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Tri-amp/DSP


JohnA

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I didn't want to take over another thread, so I started my own. 

 

I have Fastlane Eliptrac tweeter horns and DE120 drivers perched on the top of my La Scalas, placed to approximately correct for time alignment.  I like the effect, but the look is post-college geek and has to go!  Though my Pre/Pro has balanced XLR outputs, few home amps have them for inputs.  What DSP/crossover would you recommend to triamp my La Scalas and time align all 3 horns? 

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I have been running a Ashly ProTea 3.24cl (new model 3.6sp) for some time with great results. 

 

https://www.bhphotovideo.com/c/product/635992-REG/Ashly_A1VA00700_Protea_3_6SP_3.html

 

I use it for my L/C/R, biamped.

 

I believe MINIdsp has offerings with rcas vs balanced.

 

https://www.minidsp.com/products/minidsp-in-a-box/minidsp-4x10-hd

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Watching this thread. I've done same "mods" to my La Scalas and am looking for answers too.

 

John, I've looked at the Xilica XP 4080 as I want I integrate subs (tapped horn lil'mike anarchy) with mine. The miniDSP HD products look intriguing as well. 

 

I'm sure the experts will chime in.

 

Mark

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33 minutes ago, The Dude said:

I have been running a Ashly ProTea 3.24cl (new model 3.6sp) for some time with great results. 

 

https://www.bhphotovideo.com/c/product/635992-REG/Ashly_A1VA00700_Protea_3_6SP_3.html

 

I use it for my L/C/R, biamped.

 

I believe MINIdsp has offerings with rcas vs balanced.

 

https://www.minidsp.com/products/minidsp-in-a-box/minidsp-4x10-hd

 

The Ashly looks similar to what I want, except for the balanced outputs.  All of my amps have unbalanced phono inputs.  I suppose there are adapters, but before long, you've added so much in the signal path, the benefits are lost. 

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1 hour ago, John Albright said:

All of my amps have unbalanced phono inputs.  I suppose there are adapters, but before long, you've added so much in the signal path, the benefits are lost. 

I think that you're thinking in terms of a kind of "slippery slope" fallacy.  You're assuming that changing from shielded (XLR) to unshielded (RCA) somehow degrades something: it doesn't. 

 

The lack of shields on RCA-to-RCA cables is actually an issue because the cable is not shielded from external power cable line noise (60/120 Hz or 50/100 Hz ). It's very nice to have XLR-XLR or XLR-RCA cables that provide added protection from this type of noise. I use female XLR-to-RCA cables to connect my First Watt F3 amplifier. Noise levels are actually lower than using RCA-to-RCA cables since there is the benefit of the shield for the length of the cable, even if grounded only to the Xilica end of the circuit. 

 

Chris

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There's a reason why balanced ("XLR") cables are used for microphones and pro cabling...and not RCA unbalanced connections,

 

It has to do with lower noise.

 

Chris

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John, are you searching for specific brands or, are you looking to try something to see how it works....then, worry about brands?

 

I ask because I have not one, but two EV-DX-38's (and some XLR/RCA wires) that you could borrow to give it a whirl.

 

I might not have six XLR/RCA wires.... but should at least have four. 

 

If you'd like to give that a try, you are welcome to use them.  I've pulled the Dx's out of the system in lieu of the Xilica.  I wanted to get all four of my active speakers on the same box instead of two boxes.

 

 

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4 hours ago, Chris A said:

I think that you're thinking in terms of a kind of "slippery slope" fallacy.  You're assuming that changing from shielded (XLR) to unshielded (RCA) somehow degrades something: it doesn't. 

 

The lack of shields on RCA-to-RCA cables is actually an issue because the cable is not shielded from external power cable line noise (60/120 Hz or 50/100 Hz ). It's very nice to have XLR-XLR or XLR-RCA cables that provide added protection from this type of noise. I use female XLR-to-RCA cables to connect my First Watt F3 amplifier. Noise levels are actually lower than using RCA-to-RCA cables since there is the benefit of the shield for the length of the cable, even if grounded only to the Xilica end of the circuit. 

 

Chris

 

Phono cables (interconnects) are shielded.  The Vampire Wires I use are shielded, twisted-pair cables.  It was not that common 20 years ago (!!!!) when I bought them.  Most phono cables are shielded coaxial cables. 

1core-sh.jpg

 

Balanced cables are also shielded, twisted-pair cables, but the twisted pair are reverse polarity helping to cancel noise, especially in long runs (snakes).  Commonly, a transformer (balun) is used to transform one type of connection to the other. 

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1 hour ago, Coytee said:

John, are you searching for specific brands or, are you looking to try something to see how it works....then, worry about brands?

 

I ask because I have not one, but two EV-DX-38's (and some XLR/RCA wires) that you could borrow to give it a whirl.

 

I might not have six XLR/RCA wires.... but should at least have four. 

