2006 Anniversary Active 50’s vs New Active 50’s pro

[Batavier]

I have been eyeing up a pair of 2006 Anniversary Active 50's for a while now, both I am unable to figure out if its worth buying these pre owned, or for the same price purchasing a pair of Active 50 Pro's . The used towers seem extremely well cared for and they of course look great. Just not sure if I am better of sound and hassle wise with a new pair for around the same $$.

Any and all input greatly appreciated.

P.S.
I am new to the forum, so please forgive any Faux Pas

[linger63]

If it was me I would go for the Pro's due to being brand new and having the ATC tweets.
Of course the Anniversary Towers look great and are a collectible.

A very personal choice only you can really answer.
Maybe worth speaking to ATC directly for more technical info and possible recommendations.

[Batavier]

Thank you and I have been leaning towards the pro’s for that exact reason. That being said, ATC replied to my reaching out and it’s only made me doubt myself more. I am into the the upgraded amp packs, but I am also considering Mr. Pete’s advice regarding upgrading tweets, maintenance and not having the upgraded filter boards. See ATC’s full response below. All credit to Mr. Pete and ATC’s outstanding customer service.

“Morning Robert,

Regarding your query concerning a pair of SCM50ASLT Anniversary loudspeakers, serial numbers 23 and 24, from my records here these were built and tested 28/06/2005:

This is a discontinued series, so anything cabinet related would not be possible to replace or in general repair. Similarly, packing crates are no longer available. Grills may still be possible to replace.

The drive units used, SB75-234 SL LF driver and SM75-150S MF driver are all current, and we still have some stock of the discontinued SEAS tweeter used in this era, for reference, our part number:

TWE-UN-07047 SH25-110(SEAS)

The tweeters can be upgraded, if required, but would need to go to our US service department for this work to be carried out.

The amppack circuit assemblies are still in use, at present, as are the transformers used in this variant. This variant uses the "discrete" amppack, so quite different to the standard amppack used currently across most products. Here are some points to answer your query:

"Regular" amppack:
this is the "standard" Mk4 that we fit to all current variations of SCM50/SCM100/SCM150, etc. This uses integrated circuits ("opamps" or 8 pin "chips") as the basis for the design, and is a very high-performance design, with 4th order filters, and class AB amplifiers.. The same board is used in the SCM25A/45A, of course.
SCM50ASL loudspeakers from 1996 onwards used the Mk2 amppack, which has 2nd order filters, 4th order filters came in on the Mk3 amppack variant. Mk2 amppacks have fewer opamp stages because of the use of 2nd order filters.


"Discrete" amppack:
this is the one still used in the SE series, and also in the P6 amplifier, and previously in the Anniversary series.
This means all the "opamps" are made of separate "discrete" components, so no "chips", but lots of separate components, and more difficult to build, as the amppack is spread across two separate boards. It is a very high-performance design with 2nd order filters and class AB amplifiers. Power supply transformers are remote from the amppack assembly, living in the bottom of the cabinet, bolted to the plinth.

As to the difference in sound, that is a personal preference, some people really like the more expensive discrete design, many people also like the "standard" amppack. They both measure very well, with the Anniversary type "discrete" design having an extended response to well beyond 50kHz. The “standard” amppack has a gentle roll off above about 30kHz from memory.
Input impedance is lower on the discrete version at about 6k ohms, as against 18k ohms for the ”standard” amppack, from memory.

Incidentally, these predate an engineering change to the filter boards introduced in early 2006 to improve stability and noise performance.

However, I think, considering your location, it may be sensible to look for a more "standard" pair of loudspeakers, post 2006 from the point of view of upgrade/service and repair/replacement.

I hope this all helps,
Regards
Pete Guppy




Electronics tech”
Electronics tech

[saureign]

Firstly, talk to ATC and find out if the new ATC tweeters can be installed on the Anniversaries. These speakers are by far too special to miss...

[Batavier]

Thank you I did. New tweets can be installed but they need to be shipped to Las Vegas. Maybe worth taking a shot and upgrade down the road......... See ATC’s full response in my reply to linger63

[saureign]

So, that depends on your location & budget. I personally would take anniversaries, and exchange the tweeters with the same Seas - which can be done on-site.

[linger63]

OK............
Based on the new info regarding the discrete amp packs and retrofittable ATC tweets the Anniversary's are looking the goods now!!!!!!!! 😊

[Mariner]

After reading the comments i would also go for the anniversaries!
As long as the veneer fits with the rest of your listening room.
They look absolut great and if the eyes are satisfied, the sound is even better!
For me...I also don't like to look at the speaker units.
Because of this I don't like the pro versions......

[fr.jazbec]

I like the discrete amp pack and the seas tweeter, in my ATCs this is used too.
http://www.audiostereo.ro/ATC%20revi...v-hifinews.pdf
P.S. For me there is no reason to change the tweeter. I know that an ATC tweeter has it‘s own charme, but the seas tweeter ist the same(neerly)that is used in the Harbeth 40+30 and Alan Shaw said that this tweeter ist one of the best tweeters in the world for him. I got a second pair for only 100€ from Michael Notnagel, which ist the offical expert for ATC in Germany. This pair is from an upgrade box to the ATC tweeter and so I have every time a pair to change the ferrofluid if this is nessesary.

[rogesharp-3]

I have SCM40A's in use in my home system, which I bought new only a couple of years ago. I note that ATC fit a higher spec tweeter, SH25-76S in their speakers above the 'entry' series. I just wandered if it would be possible to replace the current SH25-76 fitted in my speakers. Just interested in compatibility and maybe any SQ improvement resulting. Any comments anyone ?

[jophill]

I have SCM40A's in use in my home system, which I bought new only a couple of years ago. I note that ATC fit a higher spec tweeter, SH25-76S in their speakers above the 'entry' series. I just wandered if it would be possible to replace the current SH25-76 fitted in my speakers. Just interested in compatibility and maybe any SQ improvement resulting. Any comments anyone ?

Congratulations on your purchase. IMHO they are really great loudspeakers. I think the change is not likely to be possible for more reasons than one.

One important difference between the tweeters is that the S version is 3.5 dB more sensitive [1]. Both tweeters have a smaller ±0.5 dB tolerance. Changing to the S model will require a gain adjustment in the amp pack. The amp packs do have gain trimmers set up at the factory, but I would be wary that the SCM40A amp pack design may have been centred around the standard tweeter sensitivity and the gain trim range might only cope with the small tolerance and not be large enough to accommodate the large extra sensitivity.

Having auditioned the SCM50A at my dealer with the S version tweeter back-to-back with the SCM40A, I regard the SCM40A as a really good holistically-integrated design, and I personally think it would be undesirable to disturb it. But I do recognize others may not share my view.

[1] Data sheets can be found online with a search but are probably not meant to be widely available as I think the tweeter is not supplied outside ATC.