Yamaha JA 6681B is different to Meyer MS1401
Sorry Radian, but you are quite wrong.
The Yamaha 6681B has major differences to the Meyer MS 1401 !!!
Here a quote from the original Meyer info, I have a copy of their original catalogue, but you can find it here as well:
http://de.scribd.com/doc/93567715/M...rence-for-by-Bob-McCarthy-Sound-Reinforcement
(page 61, 1.8.5 Driver Components)
An important note regarding remanufactured components: Meyer Sound remanufactures HF driver components originally manufactured by Yamaha (MS-1401A) and JBL (MS-2001A). If you examine these drivers you will plainly see the identification marks of these companies. Do not be confused. The end product is not compatible with these original parts and can not be substituted. These units are customized by Meyer Sound to achieve greatly improved performance and reliability.
Component modifications include:
Next modification was some extra feld inside the chamber to dampen fx as well.
So even if you are lucky and find an original Yamaha diaphragm, you have to get this ferrofluid out of the airgap first.
Another difference I was told: Meyer MS1401 drivers used ferrite magnets, Yamaha used alnico-5. Maybe Yamaha changed from their early 1980 versions (thats when the 6681B first was introduced) to later ferrite versions. This would also explain the price as Meyer 1401's were pretty cheap in USA while in Japan in the 80's, the 6681B was almost as dear as those expensive TAD drivers.
Also: Beware of so called "aftermarket" diaphragms!
To me, the original Yamaha is one of the worlds best drivers. But to really make them sing, you cannot work with a passive network! If you use prober bi-amping with lowpowered DHT SE-amps with passive 6dB filters right at the input of the amp and if you take into account, that an every tubeamp has kathode C's which define the low fx, then you know that you can change those C's against high-quality non-polarised Capacitors of exact that value you want the fx of your amp. This ideally is 450-500 Hz and then be prepared for something magic: All so called "horn-colourations" have gone completly. Reason: Any 6dB passive network cannot dampen the peak (R) of the driver at it's resonance frequency. 12dB kills the damping factor of the amp (which is already pretty low because we have those output transformers!). Same problem! This results in those colourations many cannot live with (including myself). But if you have a simple 6dB passive network correctly calculated in your tubeamp input, then all the sudden you have the output transformers directly on teh voicecoil, the amp has full control and all colourations are gone. And even more so, if the mid-treble-amp has changed values for the cathode C's, because high quality filmcaps sound way superior to electrolytics.
Now, the same goes for all those Altec Duplex drivers or Tannoy: Here we find the most crucial crossover near 1kHz, that very region the human ear is utmost sensitive (and 800Hz for many Altec 1" drivers is pretty damn close as well!).
If you throw out those nasty networks and swap to an bi-amp system as described above, you'll be positve surprised. Nevertheless, any 12" or 15" woofer running close to 1kHz is too me not good enough. A crossoverpoint of 400-500Hz is the best. I have heard those huge Sato horns going down to 140 Hz or so and then cut-off at 1400Hz (because above they sound pretty bad). Same problem, you come near this critical 1kHz region.
So we come to the question which woofer system? Onken or Petite Onken. Fantastic quality (but use high quality ply). Or large open baffle with one or two 15" woofers. But bi-amped! No passive network. They do just way way too much damage.
Sorry Radian, but you are quite wrong.
The Yamaha 6681B has major differences to the Meyer MS 1401 !!!
Here a quote from the original Meyer info, I have a copy of their original catalogue, but you can find it here as well:
http://de.scribd.com/doc/93567715/M...rence-for-by-Bob-McCarthy-Sound-Reinforcement
(page 61, 1.8.5 Driver Components)
An important note regarding remanufactured components: Meyer Sound remanufactures HF driver components originally manufactured by Yamaha (MS-1401A) and JBL (MS-2001A). If you examine these drivers you will plainly see the identification marks of these companies. Do not be confused. The end product is not compatible with these original parts and can not be substituted. These units are customized by Meyer Sound to achieve greatly improved performance and reliability.
Component modifications include:
- Ferrofluid injection to prevent coil overheating.
- Adhesive overhaul to improve immunity to heat and acceleration.
- Compliance modification to decrease distortion and extend mechanical life.
- Weather resistance to improve immunity to moisture.
Next modification was some extra feld inside the chamber to dampen fx as well.
So even if you are lucky and find an original Yamaha diaphragm, you have to get this ferrofluid out of the airgap first.
Another difference I was told: Meyer MS1401 drivers used ferrite magnets, Yamaha used alnico-5. Maybe Yamaha changed from their early 1980 versions (thats when the 6681B first was introduced) to later ferrite versions. This would also explain the price as Meyer 1401's were pretty cheap in USA while in Japan in the 80's, the 6681B was almost as dear as those expensive TAD drivers.
Also: Beware of so called "aftermarket" diaphragms!
To me, the original Yamaha is one of the worlds best drivers. But to really make them sing, you cannot work with a passive network! If you use prober bi-amping with lowpowered DHT SE-amps with passive 6dB filters right at the input of the amp and if you take into account, that an every tubeamp has kathode C's which define the low fx, then you know that you can change those C's against high-quality non-polarised Capacitors of exact that value you want the fx of your amp. This ideally is 450-500 Hz and then be prepared for something magic: All so called "horn-colourations" have gone completly. Reason: Any 6dB passive network cannot dampen the peak (R) of the driver at it's resonance frequency. 12dB kills the damping factor of the amp (which is already pretty low because we have those output transformers!). Same problem! This results in those colourations many cannot live with (including myself). But if you have a simple 6dB passive network correctly calculated in your tubeamp input, then all the sudden you have the output transformers directly on teh voicecoil, the amp has full control and all colourations are gone. And even more so, if the mid-treble-amp has changed values for the cathode C's, because high quality filmcaps sound way superior to electrolytics.
