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Basic questions from a basic mind.


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hello all,

just a few questions to amuse the technically adept, and further prove my own shortcomings. first, and possibly most embarassing, how do i remove the grills on my ar 2ax speakers? how can i muster the confidence to replace the foam surrounds and possibly the L-pads if i cant get the d#*$ things off? i just finished the cabinets and would like to keep them looking pretty - will this prove a challenge? i see re foaming kits on ebay for $10 - can this be? are they selling a quality product or binder paper and paste.

how can one figure the watts per channel of a receiver based on the total wattage listed on the back -- is their a correlation?

how can i have such fervent interest in classic audio equipment and be so technically dim?

how much bearing does the quality of a cd player have on the sound of a system? would a sony discman hooked to a classic amplifier and speakers cause the acoustic elite to faint?

how can one posting with so many moronic questions beg for thoughtful response?

noah.

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I will leave the other questions to the better qualified.

You will have to pry the grills off with care. A putty knife will work. Start with the long sides, and then move around the perimeter until the glue breaks free. In the 1960's, AR used staples to hold on some grills, instead of hot glue. If this is the case, Remove these staples with care.

Many of us are very fond of the AR-2ax, however, it is important to note that there are actually 2 versions of this speaker. You should know which version yours is.

There is a 1965-1969 version most easily identified by the dual "ARInc" and "a" badges. There is also an updated 1970-1976 version identified by a single "AR-2ax" badge. Both versions suffer from corrosion on their level controls however, the earlier version has a cloth surround and obviously does not require new foam. Let me know which ones you have so we can better help you.

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Mr. Evans

thank you for your prompt reply. i will follow your suggestions for removal of the grills. i have the later version of the 2ax and fear i suffer from rotted surrounds. using a flashlight to peer through the grills i see pathes of metal where foam should be. do you have any knowledge of variations in quality in replacement foam surrounds? thank you again, noah.

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I am not sure about the different surrounds on the market, perhaps someone else may have some insight. The woofers will be sealed to the cabinet with either a foam gasket or a petroleum based compound. If you have the compound, save it for reassembley.

You have the improved, more open sounding version of the AR-2ax. This version has lower crossover points than the first version. This brings in the wider dispersion drivers sooner. You also have one of the new style 10" woofers, the same as the one in the costlier AR-5. It crosses over to the 3.5" cone mid/tweeter at 1400 Hz. The .75" dome tweeter takes over at 5000HZ, just the same as the AR-5 and AR-3a.

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mr. Evans (and all more informed than myself.)

again, thanks for your attention to my question and the additional information on cross over frequencies. the grills have been successfully removed and, as is so often the case, this minor triumph is followed with further question and concern. it sounds as though the super tweeter is quiet or absent and now with the grills removed corrosion is apparent. the corrosion is focussed on three points just outside the dome. can and should these be cleaned? the controls on the back of the speaker dont seem to be responsible here, as they were initially with the mid range. (upon first playing the speakers one month ago i was horrified before discovering adjustment of the mid control allowed for spots still in order, and capable of mid range sound production.) How might i test for the condition of the tweeters - blown, quiet, or otherwise? oddly one tweeter has a badly dented dome, and as i am the first to remove the grills, hot glue and all, i find this mysterious. if the tweeters do need replacement, will the red domed older version work equally as well? apologies again for the barrage of questions. noah.

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The older 1 3/8" phenolic "Red domes" are not a suitable replacement, as they are designed to work with the older version of this speaker and it's 7500 HZ crossover.

There is no corrosion to worry about ON your tweeters. The corrosion is in the level control pots. This is almost always responsible for the loss of sound to the tweeters. Tweeters seem to get it worse than the mids. I would bet money that the tweeter pots are to corroded to have any electrical continuity. Start with cleaning the controls.

There is a REMOTE chance that one or both 0.75" tweeters are blown. If that is the case, you will have to find some from AR-2ax or AR-5 donors (8 ohm). You can not use the 4 ohm AR-3a version. Check ebay, these tweeters show up very often. Other forum members may also have some to sell you.

You said you have one dented tweeter, you may want to replace that one. I am not sure how to test tweeters, another forum member who has done more repairs is better equipped to answer this. Also, be sure to check forum archives.

