• Hello and Welcome to HiFiVision.com - an online community for the home entertainment and tech enthusiasts!

    If you would like to ask a question, participate in a discussion and view attachments please Register yourself.

DIY Ribbon Tweeter - 30 cm, playing commendably

Wharfedale Diamond 11.1 & 11.2 Speakers

turgid

New Member
Joined
Sep 9, 2012
Messages
158
Points
0
Location
Cochin / Bangalore
Hi People,

Been working on this for the last few days! My second more precise attempt at a Ribbon tweeter. Again not the best but cymbals and hi hats sound distinct like the earth and moon :lol:

I am willing to share my build details if anyone is interested in this amateur transformerless ribbon tweeter.

Best regards,

https://www.youtube.com/watch?v=z3BcsOlO2K8&feature=youtu.be
 

jls001

Well-Known Member
Joined
Feb 9, 2010
Messages
6,206
Points
113
Location
Mumbai
Of course we are interested:) Very good effort:clapping:
 

shafic

Well-Known Member
Joined
Jul 15, 2012
Messages
1,533
Points
113
Location
mumbai, India.
Hi,
I have quadral Wotan phonologue speakers. One of the ribbon tweeter is not working needs change of aluminium diaphrm. Tweeter model is Technics TH400. Any idea where to get the replacement diapharm. I already wrote to quadral awaiting for their reply. Any DIY can be done?
Regds
 

turgid

New Member
Joined
Sep 9, 2012
Messages
158
Points
0
Location
Cochin / Bangalore
Circuit: I couldn't find a suitable transformer for matching the impedance of this small ribbon which is generally in the order of milli-ohms or one tenth of an ohm for a considerably long one. So I used Stead resistors of 2 ohms rated at 50W(x2) in series since my cheapo amp is 40W into 4ohms. The problem with this approach is the mediocre sensitivity. Also, the ribbons can't handle low frequencies without distorting and therefore needs a largish cap in series, I used a 46 micro farad cap I had lying around.

Diaphragm: This is to me the toughest part of the build since the aluminium foil needs to be corrugated and ideally tension free to have the perfect coupling with air, this is hard to do and I still feel I have not succeeded. I tried several ways to corrugate it and none are all that successful. 2 of them are stripping the top layer of a cardboard to reach its corrugated layer in the middle and using 2 mosfets lying around to sandwich and stress on the aluminium against its fins. Both methods are not ideal unless they are longer than the ribbon, this is because every time you stress one part of the ribbon with such a corrugating apparatus, some other free part gets deformed. I believe this is the Hooke's law. I will soon buy foil tape to experiment with a film backing.

The frame: I got a couple of aluminium L rods for my DML project and cut it down to put nuts and bolts at either ends to a form a U-shape small compartment. I will post the photos in the next post. Then Araldite 2 part epoxy 5 minute setting resin to glue the magnets onto the frame, it is necessary to sand both the magnet and the aluminium frame for the glue to stick. No cyanoacralate will work. There is a lot of force for the magnets to fly around since the adjacent magnets are repelling and the opposite magnets are attracting. So a lot of glue to keep these forces in check.

Too much typing, rest later
 
Last edited:

turgid

New Member
Joined
Sep 9, 2012
Messages
158
Points
0
Location
Cochin / Bangalore
Hi,
I have quadral Wotan phonologue speakers. One of the ribbon tweeter is not working needs change of aluminium diaphrm. Tweeter model is Technics TH400. Any idea where to get the replacement diapharm. I already wrote to quadral awaiting for their reply. Any DIY can be done?
Regds

I apologize I over saw this post till now. I am not sure if I can help unless you want a complete replacement with a 4- 5 ft ribbon of approximately 2 ohms that I can try building. Again it's just trying! 6 micron foil tape glued onto mylar backing is my next project, I will make 4 strips running in parallel about 4 ft and connected every other end. I will solder away the excess mylar.
There are couple of limiting factors here - one is the corrugation device, second is getting mylar which is generally supplied in kilos and third is cutting the aluminium foil under 3 mm for handling the treble.

