Hi there,
Recently acquired a pair of the caption hornloaded ribbon used. THere is very little info on this beast.
For picture of it, see http://www.audiocircle.com/circles/...ame=gallery&file=index&include=view_photo.php
I want to mate this with a pair of full range Tannoy Silver 15" as "Supertweeter" . Here is my questions,
1. Does the speaker come with any crossover at all?
2. If not, how can I calculate the kind of capacitor required at a desirable frequency.
3. As I want the unit playing the role of super tweeter, I assume I need a +16000 Hz cross over point. What's your opinion on crossover point for fullranger like Tannoy.
Thanks a lot for your help.
iCefoX
Recently acquired a pair of the caption hornloaded ribbon used. THere is very little info on this beast.
For picture of it, see http://www.audiocircle.com/circles/...ame=gallery&file=index&include=view_photo.php
I want to mate this with a pair of full range Tannoy Silver 15" as "Supertweeter" . Here is my questions,
1. Does the speaker come with any crossover at all?
2. If not, how can I calculate the kind of capacitor required at a desirable frequency.
3. As I want the unit playing the role of super tweeter, I assume I need a +16000 Hz cross over point. What's your opinion on crossover point for fullranger like Tannoy.
Thanks a lot for your help.
iCefoX
I have used "Stripped" Gamma VLD-12 as super-tweeter for Magneplanar MG-II with great result 
(80Hz/6dB active filter, passive 1000Hz 6dB/oct.)
Audio Pro 2B50 mod. active subwoofer was used below 80Hz
Crossover freq. for the Gamma's was 13.200Hz/6dB (1.5µF/250V-) and no lowpass filter used for the maggie tweeters.
The power limit for the Gamma tweeter when supplied with a clean (non-clipped) signal is for me unknown!
A heavy mod. Musical Fidelity P270 with 5 pairs of MOS-FETs messured to deliver aprox. 225w/8Ohm RMS....didnt harm the Gamma's when the clean and massive power-amp made the "Maggie" bass panels hit the grills/magnets.
For instance a "brute" clipping amp like the 100watt/8Ohm Quad 405-II will burn the Gamma alu-strip ever so fast if the amp is driven hard....you will be noticed by crakling sound and next a fine dence white smoke from the tweeters............tried that one
I think the difference betwin VLD-12 and VLD-13 is/could be lack of cobolt for the magnet in VLD-13.
please ....correct me if im am wrong
(80Hz/6dB active filter, passive 1000Hz 6dB/oct.)
Audio Pro 2B50 mod. active subwoofer was used below 80Hz
Crossover freq. for the Gamma's was 13.200Hz/6dB (1.5µF/250V-) and no lowpass filter used for the maggie tweeters.
The power limit for the Gamma tweeter when supplied with a clean (non-clipped) signal is for me unknown!
A heavy mod. Musical Fidelity P270 with 5 pairs of MOS-FETs messured to deliver aprox. 225w/8Ohm RMS....didnt harm the Gamma's when the clean and massive power-amp made the "Maggie" bass panels hit the grills/magnets.
For instance a "brute" clipping amp like the 100watt/8Ohm Quad 405-II will burn the Gamma alu-strip ever so fast if the amp is driven hard....you will be noticed by crakling sound and next a fine dence white smoke from the tweeters............tried that one
I think the difference betwin VLD-12 and VLD-13 is/could be lack of cobolt for the magnet in VLD-13.
please ....correct me if im am wrong
Capacitor in Series
The Tannoys are fairly efficient so you should not need a lot of power - a few watts. Good tube amp or class a ss would do well.
Any idea what the Fs is on the ribbon? Efficiency? 8 ohm? Power handling?
I would start high with say a .47 uf capacitor in series with the + on the tweeter, then listen with low power and the Tannoys. You will hear very little in "tone", just more ambiance or added "air". At this frequency the effect is fairly subtle, though noticeable.
Remember, when using the single cap in series, you will still have significant output well below the crossover point due to the shallow slope (6dB/octave) of roll-off. As you increase the capacitor size you allow more lower frequencies through, and more overlap with the Tannoys. And as you near the free air resonance of the ribbon, there is usually substantial distortion first, then nothing. The ribbon fails. Particularly, when high power is used, or the amp is clipped that's feeding them. Fortunately, there is so little going on this high that power needed is usually minimal.
