Post by Moz on Nov 18, 2007 8:12:42 GMT 7
Anyone willing to try this at home? This tweak is supposed to reduce distortion in the 70-140hz range and thus improve the sound of the LS3/5A
source:http://translate.google.com/translate?hl=en&sl=it&u=http://www.caninialtoparlanti.it/LS3.5A.htm&sa=X&oi=translate&resnum=2&ct=result&prev=/search%3Fq%3Dls35a%26start%3D60%26hl%3Den%26client%3Dsafari%26rls%3Den-us%26sa%3DN
LS3/5A improved Sergio Canini
For many broadcasters who see these little jewels of the presence of a defect and / or a malfunction in the same can cause severe embarrassment. It is repairing them. But where? Li repaired well? Torneranno as before?. This was also the concern of my client that I led them having noticed signs of trouble with a certain level. In fact he believed that the speaker had failed and that necessitassero a repair.
But before we talk about this a little history of these broadcasters. In the early 70 BBC have big monitors designed by Mr. Tannoy. Fountain for the most demanding sound.
T However these speakers, or for the size you want and why they were not without some defect such as bass and exuberant over the high directivity not paid to listen to individual use of phonics. In particular needed a small speaker to be used in studies within the mobile vans used for filming outside. Speakers of this type were already on the market. The Denton of Wharfedale were certainly capable.
But the BBC chose progettarli scratch, and I do not think so for reasons related to the quality of representation as to the rationality building, which would have facilitated repairs, and reliability, then reasons related to professional. Dell'equipe that developed the project was part Jim Rogers who had made known for his research on identifying sound-absorbing materials in the sheep's wool fiber long as suitable for use in speaker transmission line. (TL), which he produced and which were having great success in the market HiFi at the time. A Rogers was granted the first license for the construction and supply of LS3/5A (this was the name given to these speakers). After the license was given to Chartwell. Audiomaster, Spendor, Harbet, Richard Allan. Kef provided instead components and crossover. It seems strange that there is no supra Wharfedale from this list, leading created by CABriggs, one of the founding fathers dell'HiFi English. Course each manufacturer could sell this product to others who were not the BBC. Thus was born the legend LS3/5A. Jim Rogers, already legendary for TL with the sheep's wool, became bimito.
The Rogers which later produced an improved model of the same speakers in the name attributed JR 149. The components were the same, but the cabinet was to plant cylindrical and made of aluminum. Who has heard gives them a deeper bass (the limit LS3/5A) and greater dynamic range. In 1988 the BBC in turn brought changes to the design of crossover el'mpedenza nominal passed by 15 to the current 11 ohms. He also created the possibility of biwiring, which casts a shadow on the ability of the BBC project, given the uselessness of this technical device.
Returning to our times, what my client had emphasized was indeed the limit these speakers designed, repeat it, to work inside a van, and then with modest powers, and have a volume equal to that a box of shoes. The problem, which I then analyzed in the laboratory, which was in the range 70-140 Hz, amplitude signals above 15 volts, sending saturating the small woofer Kef B110, with strong production and sudden harmonic type pernacchia, an insult that poor Jim certainly did not deserve the blame even though this was his as the author of the project. Indeed, probably in an attempt to give a bit of substance to reproduction, Jim set the factor of merit resonance system to the value of 1.3, significantly above and that left the woofer lacks control in that range, hence the distortion . A filter passaalto could solve the problem but would further penalized the bass. A filter passaalto that come into function only with strong signals would have solved without penalizing.
The circuit visible on the right has proved suitable for this purpose. The bulb filament a cold that has a resistance of less than 1 ohm and more than 30 ohms when it is glowing. In this way the bulb acts as a bypass for the condenser (that is the filter passaalto) only when the signal is weak, but loses this function gradually that the signal becomes stronger and that consequently the filament heats. The condenser is not polarized, 100uF, 100 volt (or more), the bulb-type tube 18 watt 12 volt.
The values of the components in this case was chosen because of the fact that the speakers of my client work together with dedicated subwoofer. The low range of LS3/5A is slightly relieved but in this case it is inavvertibile. The power applicable, without causing distortion, has gone from about 20 to (approximately) 90 watts
Who uses broadcasters without diving and want to penalize the bass as little as possible, you can increase the capacity up to 200 uF, adding a second element to 100 in parallel to the first (outlined in the plan) At the same purpose, the single bulb 12 volts may be replaced by two 24-volt always in parallel. It goes without saying that more permissive becomes the circuit and will be less protective against distortion. To this end, this device can be tested and finally left outside the diffuser. The link is done in the series diffuser, which is among the more and more on your Diffuser.
Who wants, having experienced what values taken on the basis of their listening habits, the device can fit within the diffuser, and fix the magnet woofer with thermal glue or two or three laps tape telato. As shown by the photo above where you see the circuit with lamp and turned off (work !!!). To access within the diffuser will disassemble the front panel on the back which are set two speakers and crossover.
There is no need to disassemble the crossover, detaches from the woofer cable connected to the + terminal and connects to circuit protection (the circuit has not polarity, and then you can choose the entry and exit), then with a new cable is connect the output circuit + remained disconnected. One advantage of the occasion to fill in the box type of absorbent material polyurethane foam or fiberglass high density. This trick is in itself sufficient to solve the problem when the onset of distortion is sporadic and minor, and, in this case, I would suggest to adopt this measure first, then assess whether you need the protection circuit.
