Jump to content

Cornwall B network cap value question


JLOUNDER

Recommended Posts

I recently purchased a pair of Cornwall 1's and would like to update the caps in the B network. Would like to try some Obbligato caps, but the place that carries them doesn't stock an exact value for the 4.0uF. Closest they have are 3.3uF aluminum/film or 4.7uF film/oil. How close in value do you need to be?

James

Link to comment
Share on other sites

Preferably 5% to 10% of the required value, best to use the exact cap value even if you have to combine two smaller caps to achieve said value.

You will need a 4uf and 2uf for each and I think a 2.5mh coil. Erse makes some nice coils that have a similar DCR to the originals.

Link to comment
Share on other sites

Thanks for the reply. I was hoping that either the 3.3 or 4.7 would work, but may have to combine two to get the correct values. They have a 2.0uF film/oil that should work. At $5.50 ea not that big a deal. Wanted to order some caps for my Bottlehead amps anyway, so might as well get busy ordering. The Cornwall's are 1975 I believe. Serial #'s 6N719/6N720. They sound pretty good as is. Could sound better.

Jim

Link to comment
Share on other sites

I sure hope so. I heard about these Obbligato caps on the Bottlehead forum so I thought I would give them a try. Can't really go wrong for the low prices they are asking. Will post back and let everyone know how they sound. Hardest part is the break-in period, but to do that you have to play them. On my previous speakers, Heresy, I replaced the whole network with a P-Trap. They took a while to settle in, but once they did they sounded really nice. Sold those to a co-worker when I bought the Cornwall's. I opened up the backs and the networks don't have the usual oil caps found in most of the Klipsch line. They look like poly caps, not sure if they were upgraded or came stock like that. I'll have to open them again and see what I really have in there. I may just build a whole new set of boards and keep the stock ones complete. that way if I decide to sell them, fat chance of that happening, I've got the stock ones to put back in. If you can't tweak it there's no sense in owning it.

James

Link to comment
Share on other sites

Why don't you ask the supplier to measure the caps and provide you with matched sets of the exact values you need? Just because they do not appear to have the values you need.......doesn't mean they don't actually have them. There are tolerances and when the parts are actually measured they can find your values. If you stray from the specified values you change the crossover parameters. You should always purchase matched parts (by having them measured) to be assured of matching networks. If one speaker ends up sounding slightly different than the other.......you will be disappointed.

Link to comment
Share on other sites

I picked up a pair of Cornwall I's last Oct. and was planning to try the obbligato's myself but instead went with the correct values

in the dynamicap line. I'm happy with them but they are costlier. I also updated the speaker wiring and installed new binding posts.

I didn't replace the inductor thinking it wouldn't make much of an improvement, the Erse 2.5mhy available at Parts express is only a 16 ga

and I wanted to go with at least a 14 or preferrably 12 ga. Still, I'm wondering if the 16 ga. Erse would be an improvement or not. Several

forum members suggested I leave the stock inductor in place and just do the caps.

Link to comment
Share on other sites

The only thing I thought of on the Obbligato caps was to use the 2.0uF film/oil and than just double up for the woofer. Supposedly diyhifi.com is going to expand the values they will carry. No word on when this will happen though. As for the inductor, there's some that believe the original is sufficient, and some that believe in replacing it. Add to that the different types of inductors one could use and it makes choosing what type challenging.

James

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...