But have you taken the tweeter apart ? Is the aluminium foil damaged ? If it's a tear, you can add a bit of cellophane and it should work fine. The problem I see here is the right aluminium or kapton RS for this tweeter else it can sound different from the other one.
Also, another idea is to use 32 awg enamelled wire and stick it to mylar using fevi bond, 2 meters of 32 awg wire will give around 5-6 ohms.

P.S> For a small ribbon to reach considerably high efficiency like that of a commercial product we need a high secondary current step down trafo to run the ribbon, it is pretty inexpensive here - a 240 to 12-0-12 IE trafo with 5 amp secondary current costs about 250 bucks but I am not sure of its linearty or performance.

Best regards,
 
Last edited:

Srinath_seshadri

New Member
Joined
Dec 1, 2012
Messages
384
Points
0
Location
Charlotte NC, USA
4-5 ft ??? how thin can it be ?
I am looking for a suitable replacement for a carver amazing ribbon replica that I would make with neo magnets. Anyway its a 4 ft, 4 strip ribbon and the mylar is very very thin.
I had a tear in one of mine and I wrote with circuit writer and put a bit of cellophane over it.

Cool.
Srinath.
 

shafic

Well-Known Member
Joined
Jul 15, 2012
Messages
1,533
Points
113
Location
mumbai, India.
Yes, the foil is damaged. Without de soldering I opened the tweeter. I thought there was a problem with the tweeter but actually the problem was in crossover which I found afterwards.

Thanks and regds
 

turgid

New Member
Joined
Sep 9, 2012
Messages
158
Points
0
Location
Cochin / Bangalore
4-5 ft ??? how thin can it be ?
I am looking for a suitable replacement for a carver amazing ribbon replica that I would make with neo magnets. Anyway its a 4 ft, 4 strip ribbon and the mylar is very very thin.
I had a tear in one of mine and I wrote with circuit writer and put a bit of cellophane over it.

Cool.
Srinath.

Neos are just too expensive and even though they give you better sensitivity over ferrites, I do not know any company that used Neos in their designs. You can save a fortune by investing in ferrites over neos. Neos are more brittle and a source of blisters and in rare cases broken bones, though ferrites share some part of this blame too but do not fly 30 cm like small sized neos. Magnepans used really weak magnets IIRC, the thin strip ones.

With an Antek Torroid step down trafo, especially since you are in US, you can get very efficient sound with a small ribbon and high sensitivity too. The toughest part I feel is the corrugation and attaching the ribbon without instilling any amount of tension to get the perfect air coupling.

The only way around this is to use 32-34 AWG enameled copper wire and stick it onto mylar using contact cement like fevi-bond. Around 210 cm which is 7 columns across a super small panel can make you a good more maintainable tweeter panel of 4-5 ohms without having the metallic timbre of Alu. foil.
Upto you with regard to the timbre but all the best in your build sir.
 

turgid

New Member
Joined
Sep 9, 2012
Messages
158
Points
0
Location
Cochin / Bangalore
Yes, the foil is damaged. Without de soldering I opened the tweeter. I thought there was a problem with the tweeter but actually the problem was in crossover which I found afterwards.

Thanks and regds

Hi Shafiq,

Refer attachment :

Case A: If the foil is not torn completely and have some part of it still in contact with each other, some cellophane tape to hold the detached ends together will work perfectly fine.

Case B: if the aluminium foil is torn completely and now two parts, best way I see and my personal solution would be to get some 36-40 AWG enamel wire, do not buy a lot, yet slightly longer than the gap between the foils. Sand both the end of the wire to access the copper wire, attach it to the center of some cellophane tape. Now put a bit of pressure on both the ends of the Al. foil to come as close together as possible, use cellophane tape with the wire to adjoin the ends meanwhile making sure the wire on the tape is making adequate contact with the both the Alu-foil and thus completing the circuiting. Once this is done, you can use fevi-bond or cyanoacrylate super glue on the wire to stick to the ribbon. Preferably this should be done on the enameled part and not the copper.

Trust OK,
 

Attachments

  • Untitled.jpg
    Untitled.jpg
    5.7 KB · Views: 77

Srinath_seshadri

New Member
Joined
Dec 1, 2012
Messages
384
Points
0
Location
Charlotte NC, USA
Neos are just too expensive and even though they give you better sensitivity over ferrites, I do not know any company that used Neos in their designs. You can save a fortune by investing in ferrites over neos. Neos are more brittle and a source of blisters and in rare cases broken bones, though ferrites share some part of this blame too but do not fly 30 cm like small sized neos. Magnepans used really weak magnets IIRC, the thin strip ones.

