New Heathkit AS101 owner - First post.

[alancohen]

So...at 52-years young, I'm finally getting around to building (starting) my bucket list audio system...albeit on a reasonable budget. I've made some DIY components and have a couple of more in the queue. Included was a nice pair of speakers with full range drivers that I thought sounded pretty great. That is until I visited Kevin (KAB) and heard his 803b horns. To say they were intoxicatingly seductive is a drastic understatement.

This led me to doing some homework on Altecs. All I can say is...I'm all in. But I'm not ready to drop $2K on a pair of multi cell horns and 288Ds, let alone a pair of 515Bs w/cabinets.

So after coming upon an available pair of Heathkit AS101s, and learning a lot about them here and elsewhere, I decided to take the plunge. I got them home yesterday and they seem to be in pretty good shape. The drivers appear mint and the cabinets are OK. The crossovers are a mixed bag. The attenuators seem to be fine. The soldering work is meh. It's the caps that are my concern at the moment. One was replaced and the other are old Chicagos with a +/- 10% tolerance. I wanted to keep the XO stock for the time being so I can hear what they were designed to sound like, then I can customize if necessary.

The schematic calls for an 8uF, 10uf and an 11uf. Thanks to this board I learned I can add capacitance by using caps in parallel so I just bought some Daytons:

4 027-226 Dayton PMPC-4.0 4.0uF 250V Precision Audio Capacitor $3.97 $15.88
4 027-234 Dayton PMPC-5.6 5.6uF 250V Precision Audio Capacitor $4.64 $18.56
2 027-244 Dayton PMPC-10 10uF 250V Precision Audio Capacitor $7.65 $15.30

I figure two 5.6s get me close enough to 11.

So here's a few picks. Other than the XOs, what should I be doing to overhaul these relics? FWIW, they sound great to me, but I don't know how much better they could sound. I know those caps are ancient.

[voice of the theater]

Hello Alan--glad you made it over to our Altec User's Board. Alan had sent me a PM a few days ago at the Lansing Heritage Forum after he read my thread over there about the AS 101's that I used to own (I had threads over there and over here when I owned those speakers). We exchanged a few PM's and I recommended that he visit this forum -- the place to go for all things Altec!

I'm glad you included pics in your thread here Alan, I was wondering if you had the classic "Altec green" drivers or the grey ones that my AS 101's had. I can see yours are green and I'm glad to hear that they're in such nice shape. Besides the new caps, I would definitely clean or replace those 40 year old L Pads. If you decide to clean them, I recommend Deoxit spray. If you want to replace them, Parts express should have something very similar in stock. Cleaning them may be all they need. I liked how my AS 101's sounded with the L Pads "all the way up/full throttle" so I ended up bypassing my L Pads altogether. Between the new caps and bypassing the L Pads, the improvement was impressive. However, cleaning or replacing the L Pads should achieve similar results to bypassing them and by not bypassing them you have more flexibility should you want to adjust them. By the way, I recommend keeping the old caps (and L Pads if you replace them) in a zip lock somewhere. If you ever sell your speakers, there are collectors who really like having the original caps--even if they are leaky and shot!

Here's what my my AS 101's with the grey drivers (8 ohm) looked like:










Another upgrade you might want to try if you want to experiment is to adjust the tuning of the cabinets. AS 101's, like Valencias, were not tuned for really "deep" bass like many later Altecs were (and many other manufacturer's speakers that came along later were--Altec Model 19's, etc.). Those are Altec 416 woofers in your cabs--and they are capable of much deeper bass than you'll get with the stock tuning of those cabs. There are people here who know a lot more about this than I do, but I can tell you that the empirical/scientific method (trial and error method) is a very good way to achieve a "better"/deeper tuning for your cabs. By reducing the port size (blocking off part of the port from the inside of the cab) you can achieve a deeper tuning. You can evaluate your results by listening or by measuring (with a microphone and computer software) combined with listening. For example, you can start by blocking off a small portion of the port by "tacking" a small piece of wood in place to see if you have noticeably improved the bass response, and then blocking off more to see if they sound even better. At a certain point, you'll have blocked off too much of the port and they won't sound right--then you have to go back to a previous tuning/whichever one you liked best and "permanently" block off that portion of the port (use screws to secure the wood you're using to block off part of the port). Properly executed, you can get much deeper bass out of those cabinets than they get with their stock tuning

Personally, I would start with just replacing the caps and cleaning or replacing the L Pads. If you listen to them like that for a while, it will be much easier for you to tell how much of an improvement in bass response has occurred if and when you decide to improve the tuning of the cabs (because by then you'll be very familiar with their bass response with their "factory tuning" using different recordings -- you'll have a good frame of reference).

