Here's my little bit of Altec porn for you guys... 
511B horns with 902-8B drivers mounted on top of a pair of '78 Klipsch Cornwalls. The only operational driver in the Cornwalls is the K33-E 15" drivers. The mid and tweet are disabled. In fact, the Type B crossovers (which have been heavily modded) are now resting peacefully in my closet.
That big black thing is a 51uF Solen just to suck up any extra turn-on juice the Crown D-75A may put out when turned on. IOW, it's soley there for protection. I believe this also rolls off the 902-8B drivers around 400Hz @ 6dB, which is below the 600Hz crossover point.
Here's another 511B with a 902-8T driver for the center channel. Here you can also see one of the modded Klipsch Type B networks. This one has be converted over to 2-way operation and seeing the 902-8T driver as a 64 ohm load to bring its output down closer to the 15" woofer's output.
This is where the heart of the system is. The Rane AC 22B crossover allows me to dial in the delay of the K33-E woofers and 902 drivers to get everything sounding just right. The Behringer DEQ1024 is used to flatten out a small peak around 1.2kHz. Also, because these 902-8B drivers are 30+ years old and came out of a large theater in Atlanta, GA, they have seen lots of action and power over the years. For this, their diaphrams are a little work-hardened, which gives them a little more than desired rolled-off top end. So I am also using the DEQ1024 to boost the top end a little as well to help things out.
This is the Technics SU-8099 integrated. My father bought this amp brand new back in '78 along with the Cornwalls, for the Cornwalls. He gave both the speakers and this amp to me. Anywho, this amp provides 115 very strong and very HOT watts to the K33-E drivers. And if you look closely to that meter, that's not peaking at 7-10 watts. The meter is in the 0.1x range, which makes that about 0.75 - 1 watt peak! And let me tell you, I had it playing pretty darn loud in there while taking these pictures!
This is my little gem right here. The awsome little Crown D-75A amp. This amp can pump out a whopping 35 watts into 8 ohms and is rated at 0.05 THD at full power. I bought this amp on eBay for $75 shipped! The guy that had it said that it was untested and that the gain knobs were real loose, so he was selling it as is.
Turns out that the amp was in MINT condition and the nuts on the knob shafts had worked loose. All it took was a couple minutes snugging down the nuts and that was it. As you can see, the gain is only at 2/3, and the output from the Rane crossover is just over half. The signal LEDs never light up unless I'm really hammering it, so I'm guessing I'm barely getting a 1/2 watt out of it most of the time, and maybe 1-1.5 watts max! With its excellent specs and super clean power, it is a perfect match for the 511B/902 combo.
Just for fun, here's the business end of the system. The Music Hall Cd25.2 is long gone. I upgraded the opamps to Burr-Browns, but it never really impressed me that much. In fact, it's really didn't sound any better than the Panisonic DVD player, so I ended up selling it.
One thing you can't see in the photo is a Rane BB22 Balance Buddy. It's behind the DVD/crossover/eq stack. The MIANS pre-out from the Pioneer Elite VSX-54TX goes into the BB22. From there, it enters the DEQ1024, then to the AC 22B crossover, then to the Technics amp and small Crown amp. No hum, no buzz, no hiss, no nothing, just music and movies.
BTW, the silver Crown XTi 1000 is for the DIY push/pull sub I built. It has two Dayton 15" DVC drivers in a 6.3cf sealed enclosure. With the sub in its current location and with 2.83V input with pink noise at 1 meter, I measured 99dB, both with my SPL meter and TrueRTA!! At my listening position, I still get between 95-96dB. Gotta love that room gain! Nominal impedance is 8 ohms, and the amp is bridged mono for a healthy 1000 watts of power. This amp has a built-in DSP, digital crossover, digital EQ and other various things (none of which I am using), but the really great thing about it is the cooling fan. The cooling fan stays off and only turns on when things really heat up. Generally, durring normal music and movie playback, the fan never comes on. It's only if I'm watching a live concert or a movie like "War Of The Worlds" where there's lots and lots of sustained, deep bass when the fan comes on, and I have to be really cranking it to get the fan to come on. Even then, I only know it's on if there's a sudden quiet spot in the music or movie that I can here the fan running.
This is an older pic before going "active" on the main channels, but you get the idea.
I think I might have gone a little overboard with this post.
511B horns with 902-8B drivers mounted on top of a pair of '78 Klipsch Cornwalls. The only operational driver in the Cornwalls is the K33-E 15" drivers. The mid and tweet are disabled. In fact, the Type B crossovers (which have been heavily modded) are now resting peacefully in my closet.
That big black thing is a 51uF Solen just to suck up any extra turn-on juice the Crown D-75A may put out when turned on. IOW, it's soley there for protection. I believe this also rolls off the 902-8B drivers around 400Hz @ 6dB, which is below the 600Hz crossover point.
Here's another 511B with a 902-8T driver for the center channel. Here you can also see one of the modded Klipsch Type B networks. This one has be converted over to 2-way operation and seeing the 902-8T driver as a 64 ohm load to bring its output down closer to the 15" woofer's output.
