captaingamez
Well-Known Member
What happened to jay? anyone else seen the blown pair on eBay?
walsh tweeter design/rebuild
- Thread starter loquatious
- Start date
I'm still here-
First, to answer Loq's questions
1-Frankly, I don't remember what brand the foil was. We bought it at the supermarket, and I haven't seen it for years. What was important were the striations in the material.
2- In early experiments, clear silicone grease was used between the foil and the plastic. It served as both an adhesive and to decouple the foil from the plastic. It was messy, difficult to apply, expensive, and it it got into the area where you were trying to glue the cone together, the glue wouldn't hold. Later, when more were being built, we switched to the 3M spray. Also, the glue used to hold the seam of the cone started with epoxy, then graduated to a very thin liquid styrene cement sold at hobby stores to weld plastic models together, and probably ended up just being the spray adhesive.
3- Yes, the Seas 1.5" dome illustrated is the device I remember using. It was very robust, and was able to work down to 1.5 KHz. Remember, the original intended crossover frequency was 2-2.5 KHz, not 10 K. It had the disadvantage of being rather expensive, at about 10 1970's dollars when Infinity was using Peerless paper cone tweeters that cost 2 bucks apiece. Granted, they were also using RTR electrostatic cells (also expensive) in their better models, but they were a crap shoot- very high failure rate, and they were implemented poorly. (the Infinity 2000 had them mounted to the side if the speaker at the front of what amounted to a "tunnel" which severely compromised the response of the cells.
The point being is that the first thing that probably happened was a much less expensive dome driver was substituted and the crossover frequency was moved up to keep them from frying at high levels.
From here, I really can't add too much regarding the history or what happened at Infinity. Shortly after I was involved in the prototype build, I got a job at a recording studio, and a year or so later went into the showrooms in Vegas where worked as an audio guy for a number of years. I never really thought much about the tweeter after that until recently when I became interested in the Walsh driver again. (the German Physik speakers look like one hell of an entertaining DIY project)
The thread I started in DIY was to see if anyone was doing anything in this area- not much interest. I then queried about the Walsh tweeter, and got a few hits, then that petered out.
In a couple of PM's with Loquatious, it has been suggested that most of your are Infinity affectionados who are trying to restore your speakers to their original glory. I can't help anyone here, because I have no idea what Infinity did later on.
Loquatious has suggested that I start a new thread concerning building the things, something I am really not inclined to do.
I will, however put together a little article showing how I built them- in fact, once I get settled from a recent move, I'll see about building a pair so you can see the step-by-step. This will take me a couple of months- I am currently building a power amp from scratch, and I have to locate the parts I have that are buried in the wasteland of my storage unit for both projects.
It's my hope that those of you trying to restore your speakers exercise caution when trying to locate drivers on fleabay. If they are claimed to be original, they may be damaged, and the dampening materials as well as the foam will undoubtedly be dried out.
From some of the photos I've seen here, don't let your enthusiasm cloud your judgement. I've sure done it myself. If you do get hosed, hold that seller accountable- Pay-Pal has a buyer protection plan in place- use it. Ebay has feedback and resolution methods in place- use them.
L8tr,
J
First, to answer Loq's questions
1-Frankly, I don't remember what brand the foil was. We bought it at the supermarket, and I haven't seen it for years. What was important were the striations in the material.
2- In early experiments, clear silicone grease was used between the foil and the plastic. It served as both an adhesive and to decouple the foil from the plastic. It was messy, difficult to apply, expensive, and it it got into the area where you were trying to glue the cone together, the glue wouldn't hold. Later, when more were being built, we switched to the 3M spray. Also, the glue used to hold the seam of the cone started with epoxy, then graduated to a very thin liquid styrene cement sold at hobby stores to weld plastic models together, and probably ended up just being the spray adhesive.
3- Yes, the Seas 1.5" dome illustrated is the device I remember using. It was very robust, and was able to work down to 1.5 KHz. Remember, the original intended crossover frequency was 2-2.5 KHz, not 10 K. It had the disadvantage of being rather expensive, at about 10 1970's dollars when Infinity was using Peerless paper cone tweeters that cost 2 bucks apiece. Granted, they were also using RTR electrostatic cells (also expensive) in their better models, but they were a crap shoot- very high failure rate, and they were implemented poorly. (the Infinity 2000 had them mounted to the side if the speaker at the front of what amounted to a "tunnel" which severely compromised the response of the cells.
