......Those test instruments are sophisticated and very expensive to own for occasional use. I had hoped to see Stereophile put the PMC EB1i through a full review. They would have done those tests and published them.

Yes Dan, I can imagine.
I suppose that if PMC does not communicate on that, it could be because of a very tortured curve !

[Face]

This is pretty accurate.

Dayton Audio WT3 Woofer Tester (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-804)

[ian@pmc]

I tried getting to Stereophile for review the EB1i. They instead chose the DB1i.:icon_thumbsdown:

I wouldn't hold your breath for an impedance curve.

[ian@pmc]

Are you guys running into problems with powering your EB's?

[jdandy]

Ian.......If memory serves me right, somewhere I saw an impedance and phase curve chart on the EB1i, but failed to bookmark it, and have not been able to locate it again. It would seem to me that this data would be readily available from the factory. Surely, Peter Thomas has made these tests on all of his designs. Why is it so difficult to get this information?

This is the post where I inquired about the EB1i impedance and phase data over two years ago. http://audioaficionado.org/19302-post1.html

[jdandy]

Here is an impedance and phase curve chart that was publish in HiFi Crtitic for the IB2i. Sorry, but it wasn't any clearer in the web page.

http://www.hificritic.com/downloads/digital/HIFICRITIC_PMCIB2i.pdf


http://i453.photobucket.com/albums/qq255/jdandy_photos/PMCIB21impedanceandphasechart.jpg

[Jerome W]

Here is an impedance and phase curve chart that was publish in HiFi Crtitic for the IB2i. Sorry, but it wasn't any clearer in the web page.

http://i453.photobucket.com/albums/qq255/jdandy_photos/PMCIB21impedanceandphasechart.jpg

The image is not sharp enough Dan : I can't read the figures...
Nice try anyway ! Thanks !

[Jerome W]

Are you guys running into problems with powering your EB's?

Ian,
Not here with the 2301's !
I' m just considering a pair of tube monoblocks of 70W in class A and it seems that they are made for 8 ohms speakers. Their power would be of only 35 W but class A on 4 ohms. I wonder how low the impedance of the EB1i goes down and at which frequency....:scratch2:

[jdandy]

Are you guys running into problems with powering your EB's?

Ian.......Not at all. I would simply like to know what the impedance and phase curve data is reporting. I love my PMC EB1i's. Were I ever to change them it would be for a pair of PMC IB2i's.

[jwhite613]

Ian.......Were I ever to change them it would be for a pair of PMC IB2i's.

Dan be careful. It always starts with an idea. :D

[ian@pmc]

Dan be careful. It always starts with an idea. :D

Absolutely..:yes:

[jdandy]

Dan be careful. It always starts with an idea. :D

Jeff.......Tell me about it. I am living proof of that.

[jdebonth]

Guys, it just so happens that I also have been requesting this data from PMC for a few weeks now. I was on the phone with them this morning and was told they would get them to me by the end of the day. I requested frequency response plots for FB, OB, PB, EB, IB1 and IB2. I will post up here if I get them. I'll also request the impedance plots from the same contact.

Fingers crossed.

[jdandy]

jdebonth.......Good news. Hope they come through for you.

[jdandy]

The image is not sharp enough Dan : I can't read the figures...
Nice try anyway ! Thanks !

Jérôme.......I was disappointed in the clarity of the chart as well, but that's the way it appeared in HiFi Critic's web article. I tried reducing it's size to clear it up, but no luck.

Still, there is some information to be taken from the chart. It is good to see that phase amplitude and impedance follow each other relatively close.

[jdebonth]

Guys, it just so happens that I also have been requesting this data from PMC for a few weeks now. I was on the phone with them this morning and was told they would get them to me by the end of the day. I requested frequency response plots for FB, OB, PB, EB, IB1 and IB2. I will post up here if I get them. I'll also request the impedance plots from the same contact.

Fingers crossed.

