2 pairs of AR3a on one amplifier?

Not sure what you mean. Quite a few posts - including mine - advocating (directly or indirectly) a separate amp capable of handling a 2 ohm load (such as the Crown XLS or similar QSC units if cost is not an issue. More ideally, again given cost no object, would be 2 such amps, since the load of both pairs on one amp will sometimes be as low as nearly 1 ohm. Using two amps would of course keep the load on any amp above 2 ohms.
 
If the original question was one of running two of the AR speakers rated at four ohms in series or parallel for the safe load to the amp... I've played around with that many times using various speakers, not always of the same make and model... and two pairs of Advents, sometimes three pairs in a series parallel combination. Series connected speakers usually do not sound good... each speaker is 'isolated' from the amp by the other at the very least creating damping issues from the back EMF... but, and I don't know why, some speaker amp combinations are fine with it. Myself... with the thought if the amp blows I'll fix it, or protection will turn on... I always hooked them in parallel, including three pairs of Advents, and while the amp would run hot I never saw one blow up... and if you don't run it at high volume they didn't actually get hot either. On the other hand.... I have a couple of QSC GX3 amps rated at 300 watts per into eight ohms at 1 kHz at some low distortion number... less than .01 I think.. and I wouldn't hesitate to connect it to just about any impedance and run it at high volume all night... it has a clipping indicator which will let you know as well as built in protection against gross abuse... they are designed to survive hostile environments... and, they sound good running home speakers, most home speakers anyway, at any level you can take and they can survive. Sounds good down low too. I'm sure many high end audiophile amps will best the QSC in a head to head comparison but not necessarily in all situations... those pro amps are very well made and versatile. For three hundred dollars those ARs would be rockin' in parallel.
 
tyella said:
I just worked on 2 pairs of AR3a for someone who, it turns out, wants to run them both at the same time. I realize this will present a 2 ohm load, sometimes dipping even lower.

Does anyone have a recommendation? I'm hoping to avoid using 2 amps but realize this may not be possible.

I have a Proton amp that claims to be capable of pushing a 2 ohm load. However, at just 60 watts it may not have enough juice to push these speakers to their potential.

I want the guy to be happy with minimal complexity, if possible.

Edit: I should mention, he currently has a Sansui 990. According to the manual it's only rated to 8 ohms.
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One pair dips lower than 3 ohms already. And current demanded of one pair is very high. And you need in the neighborhood of 130 WPC for one pair for best results. Two pair, not very many amplifiers made can handle.
 
The AR1 and 1w had a jumper that put a 3.5 ohm resister into the circuit to make the speaker impedance 8 ohms. If one amp is essential and you have enough power, that might be the better way to go. Then you can run the two pairs in parallel.
 
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spark1 said:
The thread is long, but if you had a chance to look at earlier posts you would see that several Crown owners, and others, were quite positive about these amps. There is/was only one naysayer, and his argument was not a strong one. He thought he found a flaw with Crown's frequency response spec, but it turns out that Mcintosh (and most ofthers) measure it the same way. Not to be dissuaded, he then began questioning the power ratings, suggesting that they could not be real because the amps didn't weigh enough.

In any case, I don't think anyone else in the thread was questioning the quality of the Crown amps. I have no doubts that they would perform quite adequately, and then some.
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And continue to remain skeptical this side of scientific evidence to the contrary. Thus far, none has been presented. And certainly nothing about long term reliability let alone resale (investment) value which is of considerable importance to some of us. When something goes wrong with a $250 chip amp, tell me how happy you are for the $100 charge for the tech to say "Good Morning"? You won't, therefore it's effectively totaled.

Switching amplifiers have been in existence for decades and have yet to supplant tried and true Class AB designs.

It isn't for no good reason.
 
62caddy said:
...When something goes wrong with a $250 chip amp, tell me how happy you are for the $100 charge for the tech to say "Good Morning"? You won't, therefore it's effectively totaled.

Switching amplifiers have been in existence for decades and have yet to supplant tried and true Class AB designs.

It isn't for no good reason.
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For $250 I probably wouldn't even waste my time if the 3 year warranty was past (for example on Crown XLS series).
 
