Sansui SP-3500 - An AK'er Gift and Restoration Project

[blues 66]

Hey Danzilla,

Welcome! If you glance through this thread, more towards the beginning, I tackle the crossovers with new caps. Ultimately, the fact that you replace your original caps with new ones will make the most difference. Dayton Audio, Solen, whatever poly caps, are all fine choices. I generally buy mine from parts express. I'll go with whatever brand makes the value that I require.

These crossovers are a moderate level of difficulty. The crossovers are on a circuit board, which is affixed to the plastic cup that holds the binding posts, screws into the back of the speaker. In this thread, I describe how to separate the circuit board from the plastic cup. At the time, this was the only online mention of being able to separate the two. I was pretty proud of that. However, you can simply snip the caps closest to the capacitor. This leaves some of the lead coming out of the circuit board. You can tie the new caps to the existing leads, this is an acceptable route.

As far as repairing your grills, I would suggest starting your own thread and including pictures. Without pictures, we're just speculating on what method would be best. And that doesn't do anyone any good.

Biggles

hi Biggles, it's always nice to see the interest ... of the Sansui SP 3500 now I'm ready, I bought the new capacitors, unfortunately they are 100v in polyester, not polypropylene.
the important thing is to change those old condensers, 40 years ago
reading your post, I read (highlighted in black) that you can, cut the caps closer to the condenser.
and if i did something like that? so it could go
thanks

 

[FluxT]

I snipped my leads as close to the original caps as possible, and then wrapped and soldered my new cap leads around them. The old caps are caked in with super thick epoxy, so I gave up on trying to remove them. It’ll look like this when all is said and done:

 

[blues 66]

Uauhh , FluxT : what you did, is not bad at all ... Good!! 'For the glue they told me to use; a cutter, and cut screwdriver, and a lot of patience.
I also see a cable speaker coil ! intending to change wiring ??
ciao

 

[blues 66]

hello, any of you, re-did the input terminals? 'Unfortunately by undoing the wiring of the cables that, are welded ( woofer ), pathetically I broke a faston ,see photo input 1st at the top and do not know what to do'

among other things, the connectors, of the inputs those of the black plastic panel, are dirty and make little contact !

 

[drbiggles]

hi Biggles, it's always nice to see the interest ... of the Sansui SP 3500 now I'm ready, I bought the new capacitors, unfortunately they are 100v in polyester, not polypropylene.
the important thing is to change those old condensers, 40 years ago
reading your post, I read (highlighted in black) that you can, cut the caps closer to the condenser.
and if i did something like that? so it could go
thanks

View attachment 1680784

Hey Blues,

I apologize for the huge delay, am generally working 6 days a week. Not too terribly long ago I was "self employed" and had plenty of time to reply, work on projects. At the end of the day, if you can find a creative way to get new caps installed, I say go for it. The method you described is what most people do in this situation. Go for it!

I snipped my leads as close to the original caps as possible, and then wrapped and soldered my new cap leads around them. The old caps are caked in with super thick epoxy, so I gave up on trying to remove them. It’ll look like this when all is said and done:
View attachment 1680831

I lucked out when I removed the old cap and glue. I used a cheap, battery powered vibrating multi-tool to pop the glue off. It didn't stick all that well and popped off without much effort. That's probably about the time I stopped using glue for such things, mechanical fasteners rule.

hello, any of you, re-did the input terminals? 'Unfortunately by undoing the wiring of the cables that, are welded ( woofer ), pathetically I broke a faston ,see photo input 1st at the top and do not know what to do'
View attachment 1686031
among other things, the connectors, of the inputs those of the black plastic panel, are dirty and make little contact !
View attachment 1686033

This is one of those times you simply need to get creative. If something is dirty, you gotta clean it. Something solventy and an abrasive something or other will do. If something doesn't work so well, try another angle. The broken widget thingy is a similar situation. Sit with it for a while, what's it going to take to get a connection on one side? A small solid core piece of wire, gently soldered in? Wrapped and soldered? Then bring the wire up and around? Go grab some hot cocoa, a piece of cake, and think about it for 15 minutes. If not, ponder it on The Tree of Woe and come back tomorrow. We all make mistakes, it's all about coming out the other end without being covered in $#@!.

Biggles

 

[blues 66]

Biggles, hello it's always a pleasure to see you here! 'Thank you for the answers !
yes what I did, it's just like you wrote ; I thought and thought again , in the end I did a manual work so I used 2 male Faston terminals, and tucked, in the burglary of the board, then I welded the terminals, to the eye, those d 'Once they made contact, I welded them together, then welded the cables of the Woofer 'this is to keep the project as original as possible'


you don't have to apologize at all... I'm the one who apologizes for the ball-breaking.'
Ciaoo

 

[FluxT]

I lucked out when I removed the old cap and glue. I used a cheap, battery powered vibrating multi-tool to pop the glue off. It didn't stick all that well and popped off without much effort. That's probably about the time I stopped using glue for such things, mechanical fasteners rule.