Down the road, there are other mods you can try. Zilch (who you noticed chimed in with some advice for me in my LH thread), owned Valencias and had suggested as a possible upgrade for Valencias/AS 101's replacing the stock 806 drivers with 802-8g drivers and replacing the stock crossover with Model 19 crossovers or Z19's (his version of the Model 19 crossover). If you ever decide to try this, Great Plains Audio (former Altec employees using authentic vintage Altec designs and tooling) makes brand new 802-8G drivers and brand new Model 19 crossovers or you could buy vintage Altec 802-8G drivers and Altec Model 19 crossovers on ebay. Selling your 806 drivers would give you a decent chunk of change towards 802-8G drivers. However, if you try this upgrade, I recommend keeping the 806's should you ever want to return the speakers to their "stock" configuration (if you want to sell them some day, etc.) This upgrade extends your h.f. response--you end up with speakers that are very similar to Altec Model 19's (416 woofer with the same h.f. driver and crossover that are in Model 19's). In lieu of that, you could add a tweeter to each AS 101, or you may find that after replacing the caps and cleaning the L Pads that they have plenty of sizzle for you and at that point you may or may not want to experiment with cabinet tuning to improve the bass.....

BTW, many Altec speaker systems with the green drivers are 16 ohm systems. Are your AS 101's an 8 ohm system or 16 ohm? That will affect some of the mods I've suggested..... Again, as I mentioned in a PM to you, congrats on buying a great pair of vintage Altec speakers. Also, welcome to the Altec Users Board!

[alancohen]

Thanks for the tip, VOTT. Great to be here!

Mine are 8 Ohms. At least that's what they say on the backs.

I'm planning on swapping out just the caps first and doing a good cleaning on the pots. While I'm waiting for my new caps I might try your suggestion and start playing with the ports. I have a powered 12" sub-woofer with an active XO that I can set to pick up 40-50Hz and down, so getting the 416s down that low is not mission critical. I tend to enjoy the rumble of 25Hz more than the sparkle of 18K. And neither of them are as important as what these 811b horns are doing to vocals and acoustic brass and woodwinds. I'm tickled.

Like I mentioned in my OP, I built a set of speakers utilizing full-range drivers with a bass reflex cab and found not only the port diameter made a big difference, but the length of the port as well. Tough to add more after you've cut it off though! I installed Parts Express L-pads on them to level the highs down about -2-3dB so I'm familiar with them. They look like they'll fit nicely. Did you use the 3/8" long shaft, or the 1". I'm probably OK with the 50W version since I'm only pumping a whopping 3W/ch into them at the moment. It's a glorious triode 3W though!

Here are pics of my first speaker attempt and the L-pads on the inside:

8081002207_72373bd124_b.jpg8037582100_a841cb1ea8_b.jpg

When I get around to really overhauling, they'll make a nice back up set while the Heathkits are in the "shop".

FWIW, the full-range speakers, with a bit of HF attenuation, have an almost dead flat frequency plot from like 80-20K. And they sound pretty nice for what they are, but they do not have nearly the presence of these Heathkits, which I'm willing to bet have a far less sexy response curve. My point is I really don't care much for the numbers; I care about what I hear.

[voice of the theater]

.......And neither of them are as important as what these 811b horns are doing to vocals and acoustic brass and woodwinds. I'm tickled....... FWIW, the full-range speakers, with a bit of HF attenuation, have an almost dead flat frequency plot from like 80-20K. And they sound pretty nice for what they are, but they do not have nearly the presence of these Heathkits, which I'm willing to bet have a far less sexy response curve. My point is I really don't care much for the numbers; I care about what I hear.