 

If you'd like to give that a try, you are welcome to use them.  I've pulled the Dx's out of the system in lieu of the Xilica.  I wanted to get all four of my active speakers on the same box instead of two boxes.

 

 

 

I will admit to a certain snobbery/prejudice against a few brands, like Blose and Pioneer, ;) but generally I am not looking for a particular brand.  I may well take you up on your generous offer.  Thanks!  I am short of amp channels right now.  I would like to have something like a Parasound HCA-806.  I found an older Rotel 6-channel on ebay, too. 

 

Might need more shelves! 

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7 hours ago, John Albright said:

What DSP/crossover would you recommend to triamp my La Scalas and time align all 3 horns? 

None...if you don't like XLR connections and unless you're looking cheap: in either case, I have no suggestions.

 

However, if you can get over that (and assuming you're actually asking for help) then the answer would be:

 

Xilica XP-3060 or XP-4080.  If you can find a used Yamaha SP2060, that would work well (...both with XLR connections).

 

If you want to know why then I'm sure you'll let us know if you want that answer, rather than just commenting on suggestions.

 

Chris

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Wow! I think John is asking serious questions. Not sure why the snippy reply.

 

Almost all devices with balanced outputs allow for an unbalanced connection, but it usually means a lower output and impedance change by doing so. No transformer needed, but the neg. pin is simply tied to the grounf pin. I have a schematic somewhere that includes the use of one or two resistors to keep a pseudo balanced circuit in place, but it's usually not necessary.

 

Bruce

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1 hour ago, Marvel said:

Wow! I think John is asking serious questions. Not sure why the snippy reply.

 

Bruce, I believe John's okay.  I took all of his questions seriously...as always.  The answer wasn't "snippy" but rather direct: that "issue" isn't an issue at all...at least in my experience.  (If you wish to make it one, then I guess you have an issue.)  I've detected no acoustic or other integration/connection effects of balanced/unbalanced connections without using baluns, etc.  If there were any FR issues, they'd be compensated for during the setup of the parametric equalization filters using in-room acoustic measurements.  I've already stated that they're quieter connections.

 

If the basic subject above includes "I don't want to spend more than $XXX on an active crossover", then that needs to be part of the stated question.  However, I don't believe my answer will change.  In my estimation, the second-generation miniDSP 2x4 still isn't proven for multi-way full-range loudspeakers.  But anyone can place an order for a couple of units (i.e., a 2-in, 6-out application, such as above will require two 2x4 miniDSPs).  I don't recommend it if you're truly adverse to chancing something not coming out the way that you wanted.  But if you want to try it, by all means...let us know how it goes.

 

Chris

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Yes you can go from a balanced output to an unbalanced input. Not ideal but doable of course. In a home setup you will probably not be able to detect a difference especially if you keep the XLR to Rca cable short. And as long as you are in a low electrical interference environment as homes usually are. When going from a balanced output to an unbalanced input you are negating most of the CMR(common mode rejection) that a balanced to balanced connection would have provided.

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49 minutes ago, babadono said:

Not ideal but doable of course.

This is itself a problem: I find that audiophiles talk about "ideal" like those folks that i know that deal with OCD.  The anti-digital crowd seems to inhabit this domain.  I don't have much time for those discussions.

 

I tend to talk in terms of "how does it perform in real life".  Use your ears and your measuring equipment.  Worry about those things that really are important--like your music recordings, how good your loudspeakers are, and your room acoustics.  Everything else in between is at least an order of magnitude less important to how it affects the sound.

 

Chris

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A secondary hobby is Pro Audio.  I have a bi-amped system with an electronic crossover, a couple of different mixers and other stuff to do DJ or live band audio.  It all uses balanced connections.  I could use those Crown amps as an experiment, but I wouldn't want to listen to them daily. 

 

My issue is I have good amplifiers I don't relish replacing with something that will sound inferior from the pro-audio world, or will start at $3000 a stereo pair to avoid the noise and possible frequency response anomalies an improper conversion from balanced to unbalanced connections.  Yes, I've looked at the different cable configurations that don't use a balun.  Functional, sure; excellent, I doubt it.  Can I hear it?  Maybe not easily, but at some time down the road, I would notice it.  Use it in the church, pub, or street concert?  Without hesitation. 

 

This is very like putting car tires on a motorcycle.  It's the wrong application, wrong design hoping to get more tire life while trading safety and handling to get it.  Yet, no one will admit to crashing or knowing of a death caused by a car tire.  And it's proponents INSIST is it no big deal, just as safe and that they've done it for yy years with no ..........

 

011316-skidmarks-dark-side-riders-rear-tire.jpg

 

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John, all my equipment that has balanced i/o also has the specs listed for wiring unbanced. What I mentioned above applies - an output impedance change and output level change. Noise and distortion levels don't change.

 

And no reason there should be F/R anomalies...

 

Bruce

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