Hi there,

I have the opportunity to buy a used pair of ATC SCM100 actives at a great price. I can't audition them in my room because they're far away from where I live.

They are about 20 years old from what I understand, and were recently serviced by a company in Canada, with a few parts replaced. Photo attached if it helps ID the generation / era these are from.

What I'm wondering is:

- I'm currently using SCM25As (mk1), which I love. Can I expect those older SCM100s to have a similar character to these newer 25s? I am super dialed in to the sound of the 25s. (The original owner of these 25s wants them back instead of selling the to me in the end, which is why I'm back on a speaker search in the first place. I also think, despite getting great results right now, ultimately I need something with more low end extension either way.)

- In general, are the ATC active models similar in character (like the 25s, 45, 50, 100, 150, etc.) but just increased in SPL and bass extension? The midrange and tweeters are identical from what I understand, yes?

- Are there significant new design changes in the last 20 years to the SCM100s that warrant trying to find a newer pair? I have no doubt the older SCM100s are still excellent speakers, but trying to collect as much info as I can as I can.

- What are people's experiences with listening distance from the SCM100? I work in a large, professionally designed room so I'm sure I can accommodate them, but I also don't want to lose the intimacy and detail from sitting as close as I can to the 25s / ergonomically don't enjoy sitting far away from my speakers.

I've also sent these questions to ATC but would love any input, I think I've seen the American ATC distributor contributes to the forum here so would love any input. Thanks!!!

Considering trying other contenders from Genelec or PMC, but I kind of just feel the ATC25s were so excellent and working so well I don't even want to embark on that rabbit hole.

I bought some new SCM100ASLs in 1998. In their lifetime ATC changed the mid-range wave-guide from a straight sided one to one with a curved flare, and changed the port to one with a more rounded opening. That generation of mid-range unit was also prone to developing a tizz, mine did. I took the opportunity to return them to the factory to fix that, and get the midrange surrounds and ports updated. They re-capped the amplifiers too. Then well after I sold them, ATC introduced their own tweeter, which doesn’t have ferrofluid. The ferrofluid in the original tweeters can dry up. You might be smarter buying new ATCs even if it means a smaller model. The magic comes with the mid-range unit. I’ve since had 25As and now have 50s. All good. I find I prefer listening around 2m, give or take, maybe closer with the 25As. I’m a domestic user, so ymmv.

Oren
THere has been continuous updates to SCM100s as there have the other models. Some are major some are not. They started with Mk1 amps (I have a pair of MK1 amp 100s in service now that were bought used that were modified and the buyer did not know) and then Mk 2 and then Mk 4. DOmnt ask me for dates cause I dont knwo them.

There have been 3 revisions of tweeters VIFA from 2001 or and before, SEASA afrter that and the ATC in 2017 or so.

Midranges have changed from an earliuer version that can longer be repaired to the current version that jhad updats to waveguides along the way.

Woofers started as non SL then went to SL. The cabient ususally has a SL badge on it so you can tell.

SO jsust about everything has changed and that's part of the problem: on Reverb they look almost the sama as the new ones but could be 30 yeas old and have ALL of those past parts in them. We can update them (as can ATC) but you are getting close to buying a new pair when you replace everything. SO you really have to be careful about buying old ATC's used for this reason. I prefer to look up the serial numbers and the factory can help you. Just dont expect to email them and get an answer. The engineers answer emails when they can. [That's why they have distributors because they dont have a sales department]. That's also why I hang out here to help them out.

Brad

Brad, thanks so much for your detailed reply. I'm gonna get some more info from the seller and get back to you. The serial is something you're able to look up ?

I am not able to look serials up. Unless it was something we sold in the US (since 2001) I don't have access to those non-US records. US 50s and up are hard wired to US power. 25s and 45s are switchable so how its set may not be were its from. Only the factory has serial records of all production. My suggestion is to write them and just wait. It could take a while and be patient. They could be going to a trade show, or traveling to visit me or another territory, etc.

This is not a sales and marketing focused company, as are most in the business. Many are mostly sales and marketing! ATC is a pure engineering and manufacturing company built around distributors in various countries handling sales and marketing. Very similar to the model that existed in the earlier days of pro audio, when UA was small, or JBL or Neumann, etc. I think that's what makes them so different.

Well, having used the 25s for the last year and a half, I think that approach has paid off as there is undoubtedly some serious, serious quality coming out of these speakers, I'm doing the best work of my life with them. Thanks for your help!

I recently had a pair of ancient 100A’s refurbished. They have a 1992 manufacture date. I bought them used sixteen years ago. They were getting long in the tooth. Then I had a catastrophic failure and all three drivers on one side went out.

All drivers had to be replaced. There was a chance that the woofers could be reconed so I sent one in for evaluation. No dice. The complete speaker cabinets needed to go in.

The Vifa tweeter is no longer made but there is an equivalent Peerless that ATC said would be a drop in replacement.

The mid range drivers were old and couldn’t be rebuilt. There were NOS available so those went in.

The woofers had to be SL as there were no NOS woofers. The port had to be reworked for the SL woofers.

Using all new spec drivers would have been almost as much as buying a new pair. The amp pack would have needed to be reworked.

It took a while and cost close to $10K including shipping. It was the best choice for me.