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In Reply to: RE: There's Nothing Wrong With Your c.j. amps: posted by Vinylly on July 02, 2009 at 09:47:57
my concern is that i have 12 el34 output tubes in there. If something arcs and blows a panel, it could get expensive.
Again, add the protection boards and I don't care if there are 100 EL34 they will not damage the panels. You can drive the speakers as hard and as loud as you like, 100+dB, no problems.
Arcing and blown panels are history with proper protection.
.
"If people don't want to come, nothing will stop them" - Sol Hurok
There is no down side. Since the circuit is parallel with the audio signal it actually does nothing until the the maximum voltage of the tweeter element is reached and then the board engages preventing the voltage from swinging any higher. Sounds like a tube amp clipping when this occurs.
Contrary to the claims made by our friend STP, there is no dynamic constriction caused by the board. It does the opposite actually, the speaker will have more dynamic swing than before because one need not fear toasting an element.
Hi Travis,
Installing protective boards will have plenty of down sides. The biggest one is that it will severely restrict the dynamic range of the speaker, which is probably the most cherished property of any speaker.
I have been using Quads for the last 40 years both in the single, double
and even in triple configurations. Doubling and tripling were done in order to increase their dynamic range which I value greatly.
Today, however I am using a single pair. These Quads are however not the
ordinary variety. They are modified by replacing the original treble/mid
panels by a new totally arc-proof ones that can handle any power you are
likely to throw at it without any problems giving you also markedly
extended sizzling highs with added transparency, opennes and immediacy
I haven't heard before. And all this without installing any clamping/protective boards whatsoever - If you'd like to know more about it, please send me an email.
Regards,
David
Beyond the claim of limiting dynamic range, what are the other negative sonic effects of the protection board?
Have you ever heard the protection board?
I agree with Kentaja: protection boards robbing your dynamics is total baloney. And I'd have to be rather sceptical about any 'totally new arc-proof' panels as well. At least until further specification.
Completing my earlier post:
__Kentaya wrote: "There is no down side. Since the circuit is parallel with the audio signal it actually does nothing until the the maximum voltage of the tweeter element is reached and then the board engages preventing the voltage from swinging any higher. Sounds like a tube amp clipping when this occurs."
Now precisely because the board limits the maximum voltage entering the element it prevents it being more dynamic. Quad stated that the maximum voltage the panel can handle is 35 V peak. If it could handle more than that then it's dynamic range would be much broader.
This is exactly what the SUPER TREBLE PANEL I have does.
Also when the limiter kicks in Kentaya says: "Sounds like a tube amp clipping". Now what is this if not a sonic impact?
Believe me my friend the original 1950-s technology treble panel is a dead horse. Spending more money by adding to it a protection board is nothing more than flogging that dead horse.
If you are interested to see what my SUPER TREBLE PANEL looks like then
please send me an email and in my reply to it I will send you a picture
of it and provide more detail.
Best regards,
David
G'Day,
As the title says. This is not, by some weird chance, Otto Major's Jantzenisation of the original panel with a wire grid back stator and so forth is it?
Regards,
Gary Jacobson
Hi Gary,
No it is not. The panels you bought from him in 1998 when he started
manufacturing these was nothing more than a prototype, beta version
if you like. 11 years later, the present ones are now vastly different and much better.
I know because I had them both.
Best regards,
David
G'Day,
One would hope that they would have to be better and would have to judge the present crop on their performance; of course. I was mightily **unimpressed** with the originals, I can tell you. Sounded nothing whatever like an original Quad treble panel and measured poorly also with a significant loss of HF. No dust cover, and so they were a bit prone to being unreliable for that reason as well. The back stator was composed of strands of computer data cable (separated) carrying ht music signal and would flex a great deal more than a perforated plate - this is in the style of Jantzens stator (wire) designs. Nothing new there.
However, that is, as you say, 10 years ago. I would like to see a pair for review if they are available and I imagine so would kentaja. I for one, would need to have physical measurements as well as listening tests to convince me that these panels had improved at all.
So, tell us, by all means, what has changed? Materials, mode of construction? Nothing to hide. After all the original Quad materials and structure are well known, but that doesn't mean everyone has the skills to rebuild them, as you know, so I don't see a risk in publishing the basic material and structural innovations, except those you think are truly patentable, perhaps.
Oh yes, and the ones I have were not sold as "prototypes" but equivalent production replacements for the original panel. They were not.
