Jump to content

Driving these AR3a speakers


Ray O

Recommended Posts

So I have determined I may be making huge mistakes in my choice of amp/speakers.  I have two pair of AR3a in very nice condition.  Driving them with a Pioneer SX-1280 (185W per channel).  I have one pair connected to Speaker A and the other connected to speaker B.  Usually drive both sets together.  These speakers are 4 ohm, and my receiver specs are written for 8 ohms.  There is even mention in the service manual where I may have problems with the limiter section of the amp driving speakers less than 4 ohm.  However, the guys at the local stereo repair shop say the amp should have no problem driving these speakers.  They do sound great, and I have not hit the limiter much and only when the gain is 80-85%.

So my questions; Am I making a mistake driving 4 ohm speakers with an 8 ohm amp?  And considering 185 Watts per channel may be too much, should I insert a fuse inline to protect the speakers?

Thanks, 

Ray

Link to comment
Share on other sites

the 1 pair of ar3a is 4 ohm nominal

 

driving 2 pair at once is 2 ohms or less

this is a HUGE no no.....especially with what amp you have.   the amp may have 185 w , but can it handle 4 ohm?  certainly I doubt it can handle 2 ohms.

1 pair at a time...moderate levels.....that amp should be ok.................but I recommend something better myself.   you will be sad if you take out some drivers....

Link to comment
Share on other sites

At certain frequencies, the impedance of the 3a can dip as low as 2 ohms, which means running two pairs may result in 1 ohm across the amp. 

You shouldn't even be running one pair of 4 ohm speakers on an amp rated for 8 ohm speakers.  Find another stereo repair shop.

Link to comment
Share on other sites

Ray

Please don't construe this as rude but you already know the answer. You blew 2 drivers. 

The Pio is a beautiful and powerful receiver but it can't handle those loads. According to hifi engine's site the amp can handle a minimum of 4 ohms but as Gene wrote the ARs can dip as low as 2 ohms and as you know, the Pio is only rated for 8 ohms.

There are lots of options for 4 ohm amps to drive the 3a's. Maybe use the Pio with a nice set of 8 ohm speakers.

Did the guys at the local shop know you were driving 4 AR-3's? If so, I'd say Gene is right (find another shop).

Good luck and keep us posted. Great speakers, great receiver. Just not together.

-Kent

Link to comment
Share on other sites

OK.  Thank you for telling me what I already knew.  And I was so hopeful.  I love this amp, and the speakers are oh so perfect.  With the blown AR3a I have substituted a pair of Bose 501s for the secondary speakers.  I can drive the heck out of these, and as long as I don't go above 75%, I do not have any problem with the amp limiter circuit.  

So, this brings another question.  What vintage receivers would drive the two pair of AR3a?  Maybe I should seek an external amplifier.  Any suggestions?

Really like this forum.

Link to comment
Share on other sites

20 minutes ago, Ray O said:

What vintage receivers would drive the two pair of AR3a?  Maybe I should seek an external amplifier.  Any suggestions?

I think your Pio has a Preamp Out. If so, you "could" keep the Pio tuner/preamp and add a couple of modern & powerful & cheap Crown amps. Something like the Crown XLS 1502. The 1502 delivers 525wpc into 4 ohms for $400. The XLS 1002 will give you 350wpc for $300. The subject of modern high power low impedance power amps for AR speakers has been discussed quite a bit in these pages. QSC is another brand. Or in the "almost vintage" category the Adcom 555 works well. I use a 555/II (325wpc) with some 4 ohm AR-91s.

-Kent

Link to comment
Share on other sites

Why not connect two AR3as in series (rather than in parallel) on each channel? It seems like this would solve several  problems simultaneously, particularly if you usually like to use both pairs together.  

 

Link to comment
Share on other sites

20 hours ago, Ray O said:

So, this brings another question.  What vintage receivers would drive the two pair of AR3a?  Maybe I should seek an external amplifier.  Any suggestions?

