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fedeleluigi

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About fedeleluigi

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  1. If that is the only problem the tweeter is repairable but it is a very delicate procedure and must be done by very experienced hands. The 200014-0 / -1 tweeters are very rare and very hard to find in the used market. They differ both from the tweeter used in the AR-6, 7, 8 and 4xa (# 200005) and from that used in the AR-18, 17 and 25 (200014-3) and cannot be interchanged. The AR-MST / 1 (USA) and the AR-MST improved (Europe) have 3 tweeters in parallel and, for this reason, do require high impedance tweeters. So, differently from 200005 and 200014-3 tweeters, 200014-0 and 200014-1 a
  2. The 0.5 Ohm resistors change the damping of the filter cells and must not be removed! The polarity reversal for the tweeter connections depends on the fact that the high pass filter is of the third electrical order for the AR-9LS while it is of the second electrical order for the AR-9LSI. So, if you change the filter you must also change the polarity unless you can verify the result with appropriate FR measurements. The crossover changes made by the AR engineers in the AR-9LSI crossover are very "minor". The AR-9LSI used the "new" Tonegen drivers and the small changes in the LSI crosso
  3. Adriano, for those who know a little about acoustics, those measurements are not comparable. AES paper AR-3a 2Pi frequency response measured on axis in AR "particular" anechoic chamber (please, see my previous post for details). I do hope you can appreciate the great difference between Fig.9 (4Pi anechoic response on axis) and Fig. 5 (2Pi frequency response measured in AR "particular" anechoic chamber) graphs shown in the AES paper for the same AR-3a speaker. So, as I wrote before, you cannot compare apples with oranges. Moreover, it is not a question of whether the AR-3 i
  4. As I mentioned, the graphs of the frequency response curves you posted are not comparable for several reasons. In summary, you can correctly compare measurements of two or more speaker systems only if they are acquired according to the same standards. We are sufficiently familiar with the "standards" used by AR through the AES paper (https://www.aes.org/e-lib/browse.cfm?elib=2058) from which the AR-3a graph you posted comes from but we know nothing about the "standards" adopted by High Fidelity Magazine. In the AR-3 article they just say: “The effects at 150 to 250 Hz cps are gro
  5. Adriano, No doubt that the charts you posted show two very different curves. But they were acquired in different situations and ways and for this reason they are not comparable each other otherwise you compare apples with oranges.
  6. @AadamsThank you for the link! Tom Tyson also explained the reasons for the sonic differences in the second part of his post (I highlighted it in red). I agree with him. Although many people believe that the AR-3a project is essentially the work of Allison and McShane, personally, I have always believed that Vilchur certainly and actively participated in that project that probably began immediately after the introduction of the AR-3 in 1958. Taking into account Villchur's life after the sale of Acoustic Reseach to Teledyne (in 1967, a few months before AR-3a
  7. @Anders Nilsson I do think that the paper collar of the voice coil is damaged or even totally cracked and this generally causes that kind of problems you are hearing. Unfortunately the collar damage is a problem of the 12" ferrite woofer produced before about 1977. Then AR switched to aluminum for the voice coil formers and it is much more stronger than paper. On page 5 (fig. 2.4 and 2.5) of "Restoring the AR-3a" you can see the characteristic final crack of the paper voice coil collar.
  8. I saw on Ebay two "strange" 12" Alnico woofers and I wish to share their pictures here because, as far as I remember, this is the first time I've seen this peculiar type of 12" Alnico woofer. They date Jul-Aug and Sep 1968 respectively. Although the magnet is Alnico, the cone and surround are not typical of the 12" Alnico woofers. In fact they are the same as those used in the "earliest" generation of the ferrite woofer. In other words it is used a smooth paper cone with a damping ring and the surround is made of foam. The baskets have the mesh screens (they were removed in w
  9. Ciao Michele, If your AR-LST crossover has a 10 Ohm resistor in parallel with the 2500 uF cap you are basically measuring the resistance of that resistor. You can see some AR-LST measurements here AR_LST impedance at two different switch positions (2 and 6)
  10. It's hard to say. Unfortunately I have never seen and examined the AR-3a Limited. All I know about it derive from some members of this forum especially John O'Hanlon (forum nickname Johnieo @johnieo) and Mihn Luong (forum nickname mluong303 @mluong303). Unfortunately, they have not been writing on these pages for a long time. If they still read the pages of this forum, I take the opportunity to greet them. Some aspects of your AR-3a are similar to those of the AR-3a Limited others to those of the Italian AR-3a Replica. For instance your 3a crossover (components, PCB and wires) is t
  11. @jomede Thank you Jomede, The driver is a rare paper dome tweeter manufactured by Tonegen. Unfortunately the number printed on the label is not clear (it could be 200084-0). In the early 90s there was a limited manufacturing of Ar-3a and AR-10 Pi Replicas in Italy. A very long time ago ( in 2003 ) I wrote about them here: I asked you for the tweeter part number because I saw several part numbers used for that tweeter. So if you don't mind checking also that of the other tweeter I would appreciate it very much! In 2014 I created a thread on the Italian
  12. @jomede Hi Jomede, Congratulations on your AR-3a! If you don't mind, could you please post clear photos (front and rear with part number) of their tweeters. From the first photo they look like the rare Tonegen paper dome tweeters. Thank you PS: if the domes of your 3a tweeters are made of paper be very careful with them because they are very very fragile.
  13. @budney Welcome to this forum! In my opinion you should check that woofers and midranges are the correct ones and in good electrical and mechanical conditions. If you post some pictures we can help you to identify the speakers. All AR-3a (improved) drivers are 4 Ohm. As regards DC resistance it should be around 2.6 Ohm for for woofers and around 3 Ohm for midranges. An identical mid-range was also supplied in an 8-Ω version for the AR-5. Therefore it is imperative to measure the DC resistance for each driver for the proper impedance match. You should check that the crossover has n
  14. when you can , would you please inspect carefully the sides of the ferrite magnets because the manufacturing dates were also printed there? thank you
  15. yes. no, you are not missing any pieces.
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