If you have difficulty in finding materials or build the device, contact me.
source:http://translate.google.com/translate?hl=en&sl=it&u=http://www.caninialtoparlanti.it/LS3.5A.htm&sa=X&oi=translate&resnum=2&ct=result&prev=/search%3Fq%3Dls35a%26start%3D60%26hl%3Den%26client%3Dsafari%26rls%3Den-us%26sa%3DN
LS3/5A improved Sergio Canini
For many broadcasters who see these little jewels of the presence of a defect and / or a malfunction in the same can cause severe embarrassment. It is repairing them. But where? Li repaired well? Torneranno as before?. This was also the concern of my client that I led them having noticed signs of trouble with a certain level. In fact he believed that the speaker had failed and that necessitassero a repair.
But before we talk about this a little history of these broadcasters. In the early 70 BBC have big monitors designed by Mr. Tannoy. Fountain for the most demanding sound.
T However these speakers, or for the size you want and why they were not without some defect such as bass and exuberant over the high directivity not paid to listen to individual use of phonics. In particular needed a small speaker to be used in studies within the mobile vans used for filming outside. Speakers of this type were already on the market. The Denton of Wharfedale were certainly capable.
But the BBC chose progettarli scratch, and I do not think so for reasons related to the quality of representation as to the rationality building, which would have facilitated repairs, and reliability, then reasons related to professional. Dell'equipe that developed the project was part Jim Rogers who had made known for his research on identifying sound-absorbing materials in the sheep's wool fiber long as suitable for use in speaker transmission line. (TL), which he produced and which were having great success in the market HiFi at the time. A Rogers was granted the first license for the construction and supply of LS3/5A (this was the name given to these speakers). After the license was given to Chartwell. Audiomaster, Spendor, Harbet, Richard Allan. Kef provided instead components and crossover. It seems strange that there is no supra Wharfedale from this list, leading created by CABriggs, one of the founding fathers dell'HiFi English. Course each manufacturer could sell this product to others who were not the BBC. Thus was born the legend LS3/5A. Jim Rogers, already legendary for TL with the sheep's wool, became bimito.
The Rogers which later produced an improved model of the same speakers in the name attributed JR 149. The components were the same, but the cabinet was to plant cylindrical and made of aluminum. Who has heard gives them a deeper bass (the limit LS3/5A) and greater dynamic range. In 1988 the BBC in turn brought changes to the design of crossover el'mpedenza nominal passed by 15 to the current 11 ohms. He also created the possibility of biwiring, which casts a shadow on the ability of the BBC project, given the uselessness of this technical device.
Returning to our times, what my client had emphasized was indeed the limit these speakers designed, repeat it, to work inside a van, and then with modest powers, and have a volume equal to that a box of shoes. The problem, which I then analyzed in the laboratory, which was in the range 70-140 Hz, amplitude signals above 15 volts, sending saturating the small woofer Kef B110, with strong production and sudden harmonic type pernacchia, an insult that poor Jim certainly did not deserve the blame even though this was his as the author of the project. Indeed, probably in an attempt to give a bit of substance to reproduction, Jim set the factor of merit resonance system to the value of 1.3, significantly above and that left the woofer lacks control in that range, hence the distortion . A filter passaalto could solve the problem but would further penalized the bass. A filter passaalto that come into function only with strong signals would have solved without penalizing.
The circuit visible on the right has proved suitable for this purpose. The bulb filament a cold that has a resistance of less than 1 ohm and more than 30 ohms when it is glowing. In this way the bulb acts as a bypass for the condenser (that is the filter passaalto) only when the signal is weak, but loses this function gradually that the signal becomes stronger and that consequently the filament heats. The condenser is not polarized, 100uF, 100 volt (or more), the bulb-type tube 18 watt 12 volt.
The values of the components in this case was chosen because of the fact that the speakers of my client work together with dedicated subwoofer. The low range of LS3/5A is slightly relieved but in this case it is inavvertibile. The power applicable, without causing distortion, has gone from about 20 to (approximately) 90 watts
Who uses broadcasters without diving and want to penalize the bass as little as possible, you can increase the capacity up to 200 uF, adding a second element to 100 in parallel to the first (outlined in the plan) At the same purpose, the single bulb 12 volts may be replaced by two 24-volt always in parallel. It goes without saying that more permissive becomes the circuit and will be less protective against distortion. To this end, this device can be tested and finally left outside the diffuser. The link is done in the series diffuser, which is among the more and more on your Diffuser.
Who wants, having experienced what values taken on the basis of their listening habits, the device can fit within the diffuser, and fix the magnet woofer with thermal glue or two or three laps tape telato. As shown by the photo above where you see the circuit with lamp and turned off (work !!!). To access within the diffuser will disassemble the front panel on the back which are set two speakers and crossover.
There is no need to disassemble the crossover, detaches from the woofer cable connected to the + terminal and connects to circuit protection (the circuit has not polarity, and then you can choose the entry and exit), then with a new cable is connect the output circuit + remained disconnected. One advantage of the occasion to fill in the box type of absorbent material polyurethane foam or fiberglass high density. This trick is in itself sufficient to solve the problem when the onset of distortion is sporadic and minor, and, in this case, I would suggest to adopt this measure first, then assess whether you need the protection circuit.
If you have difficulty in finding materials or build the device, contact me.