If the ribbon plays too loud, then you will have to add resistance to pad down the output. This will also provide a bit more protection for the device. Fostex makes a nice "L" pad if output adjustment is desired.
Tim
The Tannoys are fairly efficient so you should not need a lot of power - a few watts. Good tube amp or class a ss would do well.
Any idea what the Fs is on the ribbon? Efficiency? 8 ohm? Power handling?
I would start high with say a .47 uf capacitor in series with the + on the tweeter, then listen with low power and the Tannoys. You will hear very little in "tone", just more ambiance or added "air". At this frequency the effect is fairly subtle, though noticeable.
Remember, when using the single cap in series, you will still have significant output well below the crossover point due to the shallow slope (6dB/octave) of roll-off. As you increase the capacitor size you allow more lower frequencies through, and more overlap with the Tannoys. And as you near the free air resonance of the ribbon, there is usually substantial distortion first, then nothing. The ribbon fails. Particularly, when high power is used, or the amp is clipped that's feeding them. Fortunately, there is so little going on this high that power needed is usually minimal.
If the ribbon plays too loud, then you will have to add resistance to pad down the output. This will also provide a bit more protection for the device. Fostex makes a nice "L" pad if output adjustment is desired.
Tim
Gamma VLD 13 Ribbon
I found a bit more info on the ribbon at a Swedish site, but not entirely sure of the accuracy.
Frequency Range - 2400 - 40K Hz.
Assume FS is close to lower limit.
Power Handling - 60 watts at 4000 Hz.
Sensitivity - 94 dB/watt/meter.
Impedence - 8 ohm.
The Tannoy Silver 15" are about 92 dB, so some attenuation may be needed on the ribbon.
Also, the ribbon has a low enough Fs and high enough power handling to use a larger capacitor, so you may want to experiment with values from 1.0 uF to 1.5 uF.
Tim
I found a bit more info on the ribbon at a Swedish site, but not entirely sure of the accuracy.
Frequency Range - 2400 - 40K Hz.
Assume FS is close to lower limit.
Power Handling - 60 watts at 4000 Hz.
Sensitivity - 94 dB/watt/meter.
Impedence - 8 ohm.
The Tannoy Silver 15" are about 92 dB, so some attenuation may be needed on the ribbon.
Also, the ribbon has a low enough Fs and high enough power handling to use a larger capacitor, so you may want to experiment with values from 1.0 uF to 1.5 uF.
Tim
The Swedish Gamma agent shows data which cant be used for evaluate which filter or use is best for the VLD-13
I cant support the advice to start with 41.500 Hz as suggested crossover freq..............thats ultrasonic soundwaves
go for 1µF (-3dB/20KHz) which believe me will be hardly audible
Gamma did in 70's sell 2 and 3 way speakers
the showed data is taken from a 1975 Hi-Fi yearbook.
Gamma Classic:
Freq. +- 4dB 45-30.000Hz
Freq. +4/-8 dB 40-35.000Hz
3.5watt/96dB SPL
30Watt RMS power
55Watt music power
8 Ohm
Bassreflex Cab. volume 26L.
Tweeter: VLD-12
Bass: GAMMA BBK 200
Filter: 3000Hz 12/18 dB
Gamma Monitor:
Freq. +- 4dB 35-30.000Hz
Freq. +4/-8 dB 30-35.000Hz
2.5watt/96dB SPL
50Watt RMS power
85Watt music power
8 Ohm
Bassreflex Cab. volume 57L.
units
Tweeter: VLD-12
Mid: BK 138-A
Bass: 12" LA-1231
Filter: 650/3500Hz 12/12/18dB (no LP-filter for the mid-range unit)
I cant support the advice to start with 41.500 Hz as suggested crossover freq..............thats ultrasonic soundwaves
go for 1µF (-3dB/20KHz) which believe me will be hardly audible
Gamma did in 70's sell 2 and 3 way speakers
the showed data is taken from a 1975 Hi-Fi yearbook.
Gamma Classic:
Freq. +- 4dB 45-30.000Hz
Freq. +4/-8 dB 40-35.000Hz
3.5watt/96dB SPL
30Watt RMS power
55Watt music power
8 Ohm
Bassreflex Cab. volume 26L.