This is where the heart of the system is. The Rane AC 22B crossover allows me to dial in the delay of the K33-E woofers and 902 drivers to get everything sounding just right. The Behringer DEQ1024 is used to flatten out a small peak around 1.2kHz. Also, because these 902-8B drivers are 30+ years old and came out of a large theater in Atlanta, GA, they have seen lots of action and power over the years. For this, their diaphrams are a little work-hardened, which gives them a little more than desired rolled-off top end. So I am also using the DEQ1024 to boost the top end a little as well to help things out.
This is the Technics SU-8099 integrated. My father bought this amp brand new back in '78 along with the Cornwalls, for the Cornwalls. He gave both the speakers and this amp to me. Anywho, this amp provides 115 very strong and very HOT watts to the K33-E drivers. And if you look closely to that meter, that's not peaking at 7-10 watts. The meter is in the 0.1x range, which makes that about 0.75 - 1 watt peak! And let me tell you, I had it playing pretty darn loud in there while taking these pictures!
This is my little gem right here. The awsome little Crown D-75A amp. This amp can pump out a whopping 35 watts into 8 ohms and is rated at 0.05 THD at full power. I bought this amp on eBay for $75 shipped! The guy that had it said that it was untested and that the gain knobs were real loose, so he was selling it as is.
Turns out that the amp was in MINT condition and the nuts on the knob shafts had worked loose. All it took was a couple minutes snugging down the nuts and that was it. As you can see, the gain is only at 2/3, and the output from the Rane crossover is just over half. The signal LEDs never light up unless I'm really hammering it, so I'm guessing I'm barely getting a 1/2 watt out of it most of the time, and maybe 1-1.5 watts max! With its excellent specs and super clean power, it is a perfect match for the 511B/902 combo.
Just for fun, here's the business end of the system. The Music Hall Cd25.2 is long gone. I upgraded the opamps to Burr-Browns, but it never really impressed me that much. In fact, it's really didn't sound any better than the Panisonic DVD player, so I ended up selling it.
One thing you can't see in the photo is a Rane BB22 Balance Buddy. It's behind the DVD/crossover/eq stack. The MIANS pre-out from the Pioneer Elite VSX-54TX goes into the BB22. From there, it enters the DEQ1024, then to the AC 22B crossover, then to the Technics amp and small Crown amp. No hum, no buzz, no hiss, no nothing, just music and movies.
BTW, the silver Crown XTi 1000 is for the DIY push/pull sub I built. It has two Dayton 15" DVC drivers in a 6.3cf sealed enclosure. With the sub in its current location and with 2.83V input with pink noise at 1 meter, I measured 99dB, both with my SPL meter and TrueRTA!! At my listening position, I still get between 95-96dB. Gotta love that room gain! Nominal impedance is 8 ohms, and the amp is bridged mono for a healthy 1000 watts of power. This amp has a built-in DSP, digital crossover, digital EQ and other various things (none of which I am using), but the really great thing about it is the cooling fan. The cooling fan stays off and only turns on when things really heat up. Generally, durring normal music and movie playback, the fan never comes on. It's only if I'm watching a live concert or a movie like "War Of The Worlds" where there's lots and lots of sustained, deep bass when the fan comes on, and I have to be really cranking it to get the fan to come on. Even then, I only know it's on if there's a sudden quiet spot in the music or movie that I can here the fan running.
This is an older pic before going "active" on the main channels, but you get the idea.
I think I might have gone a little overboard with this post.
Cal Weldon said:
LOL! I like that!
Tweeters? I wouldn't exactly call them tweeters since they cover from 600Hz to 20kHz, but I get what you mean. And yes, they sound very good. Unfortunately, I don't get to listen to that system as much as I'd like. But when I do, boy-oh-boy is it fun!
Well, I have all that "non-Altec" stuff because I have a somewhat small-ish room. You see how much floorspace those Cornwalls, sub and center channel take up, can you imagine having A7 cabinets in there?! It would be covering up half the screen at that point!
Although, if I got a really good deal on a nice set of A7 cabinets and proper drivers to go along with them, I would gladly make the change.
Hi Michael,
It's hard to say anything without having the ability to play with them. I set one up on the back of the truck and tried to have the A7 cover the bottom end. Ain't gonna happen. These will require a dedicated spot for set up and some serious low end to keep up. At one watt they are annoying to the neighbours.
I will need to introduce some notch to it also. They have a strong mid presence.
I love the dispersion though. The multicell seems to do that a lot better than the sectoral.
I have a feeling these are destined for storage now and maybe pull them out after I purchase a mansion. I spent a lot of time on the 511 and 811 horn combo on top of the A7 box and must admit the sound from them is much sweeter than these behemoths without notch filtering.
Who knows, it's just that they are large and not easy to deal with. You almost need a buddy when you want to listen to them. Practical, no, but I do sleep well at night these days.