The point being is that the first thing that probably happened was a much less expensive dome driver was substituted and the crossover frequency was moved up to keep them from frying at high levels.
From here, I really can't add too much regarding the history or what happened at Infinity. Shortly after I was involved in the prototype build, I got a job at a recording studio, and a year or so later went into the showrooms in Vegas where worked as an audio guy for a number of years. I never really thought much about the tweeter after that until recently when I became interested in the Walsh driver again. (the German Physik speakers look like one hell of an entertaining DIY project)
The thread I started in DIY was to see if anyone was doing anything in this area- not much interest. I then queried about the Walsh tweeter, and got a few hits, then that petered out.
In a couple of PM's with Loquatious, it has been suggested that most of your are Infinity affectionados who are trying to restore your speakers to their original glory. I can't help anyone here, because I have no idea what Infinity did later on.
Loquatious has suggested that I start a new thread concerning building the things, something I am really not inclined to do.
I will, however put together a little article showing how I built them- in fact, once I get settled from a recent move, I'll see about building a pair so you can see the step-by-step. This will take me a couple of months- I am currently building a power amp from scratch, and I have to locate the parts I have that are buried in the wasteland of my storage unit for both projects.
It's my hope that those of you trying to restore your speakers exercise caution when trying to locate drivers on fleabay. If they are claimed to be original, they may be damaged, and the dampening materials as well as the foam will undoubtedly be dried out.
From some of the photos I've seen here, don't let your enthusiasm cloud your judgement. I've sure done it myself. If you do get hosed, hold that seller accountable- Pay-Pal has a buyer protection plan in place- use it. Ebay has feedback and resolution methods in place- use them.
L8tr,
J
captaingamez
Well-Known Member
I'm interested in both the design of new DIY walshes, as well as repair of our originals.
Dale Harder
New Member
Walsh style TLS-4 Tweeter/Midrange and other TLS products
Gentlemen,
Please forgive the intrusion, but this is a very intersting thread and I do try to keep up on the Walsh style or bending wave drivers.
Hello Jay, nice to see you here.
It appears that all of you have considerable interest in the old infinity tweeters and the old Ohm Walsh designs.
We here at HHR Exotic Speakers have taken the guess work out of all of this technology and are doing everything possible to bring the Walsh "style" technology back to life. Our new designs are light years beyond the originals offerings.
One of the recent products I have released new for this year is the Walsh style TLS-4 Tweeter/Midrange unit for "DIY" speaker work. This driver is currently on ebay and sell in matched pairs.
These little wonders are only 6" in diameter and 6.5" tall. they require no box or cabinet of any kind, but rigid mounting is best. The drivers have an effective range from 200 Hz to 22 KHz+, with a 90 db efficeincy.
I admit, they are a little pricey, but they did take 4 years to develope and are patent pending. They are available from us directly a little less expensive than the ebay offerings.
You may also find our other Line of TLS products interesting. Full size drivers based on the Walsh principal, including the TLS-1, 2, 4 and 5. The 5 is a hybrid tower made with two, true walsh style drivers.
Our website, www.hhrexoticspeakers.com is currently being upgraded by our IT team and will show the new TLS-4 and 5 models soon. You may contact me directly by email at dale@hhr-exoticspeakers.com if you wish.
I do hope this information is of some value to you.
Good listening to all,
Dale Harder
Gentlemen,
Please forgive the intrusion, but this is a very intersting thread and I do try to keep up on the Walsh style or bending wave drivers.
Hello Jay, nice to see you here.
It appears that all of you have considerable interest in the old infinity tweeters and the old Ohm Walsh designs.
We here at HHR Exotic Speakers have taken the guess work out of all of this technology and are doing everything possible to bring the Walsh "style" technology back to life. Our new designs are light years beyond the originals offerings.
One of the recent products I have released new for this year is the Walsh style TLS-4 Tweeter/Midrange unit for "DIY" speaker work. This driver is currently on ebay and sell in matched pairs.
