Emile Posted December 17, 2019 Share Posted December 17, 2019 Help ... Hope you experts can give me some advise Have a "hum" in my system. Not noticeable on low volume, but increases as I increase volume. Not sure if it is a "ground loop;" haha, tried to find the 60Hz sound on my PC ... of course sound on it doesn't go that low, so "not sure." OK; have a Nikko Beta II preamp, feeding a Crown K1 (corrected again) into KPT-904's. Using RCA preamp out to XLR on the Crown ... not sure if the cables are "balanced," but switched to XLR when one of my 1/4 plugs broke in the K1 ... tip only and does not affect sound . Pretty sure preamp is fine ... but; ran source direct to the Crown and get no sound at all??? CORRECTION ... works FINE; stupid me had a different source plugged in . Oops, guess I should mention, power is coming from an APC H10 Power Conditioner. Not sure if this is a new or old problem ... when we get into the 100dB level, we have usually had a couple of bottles of wine All is fine up to 1/3rd power ... then the hum starts and becomes louder when I turn the volume up Switched to a different power outlet, but problem (both channels) remains. Strangely, sometimes there is "no hum," till I turn it up to 2/3rd's power. If I then turn down the volume and slowly increase it it starts again at 1/3rd again Thanks in advance for any advice/suggestions Cheers, Emile Add-on ... hum stays on for about 10 seconds, then it is "off" for maybe 1/4 second ... then on again ... over and over again Quote Link to comment Share on other sites More sharing options...
Coytee Posted December 18, 2019 Share Posted December 18, 2019 Wonder if it's a short? I would expect a hum to STAY a hum and most likely be discernable at lower volumes. I don't know....I'm certainly not the expert. I will say however, all three of my "K's" (all K2's) are very quiet. I've got their gains on something like the 10th or 15th click (relative to zero). When I turn them up further, I can hear some background noise. 1 Quote Link to comment Share on other sites More sharing options...
babadono Posted December 18, 2019 Share Posted December 18, 2019 clarification...its a Crown K1 or K2? 1 Quote Link to comment Share on other sites More sharing options...
Emile Posted December 18, 2019 Author Share Posted December 18, 2019 Just now, babadono said: its a Crown K1 or K2 K2 Quote Link to comment Share on other sites More sharing options...
babadono Posted December 18, 2019 Share Posted December 18, 2019 Ok what happens if you unplug the input cables to the K2 and spin the gain controls from min. to max? 1 Quote Link to comment Share on other sites More sharing options...
Coytee Posted December 18, 2019 Share Posted December 18, 2019 (smartazz alert on) Two K1's as stated in your post, don't make for a K2 (smartazz alert off) 1 Quote Link to comment Share on other sites More sharing options...
Emile Posted December 18, 2019 Author Share Posted December 18, 2019 15 minutes ago, Coytee said: I would expect a hum to STAY a hum Coytee ... thanks Yes; find the split second "no hum" strange Hum starts at about "15" and gets progressively worse Quote Link to comment Share on other sites More sharing options...
Coytee Posted December 18, 2019 Share Posted December 18, 2019 I see what you've done!!! 1 Quote Link to comment Share on other sites More sharing options...
Emile Posted December 18, 2019 Author Share Posted December 18, 2019 8 minutes ago, babadono said: Ok what happens if you unplug the input cables to the K2 and spin the gain controls from min. to max? Unplugged connectors to the K2 ... same problem. Should I unplug the XLR's??? Quote Link to comment Share on other sites More sharing options...
Emile Posted December 18, 2019 Author Share Posted December 18, 2019 4 minutes ago, Coytee said: I see what you've done!!! Haha; enlighten me Will send you a bottle of ??? when you solve it Quote Link to comment Share on other sites More sharing options...
babadono Posted December 18, 2019 Share Posted December 18, 2019 ? what did you unplug? 1 Quote Link to comment Share on other sites More sharing options...
Emile Posted December 18, 2019 Author Share Posted December 18, 2019 1 minute ago, babadono said: ? what did you unplug? RCA connector at preamp; not the XLR at the K1. Also had connected Oppo CD straight to the RCA-XLR cable going into the K2 ... same result Stuff is hard to get to see pic Sorry; no pic ... haha; only allowed 60kB Quote Link to comment Share on other sites More sharing options...
Emile Posted December 18, 2019 Author Share Posted December 18, 2019 OOPS ... sorry guys ... I'm an idiot ... it's a K1 not a K2 Quote Link to comment Share on other sites More sharing options...
babadono Posted December 18, 2019 Share Posted December 18, 2019 There's that K1 reference again But yes unplug the input cables AT the input to the K2 K1. So just the K1 powered up and speakers connected of course. Then spin the gain controls. There of course will be no signal and (hopefully) no sound. Don't know how quiet your system is but there will be a little gaussian hiss which is left over from the big bang. 1 Quote Link to comment Share on other sites More sharing options...
babadono Posted December 18, 2019 Share Posted December 18, 2019 4 minutes ago, Emile said: OOPS ... sorry guys ... I'm an idiot ... it's a K1 not a K2 I thought so But its just a less powerful version of the same amp isn't it? 1 Quote Link to comment Share on other sites More sharing options...
Emile Posted December 18, 2019 Author Share Posted December 18, 2019 7 minutes ago, babadono said: There's that K1 reference again Yeah ... stupid me ... K1 it is Quote Link to comment Share on other sites More sharing options...
Emile Posted December 18, 2019 Author Share Posted December 18, 2019 12 minutes ago, babadono said: yes unplug the input cables AT the input to the K2 Babadono; you are a genius OK; unplugged XLR inputs to the K1 ... no sound, but no hum either at full volume Next?? Quote Link to comment Share on other sites More sharing options...
babadono Posted December 18, 2019 Share Posted December 18, 2019 But there was hum with just the cables plugged in at the K1 but unplugged from the pre amp? 1 Quote Link to comment Share on other sites More sharing options...
babadono Posted December 18, 2019 Share Posted December 18, 2019 Got to go home....I'll check in a little later Quote Link to comment Share on other sites More sharing options...
Emile Posted December 18, 2019 Author Share Posted December 18, 2019 1 minute ago, babadono said: But there was hum with just the cables plugged in at the K1 but unplugged from the pre amp? Yes ... spend the last 5 minutes trying to plug it in a again to double check ... hard to get to ... trying a glass of wine for assistance Quote Link to comment Share on other sites More sharing options...
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