bbbiker800
31-08-2015, 17:58
Hi All - this is my first post in this section and i'd like to ask for your help with a problem that I have with one of my JR149's. I brought these a while back at a lowish price and I've just got around to checking them out. The seller said they were perfect.
However....after adding new banana plugs, reconnecting to clean terminals, cleaning the fuse contacts, adding new fuses, checking the connections in the block connector (drives to XO) and cleaning the treble adjuster thing with a contact cleaner (as I could hear a very fizzy top end on what is now the problem speaker). That left me with what sounded a good pair or JR149's.
However within 10mins of Frank Sinatra 'Live at the Sands' one speaker became much lighter in the bass and seemed to have a lower output.
This seemed to have recovered to match the other but then it sported this rather nasty crackling noise on bass heavy material (ie Bjork !) across all different volumes (but not that loud TBH). The only way I can describe it is that is like cleaning a stylus with a carbon brush with the volume on - that's what you hear in the music.
Now, I got these as a project with the idea of using them after restoring them cosmetically as that's about my skill limit. I don't have electronics skills and my soldering skills are very poor - but I can learn (?!?!).
My newbie/uneducated thoughts were blown driver/coils or dodgy component or capacitors in the XO. I have of course found replacement drivers and cross-overs on ebay/Falcon. But I see no point in jumping to conclusions just yet.
So, three questions for the experts :
1: What are the possible causes for this ?
2: Whats the logical sequence of checks that I can apply ?
3: What equipment would I need for 2 above ?
All answers and help very gratefully received from the man from Essex, UK
However....after adding new banana plugs, reconnecting to clean terminals, cleaning the fuse contacts, adding new fuses, checking the connections in the block connector (drives to XO) and cleaning the treble adjuster thing with a contact cleaner (as I could hear a very fizzy top end on what is now the problem speaker). That left me with what sounded a good pair or JR149's.
However within 10mins of Frank Sinatra 'Live at the Sands' one speaker became much lighter in the bass and seemed to have a lower output.
This seemed to have recovered to match the other but then it sported this rather nasty crackling noise on bass heavy material (ie Bjork !) across all different volumes (but not that loud TBH). The only way I can describe it is that is like cleaning a stylus with a carbon brush with the volume on - that's what you hear in the music.
Now, I got these as a project with the idea of using them after restoring them cosmetically as that's about my skill limit. I don't have electronics skills and my soldering skills are very poor - but I can learn (?!?!).
My newbie/uneducated thoughts were blown driver/coils or dodgy component or capacitors in the XO. I have of course found replacement drivers and cross-overs on ebay/Falcon. But I see no point in jumping to conclusions just yet.
So, three questions for the experts :
1: What are the possible causes for this ?
2: Whats the logical sequence of checks that I can apply ?
3: What equipment would I need for 2 above ?
All answers and help very gratefully received from the man from Essex, UK