Tweeter: VLD-12
Bass: GAMMA BBK 200
Filter: 3000Hz 12/18 dB
Gamma Monitor:
Freq. +- 4dB 35-30.000Hz
Freq. +4/-8 dB 30-35.000Hz
2.5watt/96dB SPL
50Watt RMS power
85Watt music power
8 Ohm
Bassreflex Cab. volume 57L.
units
Tweeter: VLD-12
Mid: BK 138-A
Bass: 12" LA-1231
Filter: 650/3500Hz 12/12/18dB (no LP-filter for the mid-range unit)
Gamma Horns
Pmik,
Better to error on the safe side with ribbons by using a high crossover. They have a tendency to fail, although this one seems fairly stout (60 watts). Can find very little on them. Where are (were) they made?
The Tannoys may or may not match up well with your crossover point for the Maggie's. Different breed entirely, but maybe icefox will get lucky.
Your Gamma data says 96 dB for the VLD-12, the Swedish site says 94 dB for the 13. Close, but a different model. What makes you believe one is bad information, or the other good? Besides, they both could be 94 or 96 dB, but at what frequency? Measurements are needed, reliable frequency response plots, that sort of thing, if one were crossing at 3K Hz.
I have a set of open baffles with a Fostex horn run with only a .47uF capacitor as the crossover. Sounds good mated to a full range driver similar to the Tannoy. Adds just enough "air". Some tweeter roll-off is a good thing when paired with a less efficient midrange, and the slope is so gentle there is still noticeable output this low (14K- 16K Hz). Matter of taste, really.
Tim
Pmik,
Better to error on the safe side with ribbons by using a high crossover. They have a tendency to fail, although this one seems fairly stout (60 watts). Can find very little on them. Where are (were) they made?
The Tannoys may or may not match up well with your crossover point for the Maggie's. Different breed entirely, but maybe icefox will get lucky.
Your Gamma data says 96 dB for the VLD-12, the Swedish site says 94 dB for the 13. Close, but a different model. What makes you believe one is bad information, or the other good? Besides, they both could be 94 or 96 dB, but at what frequency? Measurements are needed, reliable frequency response plots, that sort of thing, if one were crossing at 3K Hz.
I have a set of open baffles with a Fostex horn run with only a .47uF capacitor as the crossover. Sounds good mated to a full range driver similar to the Tannoy. Adds just enough "air". Some tweeter roll-off is a good thing when paired with a less efficient midrange, and the slope is so gentle there is still noticeable output this low (14K- 16K Hz). Matter of taste, really.
Tim
You got a point and the data you refere to maybe shows,
its lack of (expencive) Cobolt thats missing in VLD-13's which gives less flux, less sensitivity....
I read an article in the late 80's about growing world pricesresulted in less speaker-units with ALNICO magnets..........im pretty sure..but many years has gone since
Its rather difficualt for me to express exactly how easy and flawless the use of Gamma VLD's are, its build and fine sound quality not to far behind the Decca
i have use my Gamma VLD's (with and without the horn) for more than ten years
I have also tried to use my Gamma with my pair of Tannoy T-165 (10" dual concentric 1978) speakers and i would expect Firefox to end up using his VLD-13 with par. 1.0 + 0,22µF capacitors for a crossover point of aprox 16KHz.
For the moment i use my "stripped" Gammas with a pair of Dali Dacapo which is a 2way hybrid speaker (8" bass-unit + 40"x1" ribbon tweeter) and my always faithful Audiopro Subwoofer
Cheers
its lack of (expencive) Cobolt thats missing in VLD-13's which gives less flux, less sensitivity....
I read an article in the late 80's about growing world pricesresulted in less speaker-units with ALNICO magnets..........im pretty sure..but many years has gone since
Its rather difficualt for me to express exactly how easy and flawless the use of Gamma VLD's are, its build and fine sound quality not to far behind the Decca
i have use my Gamma VLD's (with and without the horn) for more than ten years
I have also tried to use my Gamma with my pair of Tannoy T-165 (10" dual concentric 1978) speakers and i would expect Firefox to end up using his VLD-13 with par. 1.0 + 0,22µF capacitors for a crossover point of aprox 16KHz.
For the moment i use my "stripped" Gammas with a pair of Dali Dacapo which is a 2way hybrid speaker (8" bass-unit + 40"x1" ribbon tweeter) and my always faithful Audiopro Subwoofer
Cheers
I have come across a Bulgarian site
this site should be the best source for brand new Gamma's since its in the land of origin for Gamma units.
http://www.vissokogovoriteli.plc.bg/home.htm
Like this one original "stripped" VLD-13
http://www.vissokogovoriteli.plc.bg/pics/d/vld40.html
I remember a new Gamma product was released in the mid 80's cant remember its model number
It was a dedicated "super" ribbon-tweeter with integrated 7KHz/18dB crossover, housing was made in solid marble.