Regards,
Gary Jacobson
Hi David,Your original statement was:
Installing protective boards will have plenty of down sides. The biggest one is that it will severely restrict the dynamic range of the speaker, ....
First I'd like to suggest a change of nomenclature, and instead of 'dynamics' use 'maximum output' which is more to the point. (Dynamics implies a range, a comparison between the low and high value. That's not what we are discussing here).
According to your statement, the speaker would have lower maximum output with the protective board than without it. But without the board, the maximum output is still limited to about the same level by the capabilities of the treble panel. So I can't agree with your original statement. Installing a protection board will not lower the maximum output (or only very slightly, and you would not want to be running your panel that hot without it).
If you change the treble panel so it can withstand higher signal voltage, then yes of course the protective board would limit the maximum SPL.
For original unrefurbished speakers, I think it's wise to install the protection boards. Why? Because old panels have lost about 4 to 6 dB of SPL (because of lowered sensitivity) and one is likely to turn up the wick far enough to burn the treble panel to a crisp. With a refurbished panel this is much less likely, in fact I have never toasted a panel even without protection.
I suppose this is because the speaker is going to distort quite a bit when playing at maximum volume, especially the stock bass panel, which (IMO) is not quite up to par with the rest of the system. The sound becomes congested and I naturally turn down the volume. That's why I don't see the point of making the treble panel arc-proof if you don't address the rest of the speaker. By the way I have plenty of ideas to do just that, but time is limiting progress in that area.
Out of curiosity I would be interested to hear more about this 'super panel', where does it come from and what does it look like? Please send me a message if you can't post it on this board.
Edits: 07/05/09 07/05/09
Well the Quad has been called a 'dead horse' many times over the decades. Some how the old horse manages to keep plodding along providing a thrilling experience for their owners!
35V is a maximum value and I believe that generally Quad stated the limit at 33V. That as a practical matter is the limit because some of the original Quad produced panels will arc before 33V is hit even when new. There was WIDE variation in build quality on the Quad plant floor in those days. I can rebuild a factory type panel that will handle 35V, even greater, without arcing, without changing a thing about the panel, just careful construction.
But even if one can develop a tweeter element that will handle a 100V and play 120dB that is not of much use. The bass elements will start bottoming out and falling all over themselves way before then. On bass heavy music they will be lucky to achieve 95dB before giving up the ghost. So the limiter in terms of SPL output of the speaker is not the tweeter element but the bass elements. A stock tweeter element working correctly will easily achieve 102dB. An improved tweeter element with greater SPL capability will not change a thing with the speakers overall SPL output so what is the point? The factory tweeter in no way limits dynamic range of the speaker.
Yes the protection board inserts some small amount of distortion into the audio signal when tripped. That is the point! You have hit the wall. Time to turn things down a bit. But when the circuit is not engaged, i.e. protecting the panel, there is no sonic impact of any kind. Better a bit of benign distortion letting you know you have hit the maximum versus a flaming panel telling you the same thing don't you think? I would say that is a more than adequate trade-off.
Most folks are thrilled with the idea they can use any amplifier they wish without any fear of damaging the speaker! Count me firmly in that group. And one of the many upsides to the board is the speaker will be more muscular and dynamic since one can use a more muscular and dynamic amp versus the flea size amps that are typically recommended.
You are correct that it is time to stop fiddling with that out-of-date 1950's technology. PJW would have said the same thing. Buy an ESL63, the better speaker anway! (Tongue firmly planted in cheek.)
One can certainly produce a tweeter element for the Quad that would be 'arc-proof'. Just a combination of polarizing voltage, air gap and stator insulating material.
Of course this new 'arc-proof' panel will be totally different in character versus the stock panel because one if not all of the above mentioned parameters will have to change. One may like the 'arc-proof' panel better, nothing wrong with that, but it won't really be a Quad anymore.
Within the design parameters chosen by PJW, i.e. polarizing voltage, air gap and insulating material, making a tweeter element arc-proof is impossible except with the addition of the zener clamp board. While I have not heard the 'arc-proof' panel, I have heard many 'new' tweeter panels produced for the Quad over the years. They all sounded nice but a far cry from the stock panels.
Already here.
"If people don't want to come, nothing will stop them" - Sol Hurok
Hi Travis,
The link you provided is not relevant.
It is NOT a Quad Esl 57 loudspeaker.
O.K., I'll bite. What does an arc proof 57 panel look like and how does it work? Feel free to PM me if needed.
