Powering AR58s?

[sc-em]

Can I start by saying thanks to all the kind people who have helped me with my speaker posts. Great sources of knowledge and expertise on this forum. I thought my trusty AR18s bought new in the 80s (those good old days when you coluld take compenents in to hi fi shops and speakers to your system etc) were for the bin. But no. Foam on the way. A new kindled enthusiasm for old audio and some AR58 en route too. My Rotel not up to the job, so as you are all speaker gurus you must have qualty amps was my thinking. So any and all thoughts would be gratefully received. I hear the Sony ES are all good and Pioneer A400. Etc etc.      But as i have ARs like you guys. Well .........

[bitbandit]

I bought mine in 1984 in one of those hifi shops you describe. Rows of speakers, racks of amplifiers, oodles of turntables and cd players all connected via a switch centre so you could start with amp A, speakers A, then switch in speakers B, or C, then swap out Amp A and so on until you arrived at the perfect combination (for you, and in the shop acoustics of course, although they did try to make it as representative as possible of a living room). Anyway, at the time, I homed in on the AR58LS which is similar to the 58S but with a paper cone mid rather than the dome in your 58S. They sounded superb, and at their best (to my ears at the time) paired with the Technics amps of the time. Top of the range then was the SU-V10X. I couldn't afford that and went with the SU-V4X instead and I was well pleased with the setup when I got it home and set up. I still have my AR58LS but they are not my main listeners at the moment. I tried then with a modern so called audiophile amp whose name escapes me just now, that I was loaned a couple of years ago and they sounded dreadful. Really harsh and nasty, no bass at all. I was quite shocked, but swap in any high powered vintage amp and they sound great. So my experience, and it is only my experience of course, is that modern amps, at least the one I tried sounded pretty dreadful with the AR58LS. I currently drive mine with a Technics SU-V7X (which crop up on ebay from time to time) and they sound great. The 58 woofer appears a bit stiffer than the 3a and earlier and so sounds a bit less impressive with acoustic bass than the older speakers, but they are still great speakers, I love them. Good luck and enjoy both the restoring and listening to yours!

[sc-em]

Thanks. Good to see you were so impressed with the modern you can't even remember the name. lol. The Rotel is great for the 18's and may mate says my ears wont hear the subtly of the differences at my age........what I said!!!!

I had read a bit about the Technic range but didn't realise, much like the Sony ES lot, that they did 'proper' stuff. Growing up my dad had to have everything Sony. Stereo system, TV and of course Betamax video......bless.

[genek]

The problem with modern amps is that their power ratings are bogus compared to the stricter standards used in the 70s and 80s. An amp rated at 30wpc in 1975 produces more continuous power than one of today's so-called "100wpc" products.

100wpc of continuous vintage power or 300wpc of today's "1khz" power @ 4ohms should do a decent job with a 12" AR speaker.

[sc-em]

Hmm!  It's this ohms bit I can't get my head around. A lot of amps seem to be 8 ohms. The Sony F530ES I am looking at is 8 ohms, but I assume will still do a very good job?

Not considering anything new!!!

[Jeff_C]

I'll try and explain the Ohms rating.  Years ago the nominal impedance of many speakers was 8 Ohms. Amplifiers therefore gave specs relating to the output power available into 8 Ohm speakers. That spec does not mean that the amp will not work with 6 Ohm speakers (which are very common these days)  or 4 ohm speakers. The power spec should ideally state the continuous power or r.m.s. power available, rather than peak power, and it is helpful to see low distortion figures quoted when both channels are driven.

[Jeff_C]

3 hours ago, genek said:

The problem with modern amps is that their power ratings are bogus compared to the stricter standards used in the 70s and 80s. An amp rated at 30wpc in 1975 produces more continuous power than one of today's so-called "100wpc" products.

I do not think they are bogus, but can be confusing. I have just dug out the operating manual for my Trio KA1500 amp which I bought in January 1977 for 75 GBP. It has been a great amp. The only mention of power is the amount the amp consumes "Power Consumption 250 W at full power". Absolutely no other info' about power. I always understood the amp to be 25 wpc amp. I used that with my AR speakers for many years and the amp is still working today. I was always very happy it.

