Infinity RS 1.5 Speakers Restoration!

mikey3117

Victory is mine!
I just picked up a pair of RS 1.5's from the original owner. Great condition and woofers have been refoamed about a year ago. Some cleaning up, new cloth, caps, etc. are in order.

Here is my dilemma...:)

Do I replace those large value caps on the woofer circuit on the crossover? There is an 1100uf, 700uf and 150uf. I could string together some cheap Parts Express electrolytics but would these actually be a downgrade over the originals? The originals seem to be high quality and certainly unobtainum. I'm sure the values have drifted some but are my 46yo ears even going to hear any appreciable, sonic difference with replacements?

I'll replace the midrange and tweeter caps (75uf, 75uf, 2.83uf) with poly's.

Opinions?
 

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those large caps will be expensive.. I'd stay with electrolytic, perhaps with a poly by-pass for the mid-range ones, those 75uF... I usually go for film up to 30uF. Then, they become too large and expensive.

To answer your question, I'd say yes, replace the large caps too, with newer Non Polarized electrolytics. Electrolytics are cheap, you are not replacing expensive caps with cheap ones. You are replacing aged capacitors with new fresh ones.
 
RS1.5 is one of classic Infinity's absolute best for rock n roll music. Mine got a regular workout with classic Boston blasted through them back in the day. :D

Why a big hurry to replace the caps if none are swollen or leaking? Why not check the values first?

I'll be watching! :lurk:
 
Hey Newk!

Yep, can't wait to get these done and put on Boston's first album...

I love to restore. I'm sure the cap's values have drifted a bit and I'm a bit of a perfectionist! :)
 
Any Infinity experts out there have a source for the closest color match for new grill cloth for these?
 
I'd NOT replace those large NP electrolytics. You won't find anything nearly as good, even considering the age of the originals.

Unless you are ready to spend a fortune on paralleled film caps in order to reach the value of the big electro's, leave them alone. About all you will find in that value range in modern NP electrolytics are cheap axial caps that can't hold a candle to the originals.
 
If it ain't broke, don't fix it! I'd LOVE to have a pair of those and I listen to mostly acoustic jazz and classical BTW.
 
May be you can measure the actual value of the big caps using a tester for this purpose, then you'll have an idea of the real value. Even if you don't find a closer real value, it won't be a problem since this is normal in electrolytic caps : a tolerance sometimes as big as ±20%.
 
Those look like a great pair. Those stands are far easier on the eyes than the puppy dog ear ones. Like others have said I'd leave the big caps in place. I have yet to find one more than 6% out of tolerance. Not to say it doesn't happen but all the infinitys I have recapped the big cans were just fine. Just un solder one wire and check them if it will make you feel better.
Enjoy those classics. They are real gems.
Jim
 
I need some help...

I cleaned the level controls but the midrange control seems to have corroded and beyond repair. The tweeter control works as new. The midrange control appears to be a Rheostat. What can I replace it with? Do I need to replace it with the same or can I use an L-Pad from the regular sources? The L-Pads from Parts Express are too large for the crowded crossover. Also, does it need to be the exact value as the original? The schematic shows it as a 5 Ohm 25W.

Also, should I just replace the Rheostat with a fixed resistor since I never adjust level controls anyway? What resistor value would the flat/middle position be? I'm a stickler for originality though and if there is a direct, easy replacement, I'm all over it! :)
 

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I've purchased a 2 or 3 spare pairs of crossovers for my RSM's* specifically for the mid and treble pots.
One or two sets were from RSM's, the other from a pair of RS 5b's that had the same mid/treble pots as the RSM's.
In shopping for those I've noticed two different mid range pots (during that period) were used by Infinity. The partially ceramic pots you have, and a solid metal type with several flutes or vents on the back.
So buying from ebay is an option.
Have you googled 5ohm 25w pots? That may give some results too.


*Same as 1.5 except single VC woofer. Crossover is different obviously but I believe the same pots were used.
 
Well guys I actually had some success this morning with removing the controls, taking them apart, and cleaning the contacts. As you can see in the pics, these were quite corroded. I initially used a 400 grit sandpaper and was able to get them fairly clean. I got them cleaned, lubed and reassembled. It was a big improvement but realized there was still some dead spots. The sandpaper will only do so much. Took them apart again and used my dremel with a similar grit attachment. I was able to get the contacts completely clean. After another bath of contact cleaner, I reassembled and installed. They work as new. It's great to find an old thread on Audiokarma that saves the day (and money)! I think I will take the above advice and perhaps stock up on some cheap crossovers for future replacements.

This afternoon I turned my attention to the cabinets. Howards Restor-A-Finish Golden Oak brought out the beautiful oak veneer that Infinity applied to these. I then followed up with Howards Feed-N-Wax. The original owner seemed to have taken great care to not ding or scratch the wood but the finish itself was extremely neglected. The cabinets came out beautiful.

I replaced the grill cloth and will post some final pics in a few days. I'm still waiting on new caps, new fuses, etc.
 

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Glad it's all working out and the finish looks nice.
What did you end up using for grill cloth?
 
Glad it's all working out and the finish looks nice.
What did you end up using for grill cloth?

A chocolate brown color from Simply Speakers. Seems to be very close to the original. I even used a little brass polish on the jewel like Infinity badges...
 
A chocolate brown color from Simply Speakers. Seems to be very close to the original. I even used a little brass polish on the jewel like Infinity badges...

Thanks. We had a discussion here a year or two ago trying to decide what color the grill cloth from that time period was. It seemed to vary.
Sounds like you are having fun restoring them. Hope they sound great when you start listening to them.
 
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