AR5 pots bypass

[Amplifierz]

Hi guys, i just scored a set of AR5's. They are in desperate need of some TLC. Woofers and mids are good, although the woofs need some new foam. Both front wired tweets have loose leads and need to be fixed. (In case that fails, i can go the Hi-Vi way.)

But there is one thing that bothers me, those pots are dry AF. But really dry! I can't get any sound with those in the signalpath. I know that these things go fubar after 40+ years,but i don't tend to use tone controls anyway.

My question is, is there a way to completely bypass the tone control pots on the AR5's.? And what do i need to do, which components in the crossover do need to be removed and which ones are supposed to stay to keep the speakers sound like they should? Of course i will do the whole shebang of revitalizing the xo with fresh film caps and new terminals. 

[JKent]

Welcome Amplifierz!

Congrats on scoring the 5s. Those are great speakers!

My advice (and you will get plenty from others here) is:

1. try to keep the original tweeters
2. do not "bypass" the pots
3. no need for new terminals. The original screws work quite well.

So what to do. Roy can advise you on repairing those tweeter leads or, if all else fails maybe send them to Chris1this1 to be rebuilt. The HiVi's aren't bad but if your tweeters work.....

For the pots, just replace them with inexpensive L-pads like these: https://www.parts-express.com/speaker-l-pad-attenuator-15w-mono-3-8-shaft-8-ohm--260-248  We can advise you on how to hook them up.

If you are missing the knurled nuts for the speaker terminals I have some stainless steel ones for sale--just PM me. Or just get #8-32 knurled nuts from a hardware store.

-Kent

[Aadams]

Ditto everything Kent said above plus if your AR5s have Sprague Compulytic capacitors they probably don't need to be changed.   Get the speakers completely working, including either a tweeter rebuild or Hi Vis, before you judge whether the caps need changing.

Adams

 

[Amplifierz]

Hello guys,

Thanks for your input so far. You talked me out of bypassing the pots. L-pads will do the job. I found those locally. It is in Dutch,but you guys 'll get the idea.

https://shop.speakerenco.nl/ps8100mo-l-pad-100w-mono

 

But..then we proceed.

1. According to my local loudspeaker driver guru the tweeters are shot. (Complete rebuild will be expensive, and no guarentee it will yield much greater performance.) so it will be the Hi-Vi mod. I can acquire the Q1R locally, but i have no access to the 0.05mh 18gauge coil everyone talks about. 

2. Yes, i have the Sprague Compulytics. I pulled them en measured them. They have drifted quite a bit. The 24uf measures 28,7uf and 29,2. The 72uf drifted upwards aswell to 76,8 and 78,3. 

The small 4uf Industrial almost dubbled in capacitance. So replacement is planned. 

 

3. I need new terminals. I use 4mm² wire and banana plugs since i like to switch speaker sets from time to time. New 5-way terminals make things a hell of a lot easier. 

 

Thanks for any further input fellows!

[ligs]

I have a pair of 0.049 mh 17awg inductors(originally from Heathkits version of AR3a). I probably can help you on that.

[Amplifierz]

Thanks for the offer! I can acquire a 16awg inductor of the correct 0.05mh inductance. Only the dc resistance would be 0.07ohm instead of the 0.09ohms of the 18awg version. I don't know how precise it needs to be. 

[ligs]

16 awg inductor will do just fine. If you worry about the small difference in DCR you can always add a 0.02 ohm resistor in series with the 16 awg inductor.