These little wonders are only 6" in diameter and 6.5" tall. they require no box or cabinet of any kind, but rigid mounting is best. The drivers have an effective range from 200 Hz to 22 KHz+, with a 90 db efficeincy.
I admit, they are a little pricey, but they did take 4 years to develope and are patent pending. They are available from us directly a little less expensive than the ebay offerings.
You may also find our other Line of TLS products interesting. Full size drivers based on the Walsh principal, including the TLS-1, 2, 4 and 5. The 5 is a hybrid tower made with two, true walsh style drivers.
Our website, www.hhrexoticspeakers.com is currently being upgraded by our IT team and will show the new TLS-4 and 5 models soon. You may contact me directly by email at dale@hhr-exoticspeakers.com if you wish.
I do hope this information is of some value to you.
Good listening to all,
Dale Harder
loquatious
village elder
spied this on the 'bay. sure don't see one of these come up very often. gentlemen, :ntwrthy: a NOS infinity walsh replacement tweeter, in the original box, with paperwork.
thought i'd post the pics for reference purposes.
no affiliation with the auction.
.
thought i'd post the pics for reference purposes.
no affiliation with the auction.
.
Attachments
Coastsider
Curmudgeon
Wow.
I'd call that a deal but would still want it checked with an ohmmeter. I'm out in any event.
I'd call that a deal but would still want it checked with an ohmmeter. I'm out in any event.
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loquatious
village elder
the base does appear to be contradistinctive, and that's a different embossing pattern than i've seen before.
i'm assuming that this replacement unit was of very late production, based on the late 1991 date on the paperwork. interesting to think these were still on the shelf in sept. '91. makes me wonder if there are more buried in a warehouse somewhere...
kind of surprised at the packaging. looks a bit questionable. based on the photos i've seen of units damaged in shipping, i'd think infinity would have used more robust packaging.
.
The striations are different in the foil, but they are there. Clearly an important attribute.
Also, it appears that there is an added baseplate- the original driver seems to have 3 mounting holes and was glued to a metal stamping having 4 holes.
This suggests to me that they were using various dome tweeters, probably based on price or availability- surplus or maybe distressed inventory? This would ease production costs if the cut-out for the tweeter on the top of the enclosure was cut using CNC routers.
It also suggests that the actual dome driver make may not be at all critical- it was merely a motor platform for the cone. This make life a lot easier for those who may wish to try building their own -
Also, it appears that there is an added baseplate- the original driver seems to have 3 mounting holes and was glued to a metal stamping having 4 holes.
This suggests to me that they were using various dome tweeters, probably based on price or availability- surplus or maybe distressed inventory? This would ease production costs if the cut-out for the tweeter on the top of the enclosure was cut using CNC routers.
It also suggests that the actual dome driver make may not be at all critical- it was merely a motor platform for the cone. This make life a lot easier for those who may wish to try building their own -
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captaingamez
Well-Known Member
wawa weewa!!!!!!!!!!!!!!. i want it.
so i was talking to a guy who used to own a local speaker repair shop back in the 90s, who now works at arizona hifi about the walsh tweeters. he told me that those exact replacements were all looking at on ebay, he found them to be not working correctly from the factory a few times and had to rebuild them himself. unfortunately he couldnt remember anything about their assembly or anything, also considering the packaging, the things he had to repair could have been damaged in shipping maybe??? i dont know, interesting though.
im listening to my walshes right now, on the WTLCs. they are really amazing tweeters and a great set of speakers they put them on. i have never heard monitors or anything else with the walshes other than mine and my AXTs.
so i was talking to a guy who used to own a local speaker repair shop back in the 90s, who now works at arizona hifi about the walsh tweeters. he told me that those exact replacements were all looking at on ebay, he found them to be not working correctly from the factory a few times and had to rebuild them himself. unfortunately he couldnt remember anything about their assembly or anything, also considering the packaging, the things he had to repair could have been damaged in shipping maybe??? i dont know, interesting though.
im listening to my walshes right now, on the WTLCs. they are really amazing tweeters and a great set of speakers they put them on. i have never heard monitors or anything else with the walshes other than mine and my AXTs.
