New Heathkit AS101 owner - First post.

[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]

Thanks, Mike. That brings up an interesting question. I got these speakers from a guy that buys and sells estates. They came from a house that has been closed up for 20+ years. I guess the original owner passed away and his house was closed up until recently when it was sold.

So these speakers haven't had a hard life of use, but sometimes non-use can be worse for some things. There doesn't seem to be any mold or corrosion anywhere. But it would probably be a good idea to remove all the drivers and give them a good look over.

How would I check the magnets? Would they loose their zing more from use, or non-use? Maybe sending them off to Bill for a recharge wouldn't be a bad idea. I know he does that for free with a diaphragm replacement or re-cone, but do you know what he charges a-la-carte? I've read that while GPAs replacement diaphragms are good, they are not exactly the same and might not have that exact "Altec sound". Myth?

I'm in NJ and haven't worked since Sandy paid her visit. As of this morning, my office still had no power. If that's the case tomorrow, I'll pull the drivers and post pics of what I find.

[cradeldorf]

Thank god they survived the storm!!! If they sound good I wouldn't bother messing with them....well of course I'd mess with them but watch that slope.
I'll be posting an update on my obsession in a few minutes.

[Cal Weldon]

Hi Alan,

Not mentioned yet is the flipping your drivers 180? to help relieve the downward stress of having sat that way for how ever many years.

Also, I noticed you have wired your L-Pad as a series resistor. Doing that will alter what your XO does. You'll want to correct that. Here is how:
https://www.google.ca/search?sourcei...iring+an+L-pad

And yes I know Altec does it that way also. For the life of me I can't ever sort out why. It makes no sense to have an L-Pad and not use it as one.

[voice of the theater]

Thanks, Mike. That brings up an interesting question. I got these speakers from a guy that buys and sells estates. They came from a house that has been closed up for 20+ years. I guess the original owner passed away and his house was closed up until recently when it was sold.

So these speakers haven't had a hard life of use, but sometimes non-use can be worse for some things. There doesn't seem to be any mold or corrosion anywhere. But it would probably be a good idea to remove all the drivers and give them a good look over.

How would I check the magnets? Would they loose their zing more from use, or non-use? Maybe sending them off to Bill for a recharge wouldn't be a bad idea. I know he does that for free with a diaphragm replacement or re-cone, but do you know what he charges a-la-carte? I've read that while GPAs replacement diaphragms are good, they are not exactly the same and might not have that exact "Altec sound". Myth?

I'm in NJ and haven't worked since Sandy paid her visit. As of this morning, my office still had no power. If that's the case tomorrow, I'll pull the drivers and post pics of what I find.

Here's my take on your questions, although there are others here who know more about some of this stuff than me. BTW, I'd love to see the pics you mentioned you're taking of your drivers.

I will always use GPA for any repair work of my Altec drivers but there is some really interesting info on Alnico magnets including their magnetic properties/potential loss of charge etc. here:

Vancouver Audio Speaker Clinic - Magnet recharging

Here are a few things that caught my eye right off the bat:
"Disassembly If an Alnico magnet structure is opened, such as to re-centre a shifted pole-piece, repair a broken throat, or remove a bug-screen, the magnetic field collapses instantly. While this type of damage is not common, ill-advised repairs create very unwelcome problems."

"Pulse loss
Most Alnico compression drivers (JBL LE85, LE175, 375, 2410, 2420, 2440, 2441, Altec 288, 290, 802, 804, 806, 808, Emilar EA-175, TAD 2001, 4001, Goto Unit, etc) have tall magnets, short voice coils, and modest power inputs, so do not suffer degaussing. Those compression drivers with low aspect ratio magnets, especially if used <500Hz (Vitavox S2, University ID series, Klipsch K-55-V, Electrovoice 1823M etc) can suffer flux loss, and will benefit from remagnetization. "

Based on this info, I think your 806 drivers are probably fine as far as their magnetic charge--especially if they not only sound great but also sound identical to each other in A/B listening tests.....