Unfortunately, all of my cheap battery-powering vibrating multi-tools proved woefully inadequate for the task, so I just strapped mine in.

Jokes aside, have any tips for getting the most out of these speakers? I’ve been toying with placement for months, and I still haven’t found anything that really brings home the bacon yet. They image wonderfully, but the tweeters have horrid dispersion, and the highs almost seem to “shift” in the soundstage as you move your head toward. A cymbal coming out of the far right will move inwards and then completely disappear as you get up out of your chair. Damndest thing. Should I toe them in, get them up on stands, remove the grilles, remove the vanes, flip the tweeter wiring, or??

 

[drbiggles]

Hey Flux,

Old horns tend to be beamy. Some are so tight that if you simply tilt your head, the magic evaporates. For me, these rigs ain't for relaxing for some critical listening. They're for 1970's Rolling Stones at full volume, anything at full volume. They're designed to take a pounding, that's what I did. Over some time, I've come to realize that if I were to recap another pair, i would not go with modern poly caps. They came with electrolytic, so I put them back in. The noisy, inaccuracy of the caps play into the noisy inaccuracy of the drivers perfectly. This combination is what you want for rock, noisy inaccuracy. On the floor, backs up against the walls will increase bass. Up off the floor, away from the back wall will decrease bass. I say, don't overthink it. Set on the floor, jam something under the front lip to tilt them back a tad. They don't have to be even, just loud.

Biggles

 

[GD70]

Hey Guy!
Happy Holidays! Haven't seen you much lately and glad to hear you're working your butt off!
What kind of work are you doing, and any recent projects to play with?
Cheers, Glenn

 

[drbiggles]

Hey Guy!
Happy Holidays! Haven't seen you much lately and glad to hear you're working your butt off!
What kind of work are you doing, and any recent projects to play with?
Cheers, Glenn

Hey mang!

It's good to see you. No recent projects. Popped on my main system for the first time in 10 months on Thursday. Yeah, it's been like that. I am planning on redoing my trusonic 80FR project though. The fiberglass needs to be replaced by cotton batting. I would like to replace the Wharfedale Super 3 tweeter setup with a new pair of ESS Heil tweeters I picked up at a sale a year or two ago. That'll need a whole new crossover. I found the best job ever, it's a very interesting and lengthy tale. I've moved into running the facilities maintenance department at a local agroscience laboratory. The people are tremendous, and I have the best boss ever. Plus it's a 12 minute reverse commute, easy. I'm hoping to have more time for audio fun time, but I wouldn't count on it.

Biggles

 

[GD70]

Hey mang!

It's good to see you. No recent projects. Popped on my main system for the first time in 10 months on Thursday. Yeah, it's been like that. I am planning on redoing my trusonic 80FR project though. The fiberglass needs to be replaced by cotton batting. I would like to replace the Wharfedale Super 3 tweeter setup with a new pair of ESS Heil tweeters I picked up at a sale a year or two ago. That'll need a whole new crossover. I found the best job ever, it's a very interesting and lengthy tale. I've moved into running the facilities maintenance department at a local agroscience laboratory. The people are tremendous, and I have the best boss ever. Plus it's a 12 minute reverse commute, easy. I'm hoping to have more time for audio fun time, but I wouldn't count on it.

Biggles

That's awesome, and I'm very happy for you!
10 months! Damn, that's worse than crack withdrawal! It's ok though, the toys will be there to play with when you have some time.

 

[FluxT]

Hey Flux,

Old horns tend to be beamy. Some are so tight that if you simply tilt your head, the magic evaporates.

This is very true. I just remembered back to my first "rescue"-a pair of Pioneer CS77's. You had to be dead on axis to get any semblance of highs and the full brunt of that brutal midrange. Beautiful cabinets, but only sounded good on '60s rock. You could really smell the Agent Orange when spinning CCR or The Doors. Sold 'em quickly for a few crisp $100 bills.

I think I mispoke earlier, actually. It's really not so much that the dispersion is *that* bad, it's more that their output seems too low relative to the mids and woofer, and the treble has to be janked to sound properly balanced. Speakers have been recapped with new electrolytics, pass the toilet paper test, and IIRC registered 7 ohms on the crossover board (ie: two 14 ohm horns in parallel). I know these tweeters are known to blow out, but I'd imagine they'd either be silent or distorted if they're damaged, right?