Now, the same goes for all those Altec Duplex drivers or Tannoy: Here we find the most crucial crossover near 1kHz, that very region the human ear is utmost sensitive (and 800Hz for many Altec 1" drivers is pretty damn close as well!).
If you throw out those nasty networks and swap to an bi-amp system as described above, you'll be positve surprised. Nevertheless, any 12" or 15" woofer running close to 1kHz is too me not good enough. A crossoverpoint of 400-500Hz is the best. I have heard those huge Sato horns going down to 140 Hz or so and then cut-off at 1400Hz (because above they sound pretty bad). Same problem, you come near this critical 1kHz region.
So we come to the question which woofer system? Onken or Petite Onken. Fantastic quality (but use high quality ply). Or large open baffle with one or two 15" woofers. But bi-amped! No passive network. They do just way way too much damage.
Actual facts versus hot air
It's not much worth! People say a lot. How do they listen? What is their equipment? How much experience. Paper is patient, the www even more. An opinion is just that, an opionion. Based on what? Hearsay?
The size (1", 1,4", 2" etc) is defined by the diameter of the opening of the driver which is then connected to the horn. The Yamaha 6681B has exactly 1,4" and thus, is a 1,4" driver. Many drivers have those conical extensions. That''s part of their construction. You cannot "plug" the diaphragm directly onto the horn! Period.
The phenolic diaphragm is an aftermarket diaphragm. Maybe good as a contraceptive!
But definetly zero alternative to the original Yamaha diaphragm, which uses those fantastic Beryllium fingers for suspension. Quite similar to the Goodmans Axiom 80. It was Walt Bender (Audiomart) who made those drivers famous for Audio but he did not know the difference of the MS1401 to the 6681B then.
I have compared the Yamaha with all TAD's. The 4000 series (2") is a powerful horse, to me there is too much emphasis in the region of 400-800Hz, to much power.
My favourite TAD is the 2002 on a tratrix horn (and lets not start a discussion about which horntype is the best, you can ONLY value this when you use a bi-amped SE DHT ampsystem, anything else is Kindergarden, too prone for failure due to what I described in my previous post).
If proberly driven, it becomes a matter of taste. You cannot say white wine is better than red wine. They are different. And if you run a ZYX MC cartridge with a Yamaha or a Koetsu Urushi with a TAD, you might get similar results. But if you run a Denon DL103 or some ELAC or Shure MM, you will get no results which really count. Again, Kindergarden. Would be as if driving a Porsche with a Fiat engine.
It's not much worth! People say a lot. How do they listen? What is their equipment? How much experience. Paper is patient, the www even more. An opinion is just that, an opionion. Based on what? Hearsay?
The size (1", 1,4", 2" etc) is defined by the diameter of the opening of the driver which is then connected to the horn. The Yamaha 6681B has exactly 1,4" and thus, is a 1,4" driver. Many drivers have those conical extensions. That''s part of their construction. You cannot "plug" the diaphragm directly onto the horn! Period.
The phenolic diaphragm is an aftermarket diaphragm. Maybe good as a contraceptive!
But definetly zero alternative to the original Yamaha diaphragm, which uses those fantastic Beryllium fingers for suspension. Quite similar to the Goodmans Axiom 80. It was Walt Bender (Audiomart) who made those drivers famous for Audio but he did not know the difference of the MS1401 to the 6681B then.
I have compared the Yamaha with all TAD's. The 4000 series (2") is a powerful horse, to me there is too much emphasis in the region of 400-800Hz, to much power.
My favourite TAD is the 2002 on a tratrix horn (and lets not start a discussion about which horntype is the best, you can ONLY value this when you use a bi-amped SE DHT ampsystem, anything else is Kindergarden, too prone for failure due to what I described in my previous post).
If proberly driven, it becomes a matter of taste. You cannot say white wine is better than red wine. They are different. And if you run a ZYX MC cartridge with a Yamaha or a Koetsu Urushi with a TAD, you might get similar results. But if you run a Denon DL103 or some ELAC or Shure MM, you will get no results which really count. Again, Kindergarden. Would be as if driving a Porsche with a Fiat engine.
Read the part about Meyer vs. Yamaha - they are *identical* diaphragms.
Meyer mods the diaphragms with various shemes - foam blocks, doping, etc... otherwise they are the SAME. 100%.
As far as making them "sing" I see no reason that a passive xover will not work - depending on what you use or do. I don't know of any active xovers that are as clean *so far*. A passive xover in the amp or before the amp is also an option of interest.
_-_-bear
Meyer mods the diaphragms with various shemes - foam blocks, doping, etc... otherwise they are the SAME. 100%.
As far as making them "sing" I see no reason that a passive xover will not work - depending on what you use or do. I don't know of any active xovers that are as clean *so far*. A passive xover in the amp or before the amp is also an option of interest.
_-_-bear
Neither active nor passive networks but bi-amping
If the are *identical* diaphragms then how do you explain this:
Identical means identical, not modified. A modified diaphragm with glued on foam block etc is not identical but different.
Plus there are further mods, i.e. mentioned "ferrofluid" which damages the voicecoil.
I didn't say that a passive network will not work, of course it will work. But how it works can be heard when one compares it with the ideal.
