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#1
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Where can I find replacement JBL Speaker crossover caps, Vintage
I have a pair of JBL Decade L-36 3-ways, that I have since new way back in
'75-'76. They are in perfect condition, with the oak aging very nicely (they were more blonde originally, now have a medium patina). ANyway, I have had the woofers reconed so now I want to replace the corssover capacitors. Where is a good source to find the caps? Any ideas? |
#2
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Where can I find replacement JBL Speaker crossover caps, Vintage
On Sat, 6 Mar 2010 03:48:34 -0800, DMHenrie wrote
(in article ): I have a pair of JBL Decade L-36 3-ways, that I have since new way back in '75-'76. They are in perfect condition, with the oak aging very nicely (they were more blonde originally, now have a medium patina). ANyway, I have had the woofers reconed so now I want to replace the corssover capacitors. Where is a good source to find the caps? Any ideas? Do yourself a favor and replace your crossover caps with the same value(s) as are in the crossover NOW with polypropylene equivalents such as those shown he http://tinyurl.com/ybhqycp as well as other sources. Some brands that are good are Wonder Caps and Sidereal Caps, but there are others. http://www.laventure.net/parts4sale/capacitors.htm A little anecdote might illustrate their worth. A number of years ago, I was the owner of a "pair" of Magnepan Tympani III C speakers. I put the word 'pair' in quotes because These speakers consisted of EIGHT HUGE panels (two tweeter panels, two midrange panels and FOUR bass panels) which took-up the entire end of the room! Anyway, Magnepan shipped these speakers with the standard (at the time) oval shaped mylar capacitors in the crossover between the tweeter and the midrange (the woofers had their own amps and a low-level active crossover between the preamp and the amps). I ordered some Wonder Caps of the correct values to replace the stock mylars in the passive crossovers inside the speaker covers. The Saturday afternoon when I decided to change the caps, a buddy of mine was over at my place (as was his wont when he had nothing else to do). Now this guy was not an audio guy, but he did like music, and appreciated good sound. I got down on the floor behind the Maggies with soldering iron and tools and soon swapped out the polypropylene Wonder Caps for the stock mylars while my buddy read a magazine. He wasn't really paying any attention to what I was doing. When I was finished, I fired up the stereo and played some music. As walked back into the room (the stereo system was in an unused, adjacent bedroom) my buddy had put the magazine down and was staring in rapt attention at the speakers. "What did you just do?" He asked. I told him that I had just swapped capacitors in the crossover between the tweeters and midrange panels. Well, by this time I was in the room with the speakers and I too had noted that the speakers sounded as if several layers of blankets had been removed from them. They sounded so much cleaner and more transparent, that even my friend who hadn't been paying the slightest attention to what i was doing, noticed the improvement instantly. So did I. Putting good quality polypropylene caps in your crossover will revolutionize the sound of your speakers. It's NOT subtle. I can almost guarantee it. It is important, however to match the values in order not to move the rollover points. Many here will likely tell you that Walt Jung's research into dielectric absorption distortion in the 1980's has been largely discredited and perhaps he did misattribute the phenomenon, but the results certainly are real. I had a Hafler DH-101 preamp once that I built as a kit. Another friend bought the same kit at the same time and we both built them. He built his stock, and I replaced all the capacitors in the signal path with polypropylene units as I built mine. We arranged an ad-hoc double blind test of the two preamps at my digs. Our other buddies weren't told what the differences were between the two units. The preamps were connected to my power amps via a simple Switchcraft surface-mount 3 -in, 1-out stereo source switch. Remember, that my stereo was in a different room from the speakers. We all took turns switching between the two preamps and the outputs were matched exactly for level using an audio voltmeter. A Phillips CD player was "Y'd" between the two preamps. Everyone could hear the difference EVERY TIME the Hafler with the polypropylene caps was switched in. All kinds of music was played, and nobody ever got the two preamps mixed up the modified Hafler was cleaner, more transparent, and less fatiguing. So don't tell me that caps don't make a difference. |
#3