Is that last sentence an oxymoron?
It's hard to say anything without having the ability to play with them. I set one up on the back of the truck and tried to have the A7 cover the bottom end. Ain't gonna happen. These will require a dedicated spot for set up and some serious low end to keep up. At one watt they are annoying to the neighbours.
I will need to introduce some notch to it also. They have a strong mid presence.
I love the dispersion though. The multicell seems to do that a lot better than the sectoral.
I have a feeling these are destined for storage now and maybe pull them out after I purchase a mansion. I spent a lot of time on the 511 and 811 horn combo on top of the A7 box and must admit the sound from them is much sweeter than these behemoths without notch filtering.
Who knows, it's just that they are large and not easy to deal with. You almost need a buddy when you want to listen to them. Practical, no, but I do sleep well at night these days.
Is that last sentence an oxymoron?
Cal Weldon said:
And the Altec 'faithful' wonder why I switched to 511s for HIFI. That said, I did it back when my HF hearing was good and there was no practical way to TD a >5 kHz super tweeter, but always missed the incredible mids of the big MCs even after doubling up the 511s. With today's digital delay though, Hell would freeze over before I'd not use them if I still had them.
As you imply though, these were 'voiced' using impedance matching amps with adjustable DF, so short of the cost of an early Altec or RCA theater amp, then a L/R/C network combined with a low/no nfb SS amp is required to attenuate, flatten them out to ~12 kHz at low distortion, which will transform them into a 'living voice' when combined with dual 515Bs, whether horn loaded or not.
GM said:
Hmmm.. Not sure what you mean there, GM. Are you talking about the 1803 and the 288?
I hauled the the 1505 multicell with the Westrex CD (equivilent of the 288) all over the place. They made any amp sound good. Sure wish I could remember the crossover topology.
Maybe you were talking about the bass cabs?
I own a pair of Altec Model 15 speakers... picked them up at a garage sale for $100. Crossovers needed to be rebuilt and they also needed new voice coils.
These were just replaced this week with a pair of Urei 813a speakers (which are HUGE) using the ceramic magnet version of the 604 (-8H?) and a 15" Eminence woofer on bottom. They came out of a local university's mixing room and were in very good condition when the buyer got 'em. He had them sitting in a warehouse for a year before he decided to sell them to me. With the time align crossover and Urei horn they have a very dynamic big sound. So far I'm very pleased with 'em.
These were just replaced this week with a pair of Urei 813a speakers (which are HUGE) using the ceramic magnet version of the 604 (-8H?) and a 15" Eminence woofer on bottom. They came out of a local university's mixing room and were in very good condition when the buyer got 'em. He had them sitting in a warehouse for a year before he decided to sell them to me. With the time align crossover and Urei horn they have a very dynamic big sound. So far I'm very pleased with 'em.
Greets!
I'm talking about all speaker systems designed before the switchover to low output impedance amps, which includes all the WE/Altec, etc., horns and their bass bins if you want them to perform in a similar fashion overall as they did originally. Not the same though since the passive network can't interact with the driver's impedance in the same way a coupled tube amp can. Then there's the added aural effect of the tube amp's much higher distortion to consider.
GM
I'm talking about all speaker systems designed before the switchover to low output impedance amps, which includes all the WE/Altec, etc., horns and their bass bins if you want them to perform in a similar fashion overall as they did originally. Not the same though since the passive network can't interact with the driver's impedance in the same way a coupled tube amp can. Then there's the added aural effect of the tube amp's much higher distortion to consider.
GM
I couldn't remember if it was -8H or 8K... hence the ?. The wife is certainly no fan of the the Ureis - so they will stay down in my basement listening room. I'll take some pics once I get a chance.
The M15s aren't 'bad' - they do use the 802-8G driver for the tweet, but they are really damped down to meet the 93dB 12" ceramic magnet woofer. The woofer is supposedly sourced from RCA. The 32B horn is a 90 degree horn and I'm not sure how much it effects the overall sound quality of the 802...
The M15s aren't 'bad' - they do use the 802-8G driver for the tweet, but they are really damped down to meet the 93dB 12" ceramic magnet woofer. The woofer is supposedly sourced from RCA. The 32B horn is a 90 degree horn and I'm not sure how much it effects the overall sound quality of the 802...
Cal Weldon said:
I had the 1803B horns in a small room. Try a notch filter consisting of:
a 7 or 9mh inductor
a 1uf cap
a 24 ohm resistor
You'll need a tweeter no matter what you do.
Of course, that was a long, long time ago and I might not think so highly of the set up now. Back then it was the best thing I'd ever heard.
kstagger said:
And why I bothered to look it up.
They are much better when converted to a ~9849 with a 414 series woofer. The cast alum. version is a fine little horn, but the later plastic variant not so much. Still, without resolving the timing error either by using the original WE 800 Hz XO point and accepting its poor off axis response through the XO BW or some form of electronic delay required for the later model's 1500 Hz one, the latter's superior polar response just aggravates the problem.