Below you will find all the current updates/upgrades available for Polk Audio SDA speakers.
Performing all of these modifications will bring your SDA loud speaker to its full potential!
FOR DOWNLOAD: The SDA Handbook. By Ray Smith (Revision 3)
Check this link for Schematics: HERE (Work In Progress)
Information Regarding checking your amplifier -
Check to see if it is a COMMON GROUND AMPLIFIER by doing the following -
The easiest way to tell if the amp is common ground is to take an ohm meter that is set to continuity and take one lead of the ohm meter and touch the neg terminal on the left output of the amp and take the other lead and touch the right negative terminal output of the amp and if it shows continuity you have a common ground amp,if nothing happens then you have a non-common ground amp. Basically the amp is considered a common ground if they share a ground for all the negative outputs on the amp. Hope this answers your question. - Racer4551
1) Upgrade/Update crossovers
Capacitors -
Clarity Cap - Vr3 Mods Approved
Sound Traits - More transparent, a little brighter
Information - developed as a direct result of the 2 year research programme conducted between ClarityCap and the world renowned Acoustics Research Centre at the University of Salford. The performance of the capacitors has been dramatically enhanced by reducing resonant sonic outputs from the capacitor winding itself. This is achieved by careful selection of the highest quality polypropylene base film combined with thick pure aluminium metallisation and close control of critical production processes. The resulting ESA range offers exceptional performance in audio applications at both 250Vdc and 630Vdc. A guaranteed 3% tolerance ensures component to component consistency for a balanced system and reproducibility across production runs.
Website - Clarity Cap
Sonicap -
Sound Traits - Neutral, warmer
Information - It redefines the price-to-performance ratio for "audio capacitors". The Sonicap is the "entry level" of its design. However, the design is world class! The Sonicap will yield or exceed the performance found in the most prestigious of boutique caps, yet with a price conducive to that of "entry level".
The Sonicap is well balanced and true to the source. The word "neutral" is so loosely (and incorrectly) used, that I prefer the term "balanced". While capacitors suffer from more noise (high distortion) than most audio components, the Sonicap exhibits very low noise and parasitics. The presentation is rich in harmonics, warm, without the slightest loss of detail retrieval! As a matter of fact, the micro-dynamics of the Sonicap is unmatched by anything close to its price range.
Website - Sonicap
Resistors -
Path Audio- Vr3 Mods Approved
Developed and designed for the highest Hi-End sound quality. Their design ensures excellent transmission of the full audio band, without audible distortions and with an extremely low noise level.
PathAudio resistors feature a wide frequency response with negligibly low impedance phase shift, ensuring the highest quality audio processing.
They have a tolerance of 1%, low temperature coefficient, high heat dissipation, no vibration effect.
The resistors are made using thick film technology. A resistive layer is applied to the molded ceramic body. Then it is dried and fired repeatedly at high temperature. To obtain the highest mechanical stability and shielding advantages, the resistor is placed in a copper tube and covered with the highest quality resin.
The use of copper pipes allows for the removal of interference, and the third long lead is helpful. It is only connected to the housing and has no contact with the signal transmitted by the resistor. This third, distinctive pin should be connected to ground, if available, or simply to the “-” loudspeaker input, i.e. the ground point in the crossover.
PathAudio resistors are perfect for speaker crossovers, allowing the sound to be smooth, clear and have excellent dynamics. They can also be successfully used in audio devices, thanks to which the devices can show a new quality of sound.
Website - Path Audio
Duelund - Vr3 Mods Approved
Works together with the drive unit to offer a more stable load while providing as transparent of a signal transfer as possible. A pricier alternative to other resistors but a fantastic end result with solid build quality.
Website - Duelund
Mundorf Mox, M-Resist Supreme, MREU30 - Vr3 Mods Approved
A value priced resistor with excellent wattage and transparency. A solid performer through and through.
Website - Mundorf
Mills (MRC50) - Version 3 Audio Approved
A high powered resistor at a great price with excellent transparency and musicality. A competitor to the Duelund without the price (but not quite as transparent)
1a. Removal of the polyswitch - On most all Polk SDA crossovers there was a circular component called a polyswitch. This is kind of like a fuse that it will engage if the tweeters start to get over-driven. It has been proven this component introduces noise and distortion. The approximate resistance of this component is .5 ohm if you wish to replace it with a resistor.
Inductors -
Jantzen Audio, Perfect Lay, P Core and C-Coil - Version 3 Audio Approved
A well rounded product line with many options for multiple uses. Excellent replacements that supply a top notch, higher tolerance replacement to the original inductors with lower distortion and noise.
Website - Jantzen
Removal of the polyswitch - On most all Polk SDA crossovers there was a circular component called a polyswitch. This is kind of like a fuse that it will engage if the tweeters start to get over-driven. It has been proven this component introduces noise and distortion. The approximate resistance of this component is .5 ohm if you wished to replace it with a resistor.
Removing the old components can be a pain, but hot glue can be easily removed with isopropyl alcohol, a knife/plyers and a little patience.
2) Check your wiring!
These speakers have some age and previous owners have been digging through them and potentially have them hooked up wrong! Make sure the polarity is correct.
Schematics can be found here - Schematics for Polk Audio SDA series
3) Not feeling up to the DIY Crossover task? We offer full rebuild services with an industry leading 10 year warranty!
Click here to see Vr3 Mods crossovers.
Vr3 Mods Crossovers feature the following -
Point to point networks
Custom Aluminum terminal plates
Neutrik NL4 SDA cables
Top quality substrates, laser cut and computer designed
Top notch components from Clarity Cap, Duelund, Path Audio, Jantzen, Mundorf, Supra, WBT, and more!
4) Replace those old tweeters with newer, improved tweeters from Polk Audio!
Contact Polk Audio directly to order these (Click Here) - Make sure let them know if you are a Club Polk member.
The "RDO" line of tweeters is a replacement Polk stocks for your SDA speakers that are improved over the original designs.
RDO198 = SL3000 and SL2500 - Midwest speaker repair - Click here to order
RDO194 = SL2000 - Midwest speaker repair - Click here to order
5) Replace the SDA cable, Binding Post and Terminal Cup
Neutrik NL4 SDA Cables - Vr3 Mods Approved
A standard practice now is to replace the SDA cable with a Neutrik NL4 connection. This is a 4 conductor, locking connection that handles high power and passes a very transparent signal with 100% conductor contact.
Dreadnought A1 - Click here for excellent information on the 1000VA Dreadnought. This is a must for owners with non common ground amplifiers (and noted performance upgrade) but this is not compatible with the first generation SDA speakers.
Binding Post -
Replace the nickel binding post with top notch gold plated binding post for a better signal transfer and no corrosion over time. Recommended brands are as follows - Vampire, Cardas, WBT, etc
Terminal Plate -
If your old terminal cup is cracked, broken or if you are looking for a cosmetic upgrade that will provide a more secure seal, we recommend our terminal plate replacements which can be found HERE
6) Dynamat your woofer/PR baskets
Placing dynamat on the magnets and baskets of your drivers can reduce ringing and help improve on the clarity of your sound. This can be used on any open spaces on the baskets/magnets. Some like to put multiple layers.
7) JB Weld
Older Polk drivers are known for the magnets to potentially shift in transit. It is common to place a bead of JB weld around the the perimeter of the magnet where it meets the basket for this to be prevented.
8) Spike those enclosures
Installing floor spikes on your speakers will help couple them to the floor, tighten up your staging and bass!
These can be purchased at places such as Madisound, Parts Express etc
9) Hurricane nuts
These will help securely fasten your drivers directly to the enclosure. This will insure a tight seal to the enclosure and directly couple the drivers to the enclosure.
Hurricane nuts are available here - Parts Express
10) Gaskets
Make sure the stock gaskets are not torn. It is very important for there to be a 3 second delay when you press in the PR and hold it for the midbass drivers to return to their resting place. If you feel you need to replace the stock seals, the current recommended replacement is Armacell.
11) New grill cloth
Some like to install newer, thinner, more acoustically transparent grill cloth
This can be bought at Parts Express
12) Dampening Foam
Individuals like to install foam in the upper chambers of the speakers (away from the passive radiators) to help tone down the back waves and further dampen their enclosures.
The most popular choices are No Rez, Blackhole 5, Sonic Barrier
13) Reseal Internal Cabinet Seams
Using a product like power grab adhesive, it is best to reseal all internal cabinet seams where panels join or braces are inserted to assure an air tight seal. This will make sure the speakers are sealed and performing adequately. I recommend using the hand held dispenser, versus a gun operated caulk tube as this will allow you to hit all of the seams easier.
Identification Information -
Help Identify What Model Vintage Polk You Have
