Need the AR-6 schematic for the European version

[onplane]

A guy on AK recently posted pics of his AR-6 European version:

http://audiokarma.org/forums/showthread.php?t=102634

The cabinets are beautiful!!

(our good friend Bob (joelongwood) has already offered to take them off this poor fella's hands - Bob, you are all heart!!)

Anyhow English is clearly NOT this guy's native language and he's having trouble getting the tweeters to work. Now, we know this version is different than the US version, because his AR-6 has a 3 position switch instead of a pot.

Is there any way, we can come up with the xover diagram for that unit?

Regards,

Jerry

PS: anybody know anything about the switches they used and whether corrosion has been a problem??

[Rlowe]

Hi,

May I suggest;

Use the Forum search and look for << AR6 >>;

Then, look at << AR-6 crossover >> it may help.

It appears the first attachments have been removed.

Go to posting #4 for a PDF for the cct for AR6 European & US AR6.

The results of the search will also provided other interesting information.

[onplane]

Thank you, Richard!!

When I saw the two xovers side by side, it's amazing AR kept the same model notation.

US ==> 2nd order high pass on the tweeter

European ==> 2nd order low pass on the woofer

Regards,

Jerry

[tysontom]

>A guy on AK recently posted pics of his AR-6 European

>version:

>

>http://audiokarma.org/forums/showthread.php?t=102634

>

>The cabinets are beautiful!!

>

>(our good friend Bob (joelongwood) has already offered to take

>them off this poor fella's hands - Bob, you are all heart!!)

>

>

>Anyhow English is clearly NOT this guy's native language and

>he's having trouble getting the tweeters to work. Now, we

>know this version is different than the US version, because

>his AR-6 has a 3 position switch instead of a pot.

>

>Is there any way, we can come up with the xover diagram for

>that unit?

>

>Regards,

>Jerry

>

>PS: anybody know anything about the switches they used and

>whether corrosion has been a problem??

Jerry,

It's usually a good idea to think a bit before posting. If you first go out on the AR library site, the crossovers for the two are posted. You said, "...Now we know this version is different than the US version, because his AR-6 has a 3 position switch instead of a pot." This is incorrect, as the later US-built AR-6s had the switch and a few of the earliest European AR-6s had level controls.

The crossover changes were made due to changes in the drivers (more common versions of the woofer, etc.) and improvements in techniques and reduction in costs. It didn't mean that one AR-6 necessarily sounded different from or better than the other; there were subtle differences, but no gross changes.

--Tom Tyson

[onplane]

>

>

>Jerry,

>

>It's usually a good idea to think a bit before posting. If

>you first go out on the AR library site, the crossovers for

>the two are posted. You said, "...Now we know this

>version is different than the US version, because his AR-6 has

>a 3 position switch instead of a pot." This is

>incorrect, as the later US-built AR-6s had the switch and a

>few of the earliest European AR-6s had level controls.

>

>The crossover changes were made due to changes in the drivers

>(more common versions of the woofer, etc.) and improvements in

>techniques and reduction in costs. It didn't mean that one

>AR-6 necessarily sounded different from or better than the

>other; there were subtle differences, but no gross changes.

>

>--Tom Tyson

Tom, the very first place I look for documentation is our library. I'll be honest; I still can't find anything on the AR-6 other than a pic, an ad and wall mounting instructions.

Clearly, I'm doing something wrong, but ... I can't find those xovers! Next, I checked the timeline spreadsheet to see whether I could find any indication of changes or revisions to the AR-6 and again ... I came up "dry".

There are other differences as well. The European version had only two terminals (1 & 2) , yet the instruction sheet, attached to the back, talks about removing the strap across terminals 2 and "T" to convert to woofer only operation. Tom, no matter how much we “sugar coat it” that’s a “screw up”.

Finally, Tom, your argument that sonically the AR-6 didn't change even though ALL the drivers and the xovers were altered reminds me of the argument Oldsmobile made when they "improved" their models (without telling anybody) by switching to Chevy engines.

As I recall, the courts weren't too kind to Oldsmobile.

Regards,

Jerry

[Steve F]

I'm not aware that "all" the drivers in the AR-6 changed. Certainly the woofer did (and therefore the crossover). In the "Letters to Steve F." in the library, AR told me that explicitly: AR said to me that the 1 1/2" spec was a "typographical error."