Start by going inside and cleaning the controls.

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Hi Noah;

Many people completely by-pass the pots. Try it first with test leads ('gator clip on each end), and if you like the sound, solder on jumper wires. If not, get some new pots.

Nigel

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>how can one figure the watts per channel of a receiver based

>on the total wattage listed on the back -- is their a

>correlation?

>

>how much bearing does the quality of a cd player have on the

>sound of a system? would a sony discman hooked to a classic

>amplifier and speakers cause the acoustic elite to faint?

Hi Noah;

I'll tackle these two.

First there is no way to do it directly, and at best you'll only have a rough approximation. If you have data on another receiver in the same line, you can come alot closer. Part of the reason is that a receiver has many things other than the amplifier that draws power, such as the tuner, pre-amp, lights, etc. Another part is that amplifiers very in efficiency, with one of the biggest power sinks being the amount of bias run on the output transistors. This generally good for sound quality, but does take power. A power amplifier (not integrated amp) is easier to guess.

With regards to CD players - I can not tell the difference, but many people can. I have hooked up a discman equivalent to my home stereo, and found it satisfactory for me, though it is kinda of a pain to change discs.

Nigel

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again i am amazed with the prompt and thorough reply. you all have proved an invaluable resource - thankyou. my basic questions ( from the admittedly still basic mind) continue. What are pots? i had thought they were the inner workings of the controls at the rear of the speaker. is this so, and how do i access/recognize them? are they approachable only through the woofer? is it possible to clean pots to at least a semi functional, if not optimal condition, or must they be replaced? How do i distinguish between front and rear wired tweeters? what purpose do the two brass posts beneath the tweeter serve? does this suggest they are front wired? would the corrosion i described at the three points directly around the tweeter dome suggest their being "blown"?? i apologize for my complete lack of technical understanding. It seems that i may need my hand held here. when connecting a test lead, effectivly by-passing the pots, what will i connect from and to. i know these questions come across as laughable but the monkey IS learning. also - great info on the older phenolic type domes. i almost placed a bid through ebay on a pair and you helped me avert that blunder. also, thanks to nigel for the thoughts on cd player importance - i had suspected the same. noah.

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>again i am amazed with the prompt and thorough reply. you

>all have proved an invaluable resource - thankyou. my basic

>questions ( from the admittedly still basic mind) continue.

>What are pots?

These are level controls for the mid and tweeter.

are they approachable only

>through the woofer?

Yes, only by removing the woofer, can you access the pots/controls.

is it possible to clean pots to at least

>a semi functional, if not optimal condition, or must they be

>replaced?

I share Tom Tyson's view that cleaning the pots is the best way to ensure original performance. After 5-10 years you may have to clean them again. Some people have replaced pots with those from Layne Audio, I have never replaced any.

How do i distinguish between front and rear wired

>tweeters? what purpose do the two brass posts beneath the

>tweeter serve? does this suggest they are front wired?

Yes, be careful with these wires.

>the corrosion i described at the three points directly around

>the tweeter dome suggest their being "blown"??

No, that orange stuff is supposed to be there, that is not corrosion !

when connecting a test

>lead, effectivly by-passing the pots, what will i connect from

>and to.

You better get in there first and see for yourself. That will keep us on the same page. Bag up the insulation and try to save the crepe paper, as it keeps large chunks of insulation from interfering with the woofer operation. You will need to cut the wires to the woofer and remove it.

i know these questions come across as laughable but

>the monkey IS learning. also - great info on the older

>phenolic type domes. i almost placed a bid through ebay on a

>pair and you helped me avert that blunder. also, thanks to

>nigel for the thoughts on cd player importance - i had

>suspected the same.

I am glad I could help. I agree with Nigel on the CD players.

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  • 2 weeks later...
Guest Brian_D

Old topic, but two questions went unanswered ;)

>how can i muster the confidence to replace the foam surrounds

Put on your favorite music as you go to sleep one night, this will wet your taste for more. When you wake up in the morning, lock this music away from your access. Realize that the only way you can ever again enjoy this music is through the beautiful warmth and accuracy of the classic AR. This will provide the drive, but not the skill. Confidence is attained by learing the skill. Learn everything you possibly can about the subject then the confidence and drive will make the project a success. Oh yeah, pracitce on some other woofer first!

