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AR Tweeter replica/replacement


DavidR

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The original tweeter (200011-1) in my AR10Pi speakers went OL on the voice coil. I had read several posts on replacements; one sold by VintageAR and another from Midwest Speaker Repair. RoyC had suggested the Midwest saying it sounded very close (paraphrasing) to the originals and was suitable. I checked eBay and there were some original tweeters FS in the area of $130 each. The Midwest tweeters are $70 and are new. I thought I'd try a pair. I ordered two in case they sounded different than the 2000084-1 AR replacement tweeter in the other cabinet.

They arrived with bent terminal blades and one was loose. They had packed them one on top of the other and there was no cushioning either on the top or bottom. I placed a call to Midwest and I have to say they were quite professional about it. They paid return shipping and took steps to ensure safe arrival of the replacement tweeters; i.e. larger box so they could sit side by side and an added piece of stiff foam between the two terminals. I hooked one up and was surprised how much they sounded like the 2000084 tweeter.

The replica have a cloth dome vs paper on my two AR tweeters but look very much like the originals. The DCR of the replicas measured around 3.88 ohms and the original is around 3.5. The 10Pi are up and running. Now to compare them to the 91s. I already know the bass of the 10Pi will best the 91s.

Midwest Speaker tweeter replacement

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3 hours ago, DavidR said:

I already know the bass of the 10Pi will best the 91s.

How do you know that? I have never owned the 10-Pi or 11 but I do have the 3a with cloth surround woofer (as I understand it the 10-Pi is a more modern 3a). Als\though I love the 3a I wouldn't say they beat the 91s in the bass department. I suppose YMMV ;)

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This is solely based on listening to the 10Pi in on the work bench with a Class H Technics receiver that only goes down to 40Hz. The bass is deep, tight and authoritative.

If I change my  mind I'll post it.

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On 7/13/2018 at 12:06 AM, DavidR said:

I hooked one up and was surprised how much they sounded like the 2000084 tweeter.

The replica have a cloth dome vs paper on my two AR tweeters but look very much like the originals. The DCR of the replicas measured around 3.88 ohms and the original is around 3.5.

David,

Thank you for sharing information about  your AR 10 Pi restoration and the Midwest Speaker replacement tweeters you have used.

As regards Midwest Speaker, you told us in another thread that the first pair of tweeters they sent to you had  low output and limited frequency response compared with the good 200084 tweeter you have. The bent and loose terminals surely depend on shipment issues but the low output and the limited frequency response could also depend on not good manufacturing tolerance.

Did Midwest somehow explain the low output and limited frequency response you observed?

Please,  let us know about your impression on the sound of your restored AR 10 Pi in your listening room and especially with your different type of power amplifiers (tube and solid state).

Thank you

Luigi

 

 

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I think the low output had to do with packaging and damage. The replacements they sent are fine.

I pulled the 90's from the system and they probably won't go back in until they are re-capped - sounding dull. Hauled the 10Pi up from the basement and hooked them to the tube amp. The 91s went on the SS amp (400 watts,  high damping factor). The tube amp had no trouble driving the 10Pi. Bass was killer, deep and authoritative. I was surprised how good the mids and tweeters (using the replicas) on the 10Pi sounded. The Mundorf (tweeter cap) and Bennic (mid cap) were both bypassed with a Vishay 1837 PP.
 
It was hard to compare the two as the SS amp has much more power and damping factor and you can't turn the tube amp back on right away after shutting it down to do a speaker swap. So I just winged my assessment. Bass was good on both speakers but I felt the 10Pi was better and deeper. The tweet and mid probably goes to the 91 due to the Clarity caps and their respective bypass caps. The 10Pi did have detail but not as much as the 91s and did not have the black background as the Clarity caps provide. Overall I think I like the 'voice' of the 10Pi better but  the detail and clarity of the 91s.
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In the future, if you prefer the AR 10 Pi "voice", you can use better quality caps like in the 91.

Anyway If you want to get the best quality sound (not only in the bass) from your AR 10 PI, when you have time, I suggest that you try the original 200003  woofers in place of Tonegen's. You will get a great improvement even in the mid-range. 

Obviously the 200003 woofers  should  be the ones used for the AR 10 PI MKII (as your 10 PIs are MKII).

As I have already told you in other posts you could try your original AR 91 woofers (200003) in the 10 PI.  In fact AR 10 PI MKII and 91  had the same 200003 woofer. 

In my experience (in my listening room and with my amplifiers) the difference between AR and Tonegen woofers  is  not  negligible.

Have a nice day

Luigi

 

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I wanted to stay with NPE. There's not a lot of room to work in there. Film caps would have been difficult to install due to physical size. I did use a Vishay 1837 bypass cap on the two series caps. The Mundorf ECaps are supposed to be very good. Not a lot of choices for NPE caps. Mundorf, Bennic and Parts Express are available. Did you have a specific cap in mind?