I also did not mention active xovers as I can't stand those either. The question is how far does one's interest go by evaluating a "passive xover in the inputstage" of a tube-amp (forget solid-state with compression drivers). One has to hear it and then compare to passive networks. As mentioned, this is about bi-amping with
passive networks in both amps.
I have done so and compared it with the best passive networks (designed by Jean Hiraga). The difference is breathtaking, you can hear the huge damage passive networks produce.
If the are *identical* diaphragms then how do you explain this:
Identical means identical, not modified. A modified diaphragm with glued on foam block etc is not identical but different.
Plus there are further mods, i.e. mentioned "ferrofluid" which damages the voicecoil.
I didn't say that a passive network will not work, of course it will work. But how it works can be heard when one compares it with the ideal.
I also did not mention active xovers as I can't stand those either. The question is how far does one's interest go by evaluating a "passive xover in the inputstage" of a tube-amp (forget solid-state with compression drivers). One has to hear it and then compare to passive networks. As mentioned, this is about bi-amping with
passive networks in both amps.
I have done so and compared it with the best passive networks (designed by Jean Hiraga). The difference is breathtaking, you can hear the huge damage passive networks produce.
I have both Meyer and Yamaha. They sound identical once the foam has been carefully removed.
Never found any ferrite fluid in mine. Odeon, are you sure about this? And Odeon, there are no aftermarket diaphragms to beware of! Hence the problem with blown drivers.
I am curious of the difference between Truextent and the Yamahas.
BTW, if the TAD is more powerful in the lows it would be an excellent partner to the yamahas which to me sound more powerful above 1kHz. I need to audition the TADs and the Truextent soon!
The Yamahas still has some ringing sound that I don't always appreciate. I wonder if 100% Be would help here.
Never found any ferrite fluid in mine. Odeon, are you sure about this? And Odeon, there are no aftermarket diaphragms to beware of! Hence the problem with blown drivers.
I am curious of the difference between Truextent and the Yamahas.
BTW, if the TAD is more powerful in the lows it would be an excellent partner to the yamahas which to me sound more powerful above 1kHz. I need to audition the TADs and the Truextent soon!
The Yamahas still has some ringing sound that I don't always appreciate. I wonder if 100% Be would help here.
Last edited:
Major difference between: Meyer Sound MS-1401A and Yamaha JA6681
I am certain about this. My first 6 x Meyer drivers came from Walt Bender, who made them known through an ad in audiomart (which he run).
All of them had dried ferrofluid, damping on the aluminium diaphragms and daming
in the casing. All of them where ferrite (look like alnico from the outside). The early
Yamahas I have are alnico.
Later drivers had all removed but one could see marks
I don't know the Trueextents. Checked on their webside. TAD is Audio, Trueextent is PA. When developer (particular in Japan) create something with Audio-ears and particular with tube or single-ended amplifiers, possibly even with best vinyl as a source, I see much more sophistication behind compared to those modern developers who work with high-powered solid-state PA amps and active networks.
You can't compare PA with state of the art audio.
Which TAD? There are several. The 4000 series is more powerful in the lows as it is a 2" driver, the Yamaha is smaller, 1;4". The 2000 series is 1". Nevertheless, all will "shine in a different (sonic) light", if driven correctly, i.e. no passive network.
If you combine a TAD4003 with a Yamaha JA6681, you come into a very critical crossover region. To my ears the TAD4003 is too forward. The TAD2002, when driven without passive network, can sound beautifull.
That could come from the removal of the ferrofluid on the voicecoil. I heard that ringing as well with Meyers. Never with non-modified original Yamahas.
How do you know you've got Yamaha's and not re-modified Meyers?
The Meyer-Sound label is easely removed.
Meyer Sound stated Febr. 15th, 1999:
All Meyer Sound driver components are exclusively manufactured by Meyer Sound. Most of these are, in all aspects, proprietary designs. Other driver components are remanufactured from units originally built by outside vendors. All components are carefully designed, manufactured and rigorously tested.
The grading process routes the drivers into the enclosures where they will provide optimal performance. For example, the MS-15 (fifteen-inch LF driver) is used in both the MSL-2A and USW-1 systems. The MS-15 for MSL-2A requires a high degree of linearity from 40 Hz through the midband, whereas the USW-1 only needs to reach 100 Hz. The MS-15 for the MSL-2A is graded "Silver."
Every component of every loudspeaker manufactured by Meyer Sound is analyzed to verify that its frequency response, phase response and distortion characteristics fall within our specifications. There are no exceptions.
An important note regarding remanufactured components: Meyer Sound remanufactures HF driver components originally manufactured by Yamaha (MS-1401A) and JBL (MS-2001A). If you examine these drivers you will plainly see the identification marks of these companies. Do not be confused. The end product is not compatible with these original parts and can not be substituted. These units are customized by Meyer Sound to achieve greatly improved performance and reliability.
Component testing includes:
Component modifications include:
[SIZE=-1][SIZE=-1]Produced by Meyer Sound Laboratories
Copyright © 1999 Meyer Sound Laboratories
All rights reserved
Meyer Sound Design Reference for by Bob McCarthy Sound Reinforcement
[/SIZE][/SIZE]
I am certain about this. My first 6 x Meyer drivers came from Walt Bender, who made them known through an ad in audiomart (which he run).
All of them had dried ferrofluid, damping on the aluminium diaphragms and daming
in the casing. All of them where ferrite (look like alnico from the outside). The early
Yamahas I have are alnico.
