Sorry for the long delay in updating the project status.
I have determined that the above drivers work and make a
roughly comparable replacement for the original. They are also inexpensive. I do not believe I can say they sound or measure better, unless the original drivers are defective. The Visaton DT94 tweet requires removal of some or all of the ferrofluid as has been mentioned elsewhere to sound it's best. Also these tweeters vary enough that you have to measure and adjust the resistor values on each one to get it to correctly match the dome mid. Because fo these complications
I can not wholeheartedly recommend this pair as an improved solution.
My current plan is to evaluate other tweeters and midranges as alternatives. So far i have found a good tweeter candidate but no good replacement midranges that are good enough to be better and still reasonably priced and more importantly not on LONG backorder (some more than 6 months). So the next phase is likely to take 6 months or longer. Because my DQ10's ?are so old and had several previous owners I found there was a lot of changes necessary in order to restore them to like new stock condition.?
This is a list of the items I found wrong.
Dahlquist DQ10 changes
?
- Multiple cabinet leaks due to improper sealing when the woofers were replaced.
- Both tweets wired out of phase.
- One tweeter had a fractured voice coil wire with intermittent contact.?
- Both dome mid ranges had stiff hardened suspensions.
- Both tweeters had hardened adhesive under the surrounds that prevented proper dome motion.
- Intermittent high resistance contacts on all 4 system fuses.
- Tweeter level pots were scratchy. Totally mis-set level above 5 KHz was 3 dB too high on one speaker, 2 dB to low on the other.
- One super tweeter wire was not soldered at all.
- Multiple questionable ( cold) solder joints, two fell apart when pulled on.
- Midrange crossover caps very old bulging electrolytic caps high leakage.
- Woofers not original factory spec but balance is adequate, extension only to 75 Hz or so with no EQ.?
- Woofers both wired out of phase with rest of system.
- Many drivers had loose mounting screws.
- Cabinets were filthy and scratched.
- Crossovers and drivers had a thick coat of dust on them to the point that components value were unreadable.
- A tweeter was missing a damping pad
Because finding and fixing many of these things really benefit by the use of test equipment I suggest that anyone who wants to try the mods have at least a calibrated mic, REW or equivalent, and good multimeter. You will also need at least a folding iron, solder and rudimentary knowledge how to use these tools. I would be happy to help anyone as I can but if very many respond my ability to help will be limited. ?
That's it for now.
Charlie Conger