New Heathkit AS101 owner - First post.

[robertbartsch]

I bought a pair of these new in 1974. I can still remember soldering the crossovers and installing drivers. I think I paid about $600 or so, if memory serves me well.

...like a dope, I sold them in 1999. I missed them so much, however, I bought a pair of Velencias that have the same guts,,, You should consider installing casters on the cabs...

[Earl K]

<<<<SNIP>>>>
But I do have a problem. I use an audiophile pressing of Larry Carlton's, "Alone, But Never Alone" as my component test source since I know it well. The lows and mids are spectacular and are obviously well engineered. But there are small chimes used in several songs and now I notice their presence seems muted. They just don't sparkle the way I'm sure the recording engineer intended. I never noticed it as much before because my other amps must have muted everything else to a similar degree.

So I'm wondering if this high end limitation is a function of the stock XO, or the 806A/811B. I remember reading a bunch of Zilch's threads where he pounded on the high-end roll off of the Valencia's (and Heathkits too). He seemed to think that a reworked XO would help. If that's the case then my bi-amping with active crossover might alleviate the issue.

Thoughts?

I find tweeters ruin the imaging of horn based systems ( unless crossed above 10K ) / so I discourage their use .

Also, since I like the sound of aluminum diaphragms much more than the plastic type frams, I'd be inclined to seek out an 802 / 902 variant that could work with your AS101's .

( Strictly speaking ),a reworked XO is not going to bring back something that's missing ( though with biamping, one could conceivably suppress the midrange enough to give the HF a fair chance at being heard ) .

One needs to suppress the midrange something in the order of 12 to 15db to get the the HF on an equal footing . See ( Zilchs work ) below ;




If 14db of midrange suppression is employed, the whole horn circuit will be too low in level when compared to the woofer . It'll be something like 90db HF over 96db LF ( clearly a mismatch between the highs & lows ) .

Using an 8ohm driver ( or 8 ohm diaphragm in your existing 806 ) over an 16 ohm woofer helps reclaim most of that differential . That'll necessitate a rework of the crossover to accommodate the mixed 16 ohm and 8 ohm loads ( LF & HF respectively ) .



Reworking the stock 101 Xover would mean employing something like the HF leg of this following network ;



Then one would want to build up Altec's ( classic ) midrange suppression network ( the HF portion of the following compensation network ) and insert it inline ( after the Lpad I suppose ) .

[voice of the theater]

I find tweeters ruin the imaging of horn based systems ( unless crossed above 10K ) / so I discourage their use .

Also, since I like the sound of aluminum diaphragms much more than the plastic type frams, I'd be inclined to seek out an 802 / 902 variant that could work with your AS101's .

I agree--I'd replace your 806 drivers with 802-8G drivers (or 902-8A). Both have a nice extended high frequency response and will sound great with your 416 woofers. I own a pair of Altec Model 14's with 902-8A drivers and two pair of Model 19's with 802-8G drivers and both have a great extended H.F. response--plenty of sizzle and no need for a tweeter. Just ask AB about his Model 19's. The AS 101's are great speakers with great bass, mids, and treble up to around 13-14k. Past that is their weak point. As AB stated, the 806 drivers roll off at around 13-14k. I know the specs for them say up to 22k, but the response past 13 or 14 k drops off steadily and isn't really usable. BTW, I mentioned this potential upgrade to you on page one of this thread (in post number 2 of this thread). Zilch was a Valencia owner, and this was part of his recommended upgrade for Valencias. Since you're biamping, you won't need to replace the AS 101 crossover with the Model 19 crossover--which was the other part of Zilch's recommendation for this upgrade.....

...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)....

[alancohen]

Big thanks Earl and VOTT!

I'll take your(pl) recommendation and just get the 802-8Gs from GPA. I can tri-amp tweeters, but like you said, why mess with the 811s in their sweet spot. Besides, if I can get enough high end out of the 802s and bi-amp, then I have an extra channel left over on the active XO for a sub...if I choose.

I'm not sure whether or not I'll sell the 806s yet. I'd like to keep them in case I ever sell the HKs, but I hate unused stuff laying around. I have no room for extraneous gear. I can't imagine I'd ever sell the HKs though. I know, famous last words.

