I just got the foil you sent me. Many thanks! It's wonderfully wonderfully thin and precisely the right width for what I want to do. I'm so happy I won't have to cut it at all. Thanks also for the 4.3 micron samples -- boy, those are fragile.
In other news... I got a test amp from apexjr.com that I'm more comfortable using than the household stereo... I wired a few toroids -- fun stuff. Seems to work fine. My magnets should arrive today... and I've decimated the steel supply at the local hardware store.
The last item on my initial TODO list is to find something to corrugate the foil with. I guess I could get a couple of those gears from BG Micro and glue them together carefully? They need to be fairly wide. What other methods have people used? My friend and I, long long ago, used some conveniently shaped bottle cap, but those seem less common than they used to be.
Audiophilenoob said:
I have 8 of those gears sitting here
I matched all the teeth and glued them to make a annealing tool that supports up to 2.5" wide ribbons...
I used a dowel I shaped to run through the 1/4" Inner diameter of it and so they turn
Audiophilenoob - What a great idea! I've been wondering where I would be able to get much wider gears. I'm following your other thread with great interest. It looks like you have killer magnets (I hope that is not literaly true
)Zell - I'm happy to hear you are building ribbons too. The more, the merrier. Keep us informed.
dhenryp said:
Audiophilenoob - What a great idea! I've been wondering where I would be able to get much wider gears. I'm following your other thread with great interest. It looks like you have killer magnets (I hope that is not literaly true
Zell - I'm happy to hear you are building ribbons too. The more, the merrier. Keep us informed.
unfortunately that term killer is truer than you think
I let two of those pole pieces with all the magnets attached come together with my index finger in the way...
OUCH!!!! it more than hurt a little...
dhenryp said:
I've been annealing 4.3 micron foil and it holds it well
it doesn't even tear actually...
I've also been able to get a piece over 70" long off the roll of 4.3 without tearing... I think the humidity lately helped...
I would say that if you have the patience to trim and anneal and possibly have to do it a few times cause of mess ups... that the 4.3 micron is thick enough to use for long ribbons... once annealled it is sturdy enough for a decent amount of abuse... I could not get it to tear with small breathes... with a lot of air force though I could rip it
Could you measure the response from off-axis too (like 30 and 60 degrees), often it's the most important measurement in practise. Also sometimes a line-level crossover is the best solution (I think a direct-driver ribbon might be a such case as the amplifier is specific for the driver element type with a very low impedance).
Btw. How tightly the left and right diy ribbons can be matched, do they often differ in response?
Btw. How tightly the left and right diy ribbons can be matched, do they often differ in response?
Cryo treated foils
If any of you builders would like to have your foil cryo treated (as I have already done elswhere) either befor or after you anneal please just PM me and I will be happy to do so for you N/C.
Also have any of you thought of using positive and negative dimples rather than foulds to stiffen you foils? Best regards Moray James
If any of you builders would like to have your foil cryo treated (as I have already done elswhere) either befor or after you anneal please just PM me and I will be happy to do so for you N/C.
Also have any of you thought of using positive and negative dimples rather than foulds to stiffen you foils? Best regards Moray James
mhelin said:
My original plan was to build active crossovers and gain-clone type amps. I hope to eventually get to that but I realized if I wanted to listen to the speakers in the next year or two I needed an interim passive.
The two ribbons are pretty closely matched on-axis. I've not measured them off axis yet.
Regards,
Denis
You could also pick a cheap SI Class-T amp and a Behringer analog 24 dB/oct state-variable LR crossover (CX2310, see http://www.behringer.com/CX2310/index.cfm?lang=ENG). I'm not sure how good the Sonic Impact is with the ribbons, some review here: http://www.6moons.com/audioreviews/sonicimpact/t.html
Member
Joined 2003
moray,
I experimented with +/- dimpled ribbons but, when overdriven at lower frequencies, they tended to twist in the gap more than pleated ribbons. Given the twisting under stress, I settled on pleated ribbons. Dimpled ribbons seem to work fine at HF.
mhelin,
No progress...just happy listening
I experimented with +/- dimpled ribbons but, when overdriven at lower frequencies, they tended to twist in the gap more than pleated ribbons. Given the twisting under stress, I settled on pleated ribbons. Dimpled ribbons seem to work fine at HF.
mhelin,
No progress...just happy listening
mhelin said:
It all depends on what type of magnets they are. If they are Neodymium (say N35) they would end up being about 67% as strong as mine - still pretty good. If they are ceramic magnets, they are probably too weak for anything but initial experimenting. 1500 hz is certainly in the ballpark for a crossover frequency for this kind of driver.
Sounds like you might want to follow the path I described at the beginining of this thread. You could also take a look at my web page for a condensed version of this thread:
http://home.comcast.net/~hendentures/
Good luck and have fun!
Denis,
Yes, I've gone through your pages (and some other like the swedish ribbon threads on both forums). The magnets are Neodymium (N40), I'll make first a proto using whatever parts I found (some U-shaped steel like the shelf holder
here ). I have also downloaded FEMM and start experimenting with it.
On some ESL thread they suggested using toroid 230V / 12V (or so) power transformers. Do you think they could work with ribbons? I haven't calculated any resistances, but I think my is gonna be ~10 mm wide and 10 cm long. I've also considered using the Dahlberg's design ribbon - a stripped aluminium on mylar. That way the resistance could be increased a little bit though not enough for direct-drive. With a 0.01 ohm resistance (impedance) about 400:1 impedance ratio is needed, that's 20:1 voltage ratio (230V/12V seems to be ok).
Yes, I've gone through your pages (and some other like the swedish ribbon threads on both forums). The magnets are Neodymium (N40), I'll make first a proto using whatever parts I found (some U-shaped steel like the shelf holder
here ). I have also downloaded FEMM and start experimenting with it.
On some ESL thread they suggested using toroid 230V / 12V (or so) power transformers. Do you think they could work with ribbons? I haven't calculated any resistances, but I think my is gonna be ~10 mm wide and 10 cm long. I've also considered using the Dahlberg's design ribbon - a stripped aluminium on mylar. That way the resistance could be increased a little bit though not enough for direct-drive. With a 0.01 ohm resistance (impedance) about 400:1 impedance ratio is needed, that's 20:1 voltage ratio (230V/12V seems to be ok).
Hi mhelin,
I've got no experience using ready made transformers for impedance matching. The topic was discussed briefly in this thread but I'm a pretty hard core DIYer so I made it myself.
I'm not sure this any advantage to going with the foil on Mylar approach if you are still going to need a transformer, certainly not of you have to build a transformer. I would probably not go with the mylar unless you can get significantl more than .01 ohm. You could probably come close to that with pure aluminum.
Regards,
Denis
I've got no experience using ready made transformers for impedance matching. The topic was discussed briefly in this thread but I'm a pretty hard core DIYer so I made it myself.
I'm not sure this any advantage to going with the foil on Mylar approach if you are still going to need a transformer, certainly not of you have to build a transformer. I would probably not go with the mylar unless you can get significantl more than .01 ohm. You could probably come close to that with pure aluminum.
Regards,
Denis
Member
Joined 2003
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.