Posted to rec.audio.high-end
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Where can I find replacement JBL Speaker crossover caps, Vintage
On Mar 6, 11:24=A0am, Audio Empire wrote:
On Sat, 6 Mar 2010 03:48:34 -0800, DMHenrie wrote (in article ): I have a pair of JBL Decade L-36 3-ways, that I have since new way back= in '75-'76. They are in perfect condition, with the oak aging very nicely = (they were more blonde originally, now have a medium patina). ANyway, I have = had the woofers reconed so now I want to replace the corssover capacitors. Where is a good source to find the caps? Any ideas? Do yourself a favor and replace your crossover caps with the same value(s= ) as are in the crossover NOW with polypropylene equivalents such as those sho= wn he http://tinyurl.com/ybhqycp as well as other sources. Some brands that are good are Wonder Caps =A0an= d Sidereal Caps, but there are others. http://www.laventure.net/parts4sale/capacitors.htm A little anecdote might illustrate their worth. A number of years ago, I = was the owner of a "pair" of Magnepan Tympani III C speakers. I put the word 'pair' in quotes because These speakers consisted of EIGHT HUGE panels (t= wo tweeter panels, two midrange panels and FOUR bass panels) which took-up t= he entire end of the room! Anyway, Magnepan shipped these speakers with the standard (at the time) oval shaped mylar capacitors in the crossover betw= een the tweeter and the midrange (the woofers had their own amps and a low-le= vel active crossover between the preamp and the amps). I ordered some Wonder Caps of the correct values to replace the stock myl= ars in the passive crossovers inside the speaker covers. The Saturday afterno= on when I decided to change the caps, a buddy of mine was over at my place (= as was his wont when he had nothing else to do). Now this guy was not an aud= io guy, but he did like music, and appreciated good sound. I got down on the floor behind the Maggies with soldering iron and tools = and soon swapped out the polypropylene Wonder Caps for the stock mylars while= my buddy read a magazine. He wasn't really paying any attention to what I wa= s doing. =A0When I was finished, I fired up the stereo and played some musi= c. As walked back into the room (the stereo system was in an unused, adjacent bedroom) my buddy had put the magazine down and was staring in rapt atten= tion at the speakers. "What did you just do?" He asked. I told him that I had = just swapped capacitors in the crossover between the tweeters and midrange pan= els. Well, by this time I was in the room with the speakers and I too had note= d that the speakers sounded as if several layers of blankets had been remov= ed from them. They sounded so much cleaner and more transparent, that even m= y friend who hadn't been paying the slightest attention to what i was doing= , noticed the improvement instantly. So did I. Putting good quality polypropylene caps in your crossover will revolution= ize the sound of your speakers. It's NOT subtle. I can almost guarantee it. I= t is important, however to match the values in order not to move the rollover points. Many here will likely tell you that Walt Jung's research into dielectric absorption distortion in the 1980's has been largely discredited and perh= aps he did misattribute the phenomenon, but the results certainly are real. I= had a Hafler DH-101 preamp once that I built as a kit. Another friend bought = the same kit at the same time and we both built them. He built his stock, and= I replaced all the capacitors in the signal path with polypropylene units a= s I built mine. We arranged an ad-hoc double blind test of the two preamps at= my digs. Our other buddies weren't told what the differences were between th= e two units. The preamps were connected to my power amps via a simple Switchcraft surface-mount 3 -in, 1-out stereo source switch. Remember, th= at my stereo was in a different room from the speakers. We all took turns switching between the two preamps and the outputs were matched exactly fo= r level using an audio voltmeter. A Phillips CD player was "Y'd" between th= e two preamps. Everyone could hear the difference EVERY TIME the Hafler wit= h the polypropylene caps was switched in. All kinds of music was played, an= d nobody ever got the two preamps mixed up the modified Hafler was cleaner, more transparent, and less fatiguing. So don't tell me that caps don't ma= ke a difference. =A0 On speakers, changing the capacitor types can change the original intended sound due to changes in ESR, etc. Of course better tolerance is a good thing. Longevity is another good thing. If the sound suits you then you have done a good thing. greg |
#4
Posted to rec.audio.high-end
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Where can I find replacement JBL Speaker crossover caps, Vintage