The danish "High Fidelity' made a servere testing of it and there verdict was "its full of stars" or somthing like that was said about this unit (hehe).....biggest difference "new feture" was a new larger and better quality of stepdown transformer.
cant remember its price since it was way over my budget , but it didnt come cheap afir.
This is the budget version of the marble tweeter
i believe the performance is close to or equal to the marble version, look at the deepth...shows the large trannie is used in this model.
http://www.vissokogovoriteli.plc.bg/pics/d/vldd80.html
http://www.vissokogovoriteli.plc.bg/p01d.htm
seen in this list...the bulgarians claims less Sensitivity for the VLD-13...as far as i know it should be 94dB...not the showed 84dB
VLD-40 Sensitivity is just like whats my impression of my stripped VLD-12's
this site should be the best source for brand new Gamma's since its in the land of origin for Gamma units.
http://www.vissokogovoriteli.plc.bg/home.htm
Like this one original "stripped" VLD-13
http://www.vissokogovoriteli.plc.bg/pics/d/vld40.html
I remember a new Gamma product was released in the mid 80's cant remember its model number
It was a dedicated "super" ribbon-tweeter with integrated 7KHz/18dB crossover, housing was made in solid marble.
The danish "High Fidelity' made a servere testing of it and there verdict was "its full of stars" or somthing like that was said about this unit (hehe).....biggest difference "new feture" was a new larger and better quality of stepdown transformer.
cant remember its price since it was way over my budget , but it didnt come cheap afir.
This is the budget version of the marble tweeter
i believe the performance is close to or equal to the marble version, look at the deepth...shows the large trannie is used in this model.
http://www.vissokogovoriteli.plc.bg/pics/d/vldd80.html
http://www.vissokogovoriteli.plc.bg/p01d.htm
seen in this list...the bulgarians claims less Sensitivity for the VLD-13...as far as i know it should be 94dB...not the showed 84dB
VLD-40 Sensitivity is just like whats my impression of my stripped VLD-12's
Gamma
Huh? 84 dB is pretty far off from the previous 94 dB. Strange.
You would need to actively crossover with volume control and then use a separate amp for the Gamma highs to get levels right.
90 dB without the horn sounds about right - a common sensitivity for tweeters.
The need to measure the Gamma seems pretty clear. I guess you could still just lash it up and try it.
Prices are pretty good.
Tim
Huh? 84 dB is pretty far off from the previous 94 dB. Strange.
You would need to actively crossover with volume control and then use a separate amp for the Gamma highs to get levels right.
90 dB without the horn sounds about right - a common sensitivity for tweeters.
The need to measure the Gamma seems pretty clear. I guess you could still just lash it up and try it.
Prices are pretty good.
Tim
Guys,
To provoke further discussion, I would like to re-post and email I received from another kind soul I meet here in DIY Audio, Sjef. He has shared with me some serious info on the application of the Gamma VDL-1x tweeter.
----
Hi Icefox,
Yes I have these speakers for quite some time now and have a lot of experience with them. They can be filtered very easily because the impedance is nearly totally resistive and because of there extremely lineair frequency response.
There are different models though, mine measure about 12 ohms of
impedance while they are stated as 8 ohm units. See if you have a possibility to measure it's impedance (not with an ohmmmeter, that only measures dc resistance wich is very low)
For a quick use of them you can calculate just simple textbook
crossovers for them (calculated acoording to the real impedance of the tweeter). If you want to do better the only alternativ is to measure them yourself (as always with building speakers)
A couple of tips though. Stay away from 6dB/oct filtering, they just
don't like it. Even when you cross at say 10kHz it's better to use higher order crossovers. In the days I was filtering passivly I ended up using a 5th order butterworth at 3.5 kHz for them (30dB/oct). If you use activ filtering always put a (best quality) capacitor before the tweeters. The DC resistance of the tweeter is very very low and just a little 50Hz hum or DC offset of you amp might kill them instantly. But don't worry, when used properly they are as hard to destroy as any other tweeter.