No joy unfortunately. From Ian @ PMC:

Hi Joost, I regret the information you are requesting is not currently in the public domain.

I must apologise for the delay.

Regards
Ian

Ian Downs
General Sales Manager

[jbaudio68]

Here is an impedance and phase curve chart that was publish in HiFi Crtitic for the IB2i. Sorry, but it wasn't any clearer in the web page.

http://www.hificritic.com/downloads/digital/HIFICRITIC_PMCIB2i.pdf



Dan, I had missed this article. Thanks so much or posting. If the EB1 follows the IB2 it would explain why Jerome's speakers (and my mono-blocked 275s) might sound better using the 8 ohm taps. I know there are autoformers but I thought the IB2 was a 4 ohm speaker.

[jdandy]

Dan, I had missed this article. Thanks so much or posting. If the EB1 follows the IB2 it would explain why Jerome's speakers (and my mono-blocked 275s) might sound better using the 8 ohm taps. I know there are autoformers but I thought the IB2 was a 4 ohm speaker.

Jeremy.......Looking at the chart, it appears the impedance begins to climb above 4 ohms below 70Hz, peaking at 17 ohms at 40Hz, dropping to 8 ohms at 30Hz, then peaking again to 16 ohms at 21Hz. The impedance stays between 3.5 ohms to 10 ohms across the remainder of the frequency band. That is essentially a stable impedance, and would work quite well on 4 ohm or 8 ohm taps. Again, it is impressive that the phase curve follows the impedance. PMC crossovers are very well designed.

[PHC1]

And then there are Peak Consult speakers. Let me know if you find anything more stable. :D


http://www.stereophile.com/images/archivesart/507PEDFIG1.jpg


http://www.stereophile.com/images/archivesart/EMPFIG1.jpg

[jbaudio68]

Jeremy.......Looking at the chart, it appears the impedance begins to climb above 4 ohms below 70Hz, peaking at 17 ohms at 40Hz, dropping to 8 ohms at 30Hz, then peaking again to 16 ohms at 21Hz. The impedance stays between 3.5 ohms to 10 ohms across the remainder of the frequency band. That is essentially a stable impedance, and would work quite well on 4 ohm or 8 ohm taps. Again, it is impressive that the phase curve follows the impedance. PMC crossovers are very well designed.

Dan, would you mind explaining why phase should follow impedance? I can say that going to the 8 ohm taps created a deeper sound stage and seems to have improved the bass. Maybe somehow it is allowing more current? If so, then going solid state should be amazing...(with a tube pre). What I do know is that my IB2S amaze me on a regular basis. Somehow I stumbled onto a great brand.

[jdandy]

Jeremy.......Wikipedia explains it better than I could.

Impedance variations of the load with frequency translate into variation in the phase relationship between the amplifier's voltage and current outputs. For a resistive load, usually (but not always) the voltage across the amplifier's output devices is maximum when the load current is minimum (and the voltage is minimum across the load) and vice-versa, and as a result the power dissipation in those devices is least. But due to the complex and variable nature of the driver/crossover load and its effect on the phase relationship between the voltage and current, the current will not necessarily be at its minimum when the voltage across the output devices is maximum - this results in increased power dissipation in the amplifier output stage which manifests as heating in the output devices. The phase angle varies most near resonance in moving coil loudspeakers. If this point is not taken into consideration during the amplifier design, the amplifier may overheat causing it to shut down, or cause failure of the output devices.

Here's the link to the entire artical on electrical characteristics of dynamic loudspeakers: Electrical characteristics of dynamic loudspeakers - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Electrical_characteristics_of_dynamic_loudspeakers )

[Jerome W]

Dan,
At least in the bass, this does not look as a stable impedance to me but more like the valleys and mountains of the Alps where we had our last vacations. :D

[tdelahanty]

You guys have stumbled upon the realities of speaker design. Impedance specs are usually nominal, an average. It is a mathmatical repesentation. Two things are important considerations; 1) impedance generally is lowest at low frequencies and, if too low, can suck up a huge portion of your amp's power. 2) as frequency gets higher impedance increases thus making it more difficult for your amp to drive higher frequencies. to rated output.

