Hello after all these years! And GPA 3154s for 1202B's?

**taudo2** · February 13th, 2012, 04:04 AM

Hello to all my fellow Altec fans!

It's been almost 8 years since I last got on this board. But that's a small time compared to 40 or so years I've been enjoying the wonderful sound of Altec VOTT-like systems. I was known as taudo previously, but seem to have lost my old password, so had to re-incarnate as taudo2. It's good to see some familiar names still around! And Todd is still making it all work!

"My name is Tim and I'm an Altec-aholic..."

Back in high school I stumbled across some new Altec 1204 MI systems way in the back of North Valley Electronics in the San Fernando Valley. Being the goofy kid I was, I fell immediately in lust with their appearance and had to have a pair, even though I had never heard them. But, being broke there was no way I could buy them, so I built a set of kinda look-alike cabs and installed 811s, 802s, n801s, and 416s as I saved up and bought them. When I finally got them finished and got to actually hear something of that Altec sound, I was hooked!

Those home-brewed systems served me well for years - until I replaced them around 2005 with A7-500 systems with JBL subs in the bottom and tri-amped them. The Altec components were re-manufactured by Bill at Great Plains Audio to be better than new. The industrial gray 828 cabs with the horn on top looked ugly as sin, but sounded like heaven. They still do. They fit so nicely in the dormers of my loft that I've been accused of building the house around them. But it's just a coincidence!

I hadn't planned to acquire any more Altec systems but it seems that my Altec addiction is still active because I couldn't resist picking up a pair of real 1202B systems yesterday. They were in very good cosmetic shape and cheap but sound like what they are - PA or guitar systems. I have no real good use for them, but might use them for a hifi system in a guest room. Fortunately, I have several sets of GPA'd 802s carefully laid away to replace the raspy Symbiotic 807s. But I'm interested to know what the folks here would recommend for replacing the so-called woofers in these systems (421s I think. Haven't opened them up yet. But insufficient bottom end in any case). I haven't had time to go through the T-S calcs, but was thinking GPA 3154's would be an improvement (I think they weren't available in the last thread dealing with this issue). I don't want to make 3-ways out of them. What do you all think?

Glad to see this board still going strong!

**Old Guy** · February 13th, 2012, 09:34 AM

I like 3154's. But personally would design proper boxes for them as the PA enclosure is mid band optimized. I'd like to get GM's opinion on being able to tune the 1202's, he does that sort of thing better than I, I'm more the live sound/studio sort.

**Cal Weldon** · February 13th, 2012, 04:14 PM

Hello Tim and welcome back. I second OG's thought about having GM help you decide. I had a look at an old brochure and it seems to think you have the 422 - 8Z LF drivers in the 1202.

Good luck with the project.

GM · February 14th, 2012, 01:48 AM

The 3000 series has a relatively high inductance, so strictly for PA alignments if not corner loaded, i.e. the factory alignment [8154 cab] is about as low as I'd want to use it. I've lost all my notes on cabs, etc. and don't recall the 1202's net Vb, but for 'full-range' HIFI/HT cabs and assuming a reasonable amount of power is available, going sealed with the 411 now that it's available again seems the best choice overall in the Altec line and either reduce cab net Vb or use EQ if the mid-bass is too rolled off.

GM

**taudo2** · February 14th, 2012, 10:41 PM

The Vb of the 1202B I have appears to be about 6.4 cu ft net (after subtracting 1.2 cu ft for the 811 and driver, and .2 cu ft for a 15" LF speaker). There is a vent of 20.5" X 4" X 2" (D) across the bottom of the cab.

Anyone have a box modeling program up and running that can tell me the numbers for this thing?

Also, Greg: where are the 411s available? I couldn't find them on GPA's website.

Thanks guys!

Tim

**taudo2** · February 14th, 2012, 10:46 PM

Oh, Cal: You are correct about the 422-8Z LF drivers. That is just what I have - at least in the one cab I opened up.

Tim

GM · February 14th, 2012, 11:46 PM

Slot vents are hard to accurately calculate, but the tuning is down in the low 30s. I get a ~30-32 Hz range depending on which duct end correction factor I use.

Folks have posted buying drivers, horns not listed on GPA's site and I thought the 411 was one, but I may be wrong. Unless someone knows for sure, guess you'll have to call them.

If not, GPA's 515-LF should work fine in the cab as-is except it may need some more bracing to handle the extra gain BW if pushed with some power. On paper, the 1202 would just about move around on its castors pumping out ~112 dB/32 Hz/half space at rated power without exceeding Xmax and its near 120 Hz mid-bass slam can replicate a live drum kit, so a pair backed up against a rigid/massive wall will theoretically do a small venue band at live levels and THX reference at very low power, though a sub would be needed to handle the LFE channel. These simple programs tend to be a bit optimistic, but a typical room often allows them to 'save face' and occasionally best the predictions.

GM

**taudo2** · February 18th, 2012, 07:31 PM

GM,

Thanks a million for running those numbers. 112 dB at 32 Hz and nothing coming apart (except, maybe, the cab) is far better than I thought I'd ever get out of them! It looks like a pair of GPA 515-LFs are in my future. Get them up and running and maybe I'll get off my duff and finally install a pair of rebuilt 2245s I've had sitting in a box in my study for something like 5 years. Having 3 pair of Altecs up and running isn't excessive, is it?

But first, I have a little HF mystery to resolve. When I replaced the 807 on one of the 1202's it was a huge improvement. But not so much on the other. Clearly audible difference. I'm thinking that I'll have to verify that the crossover in the second cab isn't full of cold solder joints - or worse!

Thanks again to all!

Tim

GM · February 19th, 2012, 12:33 AM

You're welcome!

Not excessive around here, just makes us less fortunate folks envious.

GM

**taudo2** · February 20th, 2012, 01:04 AM

Well, even a broken clock is right twice a day. I pulled the malfunctioning crossover out and found - a bad solder joint! So bad that it came loose just being touched. Broke out my trusty Weller and fixed that little problem and all is now well. The guy I bought these systems from mentioned he had replaced the caps recently, so I was suspicious. Now, if I just knew if they are the correct values (18 & 3 microfarads)...

Tim