Another problem is the driver offset. The horn of the tweeter is
rather deep so you have to compensate for that in some way. I compensate it with active delay of the midrange, but if you don't have that possibilty just try to move them a little bit more to the front up until the point it sounds best.
I have read on the forum that you wanted to use them as a super
tweeter with some tannoy's. You can just try that with different value's of capacitors and a L-pad for level attenuation. But even when you cross over at say 16 kHz it works better if you put an inductor in parallel with them (say about 0.5 to 1mH). This way you create a 6dB/oct crossover witch goes steeper into 12dB/oct at lower frequency's.
The cuttoff frequency of the horn is about 1.5kHz and as with all
horn you have to be sure that the tweeter doesn't get any input near that frequency (or at least 20 dB down). That's the point where horns start to shout and that exactly the thing why horns are given such a bad name. That's also one of the reasons a very steep crossover sounds better, I'm using then at 3kHz with a 90dB/oct crossover at the moment.
Feel free to experiment and don't give up. Thes are very good tweeters. I know there are better ones but at this price or even much higher. I like it a lot more than the top range scan speak and seas domes out there, I know because I have them too. But as with all speaker, it's the combination that counts.
With best regards,
Sjef
--------- Quote End -------------
To provoke further discussion, I would like to re-post and email I received from another kind soul I meet here in DIY Audio, Sjef. He has shared with me some serious info on the application of the Gamma VDL-1x tweeter.
----
Hi Icefox,
Yes I have these speakers for quite some time now and have a lot of experience with them. They can be filtered very easily because the impedance is nearly totally resistive and because of there extremely lineair frequency response.
There are different models though, mine measure about 12 ohms of
impedance while they are stated as 8 ohm units. See if you have a possibility to measure it's impedance (not with an ohmmmeter, that only measures dc resistance wich is very low)
For a quick use of them you can calculate just simple textbook
crossovers for them (calculated acoording to the real impedance of the tweeter). If you want to do better the only alternativ is to measure them yourself (as always with building speakers)
A couple of tips though. Stay away from 6dB/oct filtering, they just
don't like it. Even when you cross at say 10kHz it's better to use higher order crossovers. In the days I was filtering passivly I ended up using a 5th order butterworth at 3.5 kHz for them (30dB/oct). If you use activ filtering always put a (best quality) capacitor before the tweeters. The DC resistance of the tweeter is very very low and just a little 50Hz hum or DC offset of you amp might kill them instantly. But don't worry, when used properly they are as hard to destroy as any other tweeter.
Another problem is the driver offset. The horn of the tweeter is
rather deep so you have to compensate for that in some way. I compensate it with active delay of the midrange, but if you don't have that possibilty just try to move them a little bit more to the front up until the point it sounds best.
I have read on the forum that you wanted to use them as a super
tweeter with some tannoy's. You can just try that with different value's of capacitors and a L-pad for level attenuation. But even when you cross over at say 16 kHz it works better if you put an inductor in parallel with them (say about 0.5 to 1mH). This way you create a 6dB/oct crossover witch goes steeper into 12dB/oct at lower frequency's.
The cuttoff frequency of the horn is about 1.5kHz and as with all
horn you have to be sure that the tweeter doesn't get any input near that frequency (or at least 20 dB down). That's the point where horns start to shout and that exactly the thing why horns are given such a bad name. That's also one of the reasons a very steep crossover sounds better, I'm using then at 3kHz with a 90dB/oct crossover at the moment.
Feel free to experiment and don't give up. Thes are very good tweeters. I know there are better ones but at this price or even much higher. I like it a lot more than the top range scan speak and seas domes out there, I know because I have them too. But as with all speaker, it's the combination that counts.
With best regards,
Sjef
--------- Quote End -------------
Guys,
As I also own the Decca Superweeter box, have had hooked up with Howard Dawson. He provided some great info on protecting the unit by statying away of 6db/octave crossover (I don't know exactly what it means, I assume it's just one capacitor in series of the +ve terminal of the driver unit).
I would like to know if what HD recommended would also apply to the Gamma unit?
Cheers, iCefoX
As I also own the Decca Superweeter box, have had hooked up with Howard Dawson. He provided some great info on protecting the unit by statying away of 6db/octave crossover (I don't know exactly what it means, I assume it's just one capacitor in series of the +ve terminal of the driver unit).
I would like to know if what HD recommended would also apply to the Gamma unit?
Cheers, iCefoX
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