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whoaru99 said:
Well, I can tell you I'd lose a lot less sleep over tossing away a 3 or 5 or 10 year old $250 amp than having to send in an amp for which I paid $1500, but the authorized service center wants $3000 to go through it...and the amp is working, not broken.
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That doesn't sound remotely close to anything I've ever experienced after having owned over 30 Mc units and I've never done worse than break even on anything I've ever sold even when factoring in repair charges. (Not saying it can't necessarily happen either)

As always, YMMV.
 
62caddy said:
That doesn't sound remotely close to anything I've ever experienced after having owned over 30 Mc units and I've never done worse than break even on anything I've ever sold even when factoring in repair charges. (Not saying it can't necessarily happen either)

As always, YMMV.
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I'm not paying it, that's for damn sure. That'll go in the scrap heap too when/if it dies.
 
62caddy said:
Neither would I have in the example you provided.
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Bear in mind the amp was about $5000 in the mid-80s so it's not like they're asking more than it cost in the first place. And I bought it used 10 - 15 years ago. It's a great amp, but there are other great, newer, amps I could buy instead of a $3000 reconditoning bill.
 
tarior said:
Just put a 2.6mH inductor in series with one speaker and report back on how that sounds. Then add in back EMF, a woofer coil, and zero damping factor.
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What kind of argument is that? Every AR-3a has a 2.85mH inductor in series with the woofer and they sound just fine thank you!

With two AR-3a's in series, you have two coils and two woofers. Half of the available voltage will be divided across each pair.

As for back EMF, have you ever measured it or seen it on a scope? I haven't and I look at my scope a lot. I suspect electrical damping might mean something to infinite baffle, but doubt it means anything to acoustic suspension. The "trapped" air in acoustic suspension provides a strong mechanical damping that significantly reduces "ringing" experienced by other speaker designs.

Regards,
Jerry
 
I love how all the ones arguing a budget solution, insisting that's what was asked for and is the premiss of your suggestion and poo pooing best option. The op never said anything about a price and was looking for a non complicated best option. I also doubt they would want to reduce SQ even though they are running two pairs of speakers at the same time in one room

Best non complicated option the OP is looking for would be

A preamp/controller that has multiple outputs/zones that's selectable with a switch.
2 stereo power amps 1 for each pair of speakers
Or 4 mono blocks power amps 1 for each speaker

This system will have no loss, will not tax anything, give the choice of one pair or the other, and both at the same time.

IMHO I would have 50watts over the speaker ratting to cover transient peaks and recovery time.
 
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onplane said:
What kind of argument is that? Every AR-3a has a 2.85mH inductor in series with the woofer and they sound just fine thank you!

With two AR-3a's in series, you have two coils and two woofers. Half of the available voltage will be divided across each pair.

As for back EMF, have you ever measured it or seen it on a scope? I haven't and I look at my scope a lot. I suspect electrical damping might mean something to infinite baffle, but doubt it means anything to acoustic suspension. The "trapped" air in acoustic suspension provides a strong mechanical damping that significantly reduces "ringing" experienced by other speaker designs.

Regards,
Jerry
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With a heavily mechanically damped speaker system like the AR3a, the back EMF and destruction of damping factor are somewhat minor (though they will still negatively effect SQ) compared with the inductive reactance of the low pass filter and the woofer.

Running full range signal through low pass filters is not a recipe for good sound. To get from one system to the next, all of the signal has to pass through an inductor and a woofer, the high frequencies don't bypass those two inductors (woofers are inductive). Woofers aren't resistors, their impedance changes with frequency. Not a big deal, until you are trying to run your mids and highs through them and their associated low pass filters.

Just think about it from the standpoint as if you were only running the crossovers in series. No manufacturer (that I know of) ever does that.

As an aside, AR3a aren't "amp killers". Just about any quality amplifier/receiver in good repair can drive one pair of them just fine.
 
tarior said:
With a heavily mechanically damped speaker system like the AR3a, the back EMF and destruction of damping factor are somewhat minor (though they will still negatively effect SQ) compared with the inductive reactance of the low pass filter and the woofer.

Running full range signal through low pass filters is not a recipe for good sound. To get from one system to the next, all of the signal has to pass through an inductor and a woofer, the high frequencies don't bypass those two inductors (woofers are inductive). Woofers aren't resistors, their impedance changes with frequency. Not a big deal, until you are trying to run your mids and highs through them and their associated low pass filters.

Just think about it from the standpoint as if you were only running the crossovers in series. No manufacturer (that I know of) ever does that.