I haven't owned 57s in about 35 years because I could never be patient enough with their delicate nature, not to mention the dynamic restrictions. My two techie friends who do own them have no such qualifications.
"If people don't want to come, nothing will stop them" - Sol Hurok
Hi Travis,
I will gladly provide you and any of your friends with a picture and more
information about my SUPER TREBLE PANEL in an email but I don't have your email address. Please send me an email yourself so that I can reply to it.
Regards
David
Hi arend-jan,
Before I answer your present post let me state that I regard you as being
one of the most valuable inmate of our beloved Asylum. I have been reading
every one of your contributions and I fully agree with all of them. The onlyone that I do not agree with is your statement in your inmate profile
("Feedback arend-jan") when in "Music Preferences and Comments" section
in "System Weakness" you wrote "NARROW SWEETSPOT". And in "System Goals/
Comments" your answer was "YOU-ARE-THERE/THEY-ARE-HERE EXPERIENCE". And why would you have this wonderful experience? Please make sure that you are safely seated before I tell you why. BECAUSE OF THE SWEETSPOT. To regard it as a weakness is a misconception shared by almost everybody. One noted person who explains this so eloquently is no other than Mr. Roger Sanders, himself a highly regarded electrostatic loudspeaker manufacturer, who saw the light and tells you about it at last year's CES.
Please click on the link below.
http://www.youtube.com/watch?v=Vdf3VA06iSA
I will complete my post in a new message.
Hi David,
I had seen the Sanders video before. I must say my alarm bells immediately start ringing when I see someone single out one aspect of speaker design and put's that much emphasis on it. Especially when it is accompanied by pseudo science (which by my definition is the presentation of claims as facts without the supporting evidence, nor any pointers to previously scientific work to support the claims). It almost always is a sales pitch and nothing new under the sun. What amazes me even further is that there are no polar plots to be found on Sanders website. So he talks a lot about directivity, but does not show the measurements for his own speakers. Sorry if I sound so harsh towards Sanders, but this is the way I see it.
I could go into the claims that he makes in the video one by one, but I chose not to do so mostly because this forum is not a technical forum and probably 99% of the readers would be bored to death. Note that I do not necessarily disagree with his point of view, but I do disagree with the way he presents and over emphasises it.
Directivity is nothing new. Let me quote a piece written by Baxandall on this subject from circa 1988. Baxandall is a true genius when it comes to electrostatic loudspeaker theory, acoustics and electronics.
"Taking all aspects into account, it is evident that some loudspeaker directivity is always desirable, but that the nature of this directivity needs to be rather carefully controlled, both for good stereo imaging, and to avoid an unpleasant or unnatural quality in the overall sound received by listeners.
The directivity of a loudspeaker at very low frequencies cannot in practice be made very great, for any totally enclosed cabinet design has substantially zero low-frequency directivity, and a doublet design has a theoretical directivity index of 4.8dB. At higher frequencies, more directivity is desirable, so that the directivity must in practice be allowed to increase with rising frequency, but it is m,ost important that this increase should be achieved in a smooth and continuous manner. It is also important that the off-axis frequency responses which accompany this increase in directivity should not have exaggerated and unnatural features, such as pronounced peaks or dips, nor be if a shelving or step-like form (ref 13 = D.E.L. Shorter, 'A survey of performance criteria and design considerations for high quality monitoring loudspeakers' - Nov 1958)
Gently falling high-frequency responses are frequently met in natural circumstances, for example when listening to sounds that have travelled round corners (ref 13) so it is hardly surprising to find that the off-axis sound from loudspeakers should be arranged to have this kind of characteristic of the overall results is to be interpreted as natural sounding.
Not only should the directivity increase smoothly and continuously with frequency above a certain frequency, but also the magnitude of the increase should be appropriately optimized - sufficient to give good stereo conditions, but not so great that listening positions become unduly critical. If any large increase in directivity is allowed to occur by 1000 Hz, the reverberant sound will appear to be bass-heavy and dull, and yet, for good stereo, some directivity at 1000 Hz is desirable. In this respect a doublet system has a real advantage, for directivity at 10000 Hz is then obtainable without having to suffer a variation in directivity below this frequency."
Note that Baxandall is discussing directivity in the light of electrostatic speakers, which by nature have an increasing directivity with frequency, but one that is far too much when no measures have been taken to prevent this. The original Quad ESL also has a number of mechanisms in place to control directivity.