"Audio Empire" wrote in message
... Putting good quality polypropylene caps in your crossover will revolutionize the sound of your speakers. It's NOT subtle. I can almost guarantee it. It is important, however to match the values in order not to move the rollover points. The most likely changes that putting film caps into a speaker crossover is that the actual capacitance values and ESR of the capacitors will change. If your speaker crossover has electrolytic caps in it, then they were probably specified to a tolerange of +/- 20% with +80, -20 being a possibility. The film caps will perform within just a few percent of their specified values. Good film caps will also reduce ESR which may or may not be good thing, but can make an audible difference. Note that if you reduce the ESR of parts in a speaker crossover, there may be adverse changes in frequency response. Many here will likely tell you that Walt Jung's research into dielectric absorption distortion in the 1980's has been largely discredited and perhaps he did misattribute the phenomenon, but the results certainly are real. I had a Hafler DH-101 preamp once that I built as a kit. Another friend bought the same kit at the same time and we both built them. He built his stock, and I replaced all the capacitors in the signal path with polypropylene units as I built mine. We arranged an ad-hoc double blind test of the two preamps at my digs. Our other buddies weren't told what the differences were between the two units. The preamps were connected to my power amps via a simple Switchcraft surface-mount 3 -in, 1-out stereo source switch. Remember, that my stereo was in a different room from the speakers. We all took turns switching between the two preamps and the outputs were matched exactly for level using an audio voltmeter. A Phillips CD player was "Y'd" between the two preamps. Everyone could hear the difference EVERY TIME the Hafler with the polypropylene caps was switched in. All kinds of music was played, and nobody ever got the two preamps mixed up the modified Hafler was cleaner, more transparent, and less fatiguing. So don't tell me that caps don't make a difference. The biggest problem with evaluations like this is that the actual performance of the equipment is rarely if ever checked out fully. I'm not just talking about a few spot frequency response checks (it's not clear what frequencies were checked above). I would like to see a test suite like the RMAA suite be performed. This can be done with minimal trouble and cost if you know what you are doing. In the case of kits, its not clear that subtle assembly problems weren't part of the evaluation. The classical "I did a listening test and heard a difference" anecdote typically includes zero safeguards to ensure that the equipment was operating properly before and after the alleged upgrade. If capacitors make an audible difference then there will be measureable changes, usually in relatively obvious areas like frequency response. Change the capacitance and ESR of capacitors, and any differences that are obvserved are hardly mysteries. |
#5
Posted to rec.audio.high-end
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Where can I find replacement JBL Speaker crossover caps, Vintage
On Mon, 8 Mar 2010 09:34:04 -0800, Arny Krueger wrote
(in article ): "Audio Empire" wrote in message ... Putting good quality polypropylene caps in your crossover will revolutionize the sound of your speakers. It's NOT subtle. I can almost guarantee it. It is important, however to match the values in order not to move the rollover points. The most likely changes that putting film caps into a speaker crossover is that the actual capacitance values and ESR of the capacitors will change. If your speaker crossover has electrolytic caps in it, then they were probably specified to a tolerange of +/- 20% with +80, -20 being a possibility. The film caps will perform within just a few percent of their specified values. Good film caps will also reduce ESR which may or may not be good thing, but can make an audible difference. Note that if you reduce the ESR of parts in a speaker crossover, there may be adverse changes in frequency response. Many here will likely tell you that Walt Jung's research into dielectric absorption distortion in the 1980's has been largely discredited and perhaps he did misattribute the phenomenon, but the results certainly are real. I had a Hafler DH-101 preamp once that I built as a kit. Another friend bought the same kit at the same time and we both built them. He built his stock, and I replaced all the capacitors in the signal path with polypropylene units as I built mine. We arranged an ad-hoc double blind test of the two preamps at my digs. Our other buddies weren't told what the differences were between the two units. The