Later drivers had all removed but one could see marks
I don't know the Trueextents. Checked on their webside. TAD is Audio, Trueextent is PA. When developer (particular in Japan) create something with Audio-ears and particular with tube or single-ended amplifiers, possibly even with best vinyl as a source, I see much more sophistication behind compared to those modern developers who work with high-powered solid-state PA amps and active networks.
You can't compare PA with state of the art audio.
Which TAD? There are several. The 4000 series is more powerful in the lows as it is a 2" driver, the Yamaha is smaller, 1;4". The 2000 series is 1". Nevertheless, all will "shine in a different (sonic) light", if driven correctly, i.e. no passive network.
If you combine a TAD4003 with a Yamaha JA6681, you come into a very critical crossover region. To my ears the TAD4003 is too forward. The TAD2002, when driven without passive network, can sound beautifull.
That could come from the removal of the ferrofluid on the voicecoil. I heard that ringing as well with Meyers. Never with non-modified original Yamahas.
How do you know you've got Yamaha's and not re-modified Meyers?
The Meyer-Sound label is easely removed.
Meyer Sound stated Febr. 15th, 1999:
All Meyer Sound driver components are exclusively manufactured by Meyer Sound. Most of these are, in all aspects, proprietary designs. Other driver components are remanufactured from units originally built by outside vendors. All components are carefully designed, manufactured and rigorously tested.
The grading process routes the drivers into the enclosures where they will provide optimal performance. For example, the MS-15 (fifteen-inch LF driver) is used in both the MSL-2A and USW-1 systems. The MS-15 for MSL-2A requires a high degree of linearity from 40 Hz through the midband, whereas the USW-1 only needs to reach 100 Hz. The MS-15 for the MSL-2A is graded "Silver."
Every component of every loudspeaker manufactured by Meyer Sound is analyzed to verify that its frequency response, phase response and distortion characteristics fall within our specifications. There are no exceptions.
An important note regarding remanufactured components: Meyer Sound remanufactures HF driver components originally manufactured by Yamaha (MS-1401A) and JBL (MS-2001A). If you examine these drivers you will plainly see the identification marks of these companies. Do not be confused. The end product is not compatible with these original parts and can not be substituted. These units are customized by Meyer Sound to achieve greatly improved performance and reliability.
Component testing includes:
- Overnight burn-in.
- Flux density analysis.
- Driver polarity verification.
- Frequency response analysis.
- Phase response analysis.
- Distortion analysis.
- Free air resonance verification.
Component modifications include:
- Ferrofluid injection to prevent coil overheating.
- Adhesive overhaul to improve immunity to heat and acceleration.
- Compliance modification to decrease distortion and extend mechanical life.
- Weather resistance to improve immunity to moisture.
[SIZE=-1][SIZE=-1]Produced by Meyer Sound Laboratories
Copyright © 1999 Meyer Sound Laboratories
All rights reserved
Meyer Sound Design Reference for by Bob McCarthy Sound Reinforcement
[/SIZE][/SIZE]
Okay, I believe you. Is there a safe way to remove the ferrofluid? I tried to remove some from my Atlas horn drivers, with paper in the magnet gap. I can't say they sounded much better. Different...
I have read the reverse - that some people favor the Truextent above TAD 4000 series. But that is hearsay, so it doesn't really matter. Remember, the JA6681B is a PA driver.
You mentioned before you put a passive crossover in the tube amp for a biamping the JA6681B. Would you explain to me how I could make this Sun Audio 2A3 tube amplifier have a 1st order highpass@330Hz before the output transformer? http://www.goodsoundclub.com/Site_Images/Sun-Audio_VT-2A3_3.JPG
With a protection capacitor at 330Hz value (30uf?) in series with the plus pole of the JA6681B I can get a 2nd order highpass in total. Right?
BTW, I am not willing to not use a protection cap with these unobtainium diaphragms.
I have read the reverse - that some people favor the Truextent above TAD 4000 series. But that is hearsay, so it doesn't really matter. Remember, the JA6681B is a PA driver.
You mentioned before you put a passive crossover in the tube amp for a biamping the JA6681B. Would you explain to me how I could make this Sun Audio 2A3 tube amplifier have a 1st order highpass@330Hz before the output transformer? http://www.goodsoundclub.com/Site_Images/Sun-Audio_VT-2A3_3.JPG
With a protection capacitor at 330Hz value (30uf?) in series with the plus pole of the JA6681B I can get a 2nd order highpass in total. Right?
BTW, I am not willing to not use a protection cap with these unobtainium diaphragms.
Last edited:
Major difference between: Meyer Sound MS-1401A and Yamaha JA6681
It is not a matter of believe, this ain't religion. What matters are facts.
No, save for sure not. Because it is hardened due to age. The problem is that almost all liquids can also attack the laquer of the voicecoil.
When I got my original Yamahas, they where not that expensive yet.
Ferrofluid dampens. With 1st order passive networks (which Radian suggested right at the beginning of this thread) you get hardly ANY curve, because the resonance frequency is not dampened. Usually you need to attenuate the driver, because there is hardly any woofer with that efficiency. So the resistors kill the damping factor which is already low due to the output transformer (of a tubeamp).
The peak of the drivers resonance-frequency goes almost undampened and thus the driver shouts (terrible colourations). Thats why I don't give a damn about the listening results of so called speaker or driver shootouts, they use a simple network
and not one which is really suited.
Not so with 1.st order network at the input of an amplifier. Here the speaker gets
the full damping factor, the amp has the voicecoil in its "claws". Full force. Full damping. The voice coil does, what the amp demands.
