Hi J!m,
Although I haven't personally disassembled/degunked any of these drivers, or even own any ferrofluid-enhanced drivers...once upon a time when I lived in southern NH I used to walk by/study the
Ferrofluid display in the Manchester airport** ...so I guess that allows me to annoint myself as a subject-matter-expert? ;0)
Disclaimer: Since this is your tweeter, and I will stop on a dime in order to watch anyone operating on a piece of audio gear, my initial response is to want to talk you into doing the Dr.
Kildriver quick-lube thing.
On the other hand, if this speaker was mine I'd want to first prove to myself that tweeter oil is the actual solution to this intermittent problem. If we do this right, it will be both fun & instructive, while at the same time avoid the frustration of fixing down the garden path, to mix metaphors a bit.
(
Important: Please read the following as I am writing this primarily for people new to the vintage audio hobby and have stumbled across this thread...and
not that I am talking down to you. It's just that your original query is something that I've been asked many a time by normal, well-adjusted folks, and what follows is a time-honored path from here to re-establishing sonic bliss. :0)
****
OK, in my humble opinion the first rule of troubleshooting an intermittent is "You
can't fix something until you can
first break it at will." This can be the hardest part of the entire repair effort, but by doing this you front load all the inevitable frustration into the beginning of the process. I know this sounds simplistic, but before I internalized this as a troubleshooter I suffered through countless episodes where I proved the maxim that "Nothing takes longer to fix than something that is
not broken." And worst-case, during the attempted repair where none was needed, I would inadvertantly insert *another* fault. Fudge!
NOTE: Of course you can fix anything using the pure 'swaptronics' method, but that's a 0% learning, 100% spending model -- there's no sport in that.
Step 1:
Let the speakers play, and the very next time you hear the 'spittiness' write down the source, (FM radio station, CD, digital feed, etc) plus song with time stamp where it happens. Now, once you corral the first failure, and you can stimulate the fault at will, you have enough info to proceed.
However, in order to build confidence in our troubleshooting theory that will guide our repair, can you stimulate the fault at will with a 2nd song, 3rd song, etc? (It may sound like unnecessary effort, but oftentimes gathering additional data points can really help sharpen our focus later on.)
Can you can further define the failure? Is it primarily frequency-dependent (ie: you hit the right freq and the problem presents, whether it is loud or quiet?) Or, does the problem occur with differing frequencies/notes/harmonics for that driver -- that is, the problem can be stimulated at will simply by upping the volume setting?
Step 2:
OK, assuming that you now have the knowledge needed to stimulate the fault at will, it's time to switch to 'geographical fault isolation'.
Let's focus on physically narrowing down the failing component:
* Is the failure from a
single specific source? (CD player,
iPod, iPhone, online streaming, FM, vinyl, cassette, Edison cylinder, etc.)
or
* source doesn't matter --
all sources can/will stimulate the fault?
NOTE: If problem occurs
only with a single source, then we need to (temporarily) shelve the bad tweeter theory, and fix the failing source first before proceeding. On the other hand, IF you can stimulate the failure with any/all sources, then proceed to the next step.
Step 3:
Swap the speakers between the L & R channels & stimulate the fault.
* Does the problem
move with the speaker, or does it stay with 1 preamp/amp channel?
Obviously, if the problem moves, we're going down the speaker rabbit hole. On the other hand, if the problem presents on the LEFT channel with either speaker, then we're looking at the left signal chain. (preamp/amp and/or interconnections between amp & speaker)
For the sake of argument, let's say that the problem moves with the speaker. (ie: Problem moved to right channel.)
Step 4:
* IF the problem moves with the speaker, then if you swap the tweeters
between the speakers...does the problem
follow the suspect tweeter, or does it stay with the crossover network / wiring harness in the 'bad' speaker?
At this point, depending on if the problem moves with the suspect tweeter or stays with the suspect speaker cabinet we will have enough information to decide if you have a bad driver (that needs the oil change?) ...or is it a capacitor that's either dried up (and altering the frequency crossover point & sending excess (low freq) power to the tweeter...or the dielectric is breaking down during larger voltage swings & that is what's causing the spittiness you are hearing? Or is the tweeter's voice-coil dragging, and can only be heard during clean, quiet passages -- and loud music actually camouflages the failure?
****
Apologies for the length, but I just wanted to provide a rational troubleshooting roadmap for
some of the good info I found in this thread.
****
I (and others?) eagerly await your next status update. Right now it could literally be anything from a single song to a single source, to a single channel in the amp, to a single speaker, to a single tweeter. Who knows? We may very well end up watching you Dr. Kildare the driver & giving it the million-mile lube job. I, for one, am headed to Wegman's for another pound bag of popcorn kernels... :0)
Happy Hunting --
3D
**You know, I
never fully trusted my recollection, even when I was half my current age -- but this time I didn't hallucinate this particular memory,
for if you look at post #9 in this thread, some dude that goes by the name "Nakdoc" referenced the same display in the same airport. (Granted, this was awhile ago...but the interwebs never forgets. :0)
