Altec Diaphragm on Ebay

[voice of the theater]

Hope everyone had a Merry Christmas. I noticed this on ebay:

Altec 23744 Diaphragm * Altec Model 19 * - eBay (item 160522819265 end time Dec-30-10 22:41:38 PST)

It's one of the "lite" 23744 diaphragms used in the early Altec 802-8G and 902-8A HF drivers. I'm just wondering what the fascination is all about regarding the 23744's. Has anyone out there measured them/compared them to the 34647 that GPA currently manufactures for these H.F. drivers? Or has anyone at least done a listening test on the same driver--to find out if there's a noticeable difference between the two? It seems to me if there's almost no difference in sound between a 23744 and a 34647 then a new diaphragm would be preferred (and probably sound better?) over a 30 year old one. On the other hand, if the 23744 sounds noticeably better than a 34647 (in an 802-8G or 902-8A driver) then would it be worth hunting down/buying old original diaphragms to have on hand as spares/replacements? Just wondering what the experts out there think/what has been measured or heard as far as differences......

[Altec Best]

I have Brand New ones 23744 in 033952 (802G's) Never seen power ! I'm supposed to measure them sometime soon but evertime i turn around I'm up to my eyeballs with something else.It hasn't been a priority for me! I have to many other things that are right now!

But i have this funny feeling I will real soon as the snow is starting to fall.And they are talking about a Blizzard. After I shovel us out that is.

Sometime after the New Year I will get that done.

WRT hunting them down.No you should only hunt them down if you like the way they sound, do they sound better than the 34647 maybe,maybe not. I have grown accustomed to them so I like them.But you should know by now Audio is all about ones preferrence.Something that sounds good to someone else may sound bad to you.The 34647 may even measure better than the 23744 but still may not sound as good to you and vice versa.


BTW I don't like the way this seller took the pictures, too far away to get a good look at the leads.The weak point on any 23744.If the leads aren't at right angles ( L ) i would say go for it.But if they are pass as they will soon be toast,unless you are good at soldering them.

[GM]

They had audibly more 'snap' in 802D Vs its OEM alum. (I forget the # ATM), but quite fragile WRT power. I had no way to reliably measure any difference up high, so don't know how measurable it was. Considering both of mine failed at the VC tab to diaphragm joints (no actual tearing), I'm of the opinion that at least in my case, its main claim to fame was due to this low signal loss junction since once super glue repaired, the then lady of the house could no longer hear any difference up high between them and the OEM 802D alum..

Regardless, alum. work hardens over time, so I'd be leery of any extreme HF benefits of used units since lower down in BW they will tend to 'ring' more than originally same as my super glued ones did, requiring a bit of heavily thinned Dammar air brush 'dusted' on the domes to smooth them back out.

Anyway, now that relatively cheap digital time delay is available, XOing to some type of super tweeter system seems the best solution overall to me.

GM

[westend9]

The seller could sure use some marketing skills:" the same used in the infamous Model 19", lol. I have 802-8g's with the lighter aluminum phrams and have listened to other 802's with the newer 34647 and couldn't hear any appreciable difference. Of course, room placement, amplification choices, and other variables trump any critical comparisons.

Interesting to note GM's reference to dome treatments. I believe there is a lot to learn about these types of materials and could bring a lot of benefit to other drivers, as well. I have been mulling over cone treatment to a pair of Fostex drivers I have in back loaded horns.

FWIW, I've tried to solder broken leads on older Altec phrams and didn't have a lot of success. I used a variety of fluxes and solder but was unable to get a good bond. IIRC, these were made with a different metal than tinned copper.

[Altec Best]

FWIW, I've tried to solder broken leads on older Altec phrams and didn't have a lot of success. I used a variety of fluxes and solder but was unable to get a good bond. IIRC, these were made with a different metal than tinned copper.

Dave is the man for that "Dgwojo" I send all my broken lead diaphragms to him.He solders them with Rotanium or something like that he said.It only added .2 ohms very acceptable. :2thumbsup: He repairable couple for me !

I even had some that had right angles (leads), he strengthened them with the rotanium,added it to the leads and they are still chugging along at moderate volumes in my 19's

Does a great job !!

[RonSSS]

For the guys who want to keep their drivers original, this is the one to have. Especially if you just need one. I don't see the bidding going out of sight on this.

Are they really thinner? Do we really know? If we could measure the thickness on a dead one vs the current ones we would know. I don't recall anyone doing this.

You can't do it on good ones, they would be ruined. Unless someone had some real high tech measuring system.

Sound difference is hard to quantify. A LOT of us hear have lost the extreem HF hearing.
It's also hard to do A/B testing because it takes too long to change drivers.