Well, you hit the nail on the head as far as I'm concerned. Vintage Altecs like your AS 101's are well known and highly acclaimed for their "midrange magic". While they also shine with clean powerful bass and great crystal clear high end as well, there's something indescribably lifelike about the midrange that they produce. I remember when I first bought my Valencias (my first Altecs with horns), I couldn't believe how lifelike brass, strings, vocals, guitars, etc. sounded. Like you could reach out and touch them...... I'm sure there are speakers that have better "numbers" than many of the classic vintage Altecs (as far as measurements), but very few that I've heard can come close to their clean, lifelike, effortless sound. FWIW, I never did the Zilch upgrades (802-8G/Model 19 crossover) to my Valencias or AS 101's--they sounded so great and have such a unique sound that I was leery of defacing a "work of art" and trying to turn them into something else. Since you had asked about what mods can be done to AS 101's, I felt it was important to mention Zilch's mods as a possibile option after you've done the caps, L Pads, and possible cabinet tuning mods....

[cradeldorf]

I started with As101's too, The Altec slide Is a slippery slope, Have a great journey I did. Kicking back and enjoying some great sound now.

I just want to gloat. : )

[Alien_Shore]

Welcome to AUB, Alan.
You certainly chose an excellent speaker to get started with (as CD says down the slippery slope!)
Recapping those XOs is a no-brainer, you'll hear vast improvement with that. Another thing to check is the diaphragms in your HF comp drivers. Depending on how they've been treated over the many years, they may be in good shape or possibly torn up. Another thing to check is the strength of the magnets on your drivers...the old Alnico drivers can lose quite a bit of their zip again depending on what they've been through.

[alancohen]

I was wondering if the Zilchlab Econo Wave boards are still available. I came across this video:

Rev Up Your Vintage Speakers, Econowave Style - YouTube

and I happen to have these "made for Ovation" Altec VHF drivers and horns in the mail. It might be fun to play with them.

5Kb5F15M83k43K93L6c9r52aacd5130dd1f56.jpg

[voice of the theater]

I was wondering if the Zilchlab Econo Wave boards are still available. I came across this video:

Rev Up Your Vintage Speakers, Econowave Style - YouTube

and I happen to have these "made for Ovation" Altec VHF drivers and horns in the mail. It might be fun to play with them.

5Kb5F15M83k43K93L6c9r52aacd5130dd1f56.jpg

I just watched the video and it references an Audio Karma thread. I'm not a member there but some of our Altec Users Board members also belong over there so maybe one of them would know about Zilch's Econowave board. If the guy in the video and/or Audio Karma thread is suggesting that this is a "one size fits all" type crossover to be used with any woofer and cabinet regardless of efficiency, frequency response, etc., then I'm very skeptical of that sort of approach. I have a feeling that Zilch would have known better than that......

[Old Guy]

and I happen to have these "made for Ovation" Altec VHF drivers and horns in the mail.
5Kb5F15M83k43K93L6c9r52aacd5130dd1f56.jpg

University, not real Altecs. Okay at best was my opinion. All the Ovation stuff was University AFAIK.

[gearfreak]

and I happen to have these "made for Ovation" Altec VHF drivers and horns in the mail. It might be fun to play with them.
5Kb5F15M83k43K93L6c9r52aacd5130dd1f56.jpg

Congrats, Welcome, and Ditto OG not altec.
Also looks like Klipsh K-55 from here, search and you will find the atlas driver part #. Can't tell precisely, so go with OG's info until otherwise.

Don't go too crazy on the VHF $ for a 3 way setup.
I suggest starting cheap, I am back to my $10 on sale Beyma CP-09's for now.
If staying 2-way, maybe just skip to Altec/GPA 902's and play with the XO.
If you can find a cheap prebuilt XO with CD compensation, that may be your quickest route to 'I want to emulate that with good components now'. I've been happy continuing to experiment with EV XEQ-808's.

( Of course perhaps you are already well versed in XO's )


* I make it up a little east of phillipsburg - way sometimes. Maybe we've got the beginnings of an Altec pony express!