As an aside, AR3a aren't "amp killers". Just about any quality amplifier/receiver in good repair can drive one pair of them just fine.
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The speaker has both a low and a high pass filter separating the frequency band. The lows pass through the woofer and the highs through the tweeter. Those frequencies are recombined at the output terminal to the next speaker, where an identical set of low and high pass filters are waiting to divide the signals in the same way, at the same frequency. The signal to the second speaker has been frist split and then recombined. The highs going to the second speaker passed through the high pass filter and tweeter and were recombined with the lows at the second wire terminal of the 1st speaker.

Lets remember that even with only one speaker on a channel, all the current, at all the frequencies, pass through the speaker on its's return to the amp. The frequencies are separated to take different paths through the speaker but recombine at the output.

I find your analysis faulty in this instance.

Shelly_D
 
shelly_d said:
The speaker has both a low and a high pass filter separating the frequency band. The lows pass through the woofer and the highs through the tweeter. Those frequencies are recombined at the output terminal to the next speaker, where an identical set of low and high pass filters are waiting to divide the signals in the same way, at the same frequency. The signal to the second speaker has been frist split and then recombined. The highs going to the second speaker passed through the high pass filter and tweeter and were recombined with the lows at the second wire terminal of the 1st speaker.

Lets remember that even with only one speaker on a channel, all the current, at all the frequencies, pass through the speaker on its's return to the amp. The frequencies are separated to take different paths through the speaker but recombine at the output.

I find your analysis faulty in this instance.

Shelly_D
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That is so totally not how it works.
With full systems in series, the mids and tweeters in one enclosure are in series with the woofer and inductor of the other enclosure, and vice-versa. There is no way around that. Sure, some signal "goes around" the woofer/low pass through the mids/tweets, but you still have crossovers and drivers with inductive (and capacitive) reactance in series. You're going to get all kinds of phasing problems/shifts and poor midrange/high frequency linearity and coherence, lobing, combing, and gawd knows what else. I've tried it, before I ever had a clue about electronics or even knew what reactance was. It sounded bad then. It will sound bad now, and we'll know why.
Split hairs all day long, but there is a reason manufacturers don't operate passive (or any) crossovers in series.
It sounds terrible
I'm outta this one.
 
tarior said:
That is so totally not how it works.
With full systems in series, the mids and tweeters in one enclosure are in series with the woofer and inductor of the other enclosure, and vice-versa. There is no way around that. Sure, some signal "goes around" the woofer/low pass through the mids/tweets, but you still have crossovers and drivers with inductive (and capacitive) reactance in series. You're going to get all kinds of phasing problems/shifts and poor midrange/high frequency linearity and coherence, lobing, combing, and gawd knows what else. I've tried it, before I ever had a clue about electronics or even knew what reactance was. It sounded bad then. It will sound bad now, and we'll know why.
Split hairs all day long, but there is a reason manufacturers don't operate passive (or any) crossovers in series.
It sounds terrible
I'm outta this one.
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Sorry, tarior, but Shelly is correct. If you go back to my original post, you'll see I have equivalent circuit examples for several frequencies. Those "equivalent circuits" are correct.

What you are missing is within each box we have parallel circuits for the woofers, mids and tweeters. The woofer circuit creates a very high (several hundred ohms) impedance for high frequencies, thus no significant current associated with those frequencies will pass through the first woofer circuit. All that gets through are low frequencies which will also pass through the 2nd speaker's low pass filter. A similar situation exists for the high frequencies. The cap (and that's all there is in the AR-3a high pass filter) creates a very high impedance for low frequencies essentially "blocking" them, but it allows current associated with high frequencies through to the tweeter. Again, these high frequencies pass easily through the high pass filter of the 2nd speaker.

Some of your concerns can be legitimate when the speakers have different xovers and drivers, but that is NOT the case here.

One final confusion is which is the first speaker? There is no such thing since audio is AC! When the Red speaker amp output terminal is negative, electrons flow from it to the speaker connect to that terminal and return via the black speaker output jack. When the Red speaker terminal is positive, electrons flow from the Black speaker output to the speaker connected to it and they return via the Red jack on the amp.

Thus the immortal question: "Who's on first?"

Regards,
Jerry
 
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Wow - has this one spiraled downward. The OP asked for suggestions, replied pages ago, and is likely shaking his head ...
 
I'm just waiting for the request for recommendation as to what speaker wire to use for this connection to the amp. Maybe we can dig deeper.
 
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