The tweeter changed in designation only from the originally-stated 1 1/2" cone to the later spec of 1 1/4". But the unit itself was the same. The only substantive change to the tweeter came with the addition of ferro-fluid some years after the 6's intro. I don't believe the 6 ever had the ferro-cooled tweeter.

Just small details, but important for historical accuracy.

Steve F.

[tysontom]

>

>Tom, the very first place I look for documentation is our

>library. I'll be honest; I still can't find anything on the

>AR-6 other than a pic, an ad and wall mounting instructions.

>

Jerry, I may stand corrected on the library. At one time I thought we *did* have the crossover schematics for the AR-6 (both versions) there, but I could not find them as well. I will try to get .pdf documents for both crossovers for the library.

> Next, I checked the timeline spreadsheet to see

>whether I could find any indication of changes or revisions to

>the AR-6 and again ... I came up "dry".

>

The timeline is not altogether accurate, and we probably should revise it. I do know that in the mid-1970s, AR changed the level control on the AR-6 to a toggle switch, and eliminated the "woofer-only" terminal that was present on the earlier level-control version. I do not believe that any of the switch-type AR-6s had the three terminals, but some very early ones might have during the transition period. Along with the switch came some subtle crossover changes, made to accomodate the "generic" 8-inch woofer that found its way into the AR-6, AR-4xa, AR-16 and numerous other 8-inch-woofer AR speakers of the day. AR was eliminating a special woofer for each speaker in order to save costs and to standardize a bit. As Steve F pointed out, there were no changes to the tweeter other than to change it to a back-wired version from the original front-wired (hard-wired) issue. All of the early 1-1/4-inch AR-6-type tweeters were made using silicone grease in the gap, but never ferro-fluid (which came into use around 1975 or 1976). The silicone grease was an excellent medium to transfer heat from the voice coil to the magnetic pole-piece and top-plate assembly, but it would literally "boil away" if the input power was too great, and then it was rendered ineffective.

>

>Finally, Tom, your argument that sonically the AR-6 didn't

>change even though ALL the drivers and the xovers were altered

>reminds me of the argument Oldsmobile made when they

>"improved" their models (without telling anybody) by

>switching to Chevy engines.

>

Well, first of all, the 350 cu. in. Chevy engine was superior to the equivalent Oldsmobile and Buick engine of the day, but it was the fact that GM did not tell the public about the "standardization" that pissed off the upscale Olds and Buick owners. Your analogy is somewhat of a non sequitur, anyway. What does that argument have to do with an AR-6?

Jerry, I don't believe I said that the AR-6 did not change sonically. I said there might have been subtle changes, but in fact I believe there were small, hardly audible, differences. And as Steve F points out, only the woofers were changed a bit, but not the tweeter. The crossover points, etc., remained the same to my knowledge.

--Tom Tyson

[Steve F]

>And as Steve F points out, only the woofers were changed a bit, >but not the tweeter. The crossover points, etc., remained the >same to my knowledge.

The crossover point did change on the AR-6, from 1800Hz originally to 1500Hz when AR changed the woofer. (Or was it the other way around? 1800 to 1500? That's the disadvantage of having your computer on the second floor and all your AR documentation in the basement. I just don't feel like running up and down two flights each way to check! I'm pretty sure it was 18 first, 15 later. But it DID change, no question.)

Steve F.

[onplane]

>

>The crossover point did change on the AR-6, from 1800Hz

>originally to 1500Hz when AR changed the woofer. (Or was it

>the other way around? 1800 to 1500? That's the disadvantage of

>having your computer on the second floor and all your AR

>documentation in the basement. I just don't feel like running

>up and down two flights each way to check! I'm pretty sure it

>was 18 first, 15 later. But it DID change, no question.)

>

>Steve F.

Steve, the reduction from 1800 to 1500 certainly makes sense with the xover change. In both xovers the woofer inductor is the same. Yet, in the later version the woofer xover was converted to a 2nd order which would cause the upper end of the woofer to roll off FASTER.

Now if we define the xover point as the frequency at which each driver contributes exactly 50% of the total sound, this change to 2nd order would LOWER the xover point.

I think it was Ken who pointed out in another thread, however, that xover points are a little more complicated than that. That is, with a 3 position switch, there will be 3 different points where each driver contributes exactly 50% to the resulting sound.

For example, as you decrease the tweeter output relative to the woofer, this has the effect of raising the frequency at which each driver contributes 50%.

Regards,

Jerry