HELP! Rescuing Dad's old PL400 S2 (pics)

[laatsch55]

I see..

 

[lightfall]

While I wait to continue my PL400 S2 restoration I am finding I am really enjoying this process. I think I have decided to restore the Infinity RS IIIa set of speakers I have had in my storage closet for the last five years. There is some dry foam rot, one of the speaker squeezer things on the terminal broke off, and one of the adjustment knobs is missing as well. The biggest issue is the foam surround on the tweeters is dried up and falling off.

Do old ribbons and dome tweeters like this age well?

What do you suppose is involved in a restoration like this? Last known to be in good working order. Good source on replacement parts? This seems like a good choice for the PL400 but I hear it takes a lot to make these sing.

 

[laatsch55]

There are some Infinity owners on this forum. Premiumplus is one....I'm sure he'll pipe in here...

 

[grapplesaw]

While I wait to continue my PL400 S2 restoration I am finding I am really enjoying this process. I think I have decided to restore the Infinity RS IIIa set of speakers I have had in my storage closet for the last five years. There is some dry foam rot, one of the speaker squeezer things on the terminal broke off, and one of the adjustment knobs is missing as well. The biggest issue is the foam surround on the tweeters is dried up and falling off.

Do old ribbons and dome tweeters like this age well?

What do you suppose is involved in a restoration like this? Last known to be in good working order. Good source on replacement parts? This seems like a good choice for the PL400 but I hear it takes a lot to make these sing.

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View attachment 17405

I some new surounds on some EPI 500 10" woofers earlier this year. It was quite easy to do. Lots of places to buy surrounds. eBay is easiest . I used Weldbond glue but others have use Sealall l, shoe goop and rubber cement. If the mids do not need refoaming then they are good to go. The tweeters may last for long time. Some electrostatics are made with Mylar as plates and these break down over time so you hear them fail, or lack of hearing them will tell you they have failed. These are often available on EBay for not bad price. Keep a look out and pick up some spares. I rebuilt some electrostatic headphone years age using new mylar sheet.

Those are defiantly worth rebuilding. Upgrade the internal wire sizes and new better caps on the crossovers are a must do you will not believe how much better a speaker set will sound with the right capacitors installed

Hope that inspires you

Glen

 

[laatsch55]

Agreed, caps are paramount....


My bad Brad, premiumplus is a Dahlquist guy..

 

[gadget73]

Those aren't one of the Infinity models that blow up Phase Linear amps is it ? I know there is some model that has a really ugly impedance curve that goes basically to a short circuit at points.

 

[laatsch55]

Yep, those are the ones!!

 

[lightfall]

Wait, so these speakers are KNOWN to blow these amps up? Is that just at high volume? I wonder if these speakers were the ultimate cause of this amp blowing out in the first place...

If I do a proper restore of these speakers and I am careful (not sure what that means exactly) do you think this would work OK?

Also, could you tell me a little more about the role of the capacitors in the speaker? Since they are electrolytic and break down over time does it mean that the speakers essentially have to draw more all the time from the amp instead of smoothing things out and working more efficiently?

 

[Northwinds]

Keep a fan on the amp on high and don't go crazy with the volume and you should be ok. I dumped my Infinity's because I did not want to chance hurting my amps and I have been known for a heavy hand on the volume LMAO!!!! Went to Cerwin Vega's and have had no issues since. I want to get a set of D9's in the future just for the extra 100w per power handling. My WOPL will kill the E-712's I have if I am not careful and they handle 300w's

FWIW, I also dumped a set of Quantum 5's for the same reason

 

[lightfall]

I found a thread on AK talking about the nature of these speakers: http://archive.audioreview.com/13/0EE90FAD.php

It seems it is all about current with these. This guy gives an amp recommendation, "Current, current and more current. Look for a good, meaty 100 Watt amp, with plenty of current and a BIG, BIG power supply (yep, it'll be heavy, thanks to the big power transformer). Make sure it is stable down to 2 Ohm loads (at least) and you'll be sweet. "

"Average efficiency. 100 Watts @ 8 Ohms, with bucket loads of current and good 2 Ohm capability. I would suggest that an amp of 100 Watts, with (say) 30 Amps of current ability, should work better with the RSIIIs, than one with (say) 200 Watts and 20 Amps of current ability."

How do you think the PL400 S2 fits into this discussion? I purchased the refoam kit. I am going to have to figure out something to replace the tweeter surround sound dampening foam which is totally dried, I will have to somehow strip that off and replace it with velvet or foam or some other sort of stuff. Then I need to figure out about crossovers and what capacitors are appropriate there. That is something of a tricky thing to research so far but I will keep digging.

 

[gadget73]

I believe the PL are rated to 4 ohm only. Here's a service bulletin about it,


http://home.earthlink.net/~dimlay/sitebuildercontent/sitebuilderfiles/Infinityspeakers.pdf

 

[lightfall]

OK so I need to buy a 500w 5ohm resistor of some sort and on the back of the single speaker terminal I connect the red and black wires coming off the back with the resistor, am I interpreting that correctly? While I am at it do I want to add a fuse of some type anywhere?

How exactly does one go from 8 to 2 ohms? Just listening to loud music with a lot of bass during a heavy section will create that situation I imagine.

 

[laatsch55]

Gadget, I had a 400 I loaned out to a guy in Phoenix, Az. . It pulled 2 ohm duty for months. It had a custom set of copper heat sinks and had forced air cooling and was White Oaked. It did just fine..

 

[laatsch55]

OK so I need to buy a 500w 5ohm resistor of some sort and on the back of the single speaker terminal I connect the red and black wires coming off the back with the resistor, am I interpreting that correctly? While I am at it do I want to add a fuse of some type anywhere?

How exactly does one go from 8 to 2 ohms? Just listening to loud music with a lot of bass during a heavy section will create that situation I imagine.

Why do you need a 500 watt 5 ohm resistor.?

 

[laatsch55]

A stock 400 on the RS' is probably not a good idea. The protection circuit on the stock driver board would be working overtime.
A 700 that is a WOPL will drive the RS' s all day long. Member FredR has some....unless he's the other Dahlquist nut...

 

[Nick Danger]

Gadget, I had a 400 I loaned out to a guy in Phoenix, Az. . It pulled 2 ohm duty for months. It had a custom set of copper heat sinks and had forced air cooling and was White Oaked. It did just fine..

Mmmmmmmm, copper heat sinks.......

 

[laatsch55]

I've built 4 sets so far. 2-400's and 2-700's. You haven't seen them? Tony has a set on the lottery 400 he got. Ed Blackwood has 2 sets and Steve in Phoenix has the other...build threads on a all of em.

 

[lightfall]

This bulletin seems to suggest I do that: http://home.earthlink.net/~dimlay/si...tyspeakers.pdf

Is there a cost effective modification I could do to make the PL400 I have more robust in respect to this set of speakers?

 

[laatsch55]

Yep. White Oak it.

 

[NavLinear]

Mmmmmmmm, copper heat sinks.......

If you haven't found the threads yet here's a couple:

http://forums.phxaudiotape.com/showthread.php/2888-Copper-Heatsinks

http://forums.phxaudiotape.com/showthread.php/4033-Stephens-Phase-Linear-400-In-for-the-works