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- Mar 27, 2010
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To my dismay , I have discovered that one of my Scanspeak midwoofers [18w/8545-00] is distorting under heavy load. It is being used for mid range duty on my pair of floorstanders. Bass duty uses another pair of the same drivers by the way.
I tested this by having my phono stage turned on , the needle on the record and tapping on the plinth to give a good midbass signal to the speakers which induces the scratchy distortion on the one channels mid driver. I double checked by swopping the drivers around and the problem transferred to the other channel. Under normal listening conditions , all sounds OK. It only occurs with a dynamic midbass surge of some impact and volume which obviously puts the driver under additional stress.
I can't say for sure what caused this or when. This is speculation but it might have been due to overload as a result of clipping which has happened briefly before , like when I tried to run the "F5" chip amp on them which only lasted a minute or so ; it was hopeless. I was also using my Sugden A51 [25 watts class A] which did struggle a bit on its own but I am now biamping with Rega monoblocks for the bottom end and there seems to be plenty of headroom.
My speakers were originally rated as 88db sensitivity [8ohm] but since everything has been replaced on them , including the scanspeaks which are only 3 years old or so , that might be slightly different although all the original specs have been stuck to as far as possible.
I could continue with it as is but I know there is something wrong and I want to sort it out and besides , they are really great sounding speakers which I love.
Anyway , can anybody refer me to someone who is good at repairing speakers who might be able to help me out. For me to import a new pair would probably cost in excess of 6k - rather to expensive for my taste
uke:
I tested this by having my phono stage turned on , the needle on the record and tapping on the plinth to give a good midbass signal to the speakers which induces the scratchy distortion on the one channels mid driver. I double checked by swopping the drivers around and the problem transferred to the other channel. Under normal listening conditions , all sounds OK. It only occurs with a dynamic midbass surge of some impact and volume which obviously puts the driver under additional stress.
I can't say for sure what caused this or when. This is speculation but it might have been due to overload as a result of clipping which has happened briefly before , like when I tried to run the "F5" chip amp on them which only lasted a minute or so ; it was hopeless. I was also using my Sugden A51 [25 watts class A] which did struggle a bit on its own but I am now biamping with Rega monoblocks for the bottom end and there seems to be plenty of headroom.
My speakers were originally rated as 88db sensitivity [8ohm] but since everything has been replaced on them , including the scanspeaks which are only 3 years old or so , that might be slightly different although all the original specs have been stuck to as far as possible.
I could continue with it as is but I know there is something wrong and I want to sort it out and besides , they are really great sounding speakers which I love.
Anyway , can anybody refer me to someone who is good at repairing speakers who might be able to help me out. For me to import a new pair would probably cost in excess of 6k - rather to expensive for my taste
uke:
