SDA 2 Identification Help

SDA connection is in the cup. More than likely pin blade therefore I'll take SDA 2b.

All blade/blade models I've seen SDA socket was outside the cup.

Wow I have never heard of anybody siliconing the PR's in place. A painter's 5 in 1 tool used carefully would be my choice of tool if it weren't for the fact that they are recessed into the baffle. Gonna be tough!

I'm thinking maybe you have SDA 2A cabinets with SDA 2B innards (MW's and Crossover). The proof will be to look at the crossovers and compare to schematics in the SDA manual and in the reference section of this forum.

Those should be RD0194-1 tweeters unless the previous owner did a TL mod to the crossovers and then they could've used RD0198-1. From the SDA Manual:

In one of your pictures it looks like there are 2 rivets that are located below the crossover/binding post cup that were probably where the original SDA 2A IC connector was located (or the old one is still there?). Also, according to the SDA Manual the studio version of the SDA 2B, while it is true that it didn't have end caps, it was fully clad in black vinyl and you appear to have walnut vinyl so it still looks to me like SDA 2A cabinets. I agree with bigmontana that the faston for the white/negative wire appears to be replaced hinting at maybe a TL mod and RD0198-1s. Check the DCR for confirmation.

Those are 2B Studio in vinyl walnut. Someone has replaced the original SDA socket with a strange one.

Whomever worked on those is a hack. Lining the cabinets with Dynamat Xtreme was a huge mistake. Best to remove it.

The crossover work looks like a 2 year old did it. Not sure what's up with those 2 smaller caps or that cheap block resistor. You need to pull the crossovers for a better look.

They likely used Mortite as a gasket for the PR. If you push really hard from the rear it will pop free. It would be a good idea to have someone in front to catch it. Once you get them off remove the Mortite and replace with a proper gasket.

The crossbrace is stock.

NAD amplifiers make the claim of high current reserve power supplies and high dynamic power ratings, as well as their full disclosure power ratings (FDP):

https://support.nadelectronics.com/hc/en-us/articles/360000158988-NAD-Full-Disclosure-Power

NAD's approach, on the other hand, is to optimize its power supply to properly drive real-world loudspeakers. This means a properly regulated, high-current power supply is supplied in all NAD amplifiers and receivers. Thus we can rate our receivers with a difficult 4-Ohm load, with ALL channels driven simultaneously, over the FULL frequency bandwidth (20Hz - 20kHz), and at rated distortion. This is the Full-Disclosure rating method on which all our amplifier and receiver specs are based, and it's a far cry from the FTC's minimal requirement of using an 8 Ohm load, any channel (singular), at an easy 1 kHz frequency, with no distortion specified!

Another aspect of power specification long championed by NAD is dynamic power. Since real-world program material requires short bursts of very high power rather than the continuous power normally specified, we also include dynamic power ratings at 8 Ohms, 4 Ohms, and even 2 Ohms! Most receivers will go into full protection mode when presented with a 2-Ohm load, but NAD's high-current power supplies, sonically transparent protection circuitry, and heavy duty output stage are easily up to the task. So to further distinguish our Full-Disclosure ratings from the barebones FTC standard, and give the consumer the most realistic description we can of real-world performance, we also specify the dynamic power our amplifiers deliver to speakers of varying impedances. And to maximize this real, useful power in daily listening, we've developed an amplifier circuit we call:

POWERDRIVE
To meet the diverse requirements of high current drive and high dynamic power, our patented PowerDrive amplifier circuit will build further on our reputation for amazingly effective power. By adding a second high-voltage rail to our well regulated high-current power supply, we get an "overdrive" that can nearly double the continuous power on a short term dynamic power basis. This is a further development and refinement of our renowned Power Envelope circuit, utilized by NAD in the 80's and 90's. PowerDrive differs from Power Envelope in that it offers greater amplifier stability and low impedance drive capability, resulting in less distortion when driving real speakers with real program material.

I would like to see the FTC require it, along with the full power rating across the entire audio band with distortion into lower impedances besides 8 ohms. Then we'd see how amps really compare.