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About Jeff_C

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    Music, HiFi, Cycling, Holidays

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  1. Welcome to the forum. I am unfamiliar with your speakers but the caps are usually glued down to the crossover board or cabinet on most speakers of this vintage. If you are going to replace the caps then cut the wires as near to the body of the old cap as you can. That gives better options for using that wire for attaching the replacement cap. Once the old cap is cut free you can work on getting it free from its glued mounting to the cabinet. If you do not know the value of the caps that need replacing make sure you do not obliterate the markings on them trying to get them away from the cabinet. Some caps age better than others so there is a possibility that the caps do not need replacing. It is always a good idea to post some pictures along the way, especially if you have any difficulties. I'm sure others will help out here who are more familiar with your speakers.
  2. To my mind that is the neater solution, especially if the switch was never going to be used to direct the signal to different rooms. What swung your decision that way finally?
  3. That fits perfectly with my thoughts on the affect on impedance of adding subs. I hope that proves to be the case.
  4. I made cloth covered wooden frames for mine. I only use them as covers and leave them off for listening. The original foam grille was extremely acoustically transparent, but the cloth (even to my aging ears) cuts out a noticeable amount of HF response. YMMV. The foam was machined out to be quite thin where the drivers are placed, that may have helped with transparency. I doubt that any foam grille replacement would have the sculpted out foam where the drivers are placed, but if they can do that as well for reasonable cost then great. That is particularly what was on my mind when I said they may be "difficult/impossible to replace". If I could replace the foam grilles for reasonable cost I would like that because it puts the speaker properly in its time zone of mid to late 1970s when many speaker manufacturers used foam grilles.
  5. They appear to be the original open cell reticulated foam grilles and they do look great. If you can delicately rub your thumb along a bottom edge of the foam grille and do not get any crumbling away of loose cells, they should be good for a few more years at least. Keeping them away from UV light may help to preserve them more. I wonder why the woofer foam surrounds have rotted when the grilles have survived. As these are now vintage I think I would put a full cover over the speakers when not in use after they have been restored. That may help preserve those grilles as much as possible. They will be very difficult/impossible to replace. I had similar foam grilles on the AR-16 (they are from a similar era, mid to late 1970s). The grilles were exposed to quite strong sunlight in the environment where they were used (well at least when the sun shone here in the UK). I remember the grilles lasted about 10 years before I gave up on them and threw them out. In the latter years of their use I used to see black foam crumb on the floor beneath the speakers. It became a weekly job to hoover it up. When doing the 'thumb-crumb' test dislodged too many foam cells from the grille I threw them away. Operating the speakers without the grilles on the woofer foam surrounds were then getting a good deal of sunlight exposure but they lasted a further 7 years before the speakers had to be 'retired' in 1993 due to woofer foam rot. During the 10 years lifetime of the grilles I used to wash them occasionally in a bowl of warm water and washing up liquid, just gently squeezing them with the palms of my hands so that the detergent could work to dislodge household dust etc. Then rinse them in clean tepid water and then lay them out to dry on newspaper before attaching them back on the speakers. I do not believe that process shortened their life.
  6. Adams - I have found out that the CR65 have nominal impedance of 8 Ohms. I would try and find out what the minimum impedance is and at what frequency(ies) the lowest impedance occurs. The fact that the CR65s are 8Ohm makes things a little easier because wiring in parallel gives a nominal impedance of 2.66 Ohms. If you set this up without a switchbox it should fall within the amp's operating spec, and you will have the advantage that the full power availability into that 2.66 Ohm load will be being used to create sound, (rather than being wasted as pure heat dissipating across a protection circuit resistor). In turn that will mean that you will not need to crank the volume up so much to get to the desired listening levels. If it were me I would try the setup without a switchbox especially if the switchbox would only serve as 'protection'. It is worth investigating whether the amp features any protection circuitry. Many just shut down if safe operating limits are exceeded. As for the wiring harness you could code all the up the cables with matching codes on the speaker terminals so the end user cannot go wrong. The only thing I am unsure about is how the subwoofers affect things as I have never used subs or even contemplated using subs. But as the subs are self-powered with their own amplifiers I doubt that they affect impedance calculations but I would certainly want to be sure about that first.