[Face]

And then there are Peak Consult speakers. Let me know if you find anything more stable. :D


http://www.stereophile.com/images/archivesart/507PEDFIG1.jpg


http://www.stereophile.com/images/archivesart/EMPFIG1.jpg
That is impressive.

[DaveNote]

I tried getting to Stereophile for review the EB1i. They instead chose the DB1i.:icon_thumbsdown:

I wouldn't hold your breath for an impedance curve.

Ian, I'm not surprised about Stereophile not reviewing the larger PMC speakers. I remember reading some years ago somewhere that John Atkinson doesn't much care for transmission line designs. I've also heard that PMC has been criticized about the published measurements of their speakers. I've owned IB2s, MB2s and now MB2is - and frankly I don't much care how they are designed or their measurements. I simply like the way they sound.

[jbaudio68]

Jeremy.......Looking at the chart, it appears the impedance begins to climb above 4 ohms below 70Hz, peaking at 17 ohms at 40Hz, dropping to 8 ohms at 30Hz, then peaking again to 16 ohms at 21Hz. The impedance stays between 3.5 ohms to 10 ohms across the remainder of the frequency band. That is essentially a stable impedance, and would work quite well on 4 ohm or 8 ohm taps. Again, it is impressive that the phase curve follows the impedance. PMC crossovers are very well designed.

Dan, as an owner of PMC EB1i speakers (the closest speaker I know to the IB2) and both the 601 and 2301 amps, which amp one would you choose if you could only have one system (and why?)? I ask because I am getting closer to making a purchase of a 2300 and either the 601 or the 2301 to drive my IB2S speakers. Thanks for your input.

[jdandy]

Dan, as an owner of PMC EB1i speakers (the closest speaker I know to the IB2) and both the 601 and 2301 amps, which amp one would you choose if you could only have one system (and why?)? I ask because I am getting closer to making a purchase of a 2300 and either the 601 or the 2301 to drive my IB2S speakers. Thanks for your input.

Jeremy.......With an 89dB/1w/1m sensitivity and 4 ohm impedance, your IB2S speakers can be driven with either the MC2301's or the MC601's without compromise. The primary difference will be peak sound pressure levels. The IB2S specifications indicate a usable frequency response sound pressure level (25Hz-25kHz Peak) of 116dB at 1 meter. To reach that sound pressure level will require 500 watts of unclipped power. To reach a sound pressure level of 113dB, just three decibels less, requires 250 watts of unclipped power. The point I am trying to make is, unless you plan to push the IB2S speakers to their limit, either amplifier noted will drive your speakers to substantial, lease breaking volume levels.

Since you asked me for my personal opinion, I would choose the MC2301 amplifiers because they offer a sense of midrange magic and breath of life to music reproduction unlike any amplifier I have ever heard. They also have all the current necessary to control the Carbon Fiber/Nomex woofer without breaking a sweat, so the bottom of the audio spectrum will be faithful to the source no matter what you are playing. It is becoming a common quote from those who have experienced the MC2301's that they are the finest amplifier McIntosh has ever produced.

This does not reduce the desirability and performance capabilities of the MC601's in the slightest. I have had both the MC601's, the MC452, and the MC2301's powering my Anniversario's with no complaints about performance or sound from any of them. The pair of MC601's that power my PMC EB1i speakers deliver a stellar performance every single day, and do it effortlessly at any volume I choose. The 601's are tremendous amplifiers. Obviously the 601's will prove to be less costly to operate over time since there are no tubes that eventually need replacing, not to mention the lower initial cost of purchase. Still, you asked for my personal opinion. I find myself more mesmerized by the MC2301's than any other amplifier I have ever owned.

