Active crossovers, anyone? Carvin XC3000 w/ nudes

J. Frum

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After last year’s purchase of a pair of Citation 7.4 (JBL LE14H-1) passive subs, I started to consider them as a possible replacement for the SVS PC12-Plus pair I use now.

But to try these new subs, I would need an amp and processor to replace the BASH plate amps in the SVS subs. I recently picked up a suitable amp, but can’t afford the MiniDSP Flex I’d like to have. In the meantime, I’d been looking for an Ashly XR1001 or another analog electronic crossover that fit my needs and sensibilities, but had been striking out.

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I ended up with a Carvin XC3000, used by one owner in his home studio. Unless you dabble in the pro audio world, you may never have heard of Carvin. They were known for their direct-to-consumer mail order business model, “closed” service infrastructure, and, until their 2017 death and rebirth, American manufacturing. They don’t enjoy a great reputation, and it’s hard to pin down how much of that was due to spotty quality, and how was due to shit-talking by salespeople and techs that couldn’t sell or readily service them.

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The XC3000 is a 2-way or 3-way 24db/octave stereo crossover. Inputs and outputs are balanced 1/4”, with an XLR option for the inputs. Crossover points can be set for 50-10,000 Hz, and there’s an optional 40 Hz low cut. We’ve got level controls and a phase switch for each output, and the lows are available through a summed mono output.

From the outside, build quality seems excellent. Opening it up, we notice that everything is laid out on a nice fiberglass PCB, and there’s a field of JRC 4558D and TI NE5532P opamps soldered directly in (pretty typical of studio gear of that era). The gold electrolytic and film caps are made by the same manufacturer, but I don’t recognize the logo. Similarly, I’m unfamiliar with the “JP” logo on the potentiometers.

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I was skeptical about Carvin, but so far, I can’t find any reason not to be optimistic about performance. I can’t find any negative reviews, and the XC3000 was part of Carvin’s stable for over 20 years. I have been able to nail down a block diagram and parts list, and there’s no surface-mount components, so service shouldn’t be a huge ordeal.

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Thoughts on active crossovers (especially those of you who have moved on to DSP)? Thoughts on Carvin? Any criticism or modding advice based on the pics?
 
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Crossovers like this one have a great advantage over DSP . They are analog circuitry. They are unlikely to fail and put full range through your tweeters which digital circuitry can do when some voltage surge scrambles what is in its instruction memory.

It also is convenient to change settings with the turn of a knob.

It is true that a miniDSP can do tricks that the analog circuitry cannot do. Some of these tricks probably are not that audible. Others probably are. Somebody gave me a pair of miniDSP 2X4HD but I haven't installed them to try them yet.

Crossovers like this one are very common in the professional sphere and mostly their performance is superior to audiophile gear. I have four similar crossovers from China labeled "McClelland" sold by the late MCM company. But I have never used them either because I have two Pioneer D-23 crossovers which is the best audio component ever made. It was made in the late seventies and still works perfectly. (Measurement on Audio Precision)

One thing that you will want to be very careful of is if you are mixing and matching xlr balanced and unbalanced circuitry. There are several different wiring conventions for for XLR (ie maybe two or three) and there also is a pseudo balanced scheme. Accordingly you will want to examine the schematics of all interfaces AND cabling to make sure everything goes to the right places. You may get lucky with plug and play but I would be very careful about that aspect.

Modding is usually inadvisable unless you really know what you are doing. There are a lot of Oppos out there now that Oppo will not service because they have been modded (even out of warranty) Most improvements are of dubious quality. You can't hear a three inch length of silver wire.

And don't just use this crossover for subs. Make your system active. You will never go back.
 
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The 4458 and 5532 op amps in that crossover are very dated. I was using both these in 1979 when I was an engineer at Altec Lansing. They were good in the day but there are now better options like OPA2134 or some similar dual op amp. I would change all the op amps to this type or equivalent.

Going active crossovers is absolutely the way to go - you get so many options on tuning the system. Just remember that when you go active, you loose all voicing that the speaker manufacturer designed into the speaker. You will either have to duplicate these filters at line level or better yet design your own to your tastes.
 
Thoughts on active crossovers (especially those of you who have moved on to DSP)? Thoughts on Carvin? Any criticism or modding advice based on the pics?
My thought is that this is the better way of adding subwoofers to your system. I anticipate you'll end up with overall better results using a real crossover than the typical filter included with the usual add-on subwoofer(s). In my opinion, the SUMO Delilah is a truly excellent subwoofer crossover. Subwoofers is all it does, and it does it well. Hard to find these days, but worth it. Six subwoofer outputs make it very flexible. I've never moved on to DSP, so I can understand if you aren't especially interested in my opinions.

Carvin is certainly not the best gear. But, I've come to learn that it is certainly NOT the worst gear either. The last place I worked they started out with a Carvin powered mixer, Carvin speakers, and a Carvin mic. A package deal. My heart sank the first time I saw it. We quickly bought more 'acceptable' gear, but kept the Carvin stuff for backup. The speakers served duty as monitors, and the powered mixer saw new life as the main setup for the stage with magicians and gun slingers. I also always used the Carvin gear for our employee meetings and orientation meetings. I had to do periodic maintenance on the Mackie, Yamaha, Behringer, Peavey, and B-52 gear, but the Carvin stuff never failed. It shut down occasionally when operated in the direct sunlight on 100 degree days in Texas, but that's understandable. After many years, I'd developed a new respect for Carvin gear.

If you want to replace the opamps, that would probably be nice. Upgrading caps can't hurt, either. But, I would see that as a huge time sink. I would feel that my time is worth a bit of money, and with that in mind I'd probably look for another piece of gear before investing all my time in it. But, if you like doing that sort of thing, you could probably squeak out a bit more performance from it. It appears to be a textbook circuit without a bunch of wizardry and tricks. I marvel when looking at circuit boards designed to a price point. I wonder how much the difference in cost would have been to go to a double-sided board without all the 0ohm jumpers needed. Also, being single-sided, it makes me wonder how good the power integrity is to each active component. But, then, this is probably over analyzing the situation.
 
Thoughts on Carvin?

They offered some really beautiful hand-made guitars in the 1980s and 90s, quality very much on par with Gibson or Fender of that period, their custom shop versions still go for big bucks on the used market:

 
Those things that look like resistors, but with one stripe, should be jumpers. It was a cheap and easy way to simulate a double-sided board, but still use conventional auto-insertion equipment. Nothing wrong with that at all. They should all read about zero ohms.
 
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