Let me finish with another quote from Baxandall:
"No single recipe can be confidently stated to be universally right, partly because personal preferences are inherently involved, but also because the optimum directional characteristcs are very considerably influenced by the acoustics of the room in which the loudspeakers will be used (ref 35, P.J. Walker, 'The sound of the room', August 1991)"
Thank you for this post. I did not want to post with this great of detail regarding directivity and directivity idex. It can be a complex subject for some to understand.
What is clear is Roger Sanders and Peter Walker/Peter Baxandall had completely different ideas about the importance of directivity. While I have not heard the Sanders speaker and the designer gives little if any details about his speaker, it is clear by the geometry of the electrostatic element, at some frequency, there will be a rapid and dramatic change in the directitivity index of the speaker. This change in directivity will be neither smooth or gradual in nature. PJW/PB would claim this sort of rapid change will produce an unnatural overall balance and unpredictable off-axis response(in-room).
PJW commented about this type of approach, i.e. rapid change in directivity 'Of course, out in the open that sounds fine, directivity doesn't come into it. And if the loudspeaker is raised up off the floor fairly close to the listener so that he hears mostly direct sound anyway, it makes practically no difference what you do with directivity. But when you move the speaker to different rooms and try them the reproduction varies from room to room more than you would like.'
'This is because the after-sound, if you like to call it that, has got the characteristic of the power output firmly attached to it, and so it's all bassy. That won't do. Neither is it any good to make the power response level and have the directivity jump up 6dB around 200-500 cycles - that would sound most unnatural.'
'So we tried about a dozen directivities and found that the best thing to do is to change the directivity gradually, never by more than a decibal in an octave, preferably less than that. The trouble with most loudspeakers is that where you change from the woofer to squawker or squawker to tweeter the diameter of the speaker changes sharply and so does the directivity.'
Nothing new or exciting about PJW comments, just science. Few loudspeaker designers pay any attention to directivity and power response. The focus is on flat on-axis frequency response. But without flat power response any given speakers performance will change dramatically from room to room. This is not the case with ESL63. It sounds remarkable predictable/similiar in various room.
I would be careful to draw any conclusions about directivity from the looks of the thing. As I understand it he's using circuit board for the stators with the copper layers in between. Or at least that is what his patent was about IIRC. So it would be possible to control directivity by means of an electrically segmented stator.
Then again, the only thing we can do is guess since there is no data available, just that it is "highly directional".
I'd be interested to get a copy of the piece that you quote P.J. Walker from. Can you tell me what it is? Or send me an e-mail if you can share a copy.
If you are interested in 'new' developments on the area of directivity, there is/has been a lively discussion going on on diyaudio about waveguides, dipoles, cardioid's and controlling directivity. Unfortunately it is a bit scattered across multiple threads (Geddes on waveguides, beyond the ariel, and some others). There are some goodies to be found though.
Another interesting source is the writings of "John Kreskovsky" on http://www.musicanddesign.com/ Lot's of good info there!
Agreed. But since I can't find any detailed information on the speaker, and I don't wish to purchase a pair for experimenting, the best one can do is guess as to what is going on.The quote from Peter Walker is from the interview he gave to The Absolute Sound issue 23, 1981. I have scanned the entire interview and have it one file. Drop me a private email and I will be happy to send you a copy.
Edits: 07/06/09
and here's some more on Sander's speakers since you said you could not find more information
If you genuinely want to help us, give us some real information. Where are the whitepapers on directivity? Where are the measurements? Polar plots? Full frequency response? Burst decay?The one's you link to classify as promotional material in my book, not as whitepapers.
Edits: 07/06/09
sorry if this did not meet your needs
maybe these articles will better meet your needs
here's some information you may find interesting, written by Sanders
I actually have a copy of that book.When I bought it many moons ago, I was hoping that it would help me understand how electrostatic loudspeakers work. It did not. This book is about following a fixed strategy to put together your own speaker, not about gaining any insight in how it works. I suppose 'cookbook' does say it all.
In that light, I don't see how mentioning this book is helping the discussion. It seems to me that you are more eager to take any opportunity to promote your husbands products, than to genuinely contribute to the discussion. Now I can understand this, but this forum is not the right place.
Regarding the cookbook, it has been of no use to me. If anyone wants to have it for shipping cost, send me a message.
Edits: 07/06/09
Arend-Jan, I have no idea who you are, but you've just come across as a nasty little bully, a sad waste of space internet-commando. Grow up.
wow......You don't know me and I find it very unfair for you to judge me. I have sincerely attempted to provide information that many others have said were very helpful to them.
have a super fantastic day,
Angela
.
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