preamps were connected to my power amps via a simple Switchcraft surface-mount 3 -in, 1-out stereo source switch. Remember, that my stereo was in a different room from the speakers. We all took turns switching between the two preamps and the outputs were matched exactly for level using an audio voltmeter. A Phillips CD player was "Y'd" between the two preamps. Everyone could hear the difference EVERY TIME the Hafler with the polypropylene caps was switched in. All kinds of music was played, and nobody ever got the two preamps mixed up the modified Hafler was cleaner, more transparent, and less fatiguing. So don't tell me that caps don't make a difference. The biggest problem with evaluations like this is that the actual performance of the equipment is rarely if ever checked out fully. I'm not just talking about a few spot frequency response checks (it's not clear what frequencies were checked above). I would like to see a test suite like the RMAA suite be performed. This can be done with minimal trouble and cost if you know what you are doing. In the case of kits, its not clear that subtle assembly problems weren't part of the evaluation. The classical "I did a listening test and heard a difference" anecdote typically includes zero safeguards to ensure that the equipment was operating properly before and after the alleged upgrade. If capacitors make an audible difference then there will be measureable changes, usually in relatively obvious areas like frequency response. Change the capacitance and ESR of capacitors, and any differences that are obvserved are hardly mysteries. No, they're not mysteries at all and since I used the SAME values as the caps that came with the unit, and since polypropylenes have far less ESR than the stock caps, the performance of the preamp is bound to be at least measurably better. Frequency sweeps over the audio passband showed that both preamps had identical frequency responses (within the accuracy of the HP audio voltmeter used, of course. It read less than +/- 0.5 dB. How accurate that is I have no way to tell). The differences heard in the DBT were probably distortion, The Hafler was an inexpensive preamp and had cheap coupling and bypass caps in the audio section. These are what I replaced (with polypropylenes). I also bypassed the power supply filter caps with polypropylenes. All of this was done with the same values as the stock caps. The filter bypass caps were chosen according to an article on the subject (by Walt Jung) in the "Audio Amateur". Anyway the amps were tested on the bench for frequency response, and DBT'd for sound. The overwhelming preference was for the Hafler with the polypropylenes caps. Good enough result for me to decide that caps do make a marked difference. well designed modern equipment comes with these types of caps and such swaps aren't necessary any more. But this guy's JBLs will certainly benefit from upgrading the capacitors. I can pretty much guarantee that. I mean, if he's going to replace the caps anyway, why not use better quality ones (of the same value as the old ones, of course, but with obviously lower ESR.) |
#6
Posted to rec.audio.high-end
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Where can I find replacement JBL Speaker crossover caps, Vintage
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#7
Posted to rec.audio.high-end
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Where can I find replacement JBL Speaker crossover caps, Vintage
"Audio Empire" wrote in message
... On Mon, 8 Mar 2010 09:34:04 -0800, Arny Krueger wrote No, they're not mysteries at all and since I used the SAME values as the caps that came with the unit, and since polypropylenes have far less ESR than the stock caps, the performance of the preamp is bound to be at least measurably better. Not necessarily. My comments about ESR related primarily to passive crossovers in loudspeakers. Frequency sweeps over the audio passband showed that both preamps had identical frequency responses (within the accuracy of the HP audio voltmeter used, of course. It read less than +/- 0.5 dB. How accurate that is I have no way to tell). I can generally perfectly ABX - identify two pieces of gear that differ by just under +/- 0.5 dB over the audio range based only on the level and FR differences. The "ABX standard" is +/- 0.1 dB, 20-20 KHz. The differences heard in the DBT were probably distortion, Unlikely. The only capacitors that have measurably greater distoriton are high-value ceramics and unbiased electrolytics, and then only if misused. I don't have a schematic for a DH 101, but I do have the schematic for a DH100. The DH 100 is actually a very high quality design with *no* electrolytic or ceramic capacitors in the signal path. The op amps are low noise, low distortion, high slew parts that I've also seen used in professional gear. The Hafler was an inexpensive preamp and had cheap coupling and bypass caps in the audio section. The DH100 parts list shows extensive use of polypropylene capacitors, as suggested by Jung/Marsh. These are what I replaced (with polypropylenes). I also bypassed the power supply filter caps with polypropylenes. All of this was done with the same values as the stock caps. The filter bypass caps were chosen according to an article on the subject (by Walt Jung) in the "Audio Amateur". Unless they appreciably cheapened the DH101 after the DH 100, you replaced a lot of polypropylene capacitors with polyproplylene capacitors. :-( |
