What kind of 1c is this?

Mr. Bubbles

Ok so the title sounds like the answer should be very simple. And maybe it is. I picked up this pair of SDA 1's as indicated by the decal on the rear of the cabinets. They have Pin / Blade interconnects and the crossovers are of the 1C type as is the driver configuration and the cabinets have the later design grooved panel on the inside. So as all of these things indicate, these are 1C's. However They are not a standard studio cabinet nor are they a standard real wood cabinet. There is no top and bottom wooden plate and there are no side panels. These aspects are like the studio cabinets. They also have a small base attached to the bottom of the cabinets. However, the driver/ passive positioning on the baffle is much like the real wood and there is a small trim piece attached to the front of the baffle at the top and bottom that resemble the shape of the real wood plates. The grilles are full length grilles similar to the real wood version with the grille cloth attached with staples all the way around. On the rear of the cabinets the decal shows the SDA connector as being mounted in the cabinet just below the terminal cup but there is a plastic plug or cover in that area and the SDA connector is in the terminal cup. I have attached a few pictures to show some of these details.

My plans and reasoning for purchasing these is to build a pair of SRS 2's as I have been searching for quite some time and have been unable to locate any to purchase. If anyone in the SC, Ga, NC, Tn. area has any for sale, please let me know and save me the trouble. Either way I found these cabinets a curiosity and though I will not likely use them I would be interested to know what they are. My first thoughts were a modified cabinet by some previous owner, but the trim panels and grilles match up perfectly to the cabinets and the cabinet laminate. The grilles also have markings like those hand written markings found on most Polk components of the time. They also don't match any of the transition models described in the stickey here on the forum.

DaveHo

Studio version. Available only in black. No?

Mr. Bubbles

Las,
I haven't measured it and sold my other 1C's for comparison but from looking at the driver width/ baffle width/ spacing around all drivers (side to side and top to bottom) It looks like a regular real wood 1c cabinet but without the top and bottom plates and without the side panels.

Dave,
The spacing of the drivers/ passive on the baffle does not match the normal studio as well as the studios (at least the ones I know of) have the trim panel attached to the front at the bottom about 3 inches tall similar to the RTA 12's.

It looks a lot like the very basic 1C cabinet with a baffle like the real wood version and the base of the studio but the grilles and trim pieces don't match either, or any other model I have ever seen. Please note that I haven't seen nearly as many as a lot of the guys on here.

dracoskeeper

Those are the extremely rare SDA 1FrankenC's

thsmith

DaveHo wrote: »

Studio version. Available only in black. No?

True, Studio's and I have only seen them in black.

Mr. Bubbles

Was there more than one version of the studio? The reason i ask is if these are studios why they look nothing like the ones found if searching for SDA 1C studio. below is a picture I pulled from the SDA site showing a studio. The ones I have do not look like this.

F1nut

Maybe that's a pre-production model used for testing that they never built in mass production.

I agree. They very well could be one of a kind and it would be a shame to not restore them.

Mr. Bubbles

F1nut wrote: »

I agree. They very well could be one of a kind and it would be a shame to not restore them.

I guess that's part of my reasoning for finding this out. Though i am not a 1C fan as I have had them before and found the sound of even my 2A's to be better to my ears. In all fairness the 2A's have a better overall tonal balance to me than even my SRS or 1.2TL's. The 1C's were just the weakest of the bunch. I think one of the biggest reasons I like the 2s better is the overall driver area to cabinet volume to passive area ratios. That was my reasoning behind searching for the SRS 2's. They appear to have the largest ratio of cabinet to passive to driver of all the SRS models. But If these are something rare I would have enough respect for the unit itself not to destroy it.

Mr. Bubbles

I have attached 3 pictures that I have marked areas on that peaked my curiosity. the first is of my speakers, the second a studio as found on the SDA site and the third I think I found on the web. I think the speakers in the third are/ were Toolfan's.

Look at the areas inside the yellow and the spacing indicated by the red lines. The yellow area at the bottom had entirely different trim as well as different spacing than the studio pictured here. Yet the trim is also different from the real wood version as well. The trim on mine is a small piece attached to the front of the cabinet at the top and bottom creating sort of a faux real wood version in black.
I'll take some measurements later and maybe someone here can compare those to their real wood and or studio versions.

thsmith

They look like the ones I use to have.

