Tweeter Capacitor Upgrade (Coincident PREs)


Hi all, looking to upgrade the Solen 4.7uF 100V caps that filter the low frequencies out of the Accuton tweeters on my Coincident PREs.  Started by looking at Duelund's, but PartsConnection doesn't even list prices for a lot of the models (or is out of stock) at that value... that motivated me to try and collect some impressions from the group.

Apparently Isreal is using Mundorfs in that position at this point.

As always, thanks for the input.
128x128cal3713
hi guys i know this isn't related to the thread topic but i don't feel like making a new thread ... should i seriously be considering coincident pre? i live close to isreal so auditioning is no problem... i had a bad experience with him in the past but my line of thought is i shouldn't let emotions get in the way of owning what is potentially a rock solid speaker that would push above its price point.

i was considering the pre vs wilson audio specalties sasha daw, avantgarde acoulstics duo xd, and maybe kef reference 5. possibly a used jbl d670000... theres been a few for sale for under $40k.
ive also considered a few active systems but i dont think here is the place to ask about those types.
Let me add a little:
If you mess up the 2nd pole in the low pass filter, you can drop the impedance through the area above the crossover point, which actually doesn’t change your LP frequency response very much, but if your amp has very much output impedance at all, it will drop the output. Weird right? Seen it 2-3 times.

If you use a crossover simulator, you'll see this in the impedance graphs, but not the frequency response graphs, unless you have one that lets you simulate amplifier output impedance, then it's super obvious.

Best,
E
Hi @erik_squires ,

I get it. 

With bypass I noticed that vocals, saxophones and acoustic guitars sound not as smooth and tonaly reach as it was without bypass. It seems it cause a deep in lover mid range.

I think that vintage oil capacitors should be replaced by something that have a natural tone. I don't want to use cheap Solen capacitors. They sound too synthetic. I avoid to use them even for tube amp power supplies.

With bypass I noticed that vocals, saxophones and acoustic guitars sound not as smooth and tonaly reach as it was without bypass. It seems it cause a deep in lover mid range.


This can certainly be a symptom of what I'm describing. The amp used matters a lot, so this will be worse with tube gear.

You can measure ESR with Dayton DATS or a home grown jig using Room EQ Wizard. It can help you compensate accordingly.

https://www.roomeqwizard.com/help/help_en-GB/html/impedancemeasurement.html



So if you are bypassing old caps, measure the ESR, and then ensure that in parallel, your new caps don’t cut that more than 0.2 Ohms or so.

You can use something like the free XSim crossover simulator to examine the impedance plot and add the appropriate resistance with the bypass cap.