51 replies to this topic

[oldguide]

Here is the revised chart reflecting what seems to be the consensus of the group so far. Again it's a JPG file so the links don't work. I would be glad to send as an Excel file, but can't unless there's something about the upload I don't understand.

Thanks to everyone for all their input.

Special thanks to johnieo for link to Vintage AR. Found some used tweeters there. So I guess my problem is solved and hope the chart will help others.



Here are the links:

Vintage AR
AB Tech
Carl's Super Mod
Vifa Closeout
AR 3A Restoration Guide

One final comment: to the people who put the restoration guide together: it is quite simply one of the best written, best illustrated, best explained guides I have ever seen. If any reader comes across this post RUN don't walk and download that guide before you DO ANYTHING.

So now on to the restoration, including a redo on the cabinet (carpentry I know). Will let you know how it all turns out in a few months when all is done.

Thanks to everyone on the site for being so free with the expertise and time.

This dead horse is ready to run.

[Pete B]

Here is the revised chart reflecting what seems to be the consensus of the group so far. Again it's a JPG file so the links don't work. I would be glad to send as an Excel file, but can't unless there's something about the upload I don't understand.

Thanks to everyone for all their input.

Special thanks to johnieo for link to Vintage AR. Found some used tweeters there. So I guess my problem is solved and hope the chart will help others.



Here are the links:

Vintage AR
AB Tech
Carl's Super Mod
Vifa Closeout
AR 3A Restoration Guide

One final comment: to the people who put the restoration guide together: it is quite simply one of the best written, best illustrated, best explained guides I have ever seen. If any reader comes across this post RUN don't walk and download that guide before you DO ANYTHING.

So now on to the restoration, including a redo on the cabinet (carpentry I know). Will let you know how it all turns out in a few months when all is done.

Thanks to everyone on the site for being so free with the expertise and time.

This dead horse is ready to run.

A potential low cost solution, I'll probably order a pair, the high Fs should
help make duplicating the response easier:
http://www.madisound...roducts_id=8316

[RoyC]

A potential low cost solution, I'll probably order a pair, the high Fs should
help make duplicating the response easier:
http://www.madisound...roducts_id=8316

Hey Pete,

That one looks promising. Hi-Vi Research is producing excellent drivers for the price.
I've had some luck with another <$10 Hi Vi tweeter with a wide enough flange to fit without modification. It is 4 ohms with a relatively high fs as well, but has the larger, 1 inch dome. I used a parallel .06mh inductor, 1 ohm series resistor, and 3.3uf cap in place of the original 6uf cap.

Roy

[oldguide]

You guys are going to keep me busy, but this dialogue is fascinating.

So here's the new chart.

[oldguide]

Roy,

Was just looking at your picture and noticed the heavier gauge wire you used on both the mod and the tweeter. What gauge did you use? Was there a particular type/brand of wire? Most of all, how did you mate it with the original tiny wires?

As I get ready to rebuild mine, those wire are a real concern. They seem so fragile and they can't be very efficient.

[dynaco_dan]

Hey, I just noticed that Madisound is closing out some "classic style" Vifa 3/4" domes.

http://www.madisound...roducts_id=1647.

These might be worth looking at as a replacement for the AR tweeters, especially since 3/4" domes are getting pretty rare. It's not going to be a drop fit, electrically or mechanically, but these guys have pretty good dispersion by contemporary standards, and would probably reward some crossover modification effort. The frequency region where their far-off-axis dispersion becomes a little rough is rather high, and so this is not likely to be a serious audible deficiency. Also, they are cheap!

Note: I used to be affiliated with Vifa, but haven't been for some time, and have no commercial interest at stake. Just happened to see the tweeters on sale. I do know that Vifa generally makes a well-engineered, consistent product.

-k

Hi Ken;

Thank you very much for the heads up, Ken.

Another alternative tweeter for the experimenter and those on a more limited budget as well, as long as they are available from them.

[dynaco_dan]

Hey Pete,

That one looks promising. Hi-Vi Research is producing excellent drivers for the price.
I've had some luck with another <$10 Hi Vi tweeter with a wide enough flange to fit without modification. It is 4 ohms with a relatively high fs as well, but has the larger, 1 inch dome. I used a parallel .06mh inductor, 1 ohm series resistor, and 3.3uf cap in place of the original 6uf cap.

Roy

Hi Roy;

Thank you for adding another reasonably priced alternative tweeter to the tweeter mod list

[RoyC]

Roy,

Was just looking at your picture and noticed the heavier gauge wire you used on both the mod and the tweeter. What gauge did you use? Was there a particular type/brand of wire? Most of all, how did you mate it with the original tiny wires?