loquatious
village elder
i contacted the seller of the NOS walsh tweeter and asked some questions. i was curious as to what info the invoice might yield. he wouldn't disclose the original price paid, but did tell me the invoice showed a part number of 902-0060, which is what would be expected. however, he said the actual tweeter had a part number of 902-0033 (and under that: 383TND) printed on the magnet. this is a new number to me. all documentation for the walsh equipped infinitys (all models) that i have found lists 902-0060 as the sole part number for the walsh tweeter.
meanwhile… more walsh tweeters have turned up adrift on the 'bay. the first 3 pics are from the auction.
again, i post only for documentation purposes, and have no connection with the sale.
these are the "exoskeleton" type with silver, diamond-embossed cones, and are from a pair of first generation infinity monitors that are being parted out. seller said they are fully functional and "sound great" (he said he originally bought the monitors because the tweeters sounded so amazing). these tweeters are interesting in that they appear to have been successfully repaired by a previous owner. the foam has obviously been redone, but even more interesting, you can see clues that a continuity issue has been addressed and that the driver motors have been replaced. the seller said the magnets are stamped "philips, made in belgium, AD 0162 28" and no infinity part number is present.
a little research showed the number he had given was not a correct philips part number (the seller said it was hard to read the printing on the magnet), and the correct number was actually AD 0162 T8. the AD 0162 T8 is an 8 ohm dome tweeter dating from 1975. the following is translated from a dutch site:
"This high-power dome tweeter with very high sensitivity (92 dB) has a 1-inch voice coil diameter. The allowable system power is 50 watts with a cross-over of 2 kHz. the dome is made of yellow polycarbonate, a short horn with diffuser built-in. frequency response to 22kHz."
the last 2 pics are of an unmodified AD 0162 T8. i find this was a tweeter used on early DCM time window speakers, and other mid 70s offerings.
it certainly appears someone successfully grafted the cones and mounting plates from original infinity walsh tweeters to a different drive motor. this does seem to indicate the drive motor is not as critical as might be thought.
it is also looking to me like the cone embossing is not critical either. judging from the great differences between the diamond tufted, diagonal striation, and hexagonal embossing types, it suggests the texture to be for simply adding extra stiffness to the cone, and may not be related to wave propagation at all. in studying photos of numerous functioning and gutted tweeters, i'm also not seeing any evidence that there is more than one layer in the construction of production cones, and cone material thickness seems to vary as well between versions.
all in all, the infinity walsh tweeter seems to go completely against everything i've read about the ohm walsh driver design, in which every element is said to be hyper-critical and can not be altered without severly compromising the function of the driver. the infinity walsh seems very forgiving in terms of altering the foam, drive motor, cone, support structure, etc. regardless of repairs made, or design variations, owners always say how great the tweeters sound. could it be that only functioning as a super tweeter, makes it more forgiving to construction variables?
.
meanwhile… more walsh tweeters have turned up adrift on the 'bay. the first 3 pics are from the auction.
again, i post only for documentation purposes, and have no connection with the sale.
these are the "exoskeleton" type with silver, diamond-embossed cones, and are from a pair of first generation infinity monitors that are being parted out. seller said they are fully functional and "sound great" (he said he originally bought the monitors because the tweeters sounded so amazing). these tweeters are interesting in that they appear to have been successfully repaired by a previous owner. the foam has obviously been redone, but even more interesting, you can see clues that a continuity issue has been addressed and that the driver motors have been replaced. the seller said the magnets are stamped "philips, made in belgium, AD 0162 28" and no infinity part number is present.
a little research showed the number he had given was not a correct philips part number (the seller said it was hard to read the printing on the magnet), and the correct number was actually AD 0162 T8. the AD 0162 T8 is an 8 ohm dome tweeter dating from 1975. the following is translated from a dutch site:
"This high-power dome tweeter with very high sensitivity (92 dB) has a 1-inch voice coil diameter. The allowable system power is 50 watts with a cross-over of 2 kHz. the dome is made of yellow polycarbonate, a short horn with diffuser built-in. frequency response to 22kHz."
the last 2 pics are of an unmodified AD 0162 T8. i find this was a tweeter used on early DCM time window speakers, and other mid 70s offerings.
