AUDIOMAN2 Posted August 4 Share Posted August 4 I've restored a number of vintage speaker systems over the years. They have been mainly Wharfedales such as Dentons, Lintons, Dovedales, etc. but also other brands. The majority of these systems had cheap bi-polar electrolytic capacitors fitted and apart from the fact that in speaker terms they were ancient, it was the general consensus to upgrade to nice poly's and as I have access to brands like Mundorf, took no hesitation in replacing the originals with these. Overkill maybe, but so be it. Apart from having to play around with values, I've recently discovered (i.e. been told) that the resistance of the older bi-polar caps was higher than is the case for modern caps and as a result can actually affect the performance to some detriment and a resistance of some low value should be incorporated to compensate. How on earth could you check an old one which has gone "off" to a new one and does it really matter in the scheme of things? Any comments would be appreciated. Link to comment Share on other sites More sharing options...
aussievintage Posted August 4 Share Posted August 4 2 hours ago, AUDIOMAN2 said: I've restored a number of vintage speaker systems over the years. They have been mainly Wharfedales such as Dentons, Lintons, Dovedales, etc. but also other brands. The majority of these systems had cheap bi-polar electrolytic capacitors fitted and apart from the fact that in speaker terms they were ancient, it was the general consensus to upgrade to nice poly's and as I have access to brands like Mundorf, took no hesitation in replacing the originals with these. Overkill maybe, but so be it. Apart from having to play around with values, I've recently discovered (i.e. been told) that the resistance of the older bi-polar caps was higher than is the case for modern caps and as a result can actually affect the performance to some detriment and a resistance of some low value should be incorporated to compensate. How on earth could you check an old one which has gone "off" to a new one and does it really matter in the scheme of things? Any comments would be appreciated. I don't believe the small difference in crossover frequency etc, will matter. Those crossovers were calculated, probably, without worrying about that small internal resistance. I mean, if they are going to use cheap bipolar caps, it wasn't a high end design to start with - as you imply when you talked about overkill. Link to comment Share on other sites More sharing options...
AUDIOMAN2 Posted August 4 Author Share Posted August 4 1 hour ago, aussievintage said: I don't believe the small difference in crossover frequency etc, will matter. Those crossovers were calculated, probably, without worrying about that small internal resistance. I mean, if they are going to use cheap bipolar caps, it wasn't a high end design to start with - as you imply when you talked about overkill. I think your probably right. Besides, I've always noticed an improvement over what I was given to work with but I guess it's always best to ask the question. Link to comment Share on other sites More sharing options...
mwhouston Posted August 4 Share Posted August 4 5 hours ago, AUDIOMAN2 said: I've restored a number of vintage speaker systems over the years. They have been mainly Wharfedales such as Dentons, Lintons, Dovedales, etc. but also other brands. The majority of these systems had cheap bi-polar electrolytic capacitors fitted and apart from the fact that in speaker terms they were ancient, it was the general consensus to upgrade to nice poly's and as I have access to brands like Mundorf, took no hesitation in replacing the originals with these. Overkill maybe, but so be it. Apart from having to play around with values, I've recently discovered (i.e. been told) that the resistance of the older bi-polar caps was higher than is the case for modern caps and as a result can actually affect the performance to some detriment and a resistance of some low value should be incorporated to compensate. How on earth could you check an old one which has gone "off" to a new one and does it really matter in the scheme of things? Any comments would be appreciated. If the caps are old new ones will always boost the sound. +/- 10% of original value will have no auditory effect on the overall sound. Link to comment Share on other sites More sharing options...
AUDIOMAN2 Posted August 5 Author Share Posted August 5 14 hours ago, mwhouston said: If the caps are old new ones will always boost the sound. +/- 10% of original value will have no auditory effect on the overall sound. I'm assuming this is because the tolerances on these old bi-polars was pretty average anyway. 1 Link to comment Share on other sites More sharing options...
mwhouston Posted August 5 Share Posted August 5 25 minutes ago, AUDIOMAN2 said: I'm assuming this is because the tolerances on these old bi-polars was pretty average anyway. Even building new from scratch slight variations in actual measured value and stated value, in practice, will have little to no audible effect. There is probably a few areas in audio electronics where absolute values are necessary but definitely not in Xovers. Parts when cold or hot vary in value and in service. But some builders are *nal about absolute values and ultra-fine tolerances so go for it if it helps you sleep at night. But really it’s not an exact science. Link to comment Share on other sites More sharing options...
AUDIOMAN2 Posted August 5 Author Share Posted August 5 2 hours ago, mwhouston said: Even building new from scratch slight variations in actual measured value and stated value, in practice, will have little to no audible effect. There is probably a few areas in audio electronics where absolute values are necessary but definitely not in Xovers. Parts when cold or hot vary in value and in service. But some builders are *nal about absolute values and ultra-fine tolerances so go for it if it helps you sleep at night. But really it’s not an exact science. I wish I could tell Colin Whatmough this. I did a recap for a friend to a pair of Whatmough 202's. Some of the wire wound 5 watt resistors looked liked they had been toasted. In order to get the preferred value, one resistance value had been achieved with (from memory) 4 resistors in parallel. I was also surprised to see that the entire crossover looked like a bowl of spaghetti and that the terminal strips had been installed with hot melt. Before you ask, these speakers had NOT been got at. It's ironic that there would be so much effort put in to get such exact values for components and then just throw the thing together. As for the internal wiring, well not going there. 1 Link to comment Share on other sites More sharing options...
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