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samberger0357

Kind of weird AR 3a amp question

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I presently have 2 amps that I can use with my restored 3a's: A Harman Kardon Citation 22, which is 200 watts@4 ohms, and has a high currrent mode, and a Nikko Alpha 230, which is 130 watts@ 4ohm, and is current limited. Both amps are fully restored. 

 

My dilemma is that the preamp I'm using is a restored McIntosh C24. While it's output impedance is not to be found anywhere, according to literature one should use amps that show a minimum of 47-50K ohms with it.  On another forum a graph was produced using the C24's schematic which indicated that McIntosh's recommendation was correct. The HK is 22K, and the Nikko is 50K. The HK produces more bass, almost to the point of bloat on some recordings, where it would seem the loudness setting is being used even if it's not. That said, it sounds very good overall. The Nikko produces less pronounced bass, and is a little drier, so it sounds more "accurate". 

So I'm looking for some guidance/thoughs  as to  the amp that  folks here would suggest using. It would be nice to find a high current amp with a higher load, but that doesn't seem to be in the cards at the moment. 

 

 

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Those are very good descriptions of the HK and Nikko power amplifiers, and probably what one should expect in this setup. And although the Citation is a beauty, I'd be inclined to use the Nikko, for its lack of plumpness with the AR-3a.

Just for the heck of it, have you considered a Mac power amp for your system, Sam? The MC2205 would play nicely with your C24, and its plain-faceplate version - the MC2200 - has been selling for about a thousand bucks, which is a pretty solid bargain. That amplifier will drive any speaker AR ever built, and sound great doing it. 

 

mc2200.jpg

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39 minutes ago, ar_pro said:

Those are very good descriptions of the HK and Nikko power amplifiers, and probably what one should expect in this setup. And although the Citation is a beauty, I'd be inclined to use the Nikko, for its lack of plumpness with the AR-3a.

Just for the heck of it, have you considered a Mac power amp for your system, Sam? The MC2205 would play nicely with your C24, and its plain-faceplate version - the MC2200 - has been selling for about a thousand bucks, which is a pretty solid bargain. That amplifier will drive any speaker AR ever built, and sound great doing it. 

 

mc2200.jpg

Thanks ar...

 

Yes I have been looking for the Mac's you refer to. In fact there's one not far from me with an ask of $1100 that I might make an offer on. But paying that much(or maybe a little less) for an amp that has the same power as the HK, and is not restored, does not bring me confidence that ultimately it would be worth it, or at least that I would find it that much better sonically. 

After giving it some thought after posting I think I'm going to leave the HK in there. The C24 would have to have an impedance of >1000 ohm to get to the 20-1 ratio that is considered reasonanble for amp/pre matches. And given the printed impedance info of similar era Mac pre's I'm  assuming it's lower. That it could be in the 100-200 ohm range that similar era Mac pre's were state at would make the HK a perfect amp for it. As I listen more to it, the bloat that I referred to really only happens on certain music. I was listenening to some of the new Dead Pacific Northwest box today and Phil's bass was huge on these speakers, but other music is much more in line with what I would expect from the 3a's. 

 

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You could be right.

 

FWIW McIntosh has informed me that output impedance for the C24 amp is 250 ohm, which makes it perfect for driving the HK22. So for the time being at least I'm going to sit tight. It sounds great with the 3a's. 

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Wow - that's a classic look. That series was the first that included the all-glass black front panel, back-lit gold lettering, and big blue meters (BBM).

I tried to buy a very clean MC2105 about  25 years ago, but  the power transformer had developed a mechanical vibration/buzz noise that was noticeable, so the sale fell through.

Be careful moving it around, Sam - lift with your legs! ^_^

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3 minutes ago, ar_pro said:

Wow - that's a classic look. That series was the first that included the all-glass black front panel, back-lit gold lettering, and big blue meters (BBM).

I tried to buy a very clean MC2105 about  25 years ago, but  the power transformer had developed a mechanical vibration/buzz noise that was noticeable, so the sale fell through.

Be careful moving it around, Sam - lift with your legs! ^_^

It's heavy, heavier still with the case. Moving this stuff around, speakers and amps, is my version of weight lifting. 

Wonderful sounding piece, jives quite nicely with the 3a's. I would say I'm set for the time being. 

 

 

 

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I'm with you on the McIntosh. I use the 2205 with a MX117 pre....and it is mighty fine with the AR3's. It brings out the butter smooth bass like no other unit I have had. The strength it puts into sound is hard to explain also.

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On 9/30/2018 at 12:47 PM, samberger0357 said:

Thanks. Interesting reading. 

yup,  it is!  My brother sent it to me.

 

got clean power?    thats important.

 

more important than most people think.   

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4 minutes ago, harry398 said:

yup,  it is!  My brother sent it to me.

 

got clean power?    thats important.

 

more important than most people think.   

Well you can see the amp that I'm currently using a few posts above yours. Unless you're talking about my home power, and yes, I believe that's clean, too. 

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I wasnt referring to YOUR amp.....just a general statement.

certainly the Tube crowd should take notice

 

I Myself can hear the differences in dynamic output between a good Yamaha rxv-2400 that measured 160 w @ 4ohms  Rms on my brothers equipment, to more dynamic action with the Kenwood m2a that measured 345 @ 4 ohm RMS.    to the mighty carver tfm 42 that measured over 550 @4 ohms.....and we arent able to even measure a dynamic output.    That is when The amp really shines.....in peaks...with no clipping.

the yamaha is a great sounding receiver.  I love it.   However, its only good till about -10db on its dial...then you hear it running out of steam......

 

sound quality is another issue, as i owned a crown XLI 2500.  Massive power.   crappy sound quality to my ears.   sold it off.  

 

 

Nothing personal here.....just sharing.

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