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Carver pm 1.5 how to crossover?

3567 Views 13 Replies 3 Participants Last post by  Wayne A. Pflughaupt
Please excuse me but im new to this. I find the threads on this forum very interesting. Theyve inspired me to build an enclosure for my SI HT18d2. But now for powering it.. Ive got an old Carver pm-1.5. Its an older professional amp that puts out around 650-700wpc @4 ohms and 1000+ watts bridged. What is the best cheapest way to cut out the high frequencies and very lows ones to if needed? Is there any other things i need in the signal chain?
Any input would be awsome. Thanks!
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You can build a low pass and hpass crossover for your subwoofer. Or purchase an electronic one

Your receiver doesn’t have its own built-in crossover? If not, you’ll need an external electronic crossover which will connect between the receiver and the Carver amp. Most typically this will be a pro-audio unit.

Thank you for the response. Any tips on where to get one?
Well first lets start with how much do you want to spend? And do you have a AVR or preamp?

If you have a AVR with a LFE preout then low pass is done. So once we know we can go from there.
I have a preamp with no LFE. And im trying to keep this build at pretty low cost. The cheaper the better.. lol

No shortage of pro-audio companies who make or have made crossovers. I recommend one with 24 dB/octave slopes and Linkwitz-Riley alignment, which is not hard to come by these days.

Your best (read cheapest) bet will probably be to find a quality used analog model. In recent years companies have been rolling crossover functions into digital speaker processors that have all kinds of other features added that may or may not be useful to the home user. A “great bang for the buck” legacy analog model is the black-face Ashly XR1000. If you don’t mind the garish green color, the later-model XR1001 is also a great unit. Rane’s vintage analog crossovers are also good, as long as you don’t stack them on top of an amplifier (they can pick up noise from the transformer).

Do you also only have a preout for your L/R?

Just wondering how are you going to get the signal to your amplifier?

I, coming from a DIY state of mind would just build a passive crossover for the sub. But when getting parts it may cost around $50 but probably less. I am used to shipping cost to Australia so your costs may be half. But you may be able to pick up a used analog crossover such as Wayne stated also for that price. Not knowing how your signal is getting there I can only just suggest two different options.

You could build a simple low pass crossover with Hpass and in line fuse if you also want to protect your driver from too many watts from a big amplifier. Although your amplifier should be fine going to a SI18.
I am going from a consumer preamp to a pro amp. Im using a rca to trs cable. Could i simply just put one of these in the chain? or should i have somthing with more options like some sort of eq or electronic crossover?
If not wanting to build something an electronic crossover is the next best thing or analog. Your suggested options can work but I have never used one of those products. Plus You dont want to add to many things in your signal chain if you can help it.

Have you thought about going from your preamp to an electronic EQ?

Then you could have the signal split from there to your amp/s for L/R and sub.
No but that sounds like a good idea. Do you know of any good cheaper ones. whats the price range on those?
Minidsp for about 130 I believe delivered. And then there is the Behringer DCX2496 for $350. There are other options also but nothing as versatile as these. These both provide EQ and crossover a long with many other features.

Sure, The F-Mods will work, but they are passive devices. With passive devices there is always signal loss. With a passive speaker-level filter like chrapladm recommended in Post #8 you lose amplifier power (read less watts and therefore output). A passive line-level device like the F-Mods will reduce signal voltage, which means you might not have enough to drive your amp to its full output (meaning, you’ll never be able to drive it to clipping, even with the gain controls all the way up).

Naturally, if your pre-amp has plenty of output voltage this might not be a concern. You might check Part 7 of my gain structure article for info on determining your pre-amps output voltage. You can access it from the link in my signature.

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