With an Antek Torroid step down trafo, especially since you are in US, you can get very efficient sound with a small ribbon and high sensitivity too. The toughest part I feel is the corrugation and attaching the ribbon without instilling any amount of tension to get the perfect air coupling.

The only way around this is to use 32-34 AWG enameled copper wire and stick it onto mylar using contact cement like fevi-bond. Around 210 cm which is 7 columns across a super small panel can make you a good more maintainable tweeter panel of 4-5 ohms without having the metallic timbre of Alu. foil.
Upto you with regard to the timbre but all the best in your build sir.

I am re engineering a carver 48" ribbon. The problem is the ferrites cause a lot of problems. They are heavy, they move around, they're not bolted down in the carver design etc etc.
Carver made them in the 80's when Neo wasn't even available.
My idea is that I'll make a long wooden strip, mill long slots in it to match the steel plate carver used front and back of the ribbons and then on the face that faces the ribbons I'll drill shallow holes 1/8" or so every 1/2" apart and put a neo in each of those holes, and then screw a long strip of steel over it. That would trap the neo's where they are and not let them fly out and drown the ribbon in magnetic flux.
Look for carver amazing 48" ribbon on google, I cant attach pics, I used up all my space.
Cool.
Srinath.
 

turgid

New Member
Joined
Sep 9, 2012
Messages
158
Points
0
Location
Cochin / Bangalore
Awesome! Do post your build in the forum. Just a suggestion if you are going to use steel you will be saturating a lot of the flux. I would suggest using aluminium L bars, they are cheaper than steel, do not corrode and don't get in the way of flux and you can make a nut bolt arrangement.

Pics to follow.


PS> I am also trying to come up with a full range ribbon ... getting my mind around how to make small aluminium traces on mylar backing. This time around I am not going to corrugate them and I will still be a happy man.
 
Last edited by a moderator:

Srinath_seshadri

New Member
Joined
Dec 1, 2012
Messages
384
Points
0
Location
Charlotte NC, USA
Aluminum wont saturate the flux - that is the problem. The 1/8th" dia magnet has to be radiated over a 1/2" area. Because I am replacing a bar ferrite magnet with dots every 1/2".
Cool.
Srinath.
 

turgid

New Member
Joined
Sep 9, 2012
Messages
158
Points
0
Location
Cochin / Bangalore
I am not sure if you will be getting equal sensitivity with the neos then. I would rather just clean and re-glue the ferrites with some 2 part epoxy especially if the ribbon is not damaged but if you are all set with the substitution, all the best!
 

Srinath_seshadri

New Member
Joined
Dec 1, 2012
Messages
384
Points
0
Location
Charlotte NC, USA
I have glued the thing for now but need to reassemble it. I hope to get it working and do this for later. The original ribbon is like 2 microns thick with vapor deposited aluinum for the conductor.
Cool.
Srinath.
 

GeorgeO

Well-Known Member
Joined
Jul 14, 2009
Messages
4,318
Points
113
Location
Cooke Town Bangalore
Good ribbons implemented well are unbeatable. I own a pair of AriaR speakers designed by Joe D'Appollito, the father of the MTM design. It uses Raven R1 ribbons, and Focal mids,I built it about 12-14 years ago and have been enjoying them ever since, the highs are simply superb. Good luck to you in your endeavours.
 

turgid

New Member
Joined
Sep 9, 2012
Messages
158
Points
0
Location
Cochin / Bangalore
Good ribbons implemented well are unbeatable. I own a pair of AriaR speakers designed by Joe D'Appollito, the father of the MTM design. It uses Raven R1 ribbons, and Focal mids,I built it about 12-14 years ago and have been enjoying them ever since, the highs are simply superb. Good luck to you in your endeavours.

Yes the highs sound very clear, distinct and the driver's speed is phenomenal. It never gets confused.

Here is a another video I captured of my ribbon playing the Cymbal song by Gavin Harris.

https://www.youtube.com/watch?v=WE6VC9Srcjw
 
Top