As I get ready to rebuild mine, those wire are a real concern. They seem so fragile and they can't be very efficient.

oldguide,

The surface wire is 22 gauge stranded "hook-up" wire...nothing fancy. (I believe it was purchased from Radio Shack.) It just needs to be small and flexible enough to easily pass through the gap between the tweeter magnet and the cabinet hole. It connects the rear tweeter terminals and the internal wiring with the front cabinet tabs, to which it is soldered. The original tinsel wire from the old tweeter is not used at all.

If you need to extend the original (copper) tinsel wire of an old tweeter, a few strands of speaker wire twisted together can be soldered to it. The small gauge wire works just fine for the very short runs required to complete the connections. Efficiency is not an issue. (The hairlike wires going into the old tweeter domes are MUCH smaller than that!) It makes me smile to watch folks struggle with fancy mega-wire when restoring these old speakers. The original crossover wires were seldom larger than 20 ga. There is nothing to be gained with anything much thicker. When wiring AR crossovers, I use tinned wire (sold as "marine wire" today), just like the original stuff. It is very durable, resistant to corrosion, and very easy to work with.

Roy

[oldguide]

oldguide,

The surface wire is 22 gauge stranded "hook-up" wire...nothing fancy. (I believe it was purchased from Radio Shack.) It just needs to be small and flexible enough to easily pass through the gap between the tweeter magnet and the cabinet hole. It connects the rear tweeter terminals and the internal wiring with the front cabinet tabs, to which it is soldered. The original tinsel wire from the old tweeter is not used at all.

If you need to extend the original (copper) tinsel wire of an old tweeter, a few strands of speaker wire twisted together can be soldered to it. The small gauge wire works just fine for the very short runs required to complete the connections. Efficiency is not an issue. (The hairlike wires going into the old tweeter domes are MUCH smaller than that!) It makes me smile to watch folks struggle with fancy mega-wire when restoring these old speakers. The original crossover wires were seldom larger than 20 ga. There is nothing to be gained with anything much thicker. When wiring AR crossovers, I use tinned wire (sold as "marine wire" today), just like the original stuff. It is very durable, resistant to corrosion, and very easy to work with.

Roy

Thanks for the tips. That must be the AB Tech driver rather than the original. Those are great pictures showing how to set that up that should be in the restoration manual or at least with the chart. Nice job!

Since I just picked up some used tweeters, I guess I will end up soldering a larger wire to the "tinsel." Those things seem so fragile that if you breathe on them they'd break, but obviously they lasted this long and lasted my removing my old drivers. Has anyone ever contemplated redoing the old surface mount wiring hookup with something more robust such as a connector block or is this a restoration issue?

I decided early on with this job that I would try to stick with originals as much as possible, but where the originals could be replaced with something more robust I would do it. So I have cleaned the old pots (which weren't that bad) and kept them, but will upgrade the crossover with the restoration "book's" suggestions. I also will probably add some decent speaker jacks to replace the the posts and nuts on the back.

Along the same lines does it make sense to upgrade the wiring to the woofer while I am at it? The run is short enough I suppose it's not that big a deal and the wires look like 20 gauge.

[RoyC]

Thanks for the tips. That must be the AB Tech driver rather than the original. Those are great pictures showing how to set that up that should be in the restoration manual or at least with the chart. Nice job!

Since I just picked up some used tweeters, I guess I will end up soldering a larger wire to the "tinsel." Those things seem so fragile that if you breathe on them they'd break, but obviously they lasted this long and lasted my removing my old drivers. Has anyone ever contemplated redoing the old surface mount wiring hookup with something more robust such as a connector block or is this a restoration issue?

Along the same lines does it make sense to upgrade the wiring to the woofer while I am at it? The run is short enough I suppose it's not that big a deal and the wires look like 20 gauge.

Thanks oldguide...We're already considering some added photos and revisions to the restoration guide.

The tinsel lead is really not all that fragile. It connects to the tiny voice coil wire under the tape, and THAT is very fragile. It is also difficult to reconnect if it becomes separated from the tinsel wire.

I wouldn't replace the cabinet terminals (front or back) as they are seldom a problem, and it would diminish the speakers value if you intend to sell them someday. I would only replace the woofer wires if they become too short after removing the woofers, which is sometimes the case. Replacing the woofer wires, and terminals will not "improve" the sound unless there is a bad connection. The capacitors, and sometimes very corroded level controls, are typically the only internal components that will require replacement.

Roy

[oldguide]

Thanks oldguide...We're already considering some added photos and revisions to the restoration guide.

The tinsel lead is really not all that fragile. It connects to the tiny voice coil wire under the tape, and THAT is very fragile. It is also difficult to reconnect if it becomes separated from the tinsel wire.

I wouldn't replace the cabinet terminals (front or back) as they are seldom a problem, and it would diminish the speakers value if you intend to sell them someday. I would only replace the woofer wires if they become too short after removing the woofers, which is sometimes the case. Replacing the woofer wires, and terminals will not "improve" the sound unless there is a bad connection. The capacitors, and sometimes very corroded level controls, are typically the only internal components that will require replacement.

Roy

Thanks much!

Kind of thought that is what you would say.

Those tiny wires still worry me. When I unsoldered them I was able to actually unravel most of them from around the posts, but some broke before I could get them completely unwound, but not enough to not be able to make the connection again. The "book"--as I am starting to call it--has a nice illustration of how to repair a broken wire, but I still wonder if going up to just a little but heavier gauge using the same type of connector would be a better solution. The one thing that worries me about that is once you decide to cut and connect there is no going back, plus you would probably have to remove the black tape the holds it to the driver which would risk just what you warn against. Maybe the best thing is to follow the old advice, "if it ain't broke, don't fix it," which it sounds like you are advising. If the tiny wire breaks, then think about replacing it.

Take care and appreciate your help immensely. I am beginning to see how you folks really get into this.

One side comment to the old AR hands, As I started refinishing the cabinets I noticed the joints and the corners--not too shabby. The corners are not just mated but actual finger joints. Not only does that make the cabinet more solid but also more air tight. Makes me admire the people who built these even more. I doubt you would find any contemporary speaker, regardless of cost, with wood joints like that.

[oldguide]

Probably time to end this thread as it has become quite long. I will try to monitor the site and add to the chart as new ideas come up and post them in a new thread.

Thanks again to everyone who contributed to this. It helped me A LOT!

[Pete B]

I've searched but cannot find Ken's tweeter study, has it been removed or can
someone post the link?

[Carlspeak]

I've searched but cannot find Ken's tweeter study, has it been removed or can
someone post the link?

The link is here, but it doesn't seem to work any more. Guess you'll have to PM KK for his report. It's post #86.

http://www.classicsp...r...=1649&st=80

[Pete B]

FWIW, I placed and order within the last few days at Madisound and spoke to
them about the Vifa DX19TD in Oldguide's chart. It is not going out of production
according to them, no problem getting more stock. I believe that it is now
part of the Peerless V-line product offering but still the same part. This tweeter
is not a 10 or 20 year old product, closer to 5.

http://www.madisound...roducts_id=1647

[Carlspeak]

FWIW, I placed and order within the last few days at Madisound and spoke to
them about the Vifa DX19TD in Oldguide's chart. It is not going out of production
according to them, no problem getting more stock. I believe that it is now
part of the Peerless V-line product offering but still the same part. This tweeter
is not a 10 or 20 year old product, closer to 5.

http://www.madisound...roducts_id=1647

It looks like it should play okay as a substitue with respect to its Fs and Re specs. However, a close look at it's power response plots shows it has pretty poor dispersion characteristics similar to 1 inch domes.

[Pete B]

It looks like it should play okay as a substitue with respect to its Fs and Re specs. However, a close look at it's power response plots shows it has pretty poor dispersion characteristics similar to 1 inch domes.

Fs is way too low to be used without a crossover mod. This is probably an
excellent tweeter but it is not drop in IMO. Not sure how you come to that
conclusion about the off axis response, I would not agree.

[Carlspeak]

Pete. The AR-LST brochure shows off-axis response (OAR) curves for the 3/4 inch dome tweeter. They look better than the Madisound tweeter.
KK's ABT tweeter study also shows 30 and 60 deg. off axis curves based on his testing. He concluded the 'new' 3a tweeter has superior OAR. The ABT 3/4 inch tweeter was about the same as the 3a at 30 deg. off-axis and somewhat inferior at 60 deg (about 10 dB down). The Madisound tweeter is -7 dB at 30 deg and -10 to -15 dB down at 60 deg. The AR303 tweeter was significantly more directional.

Believe other off-axis curves can be found elsewhere here but got tired of looking. Maybe Tom Tyson could post some fresh ones from the AR archives???.....

The numbers clearly show a difference. However, will the average listener notice a problem with the Madisound tweeter? I suspect NOT.

[genek]

The numbers clearly show a difference. However, will the average listener notice a problem with the Madisound tweeter? I suspect NOT.

Well, they certainly won't notice if they don't have originals to compare them to. But there are other little "AR experiences" they may miss out on.

I remember the first time someone who had never heard a classic AR speaker heard mine. It was a 20-something coworker (it was the early 80's and I was just 30 myself at the time) who had just bought his first "good" stereo. He walked around my living room for a while with his eyes wide open and his mouth agape, then turned to me and said, "You have a stereo image *everywhere in the room.* That's not fair!"

I'd hate to have to give up those little triumphs.