AR 9 amplifier question

[69AMX390]

The AR 9 is biampable.  Which way do most prefer. 

True Biamp:  Is it best to use one amp for the lows and one amp for the mids highs?  Could I use a big solid state for lows and solid state, or a tube amp for mids and highs?  How big of a tube amp would be needed to reach full potential? 

Or, have a bigger beast of an amp to drive both lows, mids, highs.  

My preamp (Parasound P5) has 2 outputs.  That would be a plus for biamp.  

Currently using AR 90's with a PS Audio 200CX.  It is 200 watts/8 ohms, 400watts/4 ohms and 1000 watts at 1.5 ohms.  Seems to have plenty of power for these.  When I get my AR'9s recapped, I will need to buy another amp, or 2 if biamping.  

Any suggestions would be appreciated.       

       

[Aadams]

22 minutes ago, 69AMX390 said:

Any suggestions would be appreciated.

Page 33 of the AR9 manual on bi-amping the AR9.   Your PS Audio has plenty of power.

http://www.classicspeakerpages.net/library/acoustic_research/ar-9_series_1978-1981/ar-9_series_manuals/ar-9_manual/ar-9_manual_pg33.html#previous-photo

[ar_pro]

There have been several discussions of this topic over the years, with some very good opinions presented.

Here's a couple of threads:

 

[69AMX390]

My main question was to biamp, or not.  Which has the best sound?  The schematics of horizontal or vertical biamping were new to me.  Has anyone tryed monoblocks on AR 9's?      

[DavidR]

From the AR9 Manual

[Aadams]

The manual also says, to keep it simple, the amps should be identical in model and manufacturer.   The reasons are explained on page 32

 

 

 

[DavidR]

On 4/29/2021 at 12:19 PM, 69AMX390 said:

Currently using AR 90's with a PS Audio 200CX.  It is 200 watts/8 ohms, 400watts/4 ohms and 1000 watts at 1.5 ohms.  Seems to have plenty of power for these

The PS Audio amp is rated for 400 watts into 4 ohms which is what AR recommends for power on the AR9. It's also a very well designed amp and is probably a current pushing amp which is a good thing. I don't think you will gain anything from bi-amping. My amp is a high current, 500wpc into 4 ohm and I have two identical units and have never considered bi-amping. Simply not needed.

If you had an amp with less than 200wpc into 4 ohms then it would be something to consider.

[69AMX390]

First and foremost, I would have never have thought of biamping.  But, the AR 9's came with that option.  I assumed it must be better.    

All the comments are good, and appreciated.  I did read each and give them some thought.  I can see that bridging and biamping are potential problems.        

I wasn't really thinking bridged.  I was thinking using my big PS Audio amp for low frequencies (like sub).  And a higher quality amp for the detailed sounds(mids/highs).  I was wondering how I would keep the output of the speakers at a balanced volume.  I was thinking gain controls on at least one amp.  Now I see problems with volume, phase, imaging, and other unknowns.  Since this a problem, then I will have to go to plan B.         

If bridged, I definitely see where unmatched amps will cause problems.  Phasing, timing etc.  The music could be out of synch, or even blocked by noise canceling.  Bridging is definitely not a good option for me.  

I have always liked powerful amps.  Still have my Pioneer SX-1280 that I bought new(which I just dropped off to get a total recap/transistor replacement).  It is tempting to hook it up to the AR 90's and see how it sounds.  But, I know it will not take the low impedance of the AR speakers at higher volumes.  There is too much temptation to want to turn up.  So, I will have to pass on a smoke test.       

Plan B:  Since I have AR 9 and AR 90, I will need to buy another big amp.  I was thinking Aragon 4004 MKii.  It is 400watts at 4ohm.  I am also open to other amps, if someone has a favorite that works well with AR 9's.  Budget of 1k.  So, most likely used.        

   

     

 

  

  

[DavidR]

New, this amp (see link below) is above your budget but if you check out the Emotiva Lounge For Sale (Emporium) section someone might be selling one.

 

https://emotiva.com/collections/amps/products/xpa-dr2

 

The way to have balanced sound with 2 amps is to use 'splitter' cables from your preamp.

[lARrybody]

I run my 9's with one of these Crown XLS2502 Drive Core amps. I know it is a pro amp but it is crystal clear and deadly silent. I have never had the fan turn on. Somewhere around 700 watts per channel at four ohm's. All this for less than $700.00. And here's the kicker, this amp is 2 ohm stable.

 

[69AMX390]

That could definitely be something to consider.  I have been trying to factor in very expensive service on the older amps.  That is definitely a good price.  It is a class D amp.  Although class D is coming on strong, I have never heard one in a good system.  I will research more.  Maybe they have a trial period?  I could buy and give it a chance.   

 It would be a big change from the heavyweights I have been running since 1978.  Would love to play side by side.  I have 2-Parasound P5 preamps that would allow me to set up 2 systems side by side.  I have done it with big PS Audio amp and a Parasound HCA-1000 that I have.  200 watts compared to 125 watts.  Huge transformer/caps compared to smaller.  The 72 pounder wins.    

The HCA-1000 is a good imaging amp, and well detailed, but the old PS Audio has the low end grunt that just seems punchier and faster on the bass.  I am sure the big amp was twice the price (new).  It is power hungry and not energy efficient.  I have considered having to the PS Audio serviced.  I have found the schematic, but no service manual.  It would have to be local.  Shipping falls into freight category due to size and weight.                

[briodo]

On 5/2/2021 at 8:25 PM, lARrybody said:

I run my 9's with one of these Crown XLS2502 Drive Core amps. I know it is a pro amp but it is crystal clear and deadly silent. I have never had the fan turn on. Somewhere around 700 watts per channel at four ohm's. All this for less than $700.00. And here's the kicker, this amp is 2 ohm stable.

 

Yep, what @lARrybodysays. I was wondering when the XLS line would come up in this thread.  I have two XLS 2002, one each for my AR9 and AR9LSi.  There are some who believe sound reinforcement amps are subpar, but they sound pretty darn good to me.  

[69AMX390]

I have went back and read through the old posts presented in this thread, as well as current.  Great topic and previous answers. 

I am sure my PS Audio will drive them pretty well.  It does well on AR 90's I am currently running.    

Before I posted this thread, I bought a pair of Adcom 555 MKii amps.  I knew they were bridgeable.  I should have done more research, or posted a question.  Besides increased distortion in bridged mode, the manual, that came with amps, does not recommend low impedance loads (4 ohm and less) while bridged.  So, I guess plan B on those amps.  Can use one for AR 90's or set up another system.  I have a pile of amps, seems like good preamps are a lot harder to come by.    

[Mez]

I'm running a Conrad-Johnson Sonagraphe SA400 amp rated at 200w/channel bi-amp.  Seems to work fine.