Upgrading an 030 system

Hi folks,

I am a long-time proud owner (40 years now) of a nice pair of early C36's with the 030 system, who just now discovered your wonderful site.

Anyway, I'd like to upgrade them, not because they don't sound good, but just because I am a tinkerer at heart, and I like to try to improve everything I get my hands on. I'd like to get your comments on these ideas.

First of all, I am considering putting an LE175DLH between the D130 and the 075. I plan to feed it from the HF of the N2400, and then tie the 075 to it with a capacitor to achieve a simple first-order high-pass filter with a cf of approx 9000hz. I'll just let the LE175 roll off on its own above that. My specific question is, will the highs be sufficiently improved by essentially adding the 075 on top of the 175? My research tells me that the 175 is significantly better than the 075 between 2400 and 9000, so that seems like a no brainer to use it for that. But does the 175 really need the help of the 075 above 9000? I think so. Your thoughts?

The second thing I would do would be to replace the N2400 with a home-made modern version. I'd keep the same first-order topology, just replace the components with modern polypropylene caps and large wire, air-core inductors. I will keep the original crossovers, since I want to ensure that the speakers can be returned to original without any blemishes.

Finally, in order to improve the lows, I am thinking about having the surrounds redone on the D130's with a more flexible material (which I believe is a popular mod). Again, I don't want to swap out the D130's, just improve them if possible. Also, the ports on my C36's do not have any tunnels at all. The factory spec calls for 5" tunnels. I am guessing that my boxes were very early models (the grills sure look that way), so the port tunnel may have been a later improvement. What exactly would that change? I'm guessing, lower the response.

I'm sure that by now some of you thinking "what a wacko"! Believe me, I'm not. I dearly love these speakers, I'd just like to make them the best they can be, without doing anything that can't be undone without a trace.

BTW, all this is being inspired by "finally" finishing my home-brew amp, similar (but I think much better than) the ST-70.

Dave in San Jose

I've never seen any 030 systems with port "tunnels". My C35 and C37 don't have them, just a rectangular port cut in the baffle. My upgrade path is intended to cross the LE175DLH at the normal 1200Hz and the 075 at 7000Hz. I intend to do this in tri-amp configuration using two Crown VFX2A crossovers and three Crown amps, D45, D75A, and D150A-II. I'm short on LE175DLH right now but I'm not in a hurry. The on I do have ran off the N2400 for years on one side with the 075 still connected and it worked fine. A small improvement, maybe, over the standard 2-way system but I think the mid-range "hole" in the 030 could use a LE175DLH extended lower than 2400Hz to hit that highest range of the female voice. :dont-know:

I played my 030s for years with just the N2400 and a Crown D150, and I know how loud and clear that will play, outside, on a porch, in the summer, playing to the Blue Ridge Mountains, with a bunch of college kids tapping a keg. Every speaker—and everyone—survived.

Quote:

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Originally Posted by DaveW

Hi folks,

I am a long-time proud owner (40 years now) of a nice pair of early C36's with the 030 system, who just now discovered your wonderful site.

Anyway, I'd like to upgrade them, not because they don't sound good, but just because I am a tinkerer at heart, and I like to try to improve everything I get my hands on. I'd like to get your comments on these ideas.

First of all, I am considering putting an LE175DLH between the D130 and the 075. I plan to feed it from the HF of the N2400, and then tie the 075 to it with a capacitor to achieve a simple first-order high-pass filter with a cf of approx 9000hz. I'll just let the LE175 roll off on its own above that. My specific question is, will the highs be sufficiently improved by essentially adding the 075 on top of the 175? My research tells me that the 175 is significantly better than the 075 between 2400 and 9000, so that seems like a no brainer to use it for that. But does the 175 really need the help of the 075 above 9000? I think so. Your thoughts?

The second thing I would do would be to replace the N2400 with a home-made modern version. I'd keep the same first-order topology, just replace the components with modern polypropylene caps and large wire, air-core inductors. I will keep the original crossovers, since I want to ensure that the speakers can be returned to original without any blemishes.

Finally, in order to improve the lows, I am thinking about having the surrounds redone on the D130's with a more flexible material (which I believe is a popular mod). Again, I don't want to swap out the D130's, just improve them if possible. Also, the ports on my C36's do not have any tunnels at all. The factory spec calls for 5" tunnels. I am guessing that my boxes were very early models (the grills sure look that way), so the port tunnel may have been a later improvement. What exactly would that change? I'm guessing, lower the response.

I'm sure that by now some of you thinking "what a wacko"! Believe me, I'm not. I dearly love these speakers, I'd just like to make them the best they can be, without doing anything that can't be undone without a trace.

BTW, all this is being inspired by "finally" finishing my home-brew amp, similar (but I think much better than) the ST-70.

Dave in San Jose

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I made port tubes for my C51s (Apollos) using balsa wood and the existing rectangular cut out on the front baffle

Trace your baffles' port openings onto some stiff stock or cardboard in order to have a reference template and then build your tubes out of 1/4" plank balsa assembled with a good cyanoacrylate
(you'll have to do the math to come up with the length you'll need for your boxes; your woofers' specs are in the library)

Make the rectangular tubes a little bigger than your tracing so you can sand/trim them down carefully for a nice tight friction fit with the baffle

When tightly fitted, the balsa tubes will not buzz or rattle and can easily be removed and reinstalled many many times, forgoing the need for gluing them in place if you want to preserve the originality of the cabs; that is what I did

I would suggest not cutting for final port length until you've got the fitment done