Jump to content

new crossovers


Brody

Recommended Posts

 I have a set of Cornwall I  and they are from 1977 they are in excellent visual condition as far as sound they sound good but I have nothing to compare them to.

 I was wondering what the difference might be if I put new Crites crossovers in them. The bass seems to be a little muddy to me but as I said I don't have anything to

  compare these to they are my first Klipsch. I see a lot of people do change the crossovers, I can only think the caps may be getting tired after all they are 45 years old 

any comments to help me out. I am running them with a reconditioned Marantz 2265B receiver.

Link to comment
Share on other sites

I would also recommend highly that you run a couple of 2 x 4 braces from the front to the back sides which will do a lot to eliminate the boomy box sound. The CW 4's have done this for instance at the roughly 10:00 and 2:00 o'clock positions about two or three inches past the woofer cutout. Cheapest improvement of significance you can make and always redo crossovers that old.

  • Like 2
Link to comment
Share on other sites

I have 77 Cornwalls - I replaced the Caps with a Crites kit - back when they were cheap - 40.00? - now the price has increased substantially.  I still have the oil can caps boxed up.   My speakers sound fantastic - but I made too many upgrades at once to be able to tell if they made a difference or not.

  • Like 1
Link to comment
Share on other sites

fresh caps might do something, if you will like the change is hard to say, I found my upgrade crossover seemed to peak the top end and mids more than I liked, i ended up wishing to go back to the smoother (maybe a little softer or fuzzy) sounds of my originals.  if they sound good to you now I would hold off "upgrading" crossovers. however if you want to change the sound, swapping out 1977 caps will probably be an audible change.  let us know what you decide and the results.  regards, Tony

 

 

 

 

Link to comment
Share on other sites

Well, this has been discussed here in the forum from time to time. It's not just about replacing old caps with new ones. It is about using caps that are very similar in their electrical properties to the original ones when they were still fresh. We can all make mistakes as laymen, e.g. just because many people today believe that e.g. polypropylene caps are the most modern, they do not necessarily fit the requirements of your crossovers and your loudspeakers. It could sound too bright or shrill with these speakers. With other speakers they can produce very good results without question. This is to say that there is more to it than just getting the value of the capacitance right. I would follow DeanG's advice and go with the replacement crossover he recommends. Or, to keep it more affordable, I would use the caps that Klipsch has approved as replacements and that you can buy from JEM as a certified dealer. You can solder them on your original xover or have someone else do it.

  • Like 1
Link to comment
Share on other sites

I have '77 Cornwall's also, and recapped(new crossovers actually). While I liked the way they sounded with the original caps, the new caps definitely cleaned them up some. Not to the extent that they don't still deliver the Cornwall signature sound, but brought back a bit of sparkle to the top and mids which were more veiled before the change. There was an initial period of break in, either with the caps, or my ears, so if you go this route make sure to be patient before making a final decision.

Link to comment
Share on other sites

11 minutes ago, svberger said:

I have '77 Cornwall's also, and recapped(new crossovers actually). While I liked the way they sounded with the original caps, the new caps definitely cleaned them up some. Not to the extent that they don't still deliver the Cornwall signature sound, but brought back a bit of sparkle to the top and mids which were more veiled before the change. There was an initial period of break in, either with the caps, or my ears, so if you go this route make sure to be patient before making a final decision.

Or being patient after making a final decision😀

Link to comment
Share on other sites

Hard to say really.

 

My La Scala's have the original metal can polymer/foil in oil and what I started doing about 15 years ago was do a sweep of each output of the network, woofer, tweeter, and horn for a total of 3 plots per board. One time I removed the capacitors from one board and measured ESR at frequencies of interest. What I mean is testing the 2uF caps in my AA networks for ESR at 100Hz is not useful information. The 13uF I would test 500Hz through 20kHz. The 2uF caps I would test ESR from 5kHz through 20kHz. Comparing the ESR to what the impedance/reactance of these components are between these frequencies will tell you if losses are acceptable or not. I found the caps to be functioning great and since both networks matched closely and I was happy with the sound I haven't touched them.

 

When sweeping the output of each section of the networks you are looking for a specific transfer function. If this function deviates from the desired intention the networks aren't doing what they were intended to do so one needs to figure out if the capacitors are the culprits and from the reliability of the inductors and transformers it almost always is going to be the capacitors. Basically at point of the intended frequency range where the part is at it's lowest impedance is where the ESR will have the largest losses, since capacitors impedance is lowered as frequency is increased this means that a high ESR will have the greatest losses at the extreme top range of high frequencies; I.e. at 20kHz.

 

Basically I compared to a simulation with as close a parasitic properties as I could add to the models. When you adjust ESR for the capacitors in the simulation it will show the transfer of a network with old caps and high ESR. It will steepen the roll-off slope for the network which is why you'll hear many people report the speakers are brighter after the restoration. Problem is if ESR is a large enough factor in the networks going with an extremely low ESR cap like a modern Polypropylene it may have too low of an insertion loss making the speakers slightly brighter than when they were brand new out of the box.

 

If you don't know what you are doing, or you don't know what you will like; for example an older person with severe hearing loss in the treble range may actually prefer a slightly brighter speaker. But to be safe use the Capacitors from @deang .  They use the same dielectric as the originals which is probably the most important factor. If you want to try and get even closer to the original use a polyester and foil type. The ones provided by Dean are metallized film types which won't have a huge impact at all but will still make them have slightly different properties. The dielectric layers with a foil type will be a magnitude size larger vs metallized so they will be larger in size and also the dielectric properties will be more prominent. I have the new JEM caps from Klipsch in my 1975 Heresy's and they sound great. I do plan to switch over to a paper and foil type or polyester and foil and take some measurements between the them but I need to finish other projects first.

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

How necessary is it to match ESR between each network in the pair, polyester (Mylar) having higher readings than most other types. Is there an acceptable difference that won't effect the speaker audibly and do these caps read close if they're indeed being tested to match?

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...