Contrast that with the specs given for the 11 year old AV amp I bought September 2005 for 350 GBP. I now use that Yamaha DSP-AX757SE, and am also happy with it.

Minimum RMS Output for Front, Centre, Rear, Surround, Surround Back,  20 Hz to 20 kHz 0.06% THD, 8 Ohm.....100W

Maximum Power (EIAJ) 1kHz , 10% THD ....140W

Dynamic Power (IHJ) 8/6/4/2 Ohms ...135/170/200/245 W

DIN standard Output Power  1kHz, 0.7% THD, 8 Ohm ...150W

IEC Output Power  1kHz, 0.06% THD, 8 Ohm ...110W

 

[Kuja]

I'm powering my AR-90 speakers with Mission Cyrus Two amp with external PSX power supply.

It is a high current amp and I'm very satisfied with this combination.

http://www.cyrusaudio.com/support/legacy-products/integrated-amplifiers/2-integrated-amplifier-all-versions

 

 

 

[Sonnar]

AR 58s arent' t a difficult load as classic AR : a good vintage power amp like a SAE 2200 could easily drive it. But a very reliable and affordable modern powerful amp like QSC RMXa 850 sounds better. 

[sc-em]

Thanks for input. I will take a look. 

Jeff. Your message would seem to suggest dont get hung up with ohms. Yes? 

[Jeff_C]

Exactly, no need to dwell or get anxious over th eOhm rating.

[michiganpat]

We finally rearranged our living room so I could fit my 58S's...I have them paired up with my uncle's old marantz 2265 and they are a phenomenal combination.  any marantz 22xx series in the 50+ watt range should work great.

[DavidDru]

SC,

Are you looking for an integrated amp, amp or receiver?

If just looking for an amp, the Adcom amps are a great value.  You could do just fine with something like a GFA 545 or the newer 5400.

[sc-em]

Integrated amp, similar to my Rotel but with more oomph!!!! Marantz is such a cool sounding name. lol

[genek]

19 hours ago, Jeff_C said:

I do not think they are bogus, but can be confusing. I have just dug out the operating manual for my Trio KA1500 amp which I bought in January 1977 for 75 GBP.

Sorry, I should have been clearer. I was talking about US power ratings.

Back in the 70s, the US FTC implemented requirements for amplifier power ratings based on continuous power into rated load, because the various "maximum," "average," "dynamic," "peak," etc. rating methods made it pretty much impossible to compare products.

One of the most challenging requirements was that prior to testing, the amps had to "cook" for an hour, under load, at one-third of their rated power output prior to testing. The result of this was a decade of amplifiers that typically outperformed their ratings and gained reputations for being "bulletproof." But then the industry persuaded the FTC to reduce that to one-eighth of rated power, which resulted in many amps instantly achieving a nearly 100% gain in rated power, and since then the FTC has stopped even requiring that the FTC rating be used in advertisements, which has led to the return of all those other power rating methods. 

So yes, compared to a 1970s amp whose specs state FTC continuous power, the specs listed in ads for most modern consumer audio amps sold here in the US are useless. You have to go relatively high end to find a manufacturer who still advertises continuous power ratings, and if you want to compare one of their amps to one from the 70s, reduce the continuous power rating of the modern amp by about 40% to compensate for the relaxed preconditioning requirement.

[Jeff_C]

Fair enough genek. Although I am reasonably clued up, I have no idea how amps are tested under all those different standards for my Yamaha amp shown in my last post. What's more I cannot be bothered to find out. I always advocate getting plenty of power, and too much available power is much better than not enough.

[DavidDru]

So if looking for an integrated amp I would probably look at some of the Sansui's.

NAD has always had some nice ones too.

I have an outstanding Pioneer SA-9100 (recapped) that would be a nice piece, but you may be looking for more "oomph".

[sc-em]

Don't seem to have come across many Sansuis up to buy. The odd Sony ES and Pioneer, a Cyrus sounds interesting.