RAY, not vintage, but the Sherwood RX-5502 (see datasheet attached) would handle 4 AR-3a's.  Reason for this is this unit has 4 full range amps (i.e. 2 stereo amps) in a single box.  Each amp is rated 100 wpc at 4 ohms.

Beauty of this scheme is you get two independent volume controls so you can balance the two set of speakers to get similar volume in spite of room placement. With a single amp, one speaker set with dominant the other just due to its position in your room.

 

Regards,

Jerry

Sherwood-RX-5502-datasheet.pdf

Link to comment
Share on other sites

On 2/10/2018 at 9:39 PM, Ray O said:

So, this brings another question.  What vintage receivers would drive the two pair of AR3a?  Maybe I should seek an external amplifier.  Any suggestions?

Acquiring a vintage receiver or integrated you can trust to reliably to drive 4 AR3as will probably cost as much as 3 Crown XLS 1002s that each crank out  550w per channel at 2 ohms. 

 

On 2/10/2018 at 9:51 PM, genek said:

I doubt there has ever been any receiver made designed to run two pairs of four ohm speakers at the same time. If that's what you want to do, you need another power amp for the second set of speakers.

Maybe a Macintosh Integrated or receiver will do this. Their layout gives this impression, they have protection circuitry but they will not come close to the wattage of a digital power amp and even used will cost more than the smallest QSC or Crown and almost certainly have zero warranty. 

Link to comment
Share on other sites

You will lose 3db in series, however you will now have an 8ohm load.  You gain 3db for each additional speaker, so basically a wash.  How loud are you trying to go?  I would definitely concur on the pro amp route.  Crown and Qsc will both drive a 2ohm stereo load.  You would want significant headroom so as not to overtax the amp and get fan noise.  I would go for about 500 a channel.  Pro amps use IEC rating at 1kz.  Who I will be about 10% less if converted to RMS.  Hope that helps

Link to comment
Share on other sites

  • 2 years later...

I am frustrated in trying to replace a receiver for my original AR3a speaker pair.  I made a stupid mistake when my original receiver died..I forget which it was..1969.  I remembered a number of receivers from that time period & bought a Kenwood that ‘worked’ not realizing it needs to be refurbished whatever I buy.  This was 2013...died 2019.  I did folk singing + guitar & into those vinyls.  I have a Miracord phono.  The sound from these speakers has been a delight for this music.  I have never needed any service on the speakers. The receivers that have been suggested are Marantz 2230 only 30 watts.  Original booklet said only 25 watts needed,  but at 4 ohms I can get 45 watts out of a Marantz 2240B.  Then there is Pioneer SX780 also 45 watts then someone saidPioneer 850 at 65 watts worked well with these speakers..Yamaha CR-620 might be good.  I am a senior..HELP!

Anita

Link to comment
Share on other sites

2 hours ago, Anita said:

I am frustrated in trying to replace a receiver for my original AR3a speaker pair.  I made a stupid mistake when my original receiver died..I forget which it was..1969.  I remembered a number of receivers from that time period & bought a Kenwood that ‘worked’ not realizing it needs to be refurbished whatever I buy.  This was 2013...died 2019.  I did folk singing + guitar & into those vinyls.  I have a Miracord phono.  The sound from these speakers has been a delight for this music.  I have never needed any service on the speakers. The receivers that have been suggested are Marantz 2230 only 30 watts.  Original booklet said only 25 watts needed,  but at 4 ohms I can get 45 watts out of a Marantz 2240B.  Then there is Pioneer SX780 also 45 watts then someone saidPioneer 850 at 65 watts worked well with these speakers..Yamaha CR-620 might be good.  I am a senior..HELP!

Anita

If vintage is what you require the Pioneer 850 or 780 would be good but an old 850 that you could trust with your speakers would cost about as much as a new Cambridge AXR 85 which has everything you need + a warranty and also got a great writeup on this site about a year ago, though I can't remember the member's name right now.  User "Der" gave the Yamaha 701 integrated amp good marks, the Yamaha 501 which is similar but lower cost seems to have what you need if you don't require an FM section.

Adams

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...