it certainly appears someone successfully grafted the cones and mounting plates from original infinity walsh tweeters to a different drive motor. this does seem to indicate the drive motor is not as critical as might be thought.
it is also looking to me like the cone embossing is not critical either. judging from the great differences between the diamond tufted, diagonal striation, and hexagonal embossing types, it suggests the texture to be for simply adding extra stiffness to the cone, and may not be related to wave propagation at all. in studying photos of numerous functioning and gutted tweeters, i'm also not seeing any evidence that there is more than one layer in the construction of production cones, and cone material thickness seems to vary as well between versions.
all in all, the infinity walsh tweeter seems to go completely against everything i've read about the ohm walsh driver design, in which every element is said to be hyper-critical and can not be altered without severly compromising the function of the driver. the infinity walsh seems very forgiving in terms of altering the foam, drive motor, cone, support structure, etc. regardless of repairs made, or design variations, owners always say how great the tweeters sound. could it be that only functioning as a super tweeter, makes it more forgiving to construction variables?
.
Attachments
FrankPA
Active Member
I'm currently listening to my 2000AXT's with a full compliment of Walshes - both refoamed. I also replaced the caps with Dayton polys, as well as the resistors on the tweeter pot. The 5 1W resistor network looked slightly burned on the one that had the bad Walsh. I even found loose crimp splices in the other woofer wires. The person I bought them from said he bought one replacement woofer off the bay.
The old poly caps were 10% low (20% high for the bipolars), now everything is within 1%. I was disappointed in the sound at first - granted, they're just sitting randomly in the room which is likely messing up the bass - but now that they have more than 24 hours playing time I'm liking them a lot. They are still more "forward" (vs. "warm") than before, but the harshness on the transients I noticed at first seems to have gone away. Guess I'll have to play with the driver pots. The 2 refoamed Walshes were a very positive change immediately. For something that doesn't play much of the "music", they sure add a lot to the sound quality.
Now to find another center post gold Walsh so I can rebuild the WTLC's. I've wanted to hear these since I was in high school (when they came out). This is the first pair I've seen in person.
The old poly caps were 10% low (20% high for the bipolars), now everything is within 1%. I was disappointed in the sound at first - granted, they're just sitting randomly in the room which is likely messing up the bass - but now that they have more than 24 hours playing time I'm liking them a lot. They are still more "forward" (vs. "warm") than before, but the harshness on the transients I noticed at first seems to have gone away. Guess I'll have to play with the driver pots. The 2 refoamed Walshes were a very positive change immediately. For something that doesn't play much of the "music", they sure add a lot to the sound quality.
Now to find another center post gold Walsh so I can rebuild the WTLC's. I've wanted to hear these since I was in high school (when they came out). This is the first pair I've seen in person.
FrankPA
Active Member
I want to thank Coastsider for the dismantled Walsh pics. I finally got the courage to try dismantling my open WTLC Walsh. I was thinking I might be able to graft the gold cone onto the coneless silver good VC and then make a new tube to epoxy to the center. One of the 3 little screws was broken off just below the head, it was just being held in place by the magnet. I couldn't find the open in the coil after taking it apart so I set it aside to think about a while longer. I just removed the black plastic ring from around the coil form and one of the wires came with it. The break was at the dab of glue where the wire comes away from the coil form. Poking at the end of the wire still stuck in the glue with a meter probe I got a momemtary reading (with the other probe in the opposite terminal). I just might get lucky and be able to do the "unwind one coil" to reach back to the terminal. Assuming I don't vaporize the wire trying to solder it.
Since it's late and I've had a couple, I believe I'll wait to try this with "morning eyes".
Since it's late and I've had a couple, I believe I'll wait to try this with "morning eyes".
Coastsider
Curmudgeon
You are entirely welcome and glad to help. I wish my eyes were good enough and my hands steady enough to attempt such a repair but I'm afraid that time is gone, but I wish you good luck in your attempt. If you have a magnifying glass or jeweler's loupe in your stash of tools they might come in handy.