#8
Posted to rec.audio.high-end
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Where can I find replacement JBL Speaker crossover caps, Vintage
On Mon, 8 Mar 2010 12:43:13 -0800, Arny Krueger wrote
(in article ): "Audio Empire" wrote in message ... On Mon, 8 Mar 2010 09:34:04 -0800, Arny Krueger wrote No, they're not mysteries at all and since I used the SAME values as the caps that came with the unit, and since polypropylenes have far less ESR than the stock caps, the performance of the preamp is bound to be at least measurably better. Not necessarily. My comments about ESR related primarily to passive crossovers in loudspeakers. Frequency sweeps over the audio passband showed that both preamps had identical frequency responses (within the accuracy of the HP audio voltmeter used, of course. It read less than +/- 0.5 dB. How accurate that is I have no way to tell). I can generally perfectly ABX - identify two pieces of gear that differ by just under +/- 0.5 dB over the audio range based only on the level and FR differences. The "ABX standard" is +/- 0.1 dB, 20-20 KHz. The differences heard in the DBT were probably distortion, Unlikely. The only capacitors that have measurably greater distoriton are high-value ceramics and unbiased electrolytics, and then only if misused. I don't have a schematic for a DH 101, but I do have the schematic for a DH100. The DH 100 is actually a very high quality design with *no* electrolytic or ceramic capacitors in the signal path. The op amps are low noise, low distortion, high slew parts that I've also seen used in professional gear. the DH-101 had no op-amps and is all discrete bipolar transistors (10/channel, in fact). It did have coupling caps (4/channel) in the signal path. http://www.hafler.com/techsupport/pd...preamp_man.pdf PPS 12 and 13. The Hafler was an inexpensive preamp and had cheap coupling and bypass caps in the audio section. The DH100 parts list shows extensive use of polypropylene capacitors, as suggested by Jung/Marsh. That's not the DH-101 The DH-100 was a ten-year newer model (1988). The DH-101 came out in 1978 and was sold as a kit. It had cheap push-to-cancel switches (that got noisy and intermittant) and cheap pots which also became noisy. It sounded pretty good when new, but went downhill quickly due to the low quality of the moving parts. I believe the kit was less than $200. I only kept it for about two years before moving on. These are what I replaced (with polypropylenes). I also bypassed the power supply filter caps with polypropylenes. All of this was done with the same values as the stock caps. The filter bypass caps were chosen according to an article on the subject (by Walt Jung) in the "Audio Amateur". Unless they appreciably cheapened the DH101 after the DH 100, you replaced a lot of polypropylene capacitors with polyproplylene capacitors. :-( The DH-101 was first (don't ask me why it has a higher number) and definitely did NOT have polypropylene caps in it and in fact, some of the coupling caps were actually tantalums (there's a disgusting thought for you). See the parts list on Page 13. The Wonder Caps I used in that unit were so big, that they hardly fit in the case (you can imagine the size of a 10 uFd non-polarized polypropylene capacitor (IIRC, that was as big as they came!). Luckily, there is a big empty area in the case behind the main circuit board where, with an ample supply of hot glue and tie-wraps, one could stuff the caps. Caps that were bigger than 10 uFd (and weren't coupling caps) were left in place and bypassed by 1 uFd polypropylenes. I never had a DH-100 but I did have a DH-110, also a kit, also discrete bi-polar transistor. Dunno how I missed the DH-100. Frankly, until you mentioned it, I don't recall ever having heard of it! I see by the schematic that it looks pretty good. I'll bet it performed well too. |
#9
Posted to rec.audio.high-end
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Where can I find replacement JBL Speaker crossover caps, Vintage
On Tue, 9 Mar 2010 17:55:50 -0800, Dick Pierce wrote
