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Amplifier Recommendations for AR10 pi


reza

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help needed on choosing an integrated amp that will go with my newly acquired  AR10s , any recommendations appreciated 

I'm in the UK looking to spend up to about 500 on a second hand amp and a bit confused as to what to choose especially with the 4 to 16 ohm  impedance of the AR10s 

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I know nothing about Brit amps. 220V, 50Hz, funny-looking plugs and they're on the wrong side of the road ;) but I find this discussion interesting. So here are my admittedly ignorant questions. I answered the first with a little googling:

  • The Leak 70 has "Loudspeakers 8-15 ohms" printed on the back. Ah! Just read the 10pi lit. They can be switched for 4 to 16 ohms impedance. Cool. I assumed they were 4 ohm like other AR 12" speakers. You know what happens when you assume.
  • I don't know about prices on your side of the pond but always admired Tandberg gear. 
  • Arcam?
  • How about a vintage Japanese amp? Looking at ebay.co.uk there are some very cool looking (IMHO) vintage Japanese amps in your price range: Pio SA-506, Hitachi HMA-7500, NAD 60 (you can tell I like VU meters),  Trio (AKA Kenwood) KA-7300,  Kenwood KA-7150, 

Sorry--I know this isn't helpful but it was fun to look at what's available in the UK. Good luck with your quest and congrats on scoring the 10pi's!

Kent

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Well, I have no experience with the 10pi. I DO have experience with the 3a and 91. Those 12" ARs are strictly 4 ohm and they do like a lot of power. That's an advantage of the Japanese integrateds--in the '70s and '80s they were engaged in wattage wars and some of them were crazy powerful. The Japanese also resorted to a certain amount of hype, so you have to be careful.

I use an American made Adcom 555/II power amp rated at 200 wpc RMS at 8 ohms and 325wpc at 4 ohms. These are conservative ratings and the amp provides all the power the 91s would want. Of course room size is also a factor. For the AR-3a's I use a modified Hafler DH-200. It's rated 100wpc into 8 ohms and 150wpc at 4 ohms. 

In my opinion an integrated rated for 100wpc RMS @8ohms would suffice but even though the 10pi has the ability to switch from 4 to 16 ohms I'd look for an amp that can handle 4 ohm loads. That's just an abundance of caution and I'd hope to hear from members who have experience with the 10pi.

Kent

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I drive my 10Pi with a 60wpc (in pentode) tube amp and no problems.

So your 35wpc into 8 ohm would be close to that BUT is it rated for 4 ohm ?

The 10Pi level controls actually change the impedance of the speaker (4 to 16 ohms)

I leave mine in the 4 ohm position as my amp is internally wired for 4 ohm.

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Based on AR’s power recommendations for the AR-11 (basically 4-ohm AR-10pi’s with their controls set to 2pi), 45 wpc would probably be sufficient. 

image.png.3189c929a01a122a541b343c21a044d8.png

A 3000-cubic-foot (85 cubic-meter) room is not small

If you are thinking about getting a vintage Japanese integrated amp, I would consider Pioneer.  I purchased a Pioneer SA-7500 integrated amp new 44-years ago.  I used it for about 30 years.  First powering a pair of KLH-6’s and then a pair of AR-14’s.  Then after spending some time on a closet shelf, I got it back down, cleaned it up and gave it to my daughter.  She has been using it to power a pair of 4-ohm AR-98Ls’ for the past 8 years, and has never had a problem.  She says the amp will get warm to the touch, but it never runs hot.  The 4-way 98Ls is probably more power hungry than either the 11 or the 10Pi. 

The SA-7500 is rated at 40 wpc into 8 ohms & 45 wpc into 4 ohms.  If you are interested in a Pioneer, you may want to step up to the SA-8500, which is rated at 60 wpc into 8-ohms & 75 wpc into 4-ohms.   Both should be available for less than $500.  I would stay away from Kenwood amps from that era, as some of them had issues with IM distortion.

