Powering my AR3a’s

[darren8]

Hello to all,
I was hoping to get some advice. I have a pair of restored AR3a speakers. I’m currently driving them with a Pioneer Sx-3900. I’ve been thinking about getting an integrated amplifier and selling off the pioneer to help pay for the amp.
I’ve been looking at the Marantz Pm8006 which is going for $1,199 everywhere and is getting very good reviews. My budget for the amplifier is 1200. So the marantz did nicely. Question is would I be better off keeping the pioneer and getting it completely restored. The rest of my system is a Marantz Cd6006 and a technics sl-1700 I mostly play vinyl. Thanks in advance for your response

 

[trinhsman]

I’d probably do the Marantz, or if you can find a restored vintage Marantz, go for that. Some AK members might have a restored Marantz in your budget.

 

[Tim D]

A restored vintage Marantz might hold its value better. New units will likely depreciate rapidly, but vintage will usually hold value or rise in value. Also, vintage Marantz would be a good match. Keep in mind though that vintage comes with challenges and costs to keep them running well. It's a commitment.

 

[audio-ed]

For $1200 you will have a lot of choices when it comes to vintage. That will cover purchase price and cost of restoration in most cases. I've never owned anything new so i can't comment there , but I'd keep vintage speakers with a vintage amp / receiver.

 

[darren8]

Seems like the popular opinion is a vintage marantz. I worry a little bit about that because I’m not a fix it yourself kind of guy. Any thoughts on my current Pioneer Sx-3900 like putting some money in to it to restore it? Or maybe even buying a more powerful receiver. The pioneer sounds good and I like the look I’m just always very careful about cranking it up to high.

 

[macyjrm]

I doubt if more power is going to sound any better to you. Remember it’s the first watt that’s most important. For me, I would have someone go through that Pioneer top to bottom for a complete restoration. You will also save a bunch of money this way.

 

[darren8]

I doubt if more power is going to sound any better to you. Remember it’s the first watt that’s most important. For me, I would have someone go through that Pioneer top to bottom for a complete restoration. You will also save a bunch of money this way.

I like that idea thanks

 

[Drugolf]

There is a great thread over at Classic Speaker Pages about powering Ar3's that might be worth a read. They can be finicky to say the least to get out their great full potential.

 

[darren8]

There is a great thread over at Classic Speaker Pages about powering Ar3's that might be worth a read. They can be finicky to say the least to get out their great full potential.

Great full potential? I think you’re speaking my language LOL

 

[Silentnet]

3as aren't that power hungry (at least by modern standards). The most important question is, what aren't they doing now that you think restored amplification / new amp will fix?

 

[Drugolf]

3as aren't that power hungry (at least by modern standards). The most important question is, what aren't they doing now that you think restored amplification / new amp will fix?

Oohh, I don't agree with that for the most part. I think most would say they absolutely love power and really shine with a little oomph behind them. Not many receivers do very well with them. Moving that wonderful woofer in those heavy tightly enclosed cabinets is a lot of work.

 

[Imprecise]

From everything I see, the Marantz unit is an excellent unit. The only concern I might have is that the AR3a is fairly low sensitivity (rated 86db) and the impedance can drop way way down at low frequencies (like under 2 ohms). The Marantz is rated at 70 wpc at 8 ohms and 100 wpc at 4 ohms. I suspect it could run out of available current at very low impedance and high volume levels.. You might go into serious clipping if you play bass heavy music really loud. This can even result in blowing the tweeter in extreme cases. But then I ran a pair of AR3a with a ST-120 (60 wpc by 1969 standards, not much oomph available at low impedance) for years at sometimes insane volume levels. Although tweeter failure was always in the back of my mind, it never happened.

 

[darren8]

3as aren't that power hungry (at least by modern standards). The most important question is, what aren't they doing now that you think restored amplification / new amp will fix?

I’m pretty happy with the sound my only concern is that the pioneer may be under powering them and I would like to crank them a little more with out fear of blowing them out

 

[darren8]

I guess with 120 watts per channel into 8omh I can probably feel pretty safe. Maybe I take silentnet’s advice and put the money into restoring the pioneer. And put the rest into some good msfl’s

 

[Imprecise]

I’m pretty happy with the sound my only concern is that the pioneer may be under powering them and I would like to crank them a little more with out fear of blowing them out

I know of other people blowing a tweeter on an AR3a with an under powered amp. But keep in mind that 70 wpc today is a lot bigger than my 1969 60 wpc. Back then power/distortion ratings were typically taken at 1k Hz instead of across the audible spectrum like now and test conditions were not as strict as they later became. So the picture I painted may be rather overstated. If you do not go completely insane on volume levels - like cranking it up so you cannot hear even someone else speak like we did way back then - you should be OK if you only go half crazy.

 

[Silentnet]

Oohh, I don't agree with that for the most part. I think most would say they absolutely love power and really shine with a little oomph behind them. Not many receivers do very well with them. Moving that wonderful woofer in those heavy tightly enclosed cabinets is a lot of work.

...my idea of "hard to drive" is, to be fair, pretty skewed.