FrankPA
Active Member
Oh, it certainly did. My eyes are pretty bad as well. Trying to hold the loupe and the small LED flashlight AND the dental pic was very frustrating. Then I couldn't get the end of the wire free from the black glue they used. Nothing I had (and wanted to get on the VC form) seemed to phase it. I finally used a straight pin to try and pry it free but I think I just broke the wire on the other side of the glue dot.
When I went to unwind a loop I discovered the wire went under the other wire where it was glued. Again, I'd have never managed w/o the 30 power loupe. I need to get one of those headband mounted loupes. I was finally able to use the pin to work the wire under the other one. Soldering it to the terminal was difficult as well, it just didn't want to flow on the terminal or the wire. I was relying on the heat to burn off the varnish. Finally, I got 7.2 ohms across the terminals.
Getting everything back together was another ordeal. Getting the cardboard coil form seated in the magnet all the way around took several tries. I was afraid things would shift and break a wire. It's now all back together with new foam and still reading good. I won't be able to test it until I refurb the WTLC's. I just hope the wire doesn't rub through or have a nick or crack from the flexing that causes it to break from the motion of the VC. Well, I still have one good VC with no cone. Plus one silver Walsh to try and repair.
For anyone interested, the foam I've used is cut from a piece of acoustic foam I bought from Parts Express.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=260-516
It's 1.5" thick with egg crate pattern on one side. I cut around a coffee mug at an angle using an Exacto knife, then cut the egg crate back off the disk so I had a flat disk about 1/2" thick. It cut nicely using a sawing motion with the Exacto.
When I went to unwind a loop I discovered the wire went under the other wire where it was glued. Again, I'd have never managed w/o the 30 power loupe. I need to get one of those headband mounted loupes. I was finally able to use the pin to work the wire under the other one. Soldering it to the terminal was difficult as well, it just didn't want to flow on the terminal or the wire. I was relying on the heat to burn off the varnish. Finally, I got 7.2 ohms across the terminals.
Getting everything back together was another ordeal. Getting the cardboard coil form seated in the magnet all the way around took several tries. I was afraid things would shift and break a wire. It's now all back together with new foam and still reading good. I won't be able to test it until I refurb the WTLC's. I just hope the wire doesn't rub through or have a nick or crack from the flexing that causes it to break from the motion of the VC. Well, I still have one good VC with no cone. Plus one silver Walsh to try and repair.
For anyone interested, the foam I've used is cut from a piece of acoustic foam I bought from Parts Express.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=260-516
It's 1.5" thick with egg crate pattern on one side. I cut around a coffee mug at an angle using an Exacto knife, then cut the egg crate back off the disk so I had a flat disk about 1/2" thick. It cut nicely using a sawing motion with the Exacto.
loquatious
village elder
excellent! more evidence it can be done. hope all your efforts pay off. post some pics.
the headband type jeweler's loupe does come in handy for that kind of detail work. always good to have hands available for what you need hands for. i grafted one of those headband LED lights onto mine for extra illumination in tight quarters.
did you glue the new foam to the cone and support, or go with a friction fit?
.
the headband type jeweler's loupe does come in handy for that kind of detail work. always good to have hands available for what you need hands for. i grafted one of those headband LED lights onto mine for extra illumination in tight quarters.
did you glue the new foam to the cone and support, or go with a friction fit?
.
FrankPA
Active Member
Just a friction/pressure fit. There was still a layer of slightly sticky glue left, I just cleaned the old foam off as best I could with the Exacto. So I guess it's really friction and glue.
Sorry, I didn't take any pics while it was apart. Pretty much the same as Coastsider posted, except instead of the two strips of white tape there was a black plastic ring with "tunnels" over the wires. I did use some scotch tape to hold the cone/VC in place while re-joining the magnet.
Oh, and I was able to chisel a slot in the broken screw and then turn it out with a small screwdriver. I stole a screw from the coneless magnet. I hope it works.
Sorry, I didn't take any pics while it was apart. Pretty much the same as Coastsider posted, except instead of the two strips of white tape there was a black plastic ring with "tunnels" over the wires. I did use some scotch tape to hold the cone/VC in place while re-joining the magnet.
Oh, and I was able to chisel a slot in the broken screw and then turn it out with a small screwdriver. I stole a screw from the coneless magnet. I hope it works.