Altec Crossovers

Hello--I joined this forum a few days ago and I'm already very impressed with the expertise shown here regarding classic "vintage" altecs. I would really appreciate any advice I can get here as it's not easy finding people who know about these older speakers. I have two pair of Altecs that are about 40 years old and I've heard that the caps in the crossovers should always be replaced in speakers that old. My Altec Valencias are from 1969 (for my basement stereo) and I just bought a pair of 1971 Heathkit/Altec AS-101 (same drivers as the Valencias/voice of the theater) from my local craigslist (for my living room stereo). http://www.hostboard.com/forums/hbmc...2009/02/13.jpg (left to right Altec Valencia with Altec model 9 on top, heathkit/Altec AS-101) Anyways, the Valencias and AS-101s both have all the original drivers in mint condition and even the original diaphragms. http://www.hostboard.com/forums/hbmc...2009/02/14.jpg http://www.hostboard.com/forums/hbmc...2009/02/16.jpg I have noticed that the 806A horn in one of the AS-101s is not quite as bright as the other and that motivated me to open the cabinets and look at the caps. There are 3 caps per speaker and a couple of them look like they may have leaked oil at one time--could that be the reason why one of the horns isn't quite as bright as the other?http://www.hostboard.com/forums/hbmc...2009/02/10.jpg I've been looking to find replacement caps--GPA recommended I use Solen Fast Caps. I went to the Parts Express website and checked the ratings on all their different brands of caps and the closest I've found are Solen Fast Caps. The originals are rated 8 uf 50vdc, 10 uf 50 vdc, and 11 uf 50vdc. All the caps I've seen at parts express are at least 400 vdc but I've heard that the extra vdc just gives you more headroom and won't hurt the sound--what I really need to match up is the uf rating--does anyone know if that's true? The solen has an 8.2 uf cap which I'm assuming is close enought to the original 8, they have a 10 uf cap which matches the original 10, but they don't make an 11 to match the original 11--they have a 12 uf. Is that close enough considering the solens are +/- 5% and the original caps are rated +/- 10%? Also, the "copper" in these crossovers doesn't look so great. http://www.hostboard.com/forums/hbmc...2009/02/15.jpg Is that anything to worry about or should I replace the caps first and see how they sound before worrying about the "copper".... Lastly, my Valencias have a sealed crossover box which is riveted shut! http://www.hostboard.com/forums/hbmc...2009/02/17.jpg They sound identical to each other but they are from 1969 and I can't help wondering how much better they'd sound with brand new caps. Has anyone out there ever pried open one of these Valencia (type) crossover boxes which are riveted shut? Any advice on how to do this safely? If I ruin my Valencias I'll have to put myself in the doghouse!
P.S. I also have a pair of P.A. Voice of the Theater A7 speakers (in the huge cabinets) that I use for PA for my (rock) band and I'm considering replacing the caps in those crossovers as well--has anyone out there ever opened up the crossover box for an Altec N501-8A crossover before? The speakers/horns sound identical to each other but like my Valencias, I'm wondering how much better they'd sound with new caps......The description of the Solen Fast Caps on the Parts Express website makes them sound like the best thing since sliced bread! "The exceptional Solen line of metallized polypropylene capacitors features a high purity, polypropylene film dielectric. They exhibit outstanding high frequency characteristics, low dielectric absorption factor, high current capacity, and unrivalled handling of fast high current pulses. Designed specifically for use in loudspeaker crossover networks. All values are rated at 400 VDC, except for the 130uF, 160uF, and 200uF values which are rated at 250 VDC. 5% tolerance. "

Thanks for any help on these questions that anyone out there can give me.....
Dave

I was wondering what a model 19 crossover network would sound like in a Valencia cabinet.
Since we are dealing with same components and approximately same size cabinets.

It would be worth while to get in touch with Iconic and inquire.

This change could make a substantial improvement in the sound of your cabinets.


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I know the valencias and the Model 19s both use the 416 woofer and 811 horn, but don't the Model 19's use a different high frequency driver (a tangerine/radial phase plug driver?)? Would it be a appropriate to use the model 19 crossover on the Valencias anyways?

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Originally Posted by voice of the theater

Hello--I joined this forum a few days ago.........

..........a couple of them look like they may have leaked oil at one time--could that be the reason why one of the horns isn't quite as bright as the other?

..........what I really need to match up is the uf rating--does anyone know if that's true?

The solen has an 8.2 uf cap..........Is that close enough considering the solens are +/- 5% and the original caps are rated +/- 10%?

Also, the "copper" in these crossovers doesn't look so great.

Has anyone out there ever pried open one of these Valencia (type) crossover boxes which are riveted shut? Any advice on how to do this safely?

...........has anyone out there ever opened up the crossover box for an Altec N501-8A crossover before?

The speakers/horns sound identical to each other but like my Valencias, I'm wondering how much better they'd sound with new caps......

The description of the Solen Fast Caps on the Parts Express website makes them sound like the best thing since sliced bread!

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Welcome!

Yes.

Correct.

Depends on whether all the tolerances 'stack up' to cause a significant shift Vs the OEM units, but usually it's not an issue except with the self-proclaimed 'audiophile' that can apparently hear differences normally only attributed to Bats or similarly hearing dominated species.

In a potted XO, only the caps tend to need replacing, but if you scratch off a small section along any wire's exposed length and find any corrosion, then all of it should be replaced IMO.

Haven't dis-a-s-s-embled a Valencia XO, but I've 'melted' others using a commercial electric hand held heater/blower, though these require a 20 amp dedicated outlet, so not an option without some extra wiring in a typical home/garage. Easy to ruin components with it too.

Yes.

Only one way to know for sure.......

FWIW, I prefer PIO and there's some measured proof as to why along with lots of good info on other types in your 'Dayton' thread.

GM

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Originally Posted by voice of the theater

I know the valencias and the Model 19s both use the 416 woofer and 811 horn, but don't the Model 19's use a different high frequency driver (a tangerine/radial phase plug driver?)? Would it be a appropriate to use the model 19 crossover on the Valencias anyways?

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Yes, though you may need to use a a higher value HF by-p-a-s-s cap if you want to get closer to the M19's extreme HF response. Best to upgrade to at least the 802-8G though if you don't mind losing the Valencia's vintage 'sound'. Note too that if driving them with a high output impedance that using a more extended HF driver may cause it to be too 'bright'.

GM

Just installed the Dayton 1% caps in the Heathkit/Altec AS 101s. Between bypasing the old L Pads and installing these new caps these speakers sound amazing--crystal clear with noticably improved stereo imaging! They are officially my "first string" speakers for my "main" stereo and the Valencias have been demoted to my second stereo... I'll have to do some homework since the Valencias have the same drivers as the AS 101s. I need to figure out what to do as far as their crossover to get them to sound as good as the AS 101s.... Thanks to everyone for their help on this!!!! Still open to suggestions on the Valencias.... Not sure if I would know how to modify a model 19 crossover for these horns.... I've read that crossover capacitors have a break in period of 10-100 hours before they sound good. These Daytons sounded great from the second I powered them up today--is the sound likely to change in the next 10-100 hours? I've been told that replacing the crossover in the Valencias is a better option than trying to modify the existing crossover or replace the caps because the aluminum box that holds the Altec N801 crossover is full of a black asphalt type material. I've read horror stories online of people breaking open the aluminum box and accidentally destroying the crossover. Still open to suggestions on the Valencias.... Maybe I should try to replicate the Heathkit AS 101 crossover for the Valencias--I've read that it's a better crossover than the Altec N801 crossover (and the AS-101s I own would tend to verify that since they sound noticably better than the valencias with the same Altec drivers other than the impedence). I'm wondering that since the drivers in the AS101s are 8 ohms and the drivers in the Valencias are 16 ohms--would the AS 101 crossover work in the Valencias or would it have to be modified?

If an electronic component noticably varies over its normal lifetime it is probably of poor design or manufacture or defective. Either that or you are experiencing the normal human trait of adjusting to a new situation, i.e., it is you that is 'burning-in'.

No doubt others will disagree with my view. So be it. I am an electrical engineer and I have still not seen any valid proof regarding burning-in claims, only technobabble and the sort of talk that people who believe in the healing power of pyramids might use.

Cheers, Marshall.:Can't belive it:

And just in case......

Hi-Fi - Bad Science

Again, Marshall.:eek:

Capacitor replacement:-

When a capacitor is replaced a difference in sound may be noticed. This can lead to an ***umption that the replacement item is superior to the one replaced. This may well be the case but not because the new capacitor is intrinsically better. It is likely with vintage gear that some capacitors are past their effective use by date. Time is a consideration amongst other impinging possibilities. The difference heard after replacement may only be due to the new 'on-spec' component vs the tired old one.

This link gives some idea of what can degrade a capacitor -

Reliability

Yikes! "break in" in audio.

This seems to be one of the more hotly and emotionally charged debates in audio, second only to the speaker wire/power cord debate, it also seems to suffer from a serious lack of scientific basis or analysis.

I agree with Marshall.............. completely.

When somebody finally shows me a measurable change that occurs in a new cap after a "break in" period, then i'll be a firm believer.

I'm a firm believer that "if it can be heard, it can be measured".

However, i also give merit to the idea that for a majority of folks "if you believe it, you will probably hear it". I think it's a caveat of being human.

I challenge the believers to "show me".

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Maybe I should try to replicate the Heathkit AS 101 crossover for the Valencias-

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All of the component values would need to be changed to accommodate the Valencia's 16 ohm components. At the end of the day the Valencia's are probably still not going to sound the "same" as the AS-101's on any given power source. That is not to say you wouldn't be making an improvement, rather that depending on your amplifier there still may be a significant difference in sound between the Valencia and AS-101.

There are others here who can explain the relationship between speaker impedance and amplifier output impedance far better than i can.

Thanks for all the help on this everyone! I was really impressed with the improvement in the sound of the Heathkit/Altec AS 101s after byp***ing the 38 year old L Pads (since I was keeping the L pads turned all the way up anyways) and after replacing the old original leaky caps with Dayton 1% precision caps. I don't need the Valencias to sound exactly like the AS 101s current sound and I guess it's not realistic to expect that anyways even though they have the same drivers, they do have different impedance. I guess what I'm looking to do is a similar upgrade in sound for the Valencias--ideally I'd like to replace the caps and byp*** the old treble tone control pot on the back of the speaker but I'm told those aluminum cans (that are riveted shut) that hold the Valencia crossovers are filled with an asphalt-like material and that it's virtually impossible to break open the cans and get to the components inside without destroying them. So, now I'm wondering do I buy new crossovers, or maybe replicate the crossovers in the AS 101s (which is said to be superior to the Valencia crossover) but make adjustments so they'll work with 16 ohm drivers......

It's been a while since i messed with one of these "canned" crossovers, but if you're feeling adventurous i'll bet taking it apart without damage is well within your ability. You could then just do a basic re-capping like you did with the 846A's. I think you'll also find a big ceramic resistor in there that's part of the attenuator circuit, maybe replace that with a higher quality wirewound version.

There are a couple methods, but i think baking them in a ~150degree oven to melt the goo and then pour it off is probably the best method. I think we have/had at least a couple members here who have been very successful with this.

I've also heard of fellas freezing them and carefully chipping the stuff away, though i feel this method presents more potential for damage.

Another option would be to watch ebay for another reasonably priced pair of stock 846A Valencia crossovers, recap those and leave your originals in tact. To open them requires drilling out 2 or 4 rivets if memory serves, this will render them "tampered with" to the strictest purists. Doesn't offend me in the least, but it means much more to others.

Just some food for thought.

Quote:

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Originally Posted by voice of the theater

Thanks for all the help on this everyone! I was really impressed with the improvement in the sound of the Heathkit/Altec AS 101s after byp***ing the 38 year old L Pads (since I was keeping the L pads turned all the way up anyways) and after replacing the old original leaky caps with Dayton 1% precision caps. I don't need the Valencias to sound exactly like the AS 101s current sound and I guess it's not realistic to expect that anyways even though they have the same drivers, they do have different impedance. I guess what I'm looking to do is a similar upgrade in sound for the Valencias--ideally I'd like to replace the caps and byp*** the old treble tone control pot on the back of the speaker but I'm told those aluminum cans (that are riveted shut) that hold the Valencia crossovers are filled with an asphalt-like material and that it's virtually impossible to break open the cans and get to the components inside without destroying them. So, now I'm wondering do I buy new crossovers, or maybe replicate the crossovers in the AS 101s (which is said to be superior to the Valencia crossover) but make adjustments so they'll work with 16 ohm drivers......

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If it was me and my thrifty ways, I'd build new crossovers to replace the old Valencia's potted networks. I would then compare the new vs. old. If the new ones sound better and I had made the decision to keep the Valencias to my demise, I'd sell the originals to recover costs and show a meager profit. Alternately, keep the originals to promote a sale to the Altec purist, should I decide to sell the Valencia's.