SDA 1C vs SDA SRS 2

JayMX

I’ve been watching for SDA's for a while now. Locally there is a pair of SDA 1C's and a pair of SDA SRS 2's available. Both appear to be stock with SL2000's, excellent condition, original owners. Each pair is listed at ~$500. Both include the interconnect cable (blade blade on both pairs I believe.)
Other than the fact that the SRS's have the 15” PR, are there other sonic differences to consider? What makes SRS's superior, assuming they are the better option? If I do pull the trigger, I have a 25' wall where the cabinets would be located, approximately centered and ~10’ apart. The room is 16' deep. Thoughts, comments, suggestions? Thanks!

[Deleted User]

Assuming the same price for each, I would have to think the SRS 2 is the better deal. I know the larger cabinet allows for better bass response in the SDA's. I happen to have both SDA 1 and SDA SRS 1's and the difference is mostly bass.

JayMX

The_Polkster wrote: »

the difference is mostly bass.

Thanks! That’s what I was guessing, but I wonder if imaging is any different with the way the tweeters and MW's are placed? On the SRS, everything is clustered near the top of the cabinet. On the SDA 1C's the tweets are above the MW's.

[Deleted User]

The imaging with both models is better than any modern speaker. The midrange is crazy good on both as well. The bass on the SRS will restructure you at the molecular level.

pitdogg2

SRS2 will have a bigger sound stage due to the woofers being farther apart with the tweeters in the middle. SRS2 all the way better speaker
They also do not share the same woofers.

pkquat

pitdogg2 wrote: »

SRS2 will have a bigger sound stage due to the woofers being farther apart with the tweeters in the middle. SRS2 all the way better speaker
They also do not share the same woofers.

They may share woofers, they may not. The 1C should be the same as the SRS 2, but if any are blade/blade there could be differences. The SRS 2 had a more defining line between versions, '86 vs '87 but mixes happened. The 1C's had some mix and match going on. See the link at the bottom. Some investigation and actual checking of the drivers may be necessary.

If they are both pin/blade with vertical tweeters, all the drivers are the same, and the crossover is virtually identical. Only the dual bass inductor is different. Neither of these have a "TL" schematic to use the RD0-198 tweeters (yet.. I am hoping to figure out what is needed to TL them, but it's a back burner project). RD0-194's will be needed.

@pitdogg2 is right about the sound stage and others covered the bass. The 1C's will perform better in a smaller room due to the less width required with respect to the listening position and distance from side walls.

Pin/blade 1C's go for roughly $400 in great condition. If the tweeters on the 1C's are side by side, they are not 1C's and I think they are considered less desirable, but are a classic piece of polk history and still sound better than conventional speakers.

This link should help
http://www.gimpod.com/sda-id.html

JayMX

Thanks guys. The SRS's are definitely the way I'm leaning, we'll see if I can be brave and take the plunge.

pitdogg2

pkquat wrote: »

pitdogg2 wrote: »

SRS2 will have a bigger sound stage due to the woofers being farther apart with the tweeters in the middle. SRS2 all the way better speaker
They also do not share the same woofers.

They may share woofers, they may not. The 1C should be the same as the SRS 2, but if any are blade/blade there could be differences. The SRS 2 had a more defining line between versions, '86 vs '87 but mixes happened. The 1C's had some mix and match going on. See the link at the bottom. Some investigation and actual checking of the drivers may be necessary.

If they are both pin/blade with vertical tweeters, all the drivers are the same, and the crossover is virtually identical.

He stated both are Blade/blade

First SRS2 was SDA1b design which used all MW6509 I believe

SDA1c is going to be MW6510 and MW6511

This I agree with VV

If they are both pin/blade with vertical tweeters, all the drivers are the same, and the crossover is virtually identical.

The GIMPOD link is great for information Tony put a lot of work into that.

JayMX

Yes they both have vertical tweeters. From what I can see on the photos they are both blade blade I really appreciate all the knowledge here and the fast responses!

Schurkey

The 1Cs will be compatible with an isolation transformer. WORST case is that you need to add a foot of wire inside the cabinet, or more likely, use non-stock connectors (Speakon or Banana jacks)

Far as I know, the SRS 2 never played the mix-and-match SDA Connector Game like what happened with the SDA 1C and the 2B. A blade-blade SRS 2 is going to be the big brother to the SDA 1B, and it WILL NOT be compatible with the isolation transformer. You must use a common-ground amplifier. Aside from the amplifier restriction, they're wonderful speakers.