(in article ): Audio Empire wrote: In all the speakers that I have swapped out mylars for polypropylenes, the main difference has been one of perceived clarity in the upper mids and highs. This "change in sound" is definitely for the better. I have never noticed that such a swap resulted in any change in crossover points, but if it does, it's minimal and not really noticeable. The increased clarity seems to be well worth the difference (if any). Let me illustrate a specific and demonstrable case where swapping and ostensibly "better" part is garaunteed to result in worse performance. One of my clients had me design a network for their speaker that used the Vifa 1" ring-dome radiator tweeter. It does not use ferrofluid in the gap, with the net result that its impedance peak at resonance is fairly sizable, on the order of 25 ohms or so at about 650 Hz. This was enough that it would screw up any plausible 2nd- or 3rd- order network and without impedance compensation, it is impossible to achieve the design target for the crossover response. So, an onjugate network, consisting of a series LRC was designed to go in parallel with the tweeter. The L and the C value depend upon the effective mass and compliance of the driver, and the R should be about equal to the DC resistance of the voice coil, about 3.4 ohms. Since the L and R are in series, our good friend Thevenin states that it makes no difference whether it's L followed by R, R followed by L, 10 1/10Rs interspersed with 10 1/10Ls or, in fact, an L whose DC resistance is 3.4 ohms. It just so happens that I found an of the shelf air-core inductor wound of the right value whose DC resistance was within about 3% of the value I needed, meaning I could use 1 part instead of 2 AND because it was wound with small wire, it was substantially less expensive to implement it using a single high-resistance coil instead of a low-resistance coil and a high-resistance resistor. However, a number of people, when they opened up the speaker, saw all these wonderful poly caps and this ****ty little inductor. The first step was to rip out the inductor and replace it with a hefty low-resistance inductor. Doing so completely screwed up the crossover, because it was suposed to be a 3.4 ohm resistor in series with a 4 mH inductor, NOT a 0.15 ohm resistor in seriers with a 4 mH inductor. In a similar vein, a popular "tweak" of the old KEF RS104-AB network was to rip out all the electrolytic caps and replace them with polypropylenes and, yes, it DID change the sound, but NOT necessarily for the better, because the ENTIRE crossover was designed with knowledge of how EACH part in it worked. Simply substituting parts is NOT necessarily a good way to go, no matter what someone might like about the result. Without the detailed knowledge about WHY a designer did it that way, how could one possibly know WHY a part should or should not be substituted at random. I don't really understand why you are confusing the issue with, what I consider, extreme examples of a hypothetical problem. Most speakers have used Mylar caps in their crossovers (where feasible) for decades. While it is true that polypropylene caps have somewhat lower ESR than do Mylars, it's nowhere near a big enough delta to make any real difference in this application. Now, I could see it if we were swapping polypropylenes for electrolytics or tantalums. but not for Mylars. Now if you know differently, I'd love to see some data that shows where the crossover characteristics of a speaker system have been changed significantly by swapping polypropylene caps for the same value of Mylar caps, as to make a fundamental and profound enough change to audibly impact the speaker's performance. |
#10
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Where can I find replacement JBL Speaker crossover caps, Vintage
"Audio Empire" wrote in message
I don't really understand why you are confusing the issue with, what I consider, extreme examples of a hypothetical problem. Like like a wind-up to a dismissal of an opinon from an expert witness. Most speakers have used Mylar caps in their crossovers (where feasible) for decades. Right, where feasible, which means that there are tons of speakers still being made with electrolytics in their crossovers. While it is true that polypropylene caps have somewhat lower ESR than do Mylars, it's nowhere near a big enough delta to make any real difference in this application. Now, I could see it if we were swapping polypropylenes for electrolytics or tantalums. but not for Mylars. Now if you know differently, I'd love to see some data that shows where the crossover characteristics of a speaker system have been changed significantly by swapping polypropylene caps for the same value of Mylar caps, as to make a fundamental and profound enough change to audibly impact the speaker's performance. |
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