>i see re foaming kits

>on ebay for $10 - can this be? are they selling a quality

>product or binder paper and paste.

High Fidelity Engineering Corp (DECWARE) has something to say about this: http://www.decware.com/yrkits.htm The quote to which I'm referring is "Many of the places on the Internet who now offer re-edge kits are buying and selling this surplus." Basically, they're saying that the surround will not have been designed for YOUR woofer. Read the whole thing, it's interesting.

>how can i have such fervent interest in classic audio

>equipment and be so technically dim?

Good question. It's the same one I ask myself every day I sit down at a Wintel computer. How can I have such fervent interest in computers and yet HATE THEM SO MUCH. The answer is simply this: Ability does not dictate (nor indicate) interest. Take the blind artist for example. You get the picture.

>how can one posting with so many moronic questions beg for

>thoughtful response?

It's what we're here for. Keep 'em coming!

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>how much bearing does the quality of a cd player have on the sound of a system? <

I know this isn't the central question you asked but I have a "new discovery" about this (I'm sure an ancient discovery for more avid hobbiests).

Just to qualify my comments, I listened to a Panasonic "discman" player as a source in my bedroom for years (on a pair of 2ax's in fact) and was very satisfied with the sound.

But recently I have connected a DVD/CD player, a laserdisc/CD player, and a Sony CD changer to the same preamplifier. The DVD player is connected using "digital coax", the changer is connected using an optical cable, the laserdisc uses standard RCA analog plugs /cables. It's important to point-out that the changer was, until recently, connected via analog cables.

I can't "hear" what I'm about to tell you, but then I perceive it at *some* level. Silence is "silenter" using the optical cable. The "background" is more quiet? There is less "ring?" It's not an obvious hiss vs. no-hiss thing. And it is only apparent when music is playing.

I know, I know. . . it sounds like I'm imagining things to justify the $30 I spent on the optical cable. I suppose that's possible.

Other than that I can't be sure that the differences I'm hearing aren't something else.

Anyhow, the point is that the method of delivery (optical, digital coax, analog cable) seems to make some sort of difference to me whereas the players all sound pretty-much the same when connected the same way.

Bret

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Guest Brian_D

Gread description! What you are experiencing is the physiological effects of signal to noise ratios. The S/N ratio of any cable is only as good (less good essentialy) as the preamplified output stage of the device and connectors.

Since digital cables are essentialy noiseless, the only sources of noise are internal to the preamplifier. There's a pretty cool article I read once about S/N ratio... If I find it I'll post, but what it was basically saying was that the D/A (Digital to Analog) convertor should always be in the power amplifier. I'm not aware of many (any?) true dyed in the wool amplifiers (not intergrateds) that have digital inputs, but this would be ideal. What it boils down to is from digital sources (CD/DVD/MD/DAT/etc...) the signal is just 1's and 0's, which can be transferred without noise over an almost infinite distance and modified with any amount of processing for volume, delay and such.

You would experience the effect of which you speak to a lesser extent with shielded ballanced cables. (assuming your source and preamp accepted the cable, and utilized it's capabilities)

A friend of mine uses a 3000 watt PA system to test CD players. Basically he has recorded a 30 minute track of digital silence, with 1 second test tones and music bursts along the way. Believe me, at these absurd levels, any minute amount of noise is clearly obvious, even over the noticeable hiss of the amplification stage of the PA amps. The noises you hear coming from some of these cheaper CD players is crazy. Some very nice units even have some noise problems. My favorite was an NAD CD player that would bloop and beep when changing tracks. Also, when tracking (fast forwarding) the music bursts where whole blocks of data were missed would actually clip the input stages of the preamp! Scary stuff.

For your own information, I use a Sony DVD player, connected with plain ol' RCA's (from AR, but only because they were cheaper than Radio Shacks "Monster" stuff) directly to my amplifier. The amp has volume controls for each channel on the front, but I don't adjust them much. The reason I use a DVD player? 1. It will also play DVD audio when I get the theater done. 2. The D/A convertors were designed to decode audio at six times (sometimes more) the data rate, and can handle the PCM signal easier than long division with a calculator.

Just some thoughts from a wandering mind!

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