No, it does not matter, and usually it will be PA people.
One used to say: Paper is Patient, now it is worse.
WRONG!
Yamaha designed those drivers for Audio and Monitor.
The Meyer Sound MS-1401A is a PA driver!
You cannot use the Yamaha (or Meyer) from 300Hz on. No way. It has to be used 450/500Hz.
You idea of a protection capacitor in series: Either you go passive-active, or you remain passive. To mix both is the sly-mans way of self-delusion. Why passive-active when killing it right away with a passive capacitor.
The protection of a C-R passive network at the input of a poweramp with 6dB is higher than a 12dB passive network.
You Sun-Audio, with its 100kohms input attenuator is a very straight usual design, the 6SN7 a kind of octal-version of the 12AX7.
Try (after the attenuator) 1800 picoF in series and then 200kohms resistor parallel
on ground (parallel)
A mathematical calculation is one thing, checking it with measuring instruments and fine-tuning another.
For the woofer-amp, no attenuator (no need for it, it has less efficiency):
68kohms in series, then 3000picoF parallel AND 200kohms parallel (first the C, then the R, i.e. on ground)
A better approach here for the wooferamp would be with high quality inductors, but those one would have to make oneself, as hardly available.
That .... in both cases is the -3dB point for 500Hz.
The midhigh-range amp can have much lower value cathode C's (AND HERE YOU
GET YOUR EXPTRA PROTECTION):
instead of 47uF and 100uF, use 2,2 uF high quality foil-capacitors. No need for V-Caps or similar, but I would use 250V or higher.
It is not a matter of believe, this ain't religion. What matters are facts.
No, save for sure not. Because it is hardened due to age. The problem is that almost all liquids can also attack the laquer of the voicecoil.
When I got my original Yamahas, they where not that expensive yet.
Ferrofluid dampens. With 1st order passive networks (which Radian suggested right at the beginning of this thread) you get hardly ANY curve, because the resonance frequency is not dampened. Usually you need to attenuate the driver, because there is hardly any woofer with that efficiency. So the resistors kill the damping factor which is already low due to the output transformer (of a tubeamp).
The peak of the drivers resonance-frequency goes almost undampened and thus the driver shouts (terrible colourations). Thats why I don't give a damn about the listening results of so called speaker or driver shootouts, they use a simple network
and not one which is really suited.
Not so with 1.st order network at the input of an amplifier. Here the speaker gets
the full damping factor, the amp has the voicecoil in its "claws". Full force. Full damping. The voice coil does, what the amp demands.
No, it does not matter, and usually it will be PA people.
One used to say: Paper is Patient, now it is worse.
WRONG!
Yamaha designed those drivers for Audio and Monitor.
The Meyer Sound MS-1401A is a PA driver!
You mentioned before you put a passive crossover in the tube amp for a biamping the JA6681B. Would you explain to me how I could make this Sun Audio 2A3 tube amplifier have a 1st order highpass@330Hz before the output transformer? http://www.goodsoundclub.com/Site_Images/Sun-Audio_VT-2A3_3.JPG
With a protection capacitor at 330Hz value (30uf?) in series with the plus pole of the JA6681B I can get a 2nd order highpass in total. Right?
BTW, I am not willing to not use a protection cap with these unobtainium diaphragms.
You cannot use the Yamaha (or Meyer) from 300Hz on. No way. It has to be used 450/500Hz.
You idea of a protection capacitor in series: Either you go passive-active, or you remain passive. To mix both is the sly-mans way of self-delusion. Why passive-active when killing it right away with a passive capacitor.
The protection of a C-R passive network at the input of a poweramp with 6dB is higher than a 12dB passive network.
You Sun-Audio, with its 100kohms input attenuator is a very straight usual design, the 6SN7 a kind of octal-version of the 12AX7.
Try (after the attenuator) 1800 picoF in series and then 200kohms resistor parallel
on ground (parallel)
A mathematical calculation is one thing, checking it with measuring instruments and fine-tuning another.
For the woofer-amp, no attenuator (no need for it, it has less efficiency):
68kohms in series, then 3000picoF parallel AND 200kohms parallel (first the C, then the R, i.e. on ground)
A better approach here for the wooferamp would be with high quality inductors, but those one would have to make oneself, as hardly available.
That .... in both cases is the -3dB point for 500Hz.
The midhigh-range amp can have much lower value cathode C's (AND HERE YOU
GET YOUR EXPTRA PROTECTION):
instead of 47uF and 100uF, use 2,2 uF high quality foil-capacitors. No need for V-Caps or similar, but I would use 250V or higher.
"goldenbeer is offline goldenbeer Germany
diyAudio Member
Join Date: Jan 2014
Do not try to control frequency response with bypass caps. No good for audio amps. If you need to, use the input coupling cap for this purpose."
This is the response from another fellow. It seems not everyone agrees with this idea.
diyAudio Member
Join Date: Jan 2014
Do not try to control frequency response with bypass caps. No good for audio amps. If you need to, use the input coupling cap for this purpose."
This is the response from another fellow. It seems not everyone agrees with this idea.
passive-active network for bi-amping
Yes, thats right.
Start just with the 6dB network at the input and listen.
I have calculated the network regarding you using the Yamaha with its
107dB efficiency, matching an about 100dB woofer system.
The critical point is the attenuator, one needs it to attenuate the driver
for any compression-driver usually will be more efficient than the woofer.
