Refurbishing Vintage Sansui SP2500 Speakers (Crossover Repair)
I’m always keeping my eyes out for interesting vintage hi-fi speakers from the ’60s-’70s, and found a nice set of Sansui SP2500s on Craigslist. Produced between 1960 and 1974, these beautiful walnut speakers are solid and very heavy – definitely high quality. I’ll share some photos below, and then dig into reconditioning them!
Here are the vintage ads for the Sansui speakers. Click on the image for the full-size version! The web site is down apparently, replaced with a placeholder park page redirecting to a spam site. Sorry, no vintage ad anymore! I should’ve hosted it here instead.
Unlike newer speakers (including a pair of Sansui SP7500X that are still waiting to be refurbished), these are very easy to remove. Six screws to remove the crossover panel from the back, disconnect the driver leads from the spade terminals, and pull out of the back. Like all older electronics, speakers also have components that can fail inside. The crossover network, distributing and filtering the amplified audio to the different drivers, contains capacitors which can fail with age just like the capacitors in an antique radio or in your modern electronics. It’s easy to forget speakers have parts that can degrade inside, when they’re almost always treated like a single box unit.
If you’re buying speakers from Craigslist and they have adjustable crossovers, make sure to check them on all settings to help assess their condition.
With the crossover removed, it’s easy to see the components that need replacing. The three blue cylinders are the crossover capacitors, in 2.2uF, 4.7uF and 10uF varieties. These are bipolar electrolytic capacitors, a special type that is slightly more expensive than standard electrolytic models, but they are required because speaker current is AC and must flow both directions across the capacitor. A polarized capacitor would be likely to explode if used in the same application.
Parts Express sold me everything I needed for these speakers, and a few others:
The old capacitors are glued to the board and I didn’t want to damage it, so I snipped the leads as close to the end as possible and bent them into terminals, then attached the new capacitor to the wire and soldered together.
Repeat for the other capacitors, and after trimming the leads, much nicer:
Two speakers means two crossovers:
Reinstalled and ready to rock:
My only complaint now is the diffusers send the high-frequency audio straight into my carpet, when placed on the floor. I suspect these were meant to sit on stands somewhat. I’ll experiment with different positions for the speakers in my living room, but if it ends up not helping, the hole is symmetrical so I can just rotate the top assembly and now the speaker will send its sound up, towards my ears.
I have several more pairs of speakers – Sansui SP7500X, Bose 601 Series 1 and Cerwin-Vega D-5s. I’ll post photos of refurbishing their crossovers when I get to it.
My parts list:
- 2.2uF 100V Non-Polarized Capacitor
- 4.7uF 100V Non-Polarized Capacitor
- 10uF 100V Non-Polarized Capacitor
I used 100V capacitors both because that’s the lowest voltage in this type my supplier offered, but also because they’ll last longer if they’re intentionally de-rated and with any luck, this will be the last time I’ll need to work on them.
Total cost: $1.38 + $6 shipping to restore these speakers to original working condition after 40 years of service.
What were the symptoms the speakers had that you knew to replace capacitors? I just picked up a pair of sp1500′s that sounded ok when I purchased, but when I ran them on my system, the woofer has a “scratchy” sound that I didn’t hear earlier. All the speakers are in good shape save for this noise. Thanks! Tyler
Hi Tyler, those symptoms match what I was experiencing – some crossover settings would play no audio at all; others would be scratchy, static-filled or otherwise distorted. Sounds like yours are going to need this same treatment. I’d give the controls a good cleaning while you’re at it, too, if the SP1500s have adjustable crossovers.
Hello, I have a pair of sp-z7 I cannot get any sound out of the midrange or tweeter but horn and wooofer sound fine there is one 50v 2.2 capacitor hooked to the setting adjustment and 1 50v 8.2 connected to the midrange and no visual damage so any experience with anything like this? Thank you for your time! VANCE
Thanks you for posting this online. I’m about to recap a different 70s Sansui speaker (SP-X8700), I wouldn’t have thought to leave the original capacitors on like that–very smart. Thanks again.
Dude, thanks for the excellent pictures of the crossover repair. I have a pair of Sansui XL-500 speakers. The pots spin all the way around so I assume they are shot. When I pull the crossover from the cabinet, how do I know which other parts to change? Are they usually burnt? Just change them all? Thanks!
Kyle, your crossover should have a few other components – resistors, capacitors, and inductors. In the photo of the SP2500s, the resistors are the white blocks; the inductors are the metal framed devices.
With a multimeter, you can measure the resistors and make sure the reading matches the stamped markings. For the inductors, just make sure there’s continuity through them and they haven’t gone open. Capacitors you’d definitely want to replace. I’d be surprised if a resistor or inductor in the crossovers was bad, unless the speakers were literally blown by having far too much power applied.
What is your opinion of the Sansui S-1000U speakers? What vintage would they be and how would they sound compared to similar year Advent, KLH, AR, etc?
I’d be a bit skeptical of them myself. They’re mid 1980s vintage, not exactly a period known for stereo sound quality the way speakers from the 60s-70s were, and before a lot of the modern measurement and specification techniques came onto the scene in the ’90s. The result being I’m not sure I really believe their frequency response, power rating and sensitivity. Later Sansui stuff such as these doesn’t have a very good reputation in the audio community. Those speakers also lack the iconic wood lattice grills of the ’60s and ’70s models which in my opinion looks far superior to the fabric cover. I’d expect them to sound acceptable, certainly, but not spectacular.
Unfortunately I can’t really help with the comparison to other ’80s speakers as that’s not a time period I collect much of. Most of my speakers are ’60s-70s, or ’90s+. Brief research shows them selling for $20-60 per pair (Craigslist, Kijiji, Goodwill, others). For that price, if you like the look of them and don’t need the most discerning reproduction, it would probably be worth it.
you mentioned having some sansui sp7500x – i took mine apart to freshen up and have lost the correct order of wiring to each speaker – i,m a dummie ! any help ? this is from the crossover to each spk.
very good info on the capacitor replacement. any suggestions on replacing the actual speakers?
what can you tell me about Sp 100 speakers. Purchased a pair on eBay awhile back. Both need attention,. How can you tell if the capacitors are good / bad and where can I purchase new speakers.
I’d replace the capacitors outright. You can’t really tell if they’re bad by looking, but they most likely are at this point. You can get new capacitors (and speaker drivers) at http://www.parts-express.com, I buy most of my speaker repair materials from them.