One thing is certain. No matter which amplifiers you ultimately purchase, the MC2301's or the MC601's, they will make your PMC IB2S speakers sing like you've never before heard.

[MyPal]

Jeremy.......With an 89dB/1w/1m sensitivity and 4 ohm impedance, your IB2S speakers can be driven with either the MC2301's or the MC601's without compromise. The primary difference will be peak sound pressure levels. The IB2S specifications indicate a usable frequency response sound pressure level (25Hz-25kHz Peak) of 116dB at 1 meter. To reach that sound pressure level will require 500 watts of unclipped power. To reach a sound pressure level of 113dB, just three decibels less, requires 250 watts of unclipped power. The point I am trying to make is, unless you plan to push the IB2S speakers to their limit, either amplifier noted will drive your speakers to substantial, lease breaking volume levels.

Since you asked me for my personal opinion, I would choose the MC2301 amplifiers because they offer a sense of midrange magic and breath of life to music reproduction unlike any amplifier I have ever heard. They also have all the current necessary to control the Carbon Fiber/Nomex woofer without breaking a sweat, so the bottom of the audio spectrum will be faithful to the source no matter what you are playing. It is becoming a common quote from those who have experienced the MC2301's that they are the finest amplifier McIntosh has ever produced.

This does not reduce the performance capabilities of the MC601's in the slightest. I have had both the MC601's, the MC452, and the MC2301's powering my Anniversario's with no complaints about performance or sound from any of them. The pair of MC601's that power my PMC EB1i speakers deliver a stellar performance every single day, and do it effortlessly at any volume I choose. The 601's are tremendous amplifiers, and obviously will prove to be less costly to operate over time since there are no tubes to eventually have to replace, not to mention the lower initial cost of purchase. Still, you asked for my personal opinion, and I find myself more mesmerized by the MC2301's than any amplifier I have ever owned.

One thing is certain. No matter which amplifiers you ultimately purchase, the MC2301's or the MC601's, they will make your PMC IB2S speakers sing like you've never heard before.

+1 for MC2301s with these speakers. :yes:

[Jerome W]

Agree with Dan. Excellent analysis as always.
If you love the McIntosh sound, the 2301's are the essence of it.

Sent from my iPhone using A.Aficionado

[jbaudio68]

See? That's why I love you guys! Thanks so much and I'll let you know when I have something in que. oh, Dan, thanks for the gentle nudge to repair my 5100. It's running like a pro again!

[jdandy]

See? That's why I love you guys! Thanks so much and I'll let you know when I have something in que. oh, Dan, thanks for the gentle nudge to repair my 5100. It's running like a pro again!

Jeremy.......My motto is never let a good Mac die. Good to hear the MA5100 is back in business. I enjoy mine in the vintage system. It rocks my JBL 4312A's real good. :thumbsup:

Looks like the amplifier consensus is unanimous. MC2301's :banana:

[BuffaloBill]

FWIW, McIntosh says that properly designed SS and tube amps should sound the same.

[Jerome W]

FWIW, McIntosh says that properly designed SS and tube amps should sound the same.

This is just marketing because if they sound the same, why the need for tubes ?
I think that they mean "should sound very good" but "the same" is kind of a non sense for me.

Sent from my iPhone using A.Aficionado

[jdandy]

FWIW, McIntosh says that properly designed SS and tube amps should sound the same.

Bill.......Are you playing the devil's advocate, or do you actually believe this? :wedgie:

[jbaudio68]

Bill.......Are you playing the devil's advocate, or do you actually believe this? :wedgie:

How about a tube pre matched with a Macintosh ss amp? Not trying to start trouble, just curious.

[jdandy]

How about a tube pre matched with a Macintosh ss amp? Not trying to start trouble, just curious.

Jeremy.......I have it both ways with my two system. The living room rig is the C2300 tube preamplifier feeding a pair of MC601's. The studio system is the C1000C/P solid state preamplifier feeding a pair of MC2301's. Both combinations offer superb performance, in my opinion.

