Alu VS laminated ribbon

[brunob]

Originally Posted by fivestring

No!
ERROR!!!

Do humans make mistakes or only computers?
The middle trace was incorrectly wired, the new measurement shows much higher sensitivity, some 7-8dB higher than pure alu ribbon of roughly the same impedance!

Nice to read that the problem is solved.

About the top frequency response of pure Alu ribbon, did you use an impedance transformer?

Bruno

[fivestring]

No, it was measured without a transformer, alu ribbon only.

[a.wayne]

Originally Posted by fivestring

No!
ERROR!!!

Do humans make mistakes or only computers?
The middle trace was incorrectly wired, the new measurement shows much higher sensitivity, some 7-8dB higher than pure alu ribbon of roughly the same impedance!
Did no one ever tried to measure this? There must be clear benefits with such vastly improved sensitivity of the laminate, not only drawbacks?
I apologize for misleading you...

[IMG][/IMG]

[IMG][/IMG]

Could you provide us with a pic of your laminated diaphragm .....

[fivestring]

Don`t try to laugh...

[a.wayne]

Thanks fivestrings,


Ok , it's mylar tape with foil attached ( 3) not laminated ? This setup is 6 db more efficient that straight foil ? It also exhibits a lot of wrinkles below 300 hz, according to the impedance trace you provided ....


regards,

[fivestring]

Well, it`s mylar foil (without adhesive), I spray glue the aluminum foils then attach them to the mylar foil - I guess I have used the wrong terminology? Perhaps I should say multi trace ribbon versus the single trace?
This setup is close to 8dB more efficient than..., please reread everything I have already stated. It is similar to this setup who indeed used the self adhesive tape, unlike me.
I have spread the vertical graph resolution drastically to make it easier for you guys to observe the differences in impedance and the wrinkles below 170Hz (!) are in the order of 0.3 oHms, is that a lot? I could easily use the 50dB span instead of the 10dB and then you wouldn`t notice any wrinkles.
Pure aluminum foil is very efficient only with transformers, if you use ANY kind of resistors - efficiency drops hugely.

By the way, do you have any experience with multitrace ribbons (mylar/kapton & alu) VS the single trace (alu only), have you built any and observed the differences in SQ?

[a.wayne]

I have only built full alloy , not traced , but have compared the sound to other traced units from others , i prefer the sound of the straight alloy vs laminated multi-traced ones. Efficiency and load is .... ..sonics... only good for SS, if running tubes of course traced is the way to go .

Those wrinkles in the electrical graph will show itself sonically and for sure when measuring magnitude and phase..


regards,

[fivestring]

I love the sonics of pure aluminum ribbons, but they are somewhat more sensitive to the slot diffraction effect which needs to be tamed with an RCL and laminated ribbons are much less sensitive to this phenomena, perhaps because they don`t need as deep corrugations, if at all. If you don`t use the RCL trap the sound can be very delicate (in the presence region) but also tonally incorrect and somewhat metallic in character.

I don`t know, I should do more testing before making any final conclusions but at the end I might choose the laminated multitrace ribbon out of practical reasons, maybe I will trade some sonic details for greater mechanical and sonic robustness, we`ll see...

By the way, I always thought pure alu ribbons are prime candidates for all amps that need output transformers, tubes of course, but also SS amps like Susan Parker`s Zeus amp:

Zero Feedback Impedance Amplifiers

And from 6moons this news about Raal tweeters:

"Recently, we finished development of Amorphous C-cores application in our ribbons. Some years ago, we were the first to introduce large gap approach in building ribbon transformers and now we are the first to use AMCC's in ribbons for absolutely uncompressed high power transient transfer and, at the same time, even further improving already the best low-level performance in the world today, by decreasing the width of hysteresis compared to HF ferrite cores. For direct coupled tube SE-ribbon, we succesfuly developed 175:1 ratio, -3dB at 120kHz Amorphous C-core transformers that can carry DC idle current of SET. Impedance conversion is about 30000:1, bringing the 0.1 Ohm ribbon up to 3kOhm, good for plate loading of most triodes in HF."

regards,
miro

[fivestring]

Those wrinkles in the electrical graph will show itself sonically and for sure when measuring magnitude and phase...

Almost forgot, with the expected XO around 500Hz, it will hardly show anything,
I mean these wrinkles could cause deviations in the order of less than half dB.
I`m sure that the slot anomaly in the presence range if not cured, plays a much bigger role here...

regards,
miro