Upgrading a pair of Heathkit AS101/Altec Valencia Speakers - diyAudio
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Old 8th November 2007, 09:38 PM   #1
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Default Upgrading a pair of Heathkit AS101/Altec Valencia Speakers

I recently picked up a pair of AS101 speakers. This is basically a clone of the Altec Valencia with a 416A woofer and an 806 HF driver in a 811b horn. I am new to the vintage/DIY audio world and have some questions about upgrade/repair of these units.

The cabinets and drivers seem fine. Most of the questions revolve around the electronics.

1) Upgrading the caps in the crossover
Someone has already done a partial replacement of the caps but I don't know when and the quality of the replacement caps is marginal. I have not yet measure the original caps but I suspect based on what I have already read online that they probably have drifted significantly. I have an original a manual on the way to confirm the original values for the caps but it seems from what I can tell that there is an 8uF cap and a 10uF and an 11uF in parallel to give 21uf cap. This would mean that I need an 8uF and a 21uF (or a combination of caps to give 21uF). I contacted Parts Connexxion and they suggested Mundorf Silver and Oil (the second from the top Mundorf cap, with the Silver and Gold being the top). Has anyone had any experience with these caps in vintage Lansings (or other comparable speakers like Tannoys or classic Klipsch)? How about any of the other contenders like Dueland, other members of the Mundorf line, modern production Jenson caps or Audio Note copper caps (the silver are interesting but the price is completely out to lunch)?
2) Internal wiring
I suspect that the original hookup wire is also a little past its prime. I am thinking of replacing with silver hook up wire (I already use homebrew silver interconnects in my system and am looking at switching to silver speaker cables as well). DH Labs has an appropriate hook up wire or I could use the braided silver wire that Home Grown Audio sells for interconnect purposes. Anyone with experience using silver wiring for the internal crossover to driver connections.
3) Damping the 811B horns
This has been done to death on other forums so I won't ask anything further about it
4) Moving the crossover external
I have thought about taking the crossover completely external and mounting in a wood box with the RFI blocking paper that Parts Connexxion sells. Has any one else taken their crossover external?
5) Adding a supper tweeter
I am not saying I am unhappy with the high frequency extension, I am just looking to play around a bit. I have thought of adding one of the Fostex horn supertweeters. They are over 100db efficient and seem like a reasonable match to the 811B to give it a bit more reach. They are also nice because they are designed to be free standing, so you can just plop them on top of the cabinet without any other mods being required. Has anyone tried these or other super tweeters to extend their 811B reach.
6) the L-Pad
I suspect the variable L Pad may also be a week link in the crossover. I am wondering about replacing it either with a new L-Pad (Fostex makes some that seem like they could work) or even using the Fostex transformer based attenuator instead of an LPad (which would probably move the crossover external given its size). Any experience with replacing the LPad? How about doing away with the Lpad all together an settling on a single level with a simple fixed L Pad? I am guessing you could just set the variable LPad to your desired level and the measure accross the LPads leads with a multimeter to get the value for the resistors.

Just to give some background. I am new to vintage audio. I am 32 and therefore missed the heyday for this gear. I have been into higher end audio for almost 15 years but have never really been keen on the "HiFi" kind of thing. Always more of a music lover first and gear second, hence the switch to vintage. I run a couple of different tube amps depending on my mood (300B SET or 6L6/5881 PP) with an Audible Illusions preamp (the original Mini Mite from the late 1970's, early 1980's) that has been heavily tweeked by Gilbert Yeung of Blue Circle Audio (a really neat manufacturer of tube and hybrid elctronics in Canada). While I do have a turntable (an old Oracle), I admit that I listen primarily to CDs. I have a very large listening room (almost 35 000 cubic feet, its an old converted church) but I only sit about 12-14 feet from the speakers (it depends on my wifes furniture placement of the day). I use a variety of homebrew cables with products from Furutech, Oyaide and Homegrown Audio playing strong roles. I listen to a lot of smaller scale vocal (think Johnny Cash, Frank Sinatra, a whole variety of modern singer/songwriters) but I do like to crank some rock, large scale orchestral stuff or even rap on occasion.