[jbaudio68]

Jeremy.......I have it both ways with my two system. The living room rig is the C2300 tube preamplifier feeding a pair of MC601's. The studio system is the C1000C/P solid state preamplifier feeding a pair of MC2301's. Both combinations offer superb performance, in my opinion.

Last question (I'm having some wine so the courage is up): does mc ss with tube pre come close to Mc tube sound or is it just different? It's a huge question for me directionally and I'd appreciate any input. -JB

[jdandy]

Last question (I'm having some wine so the courage is up): does mc ss with tube pre come close to Mc tube sound or is it just different? It's a huge question for me directionally and I'd appreciate any input. -JB

Jeremy.......That is a loaded question, no pun intended. McIntosh tube sound covers a great many years of tube based amplifier production. My first McIntosh tube amplifiers were a pair of MC30 mono amps that McIntosh introduced in 1960 for $120.00. Their sound was quite different from the MC275 stereo tube power amp introduced in 1961 and sold through 1970 for $444.00. The tube sound of the original MC275 is quite different from the MC275 MkV and 50th Anniversary Edition in the current catalog. All of those tube amplifiers sound different from McIntosh's MC2000, and the newest MC2301 tube power amps. The evolution of McIntosh tube amplifiers has continuously brought newer technology and higher quality internal components to their designs, and is clearly reflected in each amplifier's voicing.

When I did a direct comparison of the McIntosh C1000C/P solid state preamplifier to the C1000C/T tube preamplifier (http://www.audioaficionado.org/mcintosh-audio/2492-mcintosh-c1000p-vs-c1000t.html) I was surprised to discover there were far more similarities than differences in their sound. McIntosh manage to build two completely different components while managing to maintain a very similar and cohesive sonic signature between both of them. The same does not hold true, though, for their power amplifiers. Each power amplifier has a particular voice that makes the amp's personality independent of the others, although there is a common thread of excellence in sound woven through all McIntosh amplifiers. In their MC2301 tube amp design there is a faster sense of pace, rhythm and timing that differentiates it from the other tube based power amps. The MC2301 tube power amp also compares quite favorably with McIntosh's newest solid state offerings.

OK, I've said all that to say this. All preamplifiers and power amplifiers, no matter the design concept or the manufacturer, have a sonic signature. Putting any two components together to assemble a preamplifier/amplifier package is as much about component synergy as it is about sonic signatures. It has been my experience with the solid state power amplifiers I have owned, most sounded best to me driven with tube preamplifiers. I can also tell you that the C1000C/P solid state preamplifier I drive my MC2301's with creates an incredible sonic performance. Ultimately it boils down to your taste, not mine, on what tickles your fancy. My suggestion to you is to audition the gear you are most interested in owning, preferably in your home, and make your decision on what gives you consistent goosebumps, and what doesn't.
Cheers......:wine:

[jbaudio68]

Dan, I totally agree with you, especially the last paragraph. I know I'm not alone when I say that you and the other fine people have saved us "learners" countless hours and dollars so that we know WHAT to audition. I read and re-read what is written. It's a passion and I love to learn. Perhaps I'm a little embarrassed to admit that before this forum, I was absolutely relentless with Frank Gow asking question after question. He was so patient as are you all. If I had a claim to fame it would be that on two occasions I actually taught him something which is how I ended up with Ib2s (long story but I had tie this back to the thread right? )

Anyway thank you and whomever I do purchase from will know that I respected them enough to do some homework. -JB

[jdandy]

Jermey.......One thing I have learned through countless auditions in dealer show rooms over many years, I am better informed and knowledgeable about the audio components of interest than the salesmen who hoped I would drop my cash in their registers. Having a salesman sell me on a component has never happened to me. I know exactly what I want, do my research, do my auditions, and make my decision. A salesman serves two purposes for me, work out an amicable deal that satisfies me and get my new component delivered. The rest is up to me.