I remember what you said about the woofers. The 91 is all original. Not sure I want to mess with that at this point. I still have the AR9s to do and those need cabinet work (which I don't enjoy). Maybe in the near future.

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18 hours ago, DavidR said:

Did you have a specific cap in mind?

That is a matter of taste. As you prefer the AR91s mid and tweeter, you could use the same Clarity caps you used for recapping them. You could also get some improvement bypassing the 2500 uF npe cap with a poly cap. 

But personally I think that the clarity and detail you are missing could depend on woofers more than caps.

Luigi

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9 hours ago, fedeleluigi said:

That is a matter of taste. ………………………………………………………………...

But personally I think that the clarity and detail you are missing could depend on woofers more than caps. 

Luigi

Ditto on the woofers.

DavidR

The 10pi restored to exact specs will never sound like the 91, if you listen with an audiophile ear.  The 10pi should be more akin to the 3a in sound.   IMO opinion the 91 was never the TOTL, it was merely billed as the premier 3way of the vertical series.  If you prefer the 91 sound with its half octave higher woofer crossover it is a different matter.   

Best move now, IMO, is stop working on the 10pi and move on to your AR9s.  The 9s will eclipse the 91s in all areas as should your 90s if they are working correctly.

Just my 2 cents.

Adams

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1 hour ago, Stimpy said:

I'd offer to help, but I'm sure you want the 9's finished within this decade?  ?

I'll be showing up at your door unannounced to assist (whip) you into finishing your 90's.

I have one of the Sony speakers re-foamed. The 99 cent foams from China were actually very good. Seem to be polyether and are a great fit.

I should maximize profit RomDS9.jpg

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Looking forward to that AR-9 restoration, too! ^_^

The little base on the AR-9 is held in place by 4 screws & a bit of glue.

Hopefully, it doesn't exhibit any sign of moisture damage, as its very cheap painted mdf, and pretty much dissolves when wet. If I can suggest - this would be a great time to consider spiked feet. The Parts Express 240-730 are excellent. 

Aadams:  it's tough to generalize on the sound of the verticals without taking room size & amplification into account. I've heard both the AR-9 and AR-90 sound mediocre in undersized rooms, where the AR-91 with a common sonic signature sounded just right. Also, compared to a straight-up AR-3a, I'm sure the 91 will play more loudly, and with less chance of thermal failure.

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23 minutes ago, ar_pro said:

Aadams:  it's tough to generalize on the sound of the verticals without taking room size & amplification into account. I've heard both the AR-9 and AR-90 sound mediocre in undersized rooms, where the AR-91 with a common sonic signature sounded just right. Also, compared to a straight-up AR-3a, I'm sure the 91 will play more loudly, and with less chance of thermal failure.

Of course, you are correct.  The best tools can always be used ineffectively to get unsatisfying results.  

One may prefer the sound of properly working 91 but it will not sound like a properly working 3a except at unrealistic listening distances.

24 minutes ago, ar_pro said:

Also, compared to a straight-up AR-3a, I'm sure the 91 will play more loudly, and with less chance of thermal failure. 

Yes the verticals had something extra.  They would go to 11.  

Adams

 

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On 7/14/2018 at 5:13 PM, DavidR said:

The 10Pi did have detail but not as much as the 91s

I forgot in my previous posts to suggest that you clean from oxidation the numerous electrical connectors (faston terminal) present on the switch PCB in the AR 10 PI.

The faston terminal oxidation could be a cause for detail loss.

Before detaching the numerous faston terminal from the switch PCB, take carefully note of their wire colour and precise position on the PCB otherwise it will be impossible to reconnect them in the right position. Probably, to be on the safe side, it's better to clean one by one.

In the last picture, the oxidation present at the rivets of the faston terminals is also a certain cause of signal (and detail) loss. You should check out this possible problem as well.

20180717_233137.jpg

 

20180717_233648.jpg

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Open the AR 10 PI "door". You should very gently detach the three black "cups" ( 5, 27 on the drawing). They are glued to wood so use a cutter blade to very delicately detach them. Be careful not to deform the black cups! 

 Under the three cups there are three nuts (4 on the drawing) and you have to unscrew them and then the PCB can be removed.

Anyway if the rivets are not oxidated, I would not remove the PCB from the cabinet. I would only detach the faston terminals one by one to clean them. Without removing the switch board you  have to use a mirror or take a photo to see if the PCB rivets are oxidated or not.

Obviously, also some other AR such as AR9 may have the same sort of PCB oxidation problems or some old solder joint issue.

Should you decide to remove the switch PCB remember to resolder all the old solder joints present on the PCB itself.

AR 10 PI smontaggio.jpg

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I've only half-heartedly been following the details in this thread, but I really love it when these projects share specific "how-to" solutions that come from a close examination of the excellent drawings in the Library.

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