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ZKIT1 Hum (Read 7946 times)
Mike B
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Posts: 4
ZKIT1 Hum
06/19/13 at 22:44:38
 
Just finished the Zkit1 and it has a 5.5mv hum.  I isolated it to the amp, took the input tube out and the hum is gone.  Any help with this problem will be appreciated.  The amp sounds wonderful but I would like to get this hum below 3mv.

Mike B
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Lon
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"Love without
guts is
worthless!"
Philip K. Dick

Posts: 23305
Re: ZKIT1 Hum
Reply #1 - 06/19/13 at 23:23:44
 
Believe me, I am far from an expert, but. . .have you tried another input tube?
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HR-1,ZTPRE,ZBIT,ZROCK2,SEWE300B,CSP3-25mod,Taboo MkIV;Rega RP3 all GrooveTracer mods;PSAudio:PST+DSD,P15,NPC,PowerBases,AC-12 pwr cbls,Reference spkrcbls;Mapleshade SamsonV3;VooDoo:Cremona+Amati interconnects, IsoPods; headphones:Sennheiser HD800S,ZMF Ori,Oppo PM1
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Mike B
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Re: ZKIT1 Hum
Reply #2 - 06/20/13 at 03:18:25
 
Thanks for the reply, Lon.  Yes, I did try serveral input tubes, and also rectifier tubes.  Maybe Steve will see this post and give me a suggestion.

Mike B
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dank
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pair of dual 18
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Re: ZKIT1 Hum
Reply #3 - 06/20/13 at 12:14:15
 
I think the Zkit board has been redone to correct some of the problems found and fixed tin the "Hum Problem" thread:
https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1257041114
but you should read through that.

I believe the "Virtual CT for Edcor Heater Wires - WOW!" thread is still producing results:
https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1352929896

good luck


Dan
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Lon
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"Love without
guts is
worthless!"
Philip K. Dick

Posts: 23305
Re: ZKIT1 Hum
Reply #4 - 06/20/13 at 13:27:05
 
Well Mike, good that you tried some other tubes. I have to say that most of the time I've had hum issues with a Decware component it's been a tube that was responsible.
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HR-1,ZTPRE,ZBIT,ZROCK2,SEWE300B,CSP3-25mod,Taboo MkIV;Rega RP3 all GrooveTracer mods;PSAudio:PST+DSD,P15,NPC,PowerBases,AC-12 pwr cbls,Reference spkrcbls;Mapleshade SamsonV3;VooDoo:Cremona+Amati interconnects, IsoPods; headphones:Sennheiser HD800S,ZMF Ori,Oppo PM1
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mboxler
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Re: ZKIT1 Hum
Reply #5 - 06/20/13 at 14:39:05
 
Hey Mike

I assume you mean you replaced the output tubes, or did you go with tube rectification instead of the diodes on the board?

I know pictures are a pain, but perhaps one of us can see something.

Mike
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Mike B
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Re: ZKIT1 Hum
Reply #6 - 06/20/13 at 22:29:37
 
Mike, I replaced the input tube with new ones, no change.  I also decided to use tube rectification and tried changing rectifier tubes but there was no change.  The hum is not there with the input tube removed.  

I built and original zen amp, and there is no hum the AC voltage on the speaