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Balanced inputs? (Read 2554 times)
Steamer
Ex Member



Balanced inputs?
12/05/05 at 22:43:17
 
Hello,
        I have a pair of SE84CS monos on the way.I will be using these to power an Altec 511-B/902-T on top of my Klipch La Scala's w/an active x-over.The bass bins to be driven by a Bryston3BPro.All my interconnects are XLR type as well as the equipment connections except my Shannling PP EL-34 monos.I currently use an XLR to RCA adapter by Cardas.Is it possible to convert the Decware inputs to this style connection for grounding purposes?Can it be done within pysical limitations ie. a larger drilled hole around the input area of the amp?
                                     Thankyou,Greg
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Jason_S
Ex Member



Re: Balanced inputs?
Reply #1 - 12/06/05 at 00:50:08
 
Cut the end off your XLR cable and put a RCA on it.  Changing the amp to a balanced topology is complex with no added benefit.

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Steamer
Ex Member



Re: Balanced inputs?
Reply #2 - 12/06/05 at 02:56:17
 
I dont want to change the topology of the amp just make a balanced connection work,cut off the end,already did that in effect with the adapter,so obviously I didnt have to change the topology of the Shannling amps,I believe its about making the right grounding useing 3 wires in the interconnect vs. 2.Can someone give me a straight answer,either yes or no not some kneejerk i got an attitude answer,hey maybe I am way off base here but I thought it was a legitimate question.I read and try to contribute to these forums because of this fantastic hobby we all enjoy.I dont profess to be an electrical engineer.I have alot to learn,you guys do so much tweaking with these amps,I just want to be able to make a Decware work with what I have going on ie. balanced connections that are well grounded and low in noise,NO GROUNDLOOP PROBLEMS(hum).
                                                 Greg
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Jason_S
Ex Member



Re: Balanced inputs?
Reply #3 - 12/06/05 at 03:51:31
 
On the RANE site, are some technical papers.  I remember one of them details just about every cable configuration for going balanced to unbalanced etc and how to wire them.

I'ts good information.

... found it:

http://www.rane.com/note110.html

Jason
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« Last Edit: 12/06/05 at 03:54:49 by Jason »  
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Jason_S
Ex Member



Re: Balanced inputs?
Reply #4 - 12/06/05 at 03:57:33
 
Try also ranenote 151 and 109.
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chevelle
Ex Member



Re: Balanced inputs?
Reply #5 - 12/06/05 at 06:17:49
 
i can yak about it, as I've made up several balanced to unbalanced line cables (using those uh, pretty car stereo cables), using RCA to TRS, or XLR, but I'll show you where I learned it from:

http://www.mackie.com/pdf/1202vlzpro_om.pdf

Scroll down to "Appendix A: Connections, and the Mackie Boys tell you how to do it.

I will also throw this out: When using my sand amps, I never noticed any difference in wiring balanced line equipment to non balanced (and I went through pains to keep my audio cables away from power cables- there should be a freakin standard by audio manufacturers as to which side of the unit they run the power cable out of.. okay, I've calmed down) . But with my Zen 84CS amp, I NOTICED A DIFFERENCE. There is a loss in imaging and the "live" feel dissapeared.  My Beringer DEQ 2498 digital EQ, with absolutely no eq dialed in, did this. Same even when it was switched out of the circuit. I had to EQ it to try to bring it back, and that does not work!

When  I choose to use it this way, the only thing I found that works without ripping out the image and presence, was to throw another link in the chain (actually 2)-  an EB TECH line level shifter.

I have to go from an unbalanced line ( a Swissonic Studio D) through the EQ (balanced) and going back, unbalanced, to the Zen amp. What a freakin disaster. I don't worry about the effects patched through the mixer (not important on playback), but my signal chain going to the Zen could be better. If I'm doing some critical listening of a playback, I just rip everything out of the chain and plug into the Zen. It's that good.

Beside the dfference in levels associated with pro and "consumer level" ("Plus 4 vs -10dbv), there's an impedance matching problem when you try to make up cables to match balanced line to unbalanced, and vice versa.

As for the EbTECH Line Level shifters:  Plus side is that they are passive units (no power= no wall warts) Downside is that it is another link in the chain (in your case, for matching balanced to unbalanced. You can get them here:
http://www.musiciansfriend.com/srs7/g=home/search/detail/base_pid/189100/

I would think in your case (and hopefully mine, soon enough) that I can run everything balanced line (or digital) and then just make the final shift to unbalanced with the 84CS. I would still recommend looking into one of the Ebtech units.

When you get your amps, try using them with just a CD player hooked up on them (an unbalanced one with RCA jacks), and then listen to it with all your stuff hooked into it, with whatever you decide to use for matching the system up. I'tll give you a good idea as to how your system SHOULD sound.

Doc Sleep can probably elaborate more, as he does the same thing with his Zens as I do with mine (studio kinda stuff)



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« Last Edit: 12/06/05 at 18:26:19 by chevelle »  
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crazy bill the eel killer
Ex Member



Re: Balanced inputs?
Reply #6 - 12/06/05 at 12:21:00
 
Hey guys,

another option, though costlier, is to use a line or input transformer. In addition to solving your cable hookup and impedance matching problems ,you will eliminate ground loops and can even throw some gain into the equation if you like. Go to the Jensen, Lundahl, and Sowter websites and take a look.\

Have fun,                         Bill
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Steamer
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Re: Balanced inputs?
Reply #7 - 12/09/05 at 22:13:20
 
Thankyou everyone for your input,I now know more and have some direction.Lots of info to go thru,great links.I just tought it would all be simpler.The isolation transformer sounds like a good idea.Would be great to just make it a plug it in and forget.
                           Greg
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Jason_S
Ex Member



Re: Balanced inputs?
Reply #8 - 12/09/05 at 22:22:19
 
the main purpose of the transformer is to convert the signal level.  According to spec (but no always in reality) Balanced signals run at +10dbu and unbalanced run at -4 dbu.  If the amp has an input level control (like the zens do) you can easily pad the signal down.

I've asked steve before about putting balanced input on the Torii and his comments were to the effect that 1) there's no benefit with short interconnects.  2) it would require another tube stage to properly impliment it, one more thing in the chain messing with the signal but providing little to no advantage.

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« Last Edit: 12/09/05 at 22:22:57 by Jason »  
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