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.
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.
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.
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
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
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.
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.
The rolloff of high frequencies above ~3.5 kHz is characteristic of compression drivers, so characteristic, in fact, that most pro active crossovers and some pro amps have compensation circuitry built into them which may be engaged for the high frequencies when used with compression drivers on horns that require it.revintage said:
In the case of the Behringer CX3400 used for those measurements, you push the "CD Horn" button to, in effect, "boost" the highs and flatten the response.
It's clear from those curves that it would require ~20 dB of compensation to make Altec 806As on 811B horns play flat to 20 kHz, which is simply not practical. However, the high frequency response typical of early Altecs can certainly be extended using this approach.
Similar may be accomplished passively, as Altec did in Model 19 and other subsequent designs. In fact, there is some (insufficient) compensation built into the simple 2-pole N800-F and N800-8K crossovers used in Valencia and other similar Altec two-ways. They are NOT textbook crossovers. The series crossovers such as N1500-A (604E) incorporate CD compensation, as well....
To be fair, 806A running on the N800-F is a bit better; you can see the built-in compensation in operation in the measurements below.kevinkr said:
My point is, unless you prefer rolled-off highs and no extended bass, there seems little benefit to accrue from swapping caps and/or amps with these systems until their more fundamental deficiencies are recognized and addressed....
Attachments
I think if someone is looking for flat frequency response for 20hz to 20khz they wouldn't start with a speaker that is older than they are. If that is what you seek I don't see why you wouldn't simply stick to a more standard formula modern speaker. There are plenty of sonic standouts at all price points that you could pursue instead of putting down a product that simply has a different set of priorities than you have. Many (if not most vintage) products are bought by people who simply value different things in the reproduction of recorded music. I think rhythmic drive, mid range purity, micro and macro dynamics, cohesiveness and ultimately humanity are what most vintage speaker enthusiasts seek. My home theatre is flat from 15hz to 20knz but I can't stand listening to it with music. It has no life. It is the little imperfections that make things interesting. There is even evolutionary biology that confirms this. There are studies that show that people are more attracted to other people that have a few minor facial imperfections than those who are "perfect". I choose real and therefore often "flawed" products over perfect but unrealistic products all the time. My residence is a 115 year old church, I have solid wood doors because hollow core or MDF makes me cringe, my saxophone is a vintage 80 year old alto, I even make my own ketchup to have something that has more personality than Heinz. While I welcome and respect all opinions I will respectfully disagree with the last series of posts and say that the imperfections of the speaker are part of what makes it worth pursuing not the ultimate quest for perfection.
It should be noted that although the Heathkits are based on the Valencia there are a number of differences as well. It seems that the venting arrangement is different (I read this on another forums but have not yet had a chance to confirm).
The crossover is also different than the stock Valencia. I don't have the schematic in electronic form so bare with me as I describe it. The 806 is crossover with a 1.75mH inductor and a 8uF cap. There is also an LPad to adjust its level relative to the woofer. The woofer is crossed over using another 1.75mH inductor and a pair of caps that total 21uF connected in parallel. According to the schematic/manual that I have the design goal is a crossover that functions at 800hz. I would say that the crossover is pretty textbook and in general very simple as opposed to something with a lot of compensation in it.
The crossover is also different than the stock Valencia. I don't have the schematic in electronic form so bare with me as I describe it. The 806 is crossover with a 1.75mH inductor and a 8uF cap. There is also an LPad to adjust its level relative to the woofer. The woofer is crossed over using another 1.75mH inductor and a pair of caps that total 21uF connected in parallel. According to the schematic/manual that I have the design goal is a crossover that functions at 800hz. I would say that the crossover is pretty textbook and in general very simple as opposed to something with a lot of compensation in it.
http://audioheritage.org/vbulletin/showthread.php?p=160631&#post160631
Double the Cs and halve the Ls for your 8-Ohm version, N800-8K.
Then ask yourself why the C in the highpass is 8 uF.
Double the Cs and halve the Ls for your 8-Ohm version, N800-8K.
Then ask yourself why the C in the highpass is 8 uF.
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Dynamics
You can add a step network as well, but you run out of headroom with 806As pretty quickly, since they begin with a 3 dB deficit in comparison to the larger-magnet Altec drivers.
I suspect what we most like about them derives from compression driver technology, which has itself moved well ahead since these early implementations. For home use, it almost has to be DIY; there's not much in the way of complete product available but at prohibitive cost.
In my experience, more performance can be squeezed out of 806As in Valencia and similar, but what I've shown above actively biamped with CD compensation is about the limit. To get beyond that, it's driver swap or augmentation.
With respect to compensation, I try to stay within what Altec themselves determined was acceptable for use with their drivers, as is evidenced in their own subsequent design upgrades, e.g., tangerine phase-plug drivers and Model 19 compensation would be a rational upgrade path for Valencias within the Altec lineage. Run the box models and look to Model 19 for woofer upgrade, as well....
You can add a step network as well, but you run out of headroom with 806As pretty quickly, since they begin with a 3 dB deficit in comparison to the larger-magnet Altec drivers.
I suspect what we most like about them derives from compression driver technology, which has itself moved well ahead since these early implementations. For home use, it almost has to be DIY; there's not much in the way of complete product available but at prohibitive cost.
In my experience, more performance can be squeezed out of 806As in Valencia and similar, but what I've shown above actively biamped with CD compensation is about the limit. To get beyond that, it's driver swap or augmentation.
With respect to compensation, I try to stay within what Altec themselves determined was acceptable for use with their drivers, as is evidenced in their own subsequent design upgrades, e.g., tangerine phase-plug drivers and Model 19 compensation would be a rational upgrade path for Valencias within the Altec lineage. Run the box models and look to Model 19 for woofer upgrade, as well....
Hi, Don,
Looking at it now, since the VHF is virtually superimposed, there was no attenuation.
Other than as attributable to impedance anomalies introduced by the N800-F attenuation potentiometer, or the L-pad used in its stead in N800-8K, the compensation established by the filter elements may be viewed as constant.
Some minor variabilities in frequency response may be seen in the curve families generated at various attenuation settings using the actual crossovers.
I never figured that out, in detail, but it did ultimately prompt me to conduct an investigation of just how fixed the reflected impedance of typical L-pads actually is. Even using fixed resistors as load, they rather suck....
Looking at it now, since the VHF is virtually superimposed, there was no attenuation.
Other than as attributable to impedance anomalies introduced by the N800-F attenuation potentiometer, or the L-pad used in its stead in N800-8K, the compensation established by the filter elements may be viewed as constant.
Some minor variabilities in frequency response may be seen in the curve families generated at various attenuation settings using the actual crossovers.
I never figured that out, in detail, but it did ultimately prompt me to conduct an investigation of just how fixed the reflected impedance of typical L-pads actually is. Even using fixed resistors as load, they rather suck....
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