Because here we have not a fixed impedance but a variable, the only fixed impedance is the input R of the 6SN7.
Try to find somebody with an oscilloscope and a frequency generator. Run
the frequencies from 1kHz down to 200 Hz through your amp and see when you find the -3dB point. Adjust accordingly. Then apply the kathode C's and check again. That's the way to do it correctly
Yes, thats right.
Start just with the 6dB network at the input and listen.
I have calculated the network regarding you using the Yamaha with its
107dB efficiency, matching an about 100dB woofer system.
The critical point is the attenuator, one needs it to attenuate the driver
for any compression-driver usually will be more efficient than the woofer.
Because here we have not a fixed impedance but a variable, the only fixed impedance is the input R of the 6SN7.
Try to find somebody with an oscilloscope and a frequency generator. Run
the frequencies from 1kHz down to 200 Hz through your amp and see when you find the -3dB point. Adjust accordingly. Then apply the kathode C's and check again. That's the way to do it correctly
Okay, I will try to change the bypass cap and see what happens. I can use a software tone generator and a record a cheaper speaker with a mic. According to the calculator a 2.2uF would start decreasing below 1kHz. I should try maybe a 10uF bypass caps as well.
Regarden the attenuator - the Sun Audio 2A3 clone is integrated and I have a 100K Alps volum pot. I will put the PLLXO after the pot like in the schematic. The 15" JBL woofers have a more powerful amp anyway (800W PA amp). My woofers are actually around 100dB (~105dB in the horn?). Why would it matter though? I will use two amps in this experiment, each with its own volume pot. Right? If so, I wonder about the split. I would like to run it directly from the DAC into the tube amp without an active or passive splitter.
I have ordered some nice silver micas and teflon caps from Russia to make the PLLXO crossover you suggested. But then I read a guide to PLLXO and in that sheet the values where quite different than yours...
The guide with schematics: TLS.org | Passive Line-Level Crossover
Link to the excel spreadsheet: http://p10hifi.net/TLS/downloads/PLLXO_Calculator.xls.zip
When I put in the same values I don't get the same results as you at all. Also, if I would try 2nd order PLLXO I would run into trouble because the Sun Audio 2A3 has a 100K input impedance. It says in the spreadsheet that anything above 50K means that you should not use 2nd order.
Regarden the attenuator - the Sun Audio 2A3 clone is integrated and I have a 100K Alps volum pot. I will put the PLLXO after the pot like in the schematic. The 15" JBL woofers have a more powerful amp anyway (800W PA amp). My woofers are actually around 100dB (~105dB in the horn?). Why would it matter though? I will use two amps in this experiment, each with its own volume pot. Right? If so, I wonder about the split. I would like to run it directly from the DAC into the tube amp without an active or passive splitter.
I have ordered some nice silver micas and teflon caps from Russia to make the PLLXO crossover you suggested. But then I read a guide to PLLXO and in that sheet the values where quite different than yours...
The guide with schematics: TLS.org | Passive Line-Level Crossover
Link to the excel spreadsheet: http://p10hifi.net/TLS/downloads/PLLXO_Calculator.xls.zip
When I put in the same values I don't get the same results as you at all. Also, if I would try 2nd order PLLXO I would run into trouble because the Sun Audio 2A3 has a 100K input impedance. It says in the spreadsheet that anything above 50K means that you should not use 2nd order.
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Filter
You don't change any bypass caps, you are going to introduce a filter 1st. order
into your poweramp. The input C acts as a coupling cap and with the R as a filter.
The other C's are kathode caps
I hope you don't see much (i.e. fire, smoke, explosions
but that you HEAR..... music
bad idea. minus + minus doesn't make a plus in this case or eliminate errors.
You need to use a correct set-up. Find an engineer who knows.
If you are building amplifiers and do not use an oscilloscope... well....
With 10uF you go down in frequency. This is a cathode C
It matters, because you do NOT have 100k input impedance. Think about it
and find out why!
Sounds terrible, to use a 800W PA mudmonsteramp with a medicore 15" JBL
(have not found any useful JBL woofer yet, Lansing yes, but not JBL)
Kind of disimprovement. Wonder what midrange horn you are using.
Bad idea. You DAC most likely is not low enough in output impedance and strong enough to drive two stereo poweramps.
And what are those silver micas for?
possible start
but:
what defines the inputimpedance of your amplifier.
If you do not understand this, you should not use calculators like that.
Which components are there in the input, and which components are
variable in value and have to be estimated in relation to a desired result?
Does it really?
And why the heck use 2nd order anyway? What good is it for?
Which DAC are you using?
Which preamp do you have at hand?
Which music is your favourite and you are going to listen to with this equuipment?
You don't change any bypass caps, you are going to introduce a filter 1st. order
into your poweramp. The input C acts as a coupling cap and with the R as a filter.
The other C's are kathode caps
I hope you don't see much (i.e. fire, smoke, explosions
but that you HEAR..... music
bad idea. minus + minus doesn't make a plus in this case or eliminate errors.
You need to use a correct set-up. Find an engineer who knows.
If you are building amplifiers and do not use an oscilloscope... well....
With 10uF you go down in frequency. This is a cathode C
It matters, because you do NOT have 100k input impedance. Think about it
and find out why!
Sounds terrible, to use a 800W PA mudmonsteramp with a medicore 15" JBL
(have not found any useful JBL woofer yet, Lansing yes, but not JBL)
Kind of disimprovement. Wonder what midrange horn you are using.
better Right and Left, you are running two channels
Bad idea. You DAC most likely is not low enough in output impedance and strong enough to drive two stereo poweramps.
