MikeD

I like this idea! May go this route in the end. I painted a test piece of hardboard with the tire black, and it came out perfectly. Nice flat black, and it actually looks better on the half of the piece that I did not scuff up at all. I will test the durability this weekend, but I am pretty confident that it will work well for this purpose.

Roy - will check the wife's craft supplies. I'm always amazed what you can find in there!

Thanks to all. After scuffing the surface a bit for adhesion, I thought of rattle-can spraying them with Rustoleum flat black. I also have an old can of Dupont "Tire Black" jet black paint (7% carbon black pigment) that I may test out on a different piece. I was going to use that to touch up the exposed metal rim of the woofer after installation. The poly topcoat is an interesting idea.

Hi All, My AR-5 restoration project is nearing completion. Can't wait to listen to them for the first time! This is a question of cosmetics: I have ordered the 18-count lambswool linen and have constructed new grille panels out of 3/16" tempered hardboard. So far so good. However, I can't seem to find a definitive statement on whether or not to paint the panels flat black before covering them. I do not care for the shadows that show when they are left natural, and outside of authenticity, I can't see any reason to avoid painting them in order to minimize shadowing. Seems that the AR3a had black grille frames. Were the AR5s originally black? What is the consensus here? Paint or not paint?

Thanks, DavidR. I've been a member of that forum for many years, but haven't been out there in quite some time. I mothballed the ST70 some 10+ years ago. The AR-5 acquisition has rejuvenated my interest in building a nice vintage system. So I guess I am interested in the (switchable pentode/triode) novelty on the VTA70 build, but have no idea what I'll like best. And while I plan to use the AR-5s when they are ready, I don't know how efficient they are or aren't. It is shaping up to be a fun and rewarding project. M

Thanks for all the responses. I'm learning a lot. DavidR, the ST120 is really nice, but I wonder if I need that much power in my small listening room (13x14). An ST70 in essentially stock mode (VTA70 or not) should be plenty to drive the AR5s, correct? It was all my Advents (and my ears) could handle back in the day. Also, in your opinion, is the pentode/triode switching nice to have or just fluff? I'm curious what the difference in sound would be, but after that I wonder if would I care or ever switch back and forth.

ar_pro - I am leaning toward the VTA70 classic mod (tubes4hifi), but am VERY open to suggestion. A lot of different opinions out there. I will find out the cost of the tweeter rebuild before I decide on the final solution. I'm not in a big hurry.

Pardon - I see that you mention the "wax" capacitor box above. Will discard and get individual capacitor replacements. Are the metalized polypropylene capacitors considered "film" capacitors? The word "film" is not used at partsexpress except for the (expensive) Film and Foil caps. Also, they do not show a 24µF in the NPE style. The closest is 22, then their offering jumps to 33. So is it better to get the Metalized poly in the correct 24 size, or get the NPE 22? In general, when size can't be matched, should you get something a little lower or a little higher?

Y'all are great! So I lifted one of the capacitor boxes. Feels like a block of wax. ??? Probably going to stick with the HiVi's. Hear above 8K? I can't even hear my wife anymore. My source material is mostly choral, classical and classic jazz. I have a big collection of Mosaic Jazz box sets. So my remaining question is the coil size for the HiVI's. Seems I saw 0.05mH in reference to the AR3a and 0.10mH for the AR5. Just trying to confirm. I have NO IDEA what the impact of one over the other would be. To be honest, I don't even fully understand the function of the coil. Thanks for the affirmation of the NAD 1600. There are SO many opinions out there about component matching and it is mostly beyond me. I can hear the tube amp difference - or at least I could 10+ years ago which was the last time I used the ST70. I shut it down because it is all original and I had read that bad things can happen with some of the older components, especially the selenium rectifier. So I will modernize it a bit, but not sure which path I will take. Leaning toward the VTA70 route. I am really excited about these AR5s!

FYI, I just checked the polarity on both woofers and they are marked correctly. So one was definitely wired backwards. I measured 6.4 ohms for each, BTW. Sound correct?