[Altec Best]

I'm not sure whether or not I'll sell the 806s yet. I'd like to keep them in case I ever sell the HKs, but I hate unused stuff laying around. I have no room for extraneous gear. I can't imagine I'd ever sell the HKs though. I know, famous last words.

I can't recommend this enough... Always keep your original gear,especially when you have all the original parts..You will always receive much more money reselling vintage speakers if they are all original.. And besides, once broken up another original pair will bite the dust.. Like Altec they won't be making any more new ones.

BTW- If you ever do decide to add a super tweeter the horn in the heath is up high so you wouldn't need to cut the baffle you can simply mount/lay the tweeter on the top of cabinet without any cabinet cuts without any issues IMHO..

But as has been already noted changing driver/crossover seems to be the least amount of work to get were you would like to be.

[alancohen]

I can't recommend this enough... Always keep your original gear,especially when you have all the original parts..You will always receive much more money reselling vintage speakers if they are all original.. And besides, once broken up another original pair will bite the dust.. Like Altec they won't be making any more new ones.

BTW- If you ever do decide to add a super tweeter the horn in the heath is up high so you wouldn't need to cut the baffle you can simply mount/lay the tweeter on the top of cabinet without any cabinet cuts without any issues IMHO..

But as has been already noted changing driver/crossover seems to be the least amount of work to get were you would like to be.

I hear ya. It's not like they'll take up a lot of space.

So just thinking out loud: If I'm dropping $500+ on the 802-8Gs, what about a pair of Altec 3000 tweeters for about the same or less $$$ instead? I hear they're da' bomb.

I love the mid to mid/highs on the 806s. I have the amps, I have the XO. I can crossover the 416s, the 811s and the 3000s anywhere I want. I can fine tune the delay, the XO slope, the volume.

Or just keep things simple with the 802s?

[alancohen]

I also have these:






Similar to University HF-206s?

Worth a try before dropping the cash?

[Earl K]

Alan,

(A) I just reread this thread . A couple of things stick out .

(i) It seems you have a DCX2496 available for biamping .

(ii) It also seems you have available another amp that you can commit to the HF circuit if you actually do biamp .

(iii) Your AS-101 have 8 ohm components loaded into them .

(B) Upon review ( for you to get more HF ) I would simply biamp these 101(s), using your available electronics ( & not buy any new drivers or diaphragms ) .

(i) Build up the HF portion of the midrange suppression circuit ( that I posted above ) , put it inline with the horn-driver , turn up the HF amp to make up for the lost sensitivity and then take a listen .

(ii) The new balance ( between mids & HF ) should be more to your liking .

(iii) This is cheaper & faster to do when compared to trying to integrate a tweeter ( & should sound better ).



PS ; Forget about those Ovation horn drivers ( they'll be dying by 8K for sure ) .

AS-101 Schematic

[alancohen]

That makes perfect sense, Earl, but it might not be a good option in my case. The amp(s) I plan on driving my HFs is a pair of 1W 300B OTL monoblocks. At 1W I need as much of the efficiency that a HF CD can afford. If I'm toning down the mids almost 14dB then I think I'm shooting myself in the foot.

FWIW, once I build the 300Bs I will have 3 amps available for tri-amping. That would allow me to boost the above 14KHz range through a tweeter without muting the 800-14Khz mids through the 811.

But that might defeat the gloriousness of the 300Bs by chopping them off at 14Khz and not allowing them to reach higher. And I'm not building 4 300Bs!!

I think the 802-8Gs might be the answer. It will allow the 300Bs to play all the way up, I won't be disturbing the imaging by adding another component and I'll be able to maintain the high efficiency Altec horns are known for.

[voice of the theater]

I think the 802-8Gs might be the answer. It will allow the 300Bs to play all the way up, I won't be disturbing the imaging by adding another component and I'll be able to maintain the high efficiency Altec horns are known for.

I think you hit the nail on the head here. Not to mention, your rationale is very much in keeping with Altec's philosophy regarding the 802-8g/tangerine phase plug....