 

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8 hours ago, DavidR said:

The 10Pi level controls actually change the impedance of the speaker (4 to 16 ohms)

So the three level control switches , bass  pi 2pi 4pi  , mid and high -6db -3db 0db  actually change the impedance  so 4ohm is pi / -6db I thought they were all about sonics or is impedance sonics 

Sorry new speakers for me 

Thanks to all for your help

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18 minutes ago, DavidR said:

Its a photo from the internet just to show the labelling.

4 ohm would be with all switches to the left.

Sorry.

Really confused now the manual says highest impedance as -6db and pi (switches to  the left)

 

image.thumb.png.71fb9f31192cb36086d45d9a553dd3ea.png

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3 minutes ago, DavidR said:

I've read that the highest is 16 ohm but was on a site that lists all AR speakers and their specs. The AR Manual would be more accurate.

 

 

It is 4 to 16 ohm its just the switch position thats confusing me

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You just need to set the switches to what sounds best for you and not worry about the impedance.   It will vary across the audio spectrum regardless.  As long as your amp can handle a minimum of 4 ohms you will be fine.  

I have attached 2 pages from an AR brochure that explains the pi, 2pi & 4pi settings.  The other two switches just boost or cut the midrange & high-range responses.

 

891158840_AR10pi-1.thumb.jpg.c490d80407a7dd6f68d5b27112e4f8e4.jpg
 

AR10pi-2.thumb.jpg.1619c79691a40ec2712a4beebce60872.jpg

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16 hours ago, AR55 said:

You just need to set the switches to what sounds best for you and not worry about the impedance.

Depends on what amp he has as to whether he can do that. Many amps, especially tube amps, either have external taps for the different impedances or are internally wired like my tube amp. Would it work? Probably. Would it sound its best? No.

If I understand him correctly he was wanting to know what position the switches should be in for 4, 8 and 16 ohm. All to the left for 4 ohm, all in the middle for 8, etc. This does not mean the 3 switches all need to be in the same position. i.e. one can be all the way left, another in the middle and the 3rd to the right; or any variable that gives the best sonic results.

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I think that everyone is overthinking this.

The 10π’s specs show that the its nominal impedance is between 4 ohms and 8 ohms (see full specs below).  I couldn't see where 16 ohms is ever listed.  It is possible that its impedance could peak to as high as 16 ohms, but it would still have a nominal impedance of between 4 ohms and 8 ohms.  Almost every speaker’s impedance peaks above its nominal rating at multiple points over the audio spectrum. 

A case in point is my daughter’s AR-98Ls speakers.  In January 1985 Audio Magazine reviewed the AR-98Ls.  Their tests showed that for most of the audio spectrum the impedance of the 98Ls remained between 3 ohms and 5 ohms (confirming the nominal 4-ohm rating).  It did, however, rise up above 5 ohms a few times with the highest peak being 12 ohms at 30hz.  Her vintage Pioneer SA-7500 has no problem powering those speakers.  The same would be true if it or any other well-made £500 or even $500 solid state or tube amp, rated at both 4-ohms & 8-ohms, was used to power the AR-10π.  This would be true regardless of how the 10π’s switches are set. 

Again, I think you should set your 10π’s switches to give you the best listening experience.  For the best bass response, the π switch setting should logically be based on the placement of the speaker in your room.  For what it’s worth, I own the AR-11, which is basically an AR-10π without the π switch and the accompanying additional crossover circuitry.  My speakers are placed in a 2π position.  In my room, they sound the best to me with the midrange switch set to -3 db and the high range switch set to 0 db.  My wife thinks that they are a little bright at this setting, but not unpleasantly so.

image.thumb.png.4d2f98cfd27b7d107d579e979fbf39ba.png

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I don't see the problem, the three switches still serve to attenuate the three speakers to make them uniform correctly to the environment and to the type of listening you prefer.
They are not used to have a conformable speaker from 4 to 16 ohms, but to change the delivery and perception of sound.
Then you can match an amplifier that works well with all the loads produced by the AR10PII.
If with high power the better.

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