  7. Re (1) It is not likely to be as straightforward as that. If the amp can deliver 350W into 4 Ohms then if 3 pairs of 6 Ohm speaker are wired in parallel the resulting load will be nominally 2 Ohms. Then the protection switch may add in 2 Ohms (or more) to the circuit making the resulting load nominally 4 Ohms. Now here's an important point about power dissipation. The 350W will divide up so that 175W will be dissipated across the 3 speaker set (with a nominal 2 Ohm impedance) and the other 175W will be dissipated across the protection circuit's added 2 Ohm. For the reasons explained above it will be beneficial to know exactly what the protection switch does to the circuit. Re (2) It would be possible to run a single decent gauge wire from the amp to the location of the speakers and from there make it branch out to wire up the 3 speakers. So just a single wire on show across most of the room.
  8. I am unsure of your use purpose for the proposed Niles Speaker Switcher but these switch boxes are primarily used to locate multiple speakers in multiple rooms. If you intend to use a bank of 3 x left speaker and 3 x right speaker in the same location I would definitely wire them up without the speaker switcher. I have just had a quick look at this article The way the Niles boxes seem to 'stabilise at 4 Ohms' is by adding in some impedance when the 'protection' is switched on. That means losing some of the available power from the amp. Another thing is that the spring type speaker terminals will not take decent gauge speaker wire, and if the wire runs are long then the sound quality could be impaired. Depending on what you want to set up I would go with some DIY passive wiring arrangement. With three sets of speakers the option to wire series-parallel is not available. You would generally need 4 sets of speakers for that.
  9. That is probably true, but think of it like the glue solution painted over the cone is just adding back some weight after years of baking in that attic, with inevitable loss of moisture from the cone, making it so brittle. The cone is nowhere near its original spec and weight as it is. I think it may be a reasonable way to salvage the cone.
  10. For me the recording has to be "binaural" to get a good sense of image and spaciousness. With a standard stereo (non-binaural) recording, headphone listening for me is not that satisfying, although they do improve listening in poor acoustic environments as you say.
  11. I bought my first pair of speakers in 1974 or 1975. They were AR-6 bought jointly with my sister, and she took them with her from the family home a couple of years later when she married. I replaced them in January 1977 with AR-16 and I've had them ever since. The big bummer for me is that they were in storage with foam-rot from September 1993 to December 2013. I did not realise they could be fixed but thankfully had been reluctant to discard them. I came across this forum and re-foamed and re-capped them. I was happily using recently bought Revel Performa M22 when the AR-16 got fixed, but they were relegated so the AR-16 once again became my main listening speaker of choice. The fact that I bought the AR-6 jointly with my sister gives some clues about my financial position at that time. It would have been a lot more difficult to have afforded decent hifi on my own while still at high school.
  12. I have 4 of the black and red caps somewhere from a Pair of British built AR-16 1977 vintage. I am pretty sure they had NPE stamped on them though. If and when I find them I will update this message.
  13. That is not what I read. Have another look at the first paragraph on page 9 of the document. "We empanelled fourteen volunteer listeners, comprised of University students and staff. As a group the panel found the testing difficult and tiring, and gave no usable outcome. Most were unable to distinguish electrolytic from film capacitors, and were similarly unable to distinguish between film capacitors of varying resonance." That quote refers to the ABX testing. I remain in the dark whether the next round of subjective AB testing for the film cap construction (using skilled listeners) was even blind, but am happy to assume that it was.
  14. OK I have to admit I was wrong about this, but mainly because I overlooked mechanical resonances. I have only skim read the Clarity Caps paper, but it is interesting that they had to take a new line of approach after a panel of ordinary listeners failed to give them any meaningful and useable results in ABX tests. They then moved on to using a panel of skilled/trained/critical listeners and even then around 10% thought the sound was worse, about 30% thought it was the same, and about 60% thought it was better. So yes statistically they have proven something, but it is not overwhelming, night and day differences for your average Joe. I agree with RoyC that it seems of dubious worth using expensive speciality caps to replace electrolytics in vintage speakers which were designed using electrolytics. Replacing like with like will replicate more accurately the electrical measurements of the original cap thereby maintaining the system's original sound
  15. I do not buy this. Capacitors have no 'sound' of their own no matter how well they are constructed. What they have is electrical properties. If another 'widget' was used which replicated perfectly the electrical measurements across the frequency range in which it operated exactly matching the electrical measurements of the 'super capacitor', then I believe we could interchange the widget for the super capacitor with no alteration to the resulting sound when that widget or super capacitor is used in a crossover. Is there anyone who believes otherwise?