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Infinity RS4 (early 80s) Crossover Questions

Cheeseknot

Cheeseknot

Member
Hello friends I'm planning on replacing the capacitors in my much loved RS4. I found this technical manual unfortunately there are a couple of mistakes. This makes me hesitant to follow it.

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I was able to verify or find the actual values of everything except for 19uF midrange cap

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Does anybody know the actual value of that midrange cap. Also not super important but that tech manual shows what I think are two diodes right before the tweeter where and what are they for?

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If you can move the white cap that is part of the "unknown" cap pair I believe you'll find that it is somewhere in the 11.5uf range since it appears from the picture that the yellow cap is a 7.5uf. The other possibility is the white cap is a 19uf and Infinity decided that is needed to be 26.5uf so they added a 7.5uf in parallel. Wouldn't be the first time and as you noted, some of the other values are different from the published Tech Sheet. This is exactly why I generally use the Tech Sheet as a rough guideline for circuit/component layout only. Just about every Infinity I've recapped has had at least one component that was different from the Tech Sheet.

The diodes are there to protect the EMIT from too much power.
 
seifreit said:
If you can move the white cap that is part of the "unknown" cap pair I believe you'll find that it is somewhere in the 11.5uf range since it appears from the picture that the yellow cap is a 7.5uf. The other possibility is the white cap is a 19uf and Infinity decided that is needed to be 26.5uf so they added a 7.5uf in parallel. Wouldn't be the first time and as you noted, some of the other values are different from the published Tech Sheet. This is exactly why I generally use the Tech Sheet as a rough guideline for circuit/component layout only. Just about every Infinity I've recapped has had at least one component that was different from the Tech Sheet.

The diodes are there to protect the EMIT from too much power.
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You nailed it. It is a 12uf and a 7.5uf I feel bit silly should have removed the cap before posting the label was just on the glue side.


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If the poly caps for the EMIT and polydome measure good, leave them alone. Plenty of stories of people replacing them and regretting it later. They are part of the Infinity sound. Definitely replace the electrolytics. Personally I like the Mundorf AC Ecaps.
 
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seifreit said:
If the poly caps for the EMIT and polydome measure good, leave them alone. Plenty of stories of people replacing them and regretting it later. They are part of the Infinity sound. Definitely replace the electrolytics. Personally I like the Mindset AC Ecaps.
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Will do!! The goal is preventive work. I'll leave alone what I can. Pardon my ignorance where do get said brand capacitors?
 
Awesome appreciate the new resources. I've been browsing around and it seems film capacitors practically 6.8uF and 50uF aren't expensive. I know they are larger but there is lots of space. As far as the 450uF goes that's going to be an electrolytic and still hurt. I'm not set any brands I think I'll make a final decision this Friday and order stuff. I've never bought anything from mouser electronics so don't take this as an endorsement. They might suck but be easy to find you know? I don't. (https://www.mouser.com/ProductDetail/75-MKT1813568255R) (https://www.mouser.com/ProductDetail/647-PHC1255500KR)
 
Updates I got the parts in and soldered into the first speaker. Cat even got involved checked my work. One thing I did not consider was the lead length. I'm not to thrilled to have to glue that red cap to the potentiometer and I would have liked to get the coils further apart but it is what it is. Speaking of coils I stuck an air core inductor in there. That Mundorf brands got a 6.8uf cap for $15 on SonicCraft at the moment. I decided to save a buck and not have multiple shipping costs and just order the coils and Audyn caps form parts express. It's a mid level infinity from the 80s I love em but I don't want to spend a lot of money. I didn't order the Vishay from mouser that linked previously. From what i read people with options the matter frown at polyester caps. I did order the Nichicon cap from mouser shipping was fast I like mouser now.

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Oh my almost a month since I made this. Sorry for the flakey updates and to come back so late but I feel I should put a bow on this. The speakers are finished the operation was a success. Funny enough that 19uf-ish(18.5) cap that I wondered about was different in the other speaker. Same value but was made with three caps two 6uf caps and one 7.5uf cap. The speakers SN are far apart so they were likely brought together at some point? IDK what ever happened my OCD made me replace them with an 18uf motor run caps (big boys) I found at a local store murphy surplus they had a bunch of them so I just found two that read close to 18.5 I can't recall the brand or exact values I'm sorry. So what have I been doing with them and what do I think of them I hear you ask. Well thank you for asking I've been using them as surf boards NO I've got them and a pair of Kappa 7.1 series 2 wired to a toggle switch and I've been listening to the two or is it too to the two. Controversial opinion I like my RS4s better. They are a lot easer on the ears still plenty of treble it just doesn't get spitty when you hit those SSSsss. When there's grain or excess high end it isn't so in your face. Pre op my RS4s where light on bass post op they are a lot better and closer to the depth of the 7.1 but the 7.1 have more impact maybe just more with the RS4s having tight dull not in a bad way sound my preference between the to changes in that regard based on the material. Maybe the 7.1 need some love got to look through them one of these weekends see whats what.
Ohhhh one last thing I never found those diodes I guess that's optional.

THANK YOU ALL THIS PLACE ROCKS

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