And what are those silver micas for?
possible start
but:
what defines the inputimpedance of your amplifier.
If you do not understand this, you should not use calculators like that.
Which components are there in the input, and which components are
variable in value and have to be estimated in relation to a desired result?
Does it really?
And why the heck use 2nd order anyway? What good is it for?
Which DAC are you using?
Which preamp do you have at hand?
Which music is your favourite and you are going to listen to with this equuipment?
Addition: Filters for passive network in amplifiers
you have 3 x cathode C's:
they act as frequency filters (with their resistors).
You can calculate this very easely:
1/(RC)=2*pi*f
with f=frequency, pi=3,14...., C in farad, so *10^-6 for µF, R in ohms
For the input filter, the calculation is much more difficult because it needs to take into acount the capacity of the grid / cathode of the input tube AND the frequency filter of the cathode C and R
If you calculate just the first cathode C correctly and you have verified through measurement, that it works at 500Hz, only then you can start working out and calculating the input filter. Nevertheless, I would continue with all other cathode C's as well.
Lets put it like this:
An exact filter through corrected/altered C at the first half of the 6SN7 will work as a -6dB slope alone!
And that's already 1000 x better than ANY passive -12dB network between amplifier and horndriver. Period! I have verified this many many times. To me, passive filters are sound-killers. But everybody listens to them, is used to them. They act like a heavy curtain which obscures light.
This is the only reason why in certain circles high efficient horndrivers are despised, they say that horndrivers shout, have colourations. They hear something right there, i.e. the colouration and mess of the passive networks. Its not the driver!
So back to the passive/active filter:
To make it perfect, you calculate (and verify through measuring) the cathode C's of the second half of the 6SN7 and cathode C of the 2A3.
With this formula: 1/(RC)=2*pi*f you calculate, with frequency generator and oscilloscope you verify.
Then .... and only then, you can calculate the input-filter!
You have now the new parameters of the input tube, its capacity (grid/cathode) and you have a variable resistor at the input (100k log or lin potentiometer, log is better of course). The 220kohm resistor defines a given input impedance (I hope you got this from my first posting!). You need a fix input impedance to calculate because you cannot use a variable 100k potentiometer, because it is variable. This should be clear as springwater! The variable 100kohms potentiometer has an effect on the input impedance anyway! How could it be otherwise? But we know that this potentiometer is needed to attenuate the compressiondriver. So you could just use 4700 pF here if you can't measure. It then acts just as a savety filter.
You took it that your amplifier has an input impedance of 100kohms, but I hope now you understand that this is wrong! You need to "give it" a fix input impedance and thats what the 220k resistor is for. The 220k value is chosen because of the 100k potentiometer.
If there would be no potentiometer, you could also use 20kohms, but that is theory and depends on other factors (for example in studios they use 600ohms balanced via input- and output transformers. Here one would have to work completly different (i.e. cathode C's)
A third place where you can change the filter is the coupling C itself between the driver 6SN7 and the 2A3: here 2,2uF/630V.
You see, this is not so easy. It needs somebody who understands the basics and can work with these formulas and measurements like a professional cook works with salt and pepper: He does not need to think anymore about salt and pepper, or how much heat for which meal or how much water for noodles, he just "does it", it is in his system, it is almost an automatic process.
These formulas and verification are the salt and pepper for this very cook called engineer. But these days we have so many cobblers. They do not understand the basics but then produce tubeamplifiers which when on the table of a real engineer "shocks even monkeys" (Peter Gabriel)
I have now given a lot of time to explain this. You have now the basics, but you've got to do it right. I.e. you need a good engineer who understands and who will help you. This should not be really expensive, but it is worth it!
you have 3 x cathode C's:
they act as frequency filters (with their resistors).
You can calculate this very easely:
1/(RC)=2*pi*f
with f=frequency, pi=3,14...., C in farad, so *10^-6 for µF, R in ohms
For the input filter, the calculation is much more difficult because it needs to take into acount the capacity of the grid / cathode of the input tube AND the frequency filter of the cathode C and R
If you calculate just the first cathode C correctly and you have verified through measurement, that it works at 500Hz, only then you can start working out and calculating the input filter. Nevertheless, I would continue with all other cathode C's as well.
Lets put it like this:
An exact filter through corrected/altered C at the first half of the 6SN7 will work as a -6dB slope alone!
And that's already 1000 x better than ANY passive -12dB network between amplifier and horndriver. Period! I have verified this many many times. To me, passive filters are sound-killers. But everybody listens to them, is used to them. They act like a heavy curtain which obscures light.
This is the only reason why in certain circles high efficient horndrivers are despised, they say that horndrivers shout, have colourations. They hear something right there, i.e. the colouration and mess of the passive networks. Its not the driver!
So back to the passive/active filter:
To make it perfect, you calculate (and verify through measuring) the cathode C's of the second half of the 6SN7 and cathode C of the 2A3.
With this formula: 1/(RC)=2*pi*f you calculate, with frequency generator and oscilloscope you verify.
Then .... and only then, you can calculate the input-filter!
You have now the new parameters of the input tube, its capacity (grid/cathode) and you have a variable resistor at the input (100k log or lin potentiometer, log is better of course). The 220kohm resistor defines a given input impedance (I hope you got this from my first posting!). You need a fix input impedance to calculate because you cannot use a variable 100k potentiometer, because it is variable. This should be clear as springwater! The variable 100kohms potentiometer has an effect on the input impedance anyway! How could it be otherwise? But we know that this potentiometer is needed to attenuate the compressiondriver. So you could just use 4700 pF here if you can't measure. It then acts just as a savety filter.