But before I continue that search. My 58s have arrived and on both of them the block that holds the speaker cable posts has become detached. It looks like someone has tried to stick them back on with araldite which has broken. What is the preferred methods and best way to gain access. I suppose the woofer is so big, that may be the way. I just hope that all the moving around in transit wont have done any more damage.

[ra.ra]

It appears that the original binding posts have already been replaced, and it also looks like the entire crossover assembly panel has been removed and re-glued. As a start, it would be prudent to first confirm that your speakers have the original and appropriate drivers; then you might want to remove the woofer(s) and the fluff fill to examine the state of the crossovers. 

Two other points: many components from that Sony ES series are very good electronics; and this fairly recent thread has other members commenting on their AR-58s speakers.

 http://www.classicspeakerpages.net/IP.Board/index.php?/topic/8787-ar-58s-the-lastest-of-the-bestest-12-inch-bookshelf-speakers/ 

 

[JKent]

18 hours ago, genek said:

But then the industry persuaded the FTC to reduce that to one-eighth of rated power, which resulted in many amps instantly achieving a nearly 100% gain in rated power, and since then the FTC has stopped even requiring that the FTC rating be used in advertisements

Thanks for that info Gene! My head must be stuck in the '70s because I remember when the requirement to report true RMS power came about and just "assumed" it was still in effect 

So that's why our favorite vintage amps are described as having "big" watts. And my AR receiver with "just" 60 wpc rms seems to drive the 3a's just fine (although I do use an Adcom 555/II for the 91s.

-Kent

[nfmisso]

The AR58S is a book shelf version of the AR91 with similar amplifier desires.

Adcom 545 or 545/II works well for smaller rooms.  In older equipment, I am huge fan of the Onkyo TX8500 receiver.  The TX6500Mk2 and TX8500Mk2 will also work well.  I would not go below 100W ("BIG WATTS") per channel.

[ar_pro]

IIRC, some amplifiers of the era had problems with the required pre-conditioning component of the test, wherein an amplifier would simply overheat or shut down.

Here's the FTC Rule release from 1974:

[sc-em]

2 hours ago, ra.ra said:

It appears that the original binding posts have already been replaced, and it also looks like the entire crossover assembly panel has been removed and re-glued. As a start, it would be prudent to first confirm that your speakers have the original and appropriate drivers; then you might want to remove the woofer(s) and the fluff fill to examine the state of the crossovers. 

Two other points: many components from that Sony ES series are very good electronics; and this fairly recent thread has other members commenting on their AR-58s speakers.

 http://www.classicspeakerpages.net/IP.Board/index.php?/topic/8787-ar-58s-the-lastest-of-the-bestest-12-inch-bookshelf-speakers/ 

 

These are they if this is any help for identification purposes. If I take the woofer out tomorrow and take some more photos would that make internal diagnoses easier I assume, and hopefully if all well then get some advice on how best to secure the binding posts?

[genek]

53 minutes ago, ar_pro said:

IIRC, some amplifiers of the era had problems with the required pre-conditioning component of the test, wherein an amplifier would simply overheat or shut down.

I used to be a test engineer. In technical parlance, this would be what we used to call "failing."

 

Here are some general guides for comparing new amps to old. 

If the amp rating is continuous power over a frequency at a stated impedance and distortion (i.e., 100WPC, 20-20kHz @ 8 Ohms, 0.01% THD) and it was made after 2000, divide the rated WPC by 2.

If the amp rating is "maximum," "average," "dynamic," "peak," "music" or any other power with a gobbledygook name stated only at 1kHz, divide the rated WPC by 4.

[fedeleluigi]

On 11 gennaio 2017 at 9:29 PM, sc-em said:

These are they if this is any help for identification purposes. If I take the woofer out tomorrow and take some more photos would that make internal diagnoses easier I assume, and hopefully if all well then get some advice on how best to secure the binding posts?

hi sc-em,

your speakers are AR 58 B or LS (not 58 S). The name of these speakers was written on the tweeter-midrange flange just over the tweeter dome. The picture you posted is not focused and well-defined so the exact name is not readable.

Luigi