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Need Help with Koss CM-1030 speakers

I am trying to put a pair of these speakers back together for a friend. A previous owner ( we'll call him "idiot" for short ) hacked out all kinds of wiring and removed factory installed switches, etc... As such, i'm trying to take these back to factory stock and go from there.

The crossover is PHENOMENALLY tough to follow and i've already had Jon Risch try to figure it out. After sending him one of the crossovers to examine, he's pretty confident that he was able to get it right but i would like to make sure. If someone has a pair of these and is willing to tell me where each wire goes ( they are all color coded ), i would be forever indebted.

For those of you that aren't familiar with these speakers, they are large floorstanders that were manufactured in 1979 and retailed for $1100 per pair. The cabinets are beautifully finished, very well built and clock in at 74 lbs apiece. They make use of a 10" vented woofer, two 4.5" cone mids, a dome tweeter and a dome super tweeter. The crossover is of a very complex and advanced design and this is where the problems begin.

Jon's thoughts are that this might have been the first commercial speaker manufactured with a series crossover with impedance compensation, notch filters and padded attenuators built in. He was amazed ( to say the least ) that any manufacturer had the "guts" to use such a highly advanced and parts heavy design in a production model, especially back then. He told me that it may be the most complex passive crossover that he's ever seen and was VERY hard to try and back-track. I fully agree with him and that is why i had asked for his help in trying to figure it out.

In case you are going to suggest that i contact Koss about this, they have absolutely NO records of ever making such a product. I am 100% certain that it is a Koss product though, as all of the labels are still on the speaker and i was able to research them in several different buyer's guides of that era.

I would not bother with such an old speaker, but the drivers and cabinet are all in MAGNIFICENT shape. My guess is that the contacts that work the padded attenuators failed and the "idiot" must have tried to bypass them via hard-wiring. The only problem is that the attenuators have multiple stages and they left most of the wiring just lying inside the cabinet and pulled the switches. As such, there is no way for me to see where anything originally went and that is how we ran into the aforementioned problem.

Is there ANYBODY out there that has a pair of these and can help me out ? Sean
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sean

Showing 2 responses by sean

sean OP
6,231 posts
 
Thanks for the detective work Ozfly. I appreciate it. I'll try dropping Aargonaut an email to see if they can help me out, but i'm hoping that someone out here that has a set of these will "volunteer" to work with me on this. Convincing a total stranger to pull their speakers apart might be a bit of a task if you know what i mean .... Sean
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sean OP
6,231 posts
 
Dave, believe it or not, i still have not resolved the problems with these speakers. After trying to get them straightened out and running into one problem after another, i set them off to the side. After sitting for a long period of time, i ended up sending the crossovers out to Jon Risch to examine. He told me that it might take him a while to examine, but he would get to them.

After looking them over several times, I received several emails from Jon stating that he could not believe how complex this crossover was. He stated that this was the most advanced and complex "series" crossover that he had ever seen in his life. Given that "series" type crossovers have just come into vogue in the last few years ( save for Bud Fried ), this should tell you something about this speaker that came out in 1978.

Jon was finally able to figure things out and sent the crossovers back along with a drawn out schematic. Since that time, it has sat due to another problem that i myself created. I ended up mixing the drivers up. Given that these speakers use multiple drivers that look identical but really aren't, it has once again become part of my "things to sort out when i get the time" projects.

Your post and tip may be just the information that i need to get these things put back together and out of here. I had never thought about contacting Koss of Canada. I had contacted Koss here in the USA and they were NO help. In fact, the technical assistance department didn't even know that they had made "full sized" speakers in the past. They surmised that someone else had purchased the rights to use the Koss name and marketed these speakers with their permission. As such, they were NO help whatsoever. In fact, i ended up faxing them info on the speakers for their records : )

I'll give Koss of CA a try. THANK YOU for taking the time to post this response, even though it might not pan out. It is worth a try and i really do appreciate it. Sean
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