PC260267.jpgPC260268.jpgP4060091.jpgRight P4060077.jpgRight P4060078.jpgRight P4060079.jpgRight P4060080.jpgP4060086.jpgP4060087.jpgP4060088.jpgP4060089.jpgP4060090.jpgRight P4060084.jpg

Mr. Bubbles

OK so they are not one off's unless these made a pretty good trip around the states. I'll double check that as i can read the serial # in one of your pics. Maybe another transitional model not listed in the chart in the sticky?

thsmith

Yeah, I remember people saying they sort of looked like the hard wood 1Cs, suspect Polk decided to use vinyl to see how they looked on HW cabinets.

ANyway, I have seen a few and not really that many 1C studios in the first place. But I am no expert and have known of 1Cs since 2008 anyway.

agfrost

My 2B studios are built just like that. Mine are early 2Bs (blade-blade), but have the same trim piece at the top like you have.

PolkieMan

Yea they are like a 1C prototype. Like they still have part of the old style base and made pieces so the new style speaker grille would look flush.
If you could get all of the black off of them are they real wood veneer?
Did you get a good deal on them?

Mr. Bubbles

PolkieMan wrote: »

Yea they are like a 1C prototype. Like they still have part of the old style base and made pieces so the new style speaker grille would look flush.
If you could get all of the black off of them are they real wood veneer?
Did you get a good deal on them?

yes, they appear to be real wood veneer instead of the vinyl. The grille may be what you are referring to as new style but it is not the same size respective to the cabinet. That is assuming the same size cabinet as the normal 1C real wood cabinet. I still need to get it measured I had to carry my daughter to emergency room earlier for stitches. She was playing in the ice form our weather today and cut herself pretty bad. I'll try to get measurements tomorrow.
I'd call it a fair deal. Not as good as my last set but still much less than I sold my last set for. One of the MWs has a ripped spider and bottomed coil so I'll have to find one replacement driver, and for my planned project a couple of SW155 passives.
Speaking of that if anyone knows the difference in the 2 15 inch passives it may be of some help as well. I am not sure if the tuning is different or if they simply look different like the 12's with either the solid plastic face or the foam padded face with the same tuning.

PSOVLSK

thsmith wrote: »

They look like the ones I use to have.

PC260267.jpgPC260268.jpgP4060091.jpgRight P4060077.jpgRight P4060078.jpgRight P4060079.jpgRight P4060080.jpgP4060086.jpgP4060087.jpgP4060088.jpgP4060089.jpgP4060090.jpgRight P4060084.jpg

Those look familiar. Wish I hadn't sold them:sad: Tex, you still enjoying these???

Mr. Bubbles

Cabinet measurements not including any trim pieces, grilles, or bases.

15 7/8" wide
10 7/8" deep
42" tall

I am not sure how these measurements relate or compare to the real wood or the studio.

PolkieMan

Hope you daughter is ok.
So they are real wood.
Those would look really nice in natural wood.
Is it a bad 6511 or 6510?
15" pr mine are 12"?
1C as measured at top wood cap
16 5/8w x 11 1/2d x 44t

nooshinjohn

Could be a military version of the 1c's. Polk was making them for Base Exchanges at this time and there were more than a few special versions made for them. My first SDA's were 1B's in a very dark walnut laminate. The consumer versions were either black or medium oak.

Mr. Bubbles

PolkieMan wrote: »

Hope you daughter is ok.
So they are real wood.
Those would look really nice in natural wood.
Is it a bad 6511 or 6510?
15" pr mine are 12"?
1C as measured at top wood cap
16 5/8w x 11 1/2d x 44t

Daughter is good. 4 stitches. Just being a normal 10 year old. Thanks for the thought.


It is a 6511. First thought it may have been a shifted magnet and hoped I could fix it. Found the torn spider with the coil rubbing. I figured it was too far gone so I cut out the dust cap very easily in case I ever needed one and the bottom of the coil was actually folded under and to the inside in a spot. Somebody really had it moving. This made me worry about the other drivers. I checked all of them and they appear to be fine.

Passive is the standard 12" 1C Radiator. The SRS 2 has the 15" PR with all the same driver in a larger cabinet and a nearly identical crossover.

Those measurements should come out just right for a real wood cabinet as matching these that I have given the normal side panel thickness, thickness of the grille and the 1" thickness of each of the top and bottom plates.

PolkieMan

Original 6511's are hard to find when I got my 1C a 6510 was bad that was a relief, more common and I got one from a fine gentleman on Ebay who JB welded it and packed it for a nuclear explosion, I remember he told me to give him two days just to prepare it for shipping.

Strange, I did not know Polk made military speakers for Base Exchanges?