I have 2 pairs of 902-8A, they have the 23744 frams. I have one pair of the 802-8G which also have these. As well as 1 pair of the oddball 806 23746 drivers that have these as well. These are all Tangerine drivers.
The only drivers I have with the GPA 34647 frams, also tangerine, are my 904-8A duplexes and they sound wonderful! So I can't tell you which sounds better.

It would be fun to put together a precise measurement setup and compare. I just don't have the good microphone to do this. I have everything else.

So I have one of these 23744 frams in front of me under the microscope. amazing to look at the leads. This is orig, and one lead looks to be cracked, but not broken. I need to take it to work and use a really good microscope and get some pictures. It's pretty fascinating. I'll grab a couple and get some photos this week, work is a bit slow.

Ron

[voice of the theater]

I have Brand New ones 23744 in 033952 (802G's) Never seen power ! I'm supposed to measure them sometime soon but evertime i turn around I'm up to my eyeballs with something else.It hasn't been a priority for me! I have to many other things that are right now!

But i have this funny feeling I will real soon as the snow is starting to fall.And they are talking about a Blizzard. After I shovel us out that is.

Sometime after the New Year I will get that done.

WRT hunting them down.No you should only hunt them down if you like the way they sound, do they sound better than the 34647 maybe,maybe not. I have grown accustomed to them so I like them.But you should know by now Audio is all about ones preferrence.Something that sounds good to someone else may sound bad to you.The 34647 may even measure better than the 23744 but still may not sound as good to you and vice versa.


BTW I don't like the way this seller took the pictures, too far away to get a good look at the leads.The weak point on any 23744.If the leads aren't at right angles ( L ) i would say go for it.But if they are pass as they will soon be toast,unless you are good at soldering them.

I'd love to see those measurements. Especially if you have any 34647's that you could also measure so we could compare the differences between the two different diaphragms when measured in the same drivers. Good point about not being able to see the leads clearly--I'd have to ask the seller for better photos if I decide to bid.....

They had audibly more 'snap' in 802D Vs its OEM alum. (I forget the # ATM), but quite fragile WRT power. I had no way to reliably measure any difference up high, so don't know how measurable it was. Considering both of mine failed at the VC tab to diaphragm joints (no actual tearing), I'm of the opinion that at least in my case, its main claim to fame was due to this low signal loss junction since once super glue repaired, the then lady of the house could no longer hear any difference up high between them and the OEM 802D alum..

Regardless, alum. work hardens over time, so I'd be leery of any extreme HF benefits of used units since lower down in BW they will tend to 'ring' more than originally same as my super glued ones did, requiring a bit of heavily thinned Dammar air brush 'dusted' on the domes to smooth them back out.

Anyway, now that relatively cheap digital time delay is available, XOing to some type of super tweeter system seems the best solution overall to me.

GM

I've heard that they're more fragile but I don't think that's much of a factor in either pair of my Model 19's since they're not in huge rooms. Even when I play them pretty "loudly", I doubt if they're even experiencing 10 watt peaks. Very interesting observation about the 23744 sound--more "snap". If they are brighter sounding than the 34647's I'd probably prefer them. That's one of the things I love about the Model 19's--they are the most "crisp/clear" (bright?) sounding (most extended bandwidth) horn loaded speakers I've ever owned (I know part of this is the crossover EQ/compensation). They have plenty of sizzle on the cymbals etc. with the stock crossovers and stock diaphragms. I would be very disappointed if I ever replaced the diaphragms and found my speakers lost some high end response. I'm old school and kind of closed minded I guess as far as three way systems go. I really like the concept of a great two way system like the 19's that get really deep powerful bass with no sub woofer added (providing of course you've got the right amplification/damping factor/EQ/room acoustics) and nice crisp highs with no need to add an additional tweeter. I guess I've been sucked into the notion that less is more--if you can have a two way system that gets all the lows, mids, and highs you need (and then some!) you have a better likelihood of having more "accurate" sound reproduction with only one crossover point to contend with......

Dave is the man for that "Dgwojo" I send all my broken lead diaphragms to him.He solders them with Rotanium or something like that he said.It only added .2 ohms very acceptable. He repairable couple for me !

I even had some that had right angles (leads), he strengthened them with the rotanium,added it to the leads and they are still chugging along at moderate volumes in my 19's

Does a great job !!