"Pulse loss

For example: Low frequency drivers with 4-inch voice coils (JBL D120, D130, D140, LE15, 2205, 2215, 2231, Gauss, or TAD drivers) can lose 2~3dB, becoming 'dull' or 'slow' sounding, unless they have been grossly abused, in which case they more and sound dreadful. Drivers with short Alnico slugs and 3-inch voice coils, (JBL 2213, 123A, etc) are effected more severely, so typically show 3dB sensitivity loss, while small alnico woofers (JBL 116A, 125A, 127A etc) are commonly 4dB down after quite modest use. Conversely, speakers with higher coercivity ( taller Alnico slugs) and short voice coils, such as Tannoy dual concentrics, Altec and EV woofers, rarely suffer unless they have been badly abused."

Of course I'd never take this info as a guarantee that my Altec woofers haven't lost any of their magnetic charge, but it's interesting that many Altec woofers can be less vulnerable to this problem than many other woofers that are listed above.

To specifically answer your question, putting too much power through Alnico woofers (particularly some of the ones listed above) can cause them to lose some of their charge, I've also read somewhere that dropping them can have a similar effect. I don't recommend you drop them on the floor from a height of more than 100 feet (kidding).

In all seriousness, I've never had any of my 416 woofers tested for their magnetic charge. I've been fortunate to buy them all from audiophiles who knew enough not to try to put 300 watts through them or to drop them on the floor! I've owned 416z woofers (16 ohm), 416-8A woofers (in my AS 101's), and 416-8B woofers (in my Model 19's), and they've all sounded phenomenal. Also, when I've done A/B comparisons between a pair of 416-8A woofers for example (in their cabinets), they've sounded identical which makes me think there's an increased likelihood they're intact if they both sound not only identical to each other, but both sound incredibly clean and powerful with not only deep bass, but nice midrange as well. I've read that with woofers that are more prone to this type of loss of magnetism (like some of the more vulnerable woofers listed above), when they lose their charge it mainly effects the upper portion of their frequency response i.e. midrange..... So, I've never had a pair measured but of course it wouldn't hurt to have Bill measure them--there are stories here of people who definitely needed their Altec alnico woofers re-magnetized--most likely they were abused (way too much power or dropped) by previous owners...... Of course if you decide to do this, pack them securely because they are much more likely to be dropped by a Fedex employee (and suffer the resulting loss of magnetism) than they were when they were in their cabinets! There are ways of measuring parameters of your woofers (at home, by yourself) that could give you solid clues as to whether or not they've lost some of their "zip". If you've got suspicions about their condition, this would likely be the best way to start your investigation. I've never had to do it, but there are definitely some experts on that type of thing here on our forum.....

Doesn't hurt to check your diaphragms as long as you are proficient at removing them, cleaning the "gap", and re-installing them without damage. It's not that hard to do this safely with smaller format h.f. drivers like your 806's (and my 802's and 902's). Here's some information regarding that procedure : http://www.greatplainsaudio.com/SmDrvrDiaRpl.pdf

I've read that while GPAs replacement diaphragms are good, they are not exactly the same and might not have that exact "Altec sound". Myth?

GPA (former Altec employees) uses authentic vintage Altec designs and tooling. While a brand new diaphragm may not sound identical to a 40 year old diaphragm, of course keep in mind that a 40 year old diaphragm also may not sound like it did when it was new. Your 806-8A h.f. driver takes a 34647 diaphragm. A GPA 34647 will IMHO have the "Altec sound" that the original diaphragm had, and depending on the condition of your diaphragms, may be a nice upgrade in sound quality. Certain original vintage Altec diaphragms aren't currently manufactured by GPA. In this case, substituting a different model # diaphragm for the original will likely result in some degree of change in the "Altec sound", but fortunately the proper replacements are available from GPA for your h.f. drivers if you end up needing them......

[alancohen]

Here's my take on your questions, although there are others here who know more about some of this stuff than me. BTW, I'd love to see the pics you mentioned you're taking of your drivers.

Big thanks VOTT. Read and digested. I printed the GPA HF driver assembly doc and will read it thoroughly. I'm a little nervous about taking them apart. They really sound amazing and fairly balanced from L to R. One might be a bit louder, but can that be the capacitors? I think I'll replace them first in the next few days, reassess and then contemplate disassembly.

[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