AR5 new cabinets

[Ibis]

Hi

Im currently re housing some units from a pair of AR 5s which I picked up cheep as the previous owner had chopped them in half to fit into a bureau ! Yes true..

Ive made the cabinets but on wiring them up I think one of the crossovers is not supplying the tweeter, I have checked both tweeters so I know the unit isnt the problem and I have cleaned thoroughly the pots so I dont think its the normal cut out which is caused by dirty pots.

Unfortunately although I can solder I dont know one end of a capacitor to the other

Any ideas where I should start to look?

Thanks

[JKent]

Hi Ibis

I remember the story. Do you have a digital camera? Would love to see the custom cabinets. And photos of the suspect crossover may help.

Did you go with HiVi tweeters and inductors as you had planned?

First and easiest thing to check: There should be a jumper wire between terminal T and terminal 2 on the outside, where the speaker wires from the amp are connected to the speaker.

How did you make your connections? Solder? Wire nuts? One thing to do is to check every joint or connection in the path to the tweeter.

Sometimes the pots still don't work, even after cleaning. Do you have an ohmmeter to check the pot?

I assume you used new capacitors, right?

Check Carl's pictorial schematic here:

http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_schematicss/ar-5_schematic.pdf

Very useful because you don't have to be able to read schematic symbols--it's a nice picture of what the wiring should look like.

That's all I got for now.

Kent

[Ibis]

HI Kent

Thanks for your message and very helpful advice.

After much swopping about I now think it is one of the tweeters that has gone, which is very frustrating as I waited a long time to get the pair from the US. Oh well back to searching the web for another tweeter. I will use this time to learn how to change the capacitors. I was wondering, would capacitors in the UK be coded the same as the US as I will need 4, 24 and 72 MFD types and would these be electrolytic, bi polar, sorry I have no knowledge of these things....

Enclosed a couple of shots of the trial cabinets, I will eventually make them in a higher density ply but this is just to get the volumes.

Thanks again for your help

Best regards

Ian

[JKent]

Hi Ian

Just have a couple of minutes to make a quick comment.

Too bad about the tweeter! IMHO the HiVi replacements that RoyC worked out work very well. I believe they may be sold as "Swans" in Europe but not sure about that. Also--it is possible that the problem with your tweeter is a broken lead. Those hair-thin leads are a pain! The copper ones can be repaired but it's tricky.

Your caps may be OK. Sprague made very good capacitors and those in your speakers could still be good. OTOH, they ARE very old. If you should replace, you can use film caps, such as Solen, made in France, or you can use NON_POLAR electrolytics. Values are in micro-farads, and this is universal. Film caps cost more than electrolytics, so what some people do is use film for the smaller values (definitely the 4, maybe the 24) and NPE for the large value (72). Of course you can use all film caps or all NPEs. Those Spragues are NPEs.

You may be better off changing one thing at a time. Fix your tweeter problem before tackling the caps. That way if there is still a problem you'll be able to trace it easier.

Good luck

Kent

[Ibis]

Hi Kent

You are a star!

Because of your encouragement I went back to the shed and had another poke around the duff tweeter and low and behold its now working, I am delighted thank you !

I think what was happening was the two very fine wires before they dive under the little dome were maybe shorting on the exposed ring of metal casing which isnt protected by the black adhesive cover, the exposed metal does have a transparent sort of glue on it which I guess helps hold the cap on and stops the fine wires from shorting out?

Any way thanks again for your kind help and encouragement. New capacitors ordered, I will keep you posted.

All the best

Ian

[JKent]

I think what was happening was the two very fine wires before they dive under the little dome were maybe shorting on the exposed ring of metal casing which isnt protected by the black adhesive cover, the exposed metal does have a transparent sort of glue on it which I guess helps hold the cap on and stops the fine wires from shorting out?

Glad it's working!

The wires themselves should be coated with insulating varnish. Also, there should be black vinyl electrical tape on the tweeter faceplate to insulate the wires. The faceplate is not insulated. Then the wires go over the tape and finally more tape atop the wires.

Your utility cabinet looks very professional for what it is. Looking forward to seeing the furniture-grade ones.

Just curious. What caps did you end up buying? I forgot to mention, the caps don't have to be exactly the same value. +/- 10% is OK. But it sounds like you found what you needed.

Kent

[Ibis]

Glad it's working!

The wires themselves should be coated with insulating varnish. Also, there should be black vinyl electrical tape on the tweeter faceplate to insulate the wires. The faceplate is not insulated. Then the wires go over the tape and finally more tape atop the wires.

Your utility cabinet looks very professional for what it is. Looking forward to seeing the furniture-grade ones.

Just curious. What caps did you end up buying? I forgot to mention, the caps don't have to be exactly the same value. +/- 10% is OK. But it sounds like you found what you needed.

Kent

Yes ! I think that was the problem, I was also using brass terminal terminal small bolts coming through the baffle, not very conductive! they are actually sounding very good. I have a pair of 2ax as comparison, I may keep the bodged boxes ( once cleaned up a bit) Im using good caps on the tweet and electrolytes on the mid and bass...... Im just learning but having fun, which is what its all about.

Thanks again

Ian

[dynaco_dan]

Yes ! I think that was the problem, I was also using brass terminal terminal small bolts coming through the baffle, not very conductive! they are actually sounding very good. I have a pair of 2ax as comparison, I may keep the bodged boxes ( once cleaned up a bit) Im using good caps on the tweet and electrolytes on the mid and bass...... Im just learning but having fun, which is what its all about.

Thanks again

Ian

Hi Ian

Are you using the early AR spring loaded plunger type speaker fasteners?

I just saved and went back to look at what you did use.

You used rough brass machine screws and hex nuts.

If I may also suggest using brass washers and brass knurled nuts, available at Home Depot type stores, for less than $2.00 each.

Or the older spring loaded plunger type speaker fasteners used on the oldest AR speaker front baffles.

The interior wiring to the machine screws can be, soldered brass tinned ring connectors, and brass regular flat and brass/bronze lock washers.

Brass wing nuts may also be appropriate for their better mechanical advantage in tightening the driver leads.

I've never tested to see if AR, Advent, KLH or others used brass, chrome plated or even steel machine screws.

That would be the worst possible connectors that will only last us a few lifetimes, in other words, more than adequate for our needs.

I wouldn't suggest soldering the interior or exterior wires directly to the brass machine screws.

[Ibis]

Hi Ian

Are you using the early AR spring loaded plunger type speaker fasteners?

I just saved and went back to look at what you did use.

You used rough brass machine screws and hex nuts.

If I may also suggest using brass washers and brass knurled nuts, available at Home Depot type stores, for less than $2.00 each.

Or the older spring loaded plunger type speaker fasteners used on the oldest AR speaker front baffles.

The interior wiring to the machine screws can be, soldered brass tinned ring connectors, and brass regular flat and brass/bronze lock washers.

Brass wing nuts may also be appropriate for their better mechanical advantage in tightening the driver leads.

I've never tested to see if AR, Advent, KLH or others used brass, chrome plated or even steel machine screws.

That would be the worst possible connectors that will only last us a few lifetimes, in other words, more than adequate for our needs.

I wouldn't suggest soldering the interior or exterior wires directly to the brass machine screws.

Hi Vern

Thanks for your suggestions and advice,

So using brass machine screws through the baffle will not adversely affect the conductivity and the performance of the mid and tweeter as brass isnt such a good conductor?

Will definitely get some knurled nuts and washers, off to my local Homebase.

Thanks

Ian

[JKent]

So using brass machine screws through the baffle will not adversely affect the conductivity and the performance of the mid and tweeter as brass isnt such a good conductor?

Will definitely get some knurled nuts and washers, off to my local Homebase.

I'm not sure whether you made a typing error. Brass IS a good conductor. My only concern about your machine screws is that you may break the tiny driver leads while tightening the nuts. Can you re-use the original posts? Some ARs had the spring posts Vern described, others had tie points.

Kent

[Ibis]

Hi Kent

Yes I am keeping the brass machine screws as binding posts, The reason why I initially questioned their conductivity was because of the problem of the tweeter. (I knew that many electrical items such as sockets etc use brass but) I suddenly thought the brass may be the problem, then I looked up on the internet and found this link

http://www.kp44.org/ftp/ElectricalConductivityOfMaterials.php which implies brass its not a good conductor....In reality the tweeter problem was nothing to do with the brass but link just added to my confusion !

Unfortunately the original tie points were not on the four chopped up parts of the original AR5 speakers when I picked them up but using washers with the nuts and making sure the wires are taped and dont wind up when tightened then the connections seem firm and safe.

I have now put the old damping material back in and sealed them up. Just been listening to Bill Frissell " Good Dog Happy Man" and they sound great, very natural and integrated, very nice bass and mid range and a rolled off top end, over all Im very impressed with the units considering their age.

Thanks for your help and encouragement, and for making me go back and have another tweak at the tweeter.

Ian

[JKent]

Hey! You're holding out on us! What are those speaker stands? AR4? And how about the (custom?) big white speakers? Inquiring minds want to know!

Kent

[Ibis]

Ha Ha! the "stands" are a pair of 4xa's cloth cone surrounds that I picked up on "Gumtree" for nothing, well I gave the guy a bottle of wine!

The big white ones are Audio Note ANE's that I built from Audio Note supplied matched drivers, Audio Note developed their speakers on designs by Peter Snell, from the US.

Early Snells are wonderful speakers, which Im sure you know about. So both my favorite speakers are from the USA !

All the best

Ian