I'll have to keep him in mind if I ever need him. I have a friend who has worked at Ashly Audio for years (their headquarters is here in Rochester, NY and they make some great gear). He used to solder broken leads on diaphragms for me back in the 90's when I had a pair of original A7's hooked up to a Phase Linear 400 power amp that my band used for P.A./gigging. I was young and naive back then (still pretty naive I guess?!), and we blew diaphragms at least once a year with that set up (I think 400 watts into a pair of A7's may have been pushing it--especially when we had a substitute sound man who would cause feedback on the vocal mics--and we weren't using any kind of limiter/compressor). I still remember cringing whenever I heard feedback from a vocal mic onstage--wondering if we just blew another diaphragm (the only time we blew them was from LOUD feedback). Who knew that 400 watts of extremely high pitched feedback would blow a diaphragm? :snickerpup:

For the guys who want to keep their drivers original, this is the one to have. Especially if you just need one. I don't see the bidding going out of sight on this...... Sound difference is hard to quantify. A LOT of us hear have lost the extreem HF hearing.
It's also hard to do A/B testing because it takes too long to change drivers.

I have 2 pairs of 902-8A, they have the 23744 frams. I have one pair of the 802-8G which also have these. As well as 1 pair of the oddball 806 25746 drivers that have these as well. These are all Tangerine drivers.
The only drivers I have with the GPA 34647 frams, also tangerine, are my 904-8A duplexes and they sound wonderful! So I can't tell you which sounds better.

It would be fun to put together a precise measurement setup and compare. I just don't have the good microphone to do this. I have everything else.

So I have one of these 23744 frams in front of me under the microscope. amazing to look at the leads. This is orig, and one lead looks to be cracked, but not broken. I need to take it to work and use a really good microscope and get some pictures. It's pretty fascinating. I'll grab a couple and get some photos this week, work is a bit slow.

Ron

That would be interesting to see. I understand that a listening test is tough even if you use the same drivers in the same room etc. because of the amount of time it takes to switch diaphragms. The best way for me to do a listening test would be to do it on my main stereo system in the house (Model 19's with lite diaphragms). I've been listening to those speakers for about a year now--in the same location/same room with the same amplification/same turntable/same cd & dvd player. If I swapped diaphragms and they changed the speakers' sound, I would notice that my main system sounds different all of a sudden -- even a subtle difference would be noticeable on a recording that I've played often/numerous times recently on my system..... Of course, as some of you have mentioned, I agree that "better" sound is very subjective--but I'd at least be able to identify "brighter", more "muffled", etc...... Anyways, thanks to EVERYONE who replied, you've given me a lot to chew on.....

[GM]

Interesting to note GM's reference to dome treatments. I believe there is a lot to learn about these types of materials and could bring a lot of benefit to other drivers, as well. I have been mulling over cone treatment to a pair of Fostex drivers I have in back loaded horns.

FWIW, I've tried to solder broken leads on older Altec phrams and didn't have a lot of success. I used a variety of fluxes and solder but was unable to get a good bond.

Absolutely, especially point source drivers whether woofer or 'full-range'. Having been an airbrush artist of sorts, it's my tool of choice, but if you have the patience, Bud's nifty looking dot-dash EnABL patterns do the same thing, though I imagine the results are bit more subtle than my ~continuous and somewhat overlapping spray patterns. Of course with compression drivers, there's not much clearance to the phase plug, so very thin coatings are de riguer.

FWIW, the way I learned to do it is to apply oil to the joint so that it can be scraped/tinned without immediately oxidizing again.

GM

[GM]

I've heard that they're more fragile but I don't think that's much of a factor in either pair of my Model 19's since they're not in huge rooms.

Very interesting observation about the 23744 sound--more "snap". If they are brighter sounding than the 34647's I'd probably prefer them. That's one of the things I love about the Model 19's--they are the most "crisp/clear" (bright?) sounding (most extended bandwidth) horn loaded speakers I've ever owned (I know part of this is the crossover EQ/compensation). They have plenty of sizzle on the cymbals etc. with the stock crossovers and stock diaphragms.

That would be interesting to see. I understand that a listening test is tough even if you use the same drivers in the same room etc. because of the amount of time it takes to switch diaphragms. Anyways, thanks to EVERYONE who replied, you've given me a lot to chew on.....

You're welcome!

Probably not, but load them into 511/802D and the power requirements increase ~5x for a given wide BW peak SPL comparison referenced to the M19. Mine were already lightly imprinted with the phase plug pattern before lightning blew the VCs out.

'Snap' as in a 'faster' (rise time) sound which doesn't necessarily mean it played any higher, just a bit flatter to a higher roll off point, i.e. less CD horn EQ required which typically equates to a more highly refined ('clear') response. Really, to my ears it equated to more top end 'air' around the instruments of better recordings which normally indicates a smoother, more coherent break-up modes BW in typical cone/dome tweeters, so see no reason why it would be any different with a horn driver.

