Coytee Posted April 10, 2019 Share Posted April 10, 2019 Is the hiss there if you turn your preamp off? (if mentioned above, I missed it) What I did was worked backwards.... whole system off. Went to power amps & turned only those on. Dialed gains (which I don't know if yours has) up until I heard some hiss...backed them down till it was dead quiet. Went to active, turned it on... Went to preamp, turned it on and with the gains all the way DOWN, turned the volume control to 100%. Last, I started moving the gains on the preamp up until I had it as loud as I might want to "normally" listen to. Actually, I took it a bit higher to let me jam every now & then....but otherwise, left it at that level. Now, I have to turn the preamp up higher to get my signal and it not only sounded better but, I had no hiss. My opinion, variable gains/attenuators are your friend. 1 Quote Link to comment Share on other sites More sharing options...
Edgar Posted April 10, 2019 Share Posted April 10, 2019 44 minutes ago, CECAA850 said: You might also put something like THIS on the unused inputs and see if it helps. You can get generics on Amazon or eBay for under US$1.00 each. Search for "RCA shorting plugs". 1 Quote Link to comment Share on other sites More sharing options...
Coytee Posted April 10, 2019 Share Posted April 10, 2019 What's the input sensitivity of that amp? I looked it up and didn't see it (in an obvious location) on their website. I used to have a dbx BX-1 that as i recall, had an input sensitivity of 1v and it was a real bugger trying to keep it quiet. Quote Link to comment Share on other sites More sharing options...
Ivaols Posted April 10, 2019 Author Share Posted April 10, 2019 34 minutes ago, Chris A said: I'll send you an updated .xdat file that greatly increases the input channel gains. It appears to be a gain staging issue. I would bet it's your preamp (which you haven't identified here) not driving the signal chain with enough output. The Xilicas have all been dead quiet quiescently in the setups that I've used them in. Chris Thank you. The preamp is a receiver, Marantz SR6012. Quote Link to comment Share on other sites More sharing options...
babadono Posted April 10, 2019 Share Posted April 10, 2019 20 minutes ago, Ivaols said: There is still one input without connection, and two outputs without connection. OK we're talking about the Xilica, right? That should be ok as long as the unused input is not assigned to any of the used outputs. So the inputs of the Xilica come from a reciever over balanced or un balanced lines? Quote Link to comment Share on other sites More sharing options...
Ivaols Posted April 10, 2019 Author Share Posted April 10, 2019 2 minutes ago, babadono said: OK we're talking about the Xilica, right? That should be ok as long as the unused input is not assigned to any of the used outputs. So the inputs of the Xilica come from a reciever over balanced or un balanced lines? Yes, we're talking about the Xilica. The unused input is not assigned to anything. Signal from receiver is unbalanced. Quote Link to comment Share on other sites More sharing options...
babadono Posted April 10, 2019 Share Posted April 10, 2019 The document I referenced explains exactly how to work backwards from the amplifier to the source to scientifically identify the source of the problem. But you need dummy plugs! Quote Link to comment Share on other sites More sharing options...
Ivaols Posted April 10, 2019 Author Share Posted April 10, 2019 1 hour ago, Coytee said: What's the input sensitivity of that amp? I looked it up and didn't see it (in an obvious location) on their website. I used to have a dbx BX-1 that as i recall, had an input sensitivity of 1v and it was a real bugger trying to keep it quiet. Input sensitivity for full rated power is 1.8v. Quote Link to comment Share on other sites More sharing options...
Ivaols Posted April 10, 2019 Author Share Posted April 10, 2019 (edited) Here is what I tested: With only the amp on there is hardly any hiss. With the amp on and the Xilica turned on the hiss appears. With the amp on and the Xilica on it is no difference between pre on or off, the hiss is there all the time with same intensity. Reducing the input gain from the pre to the Xilica has no effect, the hiss is the same. Confused... Edited April 10, 2019 by Ivaols Quote Link to comment Share on other sites More sharing options...
babadono Posted April 10, 2019 Share Posted April 10, 2019 Have you tried amp and xilica on with no input cables connected to the xilica? You really need a dummy plug(s) for the input(s) but no connection can tell something useful maybe. Quote Link to comment Share on other sites More sharing options...
Chris A Posted April 10, 2019 Share Posted April 10, 2019 The Xilica mutes when it's not being driven. Something is wrong on the input side of the Xilica if it isn't automatically muting. Quote Link to comment Share on other sites More sharing options...
babadono Posted April 10, 2019 Share Posted April 10, 2019 See page 23 of manual for settings of the ISO (internal system optimizer). I think muting can be turned off. This is the Xilica I'm talking about. I can't seem to copy the manual and paste it here. ????? I r n idiot with computer stuff sometimes. Quote Link to comment Share on other sites More sharing options...
Chris A Posted April 10, 2019 Share Posted April 10, 2019 For his setup, I believe that parameter needs to be "on". Chris Quote Link to comment Share on other sites More sharing options...
Chris A Posted April 10, 2019 Share Posted April 10, 2019 In fact, I'd recommend raising the threshold of muting above the level "102" to see if that controls the quiescent hiss. Quote Link to comment Share on other sites More sharing options...
babadono Posted April 10, 2019 Share Posted April 10, 2019 Does this muting involve the actual relays and buttons on the front of the unit? Or is it a software muting of the DSP? I need to go home and mess with mine. Is this setting, the threshold of the mute, available in the XConsole App.? Quote Link to comment Share on other sites More sharing options...
Chris A Posted April 10, 2019 Share Posted April 10, 2019 I accessed the function from the front panel-turning it to "bypass". I heard no increased hiss levels after doing this--there was no audible hiss. So I believe that, in my setup, there is no need for the Internal System Optimizer (ISO) muting function. However, in Ivan's case--there may be a need. Chris 1 Quote Link to comment Share on other sites More sharing options...
babadono Posted April 10, 2019 Share Posted April 10, 2019 Ok but to just test the speaker+amp+Xilica combo with no input to the Xilica I would think you would turn the muting off, no? Quote Link to comment Share on other sites More sharing options...
Chris A Posted April 10, 2019 Share Posted April 10, 2019 In Ivan's case, if he's already got audible hiss then either the muting function is not set high enough or there is significant EMI on the XLR output cables to his amplifier. The Xilica is dead quiet in all the setups that I've used (XP-4080s for others , XP-8080 in my setup). 1 Quote Link to comment Share on other sites More sharing options...
babadono Posted April 10, 2019 Share Posted April 10, 2019 I re read the manual about the ISO and it is a "noise gate" and I'm sure its done in the DSP. So Ivan should be able to adjust it until he can definitely hear it cutting in and out if it is like any kind of noise gate I've ever used. Now I definitely want to see where mine is set and experiment with it. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted April 11, 2019 Share Posted April 11, 2019 9 hours ago, Ivaols said: As of now I have to lower the gain by minus 9.5db in the Xilica for the K-402 output. If I can open it up to 0 dB and lower the gain on the amp side it will provide better s/n ratio. 5 hours ago, Ivaols said: With only the amp on there is hardly any hiss. Are you lowering the gain by -9.5 so that you can drive the Xilica’s Input at a good level as read on the Xilica’s Input Meters..? If the above is the case then even if you can adjust the Mute level of the Xilica it sure looks to me like you would benefit from attenuators on the amplifiers inputs due to the input sensitivity and gain of the amplifier. miketn Quote Link to comment Share on other sites More sharing options...
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