SRS 2s that have one pair of binding posts are the first-series (similar to the SDA 1B.) SRS 2 that have two pair of binding posts should also have a pin-blade SDA jack, and will be the second series (similar to the SDA 1C.)

In a small-medium room, I'd get the 1Cs. In a medium-large room, I'd get the SRS 2, knowing that I can never use bridged or balanced amps, or an amp that inverts one channel (Carver had some of those.) The blade-blade SRS 2 is common-ground ONLY.

No matter which ones you buy, you'll need all the usual repairs and upgrades.

leftwinger57

Talk about mix and match and use what's on hand I've had that. My left 2B x-over had the entire quick disconnect complement and the right side had the tweeter leads hard soldered to the board. Use what's left on the shelf,thinking whose going to look inside these things 30/40 odd years later. It was replaced when x-overs were redone.

gimpod

JayMX wrote: »

Yes they both have vertical tweeters. From what I can see on the photos they are both blade blade I really appreciate all the knowledge here and the fast responses!

If in fact the SDA SRS 2's do have the blade/Blade I.C. they are the 1986 Gen 3 version & IMO less desirable then the later 1987 pin/Blade gen 4 version for two reasons. First - You can not use a AI-1 or Dreadnought I.C. in order to run a non-common ground amp including mono blocks (The crossover design won't allow it). Second - The cost of upgrading a gen 3 crossover, It can be very expensive depending on what caps you chose.

The 2 versions of the SDA SRS 2

1986 SDA SRS 2 (Gen 3) w Wood End caps & Black Cloth sides with a Wood stripe, blade/Blade I.C. (It will have 2 binding posts), Dual board crossover, with 2 MW6509 Stereo Drivers, 2 MW6509 Dimensional Drivers, 2 SL2000 Tweeters & a SW150 Passive Radiator.

1987 SDA SRS 2 (Gen 4) w Wood End caps & Black Cloth sides with a Wood stripe, a pin/Blade I.C. (It will have 4 binding posts), Single board crossover with 2 MW6511 Stereo Drivers, 2 MW6510 Dimensional Drivers, 2 SL2000 Tweeters & a SW155 Passive Radiator.

Now the SDA 1C, Most people don't realize that there are at least 3 versions of these.

An very early (1987 i believe) Studio version (Basically a left over SDA 1B cab) with a dual board crossover, with 2 MW65211 Stereo Drivers, 2 MW6510 Dimensional Drivers, 2 SL2000 Tweeters & a SW120 Passive Radiator.

Now what's interesting is component & value wise the Capacitors, Resistors & Inductors are the same as the the single board pin/Blade crossover. The only way to tell for sure is to pop a driver out and check the model #, if it's a MW6510 or MW6511 they are indeed SDA 1C's but if it is a MW6509 they are SDA 1B's.

SDA 1C Studio (Black) with a pin/Blade I.C., Single board crossover (BE1618-B) with 2 MW65211 Stereo Drivers, 2 MW6510 Dimensional Drivers, 2 SL2000 Tweeters & a SW120 Passive Radiator.

SDA 1C w Wood End caps & Black Cloth sides with a pin/Blade I.C., Single board crossover (BE1618-B) with 2 MW65211 Stereo Drivers, 2 MW6510 Dimensional Drivers, 2 SL2000 Tweeters & a SW120 Passive Radiator.

Either model would be a good be fit for that room. If it was me and the SRS 2's were the pin/Blade 1987 Gen 4 model I would take those if not take the SDA 1C's. Or with that room (25x16) I think I'd hold off & save up my money and go for a pair of SDA SRS 2.3TLs or SDA SRS 1.2TLs (If you have the room "Go Big or Go Home" )

Do some more investigation, If you can get a 4th or 5th generation SDA they will serve you better down the road, Remember the 4th or 5th generation SDAs are the only ones that can use the AI-1 or Dreadnought I.C. so they will work with non-common ground amps.

There's nothing wrong with the earlier SDAs there wonderful speakers just be aware of there limitations amp wise (Common Ground only).