Remember, the highest frequencies of these (its 'brilliance') is just noise generated by the patterned surround, not the diaphragm proper and why for the truly discerning ear, a tiny diaphragm super tweeter horn, ribbon or electrostatic is well worth the trade-off of another XO. So few men have such keen hearing though that statistically it's zero, but we can perceive VHF tactility, or so goes the argument for having systems and source material that's flat out to at least 40 kHz for the violin and other instruments with extremely high harmonics.

Hmm, you compare one of each in a stereo pair at the same time by feeding them a mono signal. The woofers should be disconnected and of course they need to be closely level matched since we are amplitude oriented animals. Better to reverse wire one and listen for what's not there, i.e. in a perfect match there would be no sound due to complete cancellation, so listen to different BWs to see which driver dominates, if either.

GM

[voice of the theater]

....'Snap' as in a 'faster' (rise time) sound which doesn't necessarily mean it played any higher, just a bit flatter to a higher roll off point, i.e. less CD horn EQ required which typically equates to a more highly refined ('clear') response. Really, to my ears it equated to more top end 'air' around the instruments of better recordings which normally indicates a smoother, more coherent break-up modes BW in typical cone/dome tweeters, so see no reason why it would be any different with a horn driver......
GM

Hmmm. Your description pretty much sums up what I like so much about the high frequency "sound" of the Model 19's. They have a "highly refined ('clear')" high frequency response with plenty of sizzle/ "top end 'air' around the instruments of better recordings". They sound as if they are "flatter to a higher roll off point" than the 806 drivers in my old speakers. I know that a substantial amount of this is of course driver/tangerine phase plug/crossover compensation related, but the fact that you're saying part of it is also 23744 related makes me ask the obvious (?) question.

GPA currently manufactures a variety of replacement diaphragms for Altec drivers. Why no 23744? From the amount of fascination/discussion about the 23744 on this forum--I've seen it mentioned here many times--I would think it would be one of Bill's hottest sellers. Particularly if it is even a minor ingredient to the ORIGINAL Model 19 sound (not to mention some of the vintage Altecs that came with a 902 driver for example the highly regarded 9842-8D Monitors or the Model 14's that also used the 23744). I mean, the Model 19 was Altec's flagship/top of the line speaker for many years--and still seems to be one of their more popular/sought after/highly regarded vintage speakers today. I may be way off but I would think they'd sell a lot of these compared to some of the other diaphragms they offer--or worst case scenario they'd at least sell a similar amount of them compared to some of their other diaphragms. I can only guess at why they don't make this diaphragm--perhaps someone can chime in with an answer to this question that I'm sure many of us have wondered about at one time or another.

Is it because: 1) They are a fragile diaphragm and GPA is convinced that it's not worth getting a little more sizzle out of a diaphragm (compared to the 34647) if the trade off is that it's more fragile? I guess if that's their reason, I understand it but I would say most Model 19 owners aren't playing their speakers so loudly that they'll likely blow many of these. Especially considering the fact that in the 811B horn/Model 19 application they only have to withstand about 1/5 of the "punishment" that they'd receive in some 511 applications.....

You're welcome!

......load them into 511/802D and the power requirements increase ~5x for a given wide BW peak SPL comparison referenced to the M19.......
GM

Or is it because 2) It is a difficult/expensive diaphragm to manufacture -- more difficult or expensive to produce than a 34647 for example?

Or is it because 3) The 23744 was discontinued a LONG time ago by Altec and the plans/manufacturing specifications/tooling/"blueprints" (?!) and or knowledge required to build them was lost over time (maybe when Mt. Vesuvius erupted?)?

Or is it because 4) The 23744. in certain audiophile applications, has been found to open a wormhole to a parallel universe and GPA is just trying to protect us all from ourselves?

If anyone knows or has an educated guess as to why the 23744 has been left out of GPA's "lineup", your input here would be appreciated. Please don't take this question as a slam on GPA. Quite the contrary, if they weren't around today I would be hesitant to keep buying vintage Altecs. The only reason I was confident buying a used pair of all original A7's back in the 90's for example, was because I knew Altec Pro was around to sell replacement diaphragms, recone kits, etc. The only reason I've bought four pair of vintage Altecs in the last two years is that I know that GPA is there with replacement diaphragms, recone kits etc. and I've been 1000% satisfied with the parts/service I've received from them to date. As I've said before, it's hard to beat a company made up of former Altec employees, manufacturing replacement parts/doing repairs for Vintage Altec speakers/drivers/etc. using Altec's original tooling and specifications...... They are, to coin a cliche, "keeping the flame alive". So, no disrespect or slam intended with this question. I'd just love to see the 23744's come back and I'd love to see Bill driving a brand new Rolls Royce lighting his cigars with $1,000 bills from all the revenue my question (suggestion/request) generates......