 

[drbiggles]

This is very true. I just remembered back to my first "rescue"-a pair of Pioneer CS77's. You had to be dead on axis to get any semblance of highs and the full brunt of that brutal midrange. Beautiful cabinets, but only sounded good on '60s rock. You could really smell the Agent Orange when spinning CCR or The Doors. Sold 'em quickly for a few crisp $100 bills.

I think I mispoke earlier, actually. It's really not so much that the dispersion is *that* bad, it's more that their output seems too low relative to the mids and woofer, and the treble has to be janked to sound properly balanced. Speakers have been recapped with new electrolytics, pass the toilet paper test, and IIRC registered 7 ohms on the crossover board (ie: two 14 ohm horns in parallel). I know these tweeters are known to blow out, but I'd imagine they'd either be silent or distorted if they're damaged, right?

Flux,

Ah, imbalanced? Shouldn't be imbalanced, so maybe they're on their way out. Yes, when they're completely blown, they silent or distorted. An odd situation, I cannot say for sure from here.

OH MAN, you're killing me !!!!!!!! A friend let me borrow, for a very long time, a little over a year ago, a pair of CS-77's. My impression was yours, dead on !!!! It seemed as though they were built to play Some Girls, and that was pretty much it. But DAMN man, they did so well I still have them. I too found that midrange driver evil. I put all 3 drivers up on my trusty DATS v.2 to see what the impedance curve was like. It was nearly like a figure 8 it was so poor. Which means the crossover points never stayed the same, not even for a moment. The woofer was a close runner-up, and oddly enough, the tweeter was nearly flat. Yeah, I don't get it either. My buddy had recapped them with new polys, those are still in there. I need to remove them and go with new electrolytics, they're still a tad hot. What I was able to do, was build a Zobel network for both the midrange and woofer. This evened out their response, tamed them a bit. They still have the same "signature sound", but it's not so horrendous. I'm figuring with new electrolytics and some 45 watts worth of splendid tube amplification, I think they're going to be a great rock-only addition. You can hear the studio or club that the band is in, what's going on, the air. It's pretty freakin' cool. They're also in near mint cosmetic condition, so there's that as well.

Biggles

 

[FluxT]

Well, I took 'em apart, and did some sweeps yesterday. Annoyingly, everything tested out fine, except for the fact that I wired the tweeters out of phase when I recapped the crossovers. The real culprit was having my new Pioneer SXS30 amp in Pure Direct Mode. I'm guessing it's voiced to cool off the overhyped highs of most "audiophile" speakers. It's a good little amp, though. Putting it in Direct mode cleared things right up, and that's the mode I used for testing them here. The room also played a pretty big role. They sounded just fine in the relatively small bedroom with tile floors, but clammed right up once I put them back out in the lightly carpeted living room.


My mic isn't flat, but I made some sweeps and did rough adjustments per the published FR of the mic. Speakers were set on the floor, with the mic 1' away from the woofer's dustcap, and then I put the mic on a box to get it on axis with the mids and tweeters. This was done in a small bedroom, with the speaker placed upon a carpet in the middle of the room-hardly an anechoic chamber (the opposite, honestly), so I took out what appeared to be room/boundary effects at 300Hz. I disconnected the other drivers at the crossover boards, so each sweep is just that driver in the box, with the crossover circuit engaged.

Bigs hit the nail on the head here with the "noisy inaccuracy" comment. Definitely some rough jagged edges, most notably that big spike at 2k that seems baked into the woofer. Since it's running full-range, a simple choke should be able to get rid of it. Knocking the 2k down on the Pioneer's EQ took a LOT of edge off the vocals. Looks like phasing stuff at the crossover point between the mids and tweeters, too. As for the tweeter diffuser, it does roll off the highs a bit, but it definitely tames their hotness and just looks cool, so I'm going to leave mine on. I believe Sansui made an SP-2500A (and SP-3500A) model that eliminated the diffuser, so you wouldn't exactly be destroying whatever grand vision the designer(s?) had in mind.



Woofer

Note the strong 2k peak. That's cone cry, if I ever done saw it.
Midrange


Phasing, as is to be expected with
Tweeter



Composite:



Full Frequency Response:


Barring the nasty spike at 2k, I'd say these are flat from 50Hz-19khz +/-4dB.
Effect of the Diffuser:


Yes, I do a lot of measurements.

 

[ThreadKiller]

FluxT thanks for doing the work above. It is appreciated. (Sorry old thread bump)

 

[FluxT]

Hey, no problem!