View Full Version : Powering Altec 846As.Do I have enough power?

08-06-2007, 01:34 AM
I just got through reading all five pages of Storm's enquiry about powering the 250s. I'm running Altec Valencia 846As in a DIY active configuration via a Behringer CX3400 active crossover. The treble poweramp is a Yamaha B-2 v-fet (100W per channel). The bass amp is a Kenwood Basic M2(225W per channel) I'm no wiz with the technicalities of the amp/speaker interface,but from what I've read it seems to me that the removal of the passive crossover between the amps and the drivers gives the amplifier power an easier ride. The Storm/amp power thread has given me pause to ask the same question; Do I have a safe enough power-margin that I can generally put aside having issues with clipping? I like my music loud(around 95-100 dB),but not really much louder.The room is around 24ft x 40ft. Thanks in advance to any respondents.

08-06-2007, 05:03 AM

You are running a biamped active set-up. Clipping is less of an issue because you have divided your bandwidth. Most of the power is in the lower half, bass and lower midrange, so your compression driver would be isolated from any clipping in the amp used for the woofer. Also keep in mind compression drivers are much more robust than your typical tweeter. They have larger voice coils and a massive heat-sink with their large motors.

If I remember right your compression driver goes down to 500Hz and is speced for 15 watts continuous. 100 watts should give you plenty of headroom. Figure you have at least 6db over your maximum long term average input power. As long as it sounds clean you should be fine. Do you have a protection capacitor in series with the compression driver?? If not that would be a concern.

Rob :)

08-06-2007, 06:29 AM
Thanks Rob, I wasn't fretting over the issue because I understood that there wasn't the same risks involved with two seperate amps completely isolated from each other. I guess just to see your post was the simple reassurance I was looking for. I've actually applied some treble correction since seeing Zilch's posts on the 846As. My Kenwood 700C preamp's tone controls are active filters(not negative feedback-loop Baxandall),with a selectable turnover frequency of 6KHz,so I've applied some boost to the treble of the 806As. The whole set-up sounds very "true".

08-06-2007, 10:21 AM
I owned a set of 846B's before I got the 250TIs. I can safely say that if the JBLs never have fell into my lap, I would still be using the 846B Altecs. Nice speakers, for sure.

Just curious...got any pictures of your setup?


I am sure I am not the only one who would like to see it.

Are you the original owner?


08-07-2007, 03:00 AM
Sorry Storm, I haven't got a digital(or any)camera. I bought my 846As in December '02. I went into the local Salvation Army store,and there in the middle of the showroom,stacked one atop of the other,were two of the ugliest speakers I had ever seen in my life.The Altec Valencia 846As. I looked them over,noted that they were Altecs and left the showroom. In the back of my head was a recollection of an ad which ran in the abso!ute sound,every month;"Wanted to buy Altec,JBL,McIntosh etc". That ad ran every month.So I figured if someone wants to buy this stuff,there must be plenty of other people wanting to buy them from him also. When I got paid I went back to the Salvation Army store,and they were still there $350 Aussie dollars(at the time about $190 US). I bought 'em.The rest is history. I went back about a year ago,and asked the guy at the Sally Anne's,"Who in their right mind would sell such a great speaker?".He told me that there had been a demolition of a local pub,there had been 3 pairs of Valencias in the pub.The demolition guys kept 2 pairs for themselves and donated the other pair to Sally Anne's. Apparently while they were on the shop floor at the SA,lots of people were asking about them,with plenty saying"I'll give ya fifty bucks for 'em".The guy at the SA knew they were really good speakers and figured that $350 was a fair price. Indeed it was.Best $350 I've ever spent. I got them home in the back of my estate wagon,hooked them up,and retired my ProAcs permanently the next day. I've built the entire rest of my system around them,finding them to be the most revealing,discriminative speakers I've ever owned(or heard) in my life. The system both ROCKS,and reveals Bach Cantatas like nothing else in my experience. Thank YOU,GOD for letting me stumble across these speakers(and holding them for me until I got paid).