VSAT88

To quote gimpod "1987 SDA SRS 2 (Gen 4) w Wood End caps & Black Cloth sides with a Wood stripe, a pin/Blade I.C. (It will have 4 binding posts), Single board crossover with 2 MW6511 Stereo Drivers, 2 MW6510 Dimensional Drivers, 2 SL2000 Tweeters & a SW155 Passive Radiator."

These came to roost here and will fly when I die. A fine speaker indeed. The guys here helped me every kind of way with mods. Great speaker is an understatement of great magnitude.

JayMX

Thank you so much guys, I’m always so impressed with the depth of knowledge and the willingness to share. I’m totally leaning towards the SRS's. I’ll defintley be reporting back when/if I pull the trigger!

nooshinjohn

JayMX wrote: »

Thank you so much guys, I’m always so impressed with the depth of knowledge and the willingness to share. I’m totally leaning towards the SRS's. I’ll defintley be reporting back when/if I pull the trigger!

Just do it and enjoy. Stop teasing yourself, as once they are gone they may be hard to find locally again.

JayMX

Well, eight hours round trip drive later... this isn’t their final installation location but oh my!!! I’m sure smiling. These ol gals are flawless! Too late to crank them up but so far, wow! They’re the blade/blade single binding post vintage but they seem to be working fine on my B&K @ ~185wpc Also I didn’t realize how big they would be!

Tony M

WOW is usually the first word I hear when I demonstrate the SDA-SRS2's Ver. 3 I believe, abilities to people who have never heard, let alone seen, these gems in the speaker world. I have loved mine for years and years. People have left here and got there own within a week by making a road trip just like you did. Except they had heard what they were going to get, you didn't.
CONGATS and ENJOY listening to music in a whole nother light.

Schurkey

Tony M wrote: »

WOW is usually the first word I hear when I demonstrate the SDA-SRS2's Ver. 3 I believe

Version 3???

Tony M

Schurkey wrote: »

Tony M wrote: »

WOW is usually the first word I hear when I demonstrate the SDA-SRS2's Ver. 3 I believe

Version 3???

Gen 3....sorry

Schurkey

It took me awhile to figure out what you meant. I tend to think of the SRS 2s as having an "early" and a "late" style, based on SDA 1B and 1C respectively. I don't generally think of them as being part of the third (blade/blade, 1B) and fourth (pin/blade, 1C) generation of SDA speakers.

At first I though you were saying there were three versions of SRS 2 speakers. My mistake.

nooshinjohn

Another happy camper. Congrats on the score. Once you get them set properly, your "wow" moment will become "HOLY SH*#!"...

audio_alan

Nice score! Soon you'll be pulling out every CD you own to listen to an entirely new experience in music. If setup correctly, you'll hear sounds come from directions you never thought were possible out of two speakers...

I remember getting my first set of SDAs. Ahhh, memories. haha What a revelation on what music could sound like! You almost can't go wrong with any of the SDAs. Some models are superior to others, sure, but their unique circuitry puts them head and shoulders above "regular" speaker design, imo.

JayMX

It is truly amazing. I’ve been enjoying them every evening. The fact that it’s simply physics at work, playing tricks on your mind makes the effect that much more compelling. Sometimes it gets a little weird and “spacey” but I think that's as much a function of how the studio engineers initially placed mics and assembled the tracks into a stereo pair as anything. Mixes that are saturated with DSP and reverb do strange things sometimes... Honestly, I've double checked several times to ensure I didn't accidentally forget to switch off the surrounds! Also, I think I’m expecting to hear the song in stereo like I’m used to hearing it, but the SDA effect just presents the sound in such a different manner; it adds a surreal, immersive nature to the music at times. Really fun. It's definitely something anyone that enjoys listening should experience. I love it!

pkquat

A small FYI, while it does depend on the material, IMO if stuff starts to sound too much surround sound like you are getting too many reflections off side walls or objects. Looking at the room, there may be reflections.

For me one of the fun things to do is place the 5's in line and about 1 or 2 feet outside of where the SDA's are. It will seam like the very big sound is coming from the 5's.



Also anything mono, a lot of movie dialogs, and certain music tracks will also have a laser focused center. On movie dialogs when running a phantom center, I swear it is on sometimes. For some music tracks where the stereo is in enhance, but the singer is mono singing into a studio mic, if the engineer recorded it specifically like this, the stereo ambiance is amazing, while the singer is emanating from a pin point center directed right at you.