You took it that your amplifier has an input impedance of 100kohms, but I hope now you understand that this is wrong! You need to "give it" a fix input impedance and thats what the 220k resistor is for. The 220k value is chosen because of the 100k potentiometer.
If there would be no potentiometer, you could also use 20kohms, but that is theory and depends on other factors (for example in studios they use 600ohms balanced via input- and output transformers. Here one would have to work completly different (i.e. cathode C's)
A third place where you can change the filter is the coupling C itself between the driver 6SN7 and the 2A3: here 2,2uF/630V.
You see, this is not so easy. It needs somebody who understands the basics and can work with these formulas and measurements like a professional cook works with salt and pepper: He does not need to think anymore about salt and pepper, or how much heat for which meal or how much water for noodles, he just "does it", it is in his system, it is almost an automatic process.
These formulas and verification are the salt and pepper for this very cook called engineer. But these days we have so many cobblers. They do not understand the basics but then produce tubeamplifiers which when on the table of a real engineer "shocks even monkeys" (Peter Gabriel)
I have now given a lot of time to explain this. You have now the basics, but you've got to do it right. I.e. you need a good engineer who understands and who will help you. This should not be really expensive, but it is worth it!
Are these the drivers you've been discussing here?
Yamaha Ja 4281B Professional Horn Type 16 Ohm Tweeters Pair RARE | eBay
Expensive for vintage PA gear. You would think today's tech would trump this stuff any day of the week. Go figure!
Yamaha Ja 4281B Professional Horn Type 16 Ohm Tweeters Pair RARE | eBay
Expensive for vintage PA gear. You would think today's tech would trump this stuff any day of the week. Go figure!
Super-Twitters
Very good question. I love those advanced questions.
You can read, yes?
You can spell, yes?
This is no vintage PA gear, this is Audiogear and of very nice quality.
Thinking won't help... anyway, this is not thinking but daydreaming.
Real thinking helps you find out what technology is behind a product
and helps you to verify.
And then you make a choice based on weighing.. another faculty of thinking.
You are interested or not.
Then .... if you can... you listen and best leave thinking out completly.
Listening is like surfing, you need to learn it, by practice.
And then you think again: is it worth it.
Very good question. I love those advanced questions.
You can read, yes?
You can spell, yes?
This is no vintage PA gear, this is Audiogear and of very nice quality.
Thinking won't help... anyway, this is not thinking but daydreaming.
Real thinking helps you find out what technology is behind a product
and helps you to verify.
And then you make a choice based on weighing.. another faculty of thinking.
You are interested or not.
Then .... if you can... you listen and best leave thinking out completly.
Listening is like surfing, you need to learn it, by practice.
And then you think again: is it worth it.
odeon,
some of what you are saying does not always agree with my knowledge and experience.
1) Meyer managed to patent the drivers that Yamaha produced (this is a US patent). There are two patents. How this happened is entirely unclear, especially since it appears that the production of the 6681B in Japan predates the patents.
2) Meyer says a lot of things, but there is zero difference other than the doping that Meyer put on the diaphragms and the label on the back between them.
3) The 6681B has always been a ferrite magnet. See their original ads. They show a cutaway. Yamaha did make another model that was Alnico. Afaik, it had a standard diaphragm.
4) I have owned, tested and taken apart at least 20+ pairs of these drivers, all originally sold by Meyer with his label, none have shown any signs of ferrofluid. Not one. Ferrofluid can be wicked out then the gap cleaned with solvent. It is a silicone oil with microfine iron particles, so it ought to have no effect on the VC or formers. Ought not harden or thicken over time. Maybe if the VC was burned at high temps it might.
5) I use and have used these drivers down to ~250Hz. with a first order filter, in a home system (mine) for years. No problems at all. Would not suggest doing this for PA/SR work, or if you want to run at PA/SR levels. Just FYI I have played live as a band mixed with my system as the only in-room monitor, modest levels, probably ~95-97dB SPL average. Again no problems with the drivers.
6) more another time...
mayhem 13: no. those are different, but interesting drivers.
some of what you are saying does not always agree with my knowledge and experience.
1) Meyer managed to patent the drivers that Yamaha produced (this is a US patent). There are two patents. How this happened is entirely unclear, especially since it appears that the production of the 6681B in Japan predates the patents.
2) Meyer says a lot of things, but there is zero difference other than the doping that Meyer put on the diaphragms and the label on the back between them.
3) The 6681B has always been a ferrite magnet. See their original ads. They show a cutaway. Yamaha did make another model that was Alnico. Afaik, it had a standard diaphragm.
4) I have owned, tested and taken apart at least 20+ pairs of these drivers, all originally sold by Meyer with his label, none have shown any signs of ferrofluid. Not one. Ferrofluid can be wicked out then the gap cleaned with solvent. It is a silicone oil with microfine iron particles, so it ought to have no effect on the VC or formers. Ought not harden or thicken over time. Maybe if the VC was burned at high temps it might.
5) I use and have used these drivers down to ~250Hz. with a first order filter, in a home system (mine) for years. No problems at all. Would not suggest doing this for PA/SR work, or if you want to run at PA/SR levels. Just FYI I have played live as a band mixed with my system as the only in-room monitor, modest levels, probably ~95-97dB SPL average. Again no problems with the drivers.
6) more another time...
mayhem 13: no. those are different, but interesting drivers.