Great - thanks to both of you for the information. So how do I pursue having the tweeters rebuilt? I know I read somewhere in this site, probably older information, that they couldn't be rebuilt or at least not to match the original sound. Again, I am skeptical that my ears are sensitive enough to appreciate the differences. And i'd rather save some bucks for a suitable preamp, if I decide the NAD1600 isn't right for the setup. I still have about $200 to spend on revamping the ST70, but I have solid-state ST120 I am using in the interim. The film vs. NPE statement was very helpful. I'm guessing the only "low-value" cap would be the 4µF. I will look more into Lpads based on your advice. I have read so much from this site that my eyes are beginning to roll back a bit. GREAT source for an amateur like me.

Originality of sound is important, yes, and I would like to maintain close-to-original cosmetics as well. I will be purchasing the 18 count lambswool linen and the reproduction emblems. The walmut cabinets are in mostly excellent shape. However, I am less concerned about the internal look of the tweeters, but will probably keep the originals in case that is important to somebody someday. Or I may sell them to defray some of the restoration costs. Yes, I have read the AR3a restoration guide - fantastic information. My questions are outside of that excellent write-up as far as I can tell. In fact, that write-up seemed to favor the pots over Lpads. I have yet to pull and inspect them and may have to replace them once I have a look. With Lpads, you must add additional resistance, correct? Do these values change with the AR5 compared to the AR3a references in the guide? Here is a summary of my remaining questions: Regarding the HiVi Q1R tweeters, I have seen conflicting coil advice on this site - should I use a 0.05mH coil or 0.1mH coil? The woofers were wired oppositely - one was red wire to positive, the other was blue wire to positive. Any reason to think this was intentional? Is there any significance to the box housing for the two larger capacitors? I have not opened one yet and maybe the answer will be more clear when I do open it up. How closely do I need to match the 72µF cap? Since I can't find one, should I use a 50 and a 22 together, or just go with a 68 or 75? Finally, my ears are 63 years old and never really were at the audiophile level anyway. Will the construction or brand of capacitors really make a difference? Thanks!

New to the forum and have just acquired a pair of AR-5s and begun to restore them. Foam surrounds are coming, and I plan to install the HiVi Q1R tweeters, as one of the originals are damaged and not working at all. I have seen conflicting advice on these - should I use a 0.05mH coil or 0.1mH coil? The serial numbers are K 18576 and K 17982. There are no dates on the woofers, and the dates on the tweeters are Feb 9 1971 and Dec 31 1970. I do not plan to pull the mids as they seem to be working fine. I will be cleaning/refurbishing the pots. They mostly work but are clearly dirty. It is clear that these AR5s have been opened previously. The fill is mixed bag: some fabric, some fiberglass and some chunks of foam. Each weighed in at 22oz. There are newer white foam speaker "seals" instead of the black gunk that I have read about between the speaker frame and the cabinet. Interestingly, one of the woofers was wired in reverse: one was blue to positive, red to negative and the other was opposite. Any reason to think this was intentional? Also, one of the woofers has the black sealant around the magnet. Wondering why. I don't have a device to test the caps but I'm going to assume that after 50 years they should be replaced. The layout looks original, but my question is why are there two capacitors isolated in a box, and the third on the crossover board? I've seen pictures on this site where the 72µF and 24µF caps are exposed. Do I need to keep the box layout? I have not yet opened either one. Also, how close must the values be to the originals? I can't seem to locate a 72µF, (I see 68 and 75), but have found 24µF and 4µF on partsexpress.com. Any real reason to replace the crossover coils? Again, my testing ability is limited. The wealth of knowledge on this site is amazing. I am an amateur but can handle a schematic and a soldering iron well enough. I am so looking forward to pairing these with my Dynaco ST70 amp (dead-stock original but I will be refreshing it as well) and not sure yet about a preamp. I currently have a NAD 1600, not exactly period vintage but it works. May go with something like a Dynaco PAS 2 or 3, however I would really like to keep my remote! I've owned Large Advents since 1977 and will be moving these once the AR5s are good-to-go. My listening habits have changed somewhat over the years.