 

[Putterman]

While I tend to agree with the consensus that you're unlikely to get an improvement subbing the new albeit lower wattage Marantz, there are some options. Both the Pioneer and Marantz have preamp in/power amp outs, i.e. using the new Marantz as a preamp and the higher powered Pioneer as a power amp or vice versa.

My gut says to get the Pioneer restored if you know a good tech or can DIY, because you can likely get most of that cost back if you sell it and also as an insurance policy that it will continue to work. You might then look for a power amp to make those AR's boogie.

 

[twiiii]

Which, whose, what am I hearing. 70 watts is 70 watts, 60 is 60. Now if we are talking perfect SS amps with big power supplies and lots of heat sink area it might be true todays amps rated at 8 ohms might put out more than an older amp at 4 ohms. But if you are talking top of the line there isn't going to be much difference. If you are speaking about budget pieces I will consider your statement to be mostly true. My D-150'a's did very well at 8 ohms and 4 ohms and were very stable down close to two ohms. HAfler amps performed well to below 4 ohms. A Mcintosh MC 7100 rated at 100 watts would put out close to 300 approaching 2 ohms. Pioneer and Marantz SS separates were good, too. Though Sansui had a great sound they didn't perform that well approaching or going below 4 ohms on some models. Kenwoods, Aiwa, Sony, and others didn't do well with 4 ohm loads. I am not sure about todays pieces either. Units using output modules should be looked at with caution. Class D amps and amps with switching power supplies may be able to put out the power, but what about the quality? Remember Quality first, quantity second. I 'd much rather have 40 high quality watts with great signal to noise than 70 watts of so so quality. remember we are talking in your case less than a couple of Db and it takes almost 4 db difference in power output capability to make any appreciable difference. If your amp is only rated at 70 watts that isn't enough for AR-3a in a larger room. 1 watt is 85 db at 4 ft or about 77 db at 10 ft. Average people listen at 85 db for pop music played rather loudly and figure 6 db peaks. thats 91 db. Or in your case about 50 watts. So 70 leaves you very little head room for life like presentations. That is what Hifi is all about. Life like realism. If thats your thing, then some changes have to be made. Thats why I never considered AR-3 or 3 A's. They required to much power in the late 60 and early 70's for the amount of sound level I wanted. My Speakers are rated 95 db 4 ft I watt. Most of the time I listen at 2 watt levels for loud passages with very rare 20 watt peaks. That would mean 200 watts for AR-3/3a, which is way beyond its capabilities.

 

[Imprecise]

The Dynaco ST-120 was introduced in 1966. In those days power ratings were rather less than honest. Dynaco was among the most honest, giving continuous RMS power into 8 ohms at 1K Hz relative to the rated distortion. Some other vendors gave the 4-ohm rating without saying so, added the two channels together, ‘music power’ (brief peaks), power at clipping at 1K Hz or even the thoroughly dishonest ‘peak power’, power calculated from peak to peak voltage, i.e., twice the real power. Or all of the above. Or just plain lying. The FTC put the kibosh on all of that nonsense in a series of rulings that would ultimately even forbid having the sum of the two-channel power rating appear in the product name.

One of the FTC rulings was that the power rating and associated distortion level had to be over a specified frequency range. Pretty much everyone used 20 Hz to 20K Hz because to not do so would look like an admission of inferiority. Which brings us to power bandwidth. One rarely sees this rating these days. What it meant was the frequency bandwidth over which the rated distortion would not be exceeded at a power level no lower than -3dB from rated power. The ST-120 power bandwidth rating was 25 Hz to 15K Hz. That is, it would not exceed the rated distortion at half power (30 wpc) until the frequency went below 25 Hz or above 15K Hz,

If the modern practice of giving the power rating relative to the rated distortion over 20 Hz to 20K Hz, the ST-120 would probably be rated at about 25 watts per channel.

 

[Imprecise]

"Which, whose, what am I hearing. 70 watts is 70 watts, 60 is 60."

The Dynaco ST-120 was introduced in 1966. In those days power ratings were rather less than honest. Dynaco was among the most honest, giving continuous RMS power at 1K Hz relative to the rated distortion. Some other vendors gave the 4-ohm rating without saying so, adding the two channels together, ‘music power’ (brief peaks), power at clipping at 1K Hz or even the thoroughly dishonest ‘peak power’, power calculated from peak to peak voltage, i.e., twice the real power. Or all of the above. Or just plain lying. The FTC put the kibosh on all of that nonsense in a series of rulings that would ultimately even forbid having the sum of the two-channel power rating appear in the product name.

One of the FTC rulings was that the power rating and associated distortion level had to be over a specified frequency range. Pretty much everyone used 20 Hz to 20K Hz because to not do so would look like an admission of inferiority. Which brings us to power bandwidth. One rarely sees this rating these days. What it meant was the frequency bandwidth over which the rated distortion would not be exceeded at a power level no lower than -3dB from rated power. The ST-120 power bandwidth rating was 25 Hz to 15K Hz. That is, it would not exceed the rated distortion at half power (30 wpc) until the frequency went below 25 Hz or above 15K Hz,

If the modern practice of giving the power rating relative to the rated distortion over 20 Hz to 20K Hz, the ST-120 would probably be rated at about 25 watts per channel.