Any comments or advice on my repair and upgrade project would be appreciated.
Dan
PS In the interest of complete disclosure this has also been posted on the Altec Lansing heritage site (www.audioheritage.org) but they seem a little more focused on the finer point of which driver/horn/cabinet combo is best and I am looking to maximize the performance of what I already have.
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Old 8th November 2007, 10:06 PM   #2
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Quote:
I contacted Parts Connexxion and they suggested Mundorf Silver and Oil (the second from the top Mundorf cap, with the Silver and Gold being the top). Has anyone had any experience with these caps in vintage Lansings (or other comparable speakers like Tannoys or classic Klipsch)? How about any of the other contenders like Dueland, other members of the Mundorf line, modern production Jenson caps or Audio Note copper caps (the silver are interesting but the price is completely out to lunch)?
Yep, they'll take your money if you hold it out there. My advice would be to wait for the schematic, and then look for motor run caps on ebay that are close to the values needed. After this, you can add "boutique" values in parallel to make up the difference. After this, you can spend the considerable money saved on music...or send it to my PayPal account.

I would stay away from the pricey oilers. At this point, you don't know what is important and what isn't.
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Old 8th November 2007, 10:07 PM   #3
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The Altec N 800 crossover series used an L pad with resistors.

Here is the schematic of the N-809 8A
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Old 10th January 2008, 07:49 AM   #4
srbliss is offline srbliss  United States
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Default Valencia's

I have discovered in my speakers that the real problem is that the woofers have no bass and the compression drivers have no highs and are distorted everywhere. Just for fun I dropped in a JBL 2235H woofer to see how it worked - vast improvement even if the crossover is all wrong for it. Much more bass, nice warm sound. Really brings out the defect in the horn.
I like the cabinets and will be reusing them, with JBL drivers and new crossovers.
Steve
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Old 10th January 2008, 05:50 PM   #5
kevinkr is offline kevinkr  United States
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Take a look at the Clarity Cap SA offered at Madisound for reasonable prices. I've used them to refresh the caps in a pair of JBL Rhodes C-37s and more recently in the cross-overs of my Onken based system which uses JBL 4333 mid horns and 2402 annular ring horn tweeters. Very pleased with the overall performance..

I've also used the Erse Pulse and low cost Solens. The Erse are quite good - the Solens more romantic and more veiled. The Erse Pulse are available from www.diycable.com at very good prices - but they would be my second choice to the Clarity SA.

I had a pair of 811's and liked their lively sound, but there is a midrange resonance and they are a bit rolled in the highs. There is a lot you can do to damp the horns themselves.. I think the actual drivers (806?) are pretty decent.

**A zobel network can be tuned to tame that resonance which iirc is right around 2kHz and makes them a bit "shouty" on some material.. My recollection of the resonant peak frequency might be a bit off, and I have the distinct memory of there also being something like a -6dB shelf (-3dB?) in the response starting around 2.5 - 3kHz. (A step network can compensate for this.) All of this is to the best of my recollection which could be quite faulty, this was measured using LMS on a pair of horns I no longer have, and unfortunately a computer crash took care of the graphs.. Just a heads up..**

I love the JBL 2402/075 alnicos (ferrite are good too - and are what I currently use) for their airy treble and great dispersion. (Fast as blazes too) but they should be crossed in >2.5kHz for most applications.
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Old 11th January 2008, 09:18 AM   #6
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Default Active Biamp

With CD compensation:
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Old 11th January 2008, 06:23 PM   #7
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Here is the breakdown on the Valencia Cabinets.

First model onward.

846 A 8-16 ohms HF 806-A LF 416-16Z XO N800-F

846 B 8 ohms HF 806 8-A LF 416 -8a XO N800-K

846 U 8 ohms HF 806 8-A LF 416-8B X0 N800-K

.................................................. ...........
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Old 11th January 2008, 06:24 PM   #8
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806A on 811B with and without CD compensation:
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Old 11th January 2008, 06:51 PM   #9
kevinkr is offline kevinkr  United States
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Quote:
Originally posted by ZilchLab
806A on 811B with and without CD compensation:
The lower curves shown match my recollections quite well.
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Old 11th January 2008, 06:58 PM   #10
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Please enlighten me! What is CD compensation?
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