New SL3 owner - schematics available anywhere

[donberry]

I have actually been wanting a pair of magnepan MG1.6, but those are a definite no-no as far as the waf. Came across these SL3 for what I thought was a good price so thought I would give them a try. After I bought them, so I doubt he was lying, the guy told me he had changed the panels out about 5 years ago, which I thought was a great thing and made the price seem even better.

Sound wise, about what I expected except the bass. Was very surprised as to my ears anyway, it sure seemed pretty seamless to me and do not see how anyone would need a sub with these things. It may only go to 30hz, but it is tight and sounds great to me. I do have a ML Abyss sub, doubt if I even hook it up to these.
Midrange was not as liquid as the Magnepan, imo, but is still very good and a huge plus on the aesthetics. The Magnepans look like they were made by cheap child labor after seeing the SL3.
Of course I like to tinker, so was wondering if anyone had the schematics to these as the first thing I like to take a look at are the capacitors. Not sure what I would use until I saw the values, hate to take them apart just to see.
I normally use Dynamicaps and maybe some Obbligato premium oil filled, but again, need to see what is in it as I may have to go a little higher up the capacitor chain on these things.
I tried them out at first just using one amp, a restored Pioneer Spec 2 with a Conrad Johnson PV2AR that has been modified, then I biamped them using a restored Bose 1801 amp (around 600wpc into 4 ohms - weighs 90 pounds. Is not the Bose crap u may be thinking of) on the woofers with the Spec 2 on the panels. Sounds much better.
Thinking I want to get a tube amp to drive the panels -any idea what the minimum wpc should be for this ? At fairly high volumes, the meters on my Spec 2 were barely working, so I figured anything over 50wpc should do ?
I would put the Spec 2 on the woofers.
Now that my speakers have gotten a tad better, is also time for me to upgrade speaker wire, so will be doing some research on that, and any recommendations are appreciated.....
Would really like to find out the cap values without having to open them up.....thanks

 

[Tosh]

I would want to have a look inside to satisfy myself that everything appeared snug, especially knowing previous owner had worked on them and also knowing that things inside my own May 2000 SL3 needed screws tightening and wires re-connecting.

From what year are yours? (You can use the serial number decoder on this forum.)

There are a few threads here specifically about SL3 caps (and more).

 

[Bernard]

Here's the schematic. I suggest you open up the speakers before buying caps, to make sure you have enough room for the replacements.

 

[donberry]

thanks so much for the schematic. I will crawl back and get the serial numbers soon. I had some minor damage by a tornado that went thru here so been kind of busy messing with cleanup etc........guy that owned them was a recording engineer. He said he wasn't sure if the panels needed replaced or not, so he did it to make sure they were sounding as they should. Said he didn't notice a difference so they probably did not need replaced. He had an awesome room, all acoustically designed of course......had a pair of Krell amps driving these. He told me all of this AFTER I bought them, so I have no reason to doubt him. Would love to have half the room he had tho......here is the picture from the CL ad....was not the room he had them in when I picked them up.

also, curious if anyone has changed out the resistors to a much higher quality one, and if the did, did it make a difference in the sound ?
Thanks

 

[donberry]

been looking around, will have to check to make sure I can make them fit, but think I am going to go with the Gold Obbligato film cap for the 30uf and a Obbligato oil filled for the 33. I have used Obbligato in other speakers and I am a big, big fan. Great bang for the buck.
I can get pretty creative when it comes to fitting capacitors, but will have to open them up to make sure.
I am loving these speakers. Not sure why, but at first I was thinking I should have stuck with a pair of magnepans...now, no way.
I think the biggest thing may be junk in, junk out.
Turns out a whole bunch of recordings I have that I thought were very good are only so-so. The SL3 reveals it all where my previous speakers masked it some what.
I have never been the type who upgraded power cords and speaker wire, but that is now my next step. I have my eyes on a pair of Nelso Audio Image 70 watt EL34 monoblocks to drive the panels.....but even as is, I believe I have come close to the end of my search.

 

[Bernard]

I replaced the 30uF caps in my SL3's with Black Gates, and it made no difference, though with my past DAC there was a huge improvement with them in place.. Please let me know how your replacements turn out.

 

[Tosh]

If the PO was so particular, perhaps he also swapped in the later Vifa woofer, which should be a noticeable improvement in bass and midrange?

I tried a Riedon 1R0 metal oxide film resistor on a heat sink for the RX1, RX2, RX3 combo. Possibly more detailed, but if nothing else, it makes for a tidier layout.... (perhaps I should have splurged for a Caddock?)

I've also been putting off swapping in 3 of Apex Jr's 10uF Rifa caps ($3 each - not listed on website, so call) bypassed w a 0.1 Vishay MKP1837 (for CX2), and then moving the freed-up 30uF Solen into the 30uF generic film's position (CX1). I really should get on that...!

 

[Gordon Gray]

Don,

You may want to look at my suggested mods to the SL3's. See the "Tweaks" section on the home page. They do work and are, IMHO, well worthwhile.

GG

 

[donberry]

Already read and re-read your suggestions Gordon - figured when i do the caps would be a good time to attack that.
I used the Vishay bypass caps on a pair of HPM-150 I have.
just my opinion and my ears, but I thought the HPM-150 was a decent speaker, but there were better at that price point.
I totally rebuilt the crossovers using Obbligato oil caps and Dynamicaps - with the Vishay MKP1837 as bypass caps per Humble Homemade's advice.......of course I am biased, but I would now put those speakers up against any box speaker (within reason of course) that I have heard, and i have been thru quite a few box speakers.
I was not so sure before, but now I am a HUGE believer in cap upgrades. For me and me only, I am also now a huge believer in cap burn in.

I doubt I will hear such a drastic difference in the SL3, but I am guessing it may squeak out a little more from them.

I am busy cleaning up after a minor tornado hit, but when i get the garage fixed and things slow down some, i will put new caps in and report back....tho as always with anything audio....YMMV

 

[donberry]

have not got around to doing any upgrades yet, will probably be mid summer before I get around to it. Just wanted to say, that after extended listening to these, I am very, very happy. I am constantly surprised at how good the bass is (yes, I plan to dampen them per instructions).
At the moment I am bi-amping them with 2 ss amps (both over 400wpc into 4 ohms), but I am hoping to add a 70 watt tube amp to drive the panels in a month or so.
I would guess these speakers are not very far up the MartinLogan totem pole, but I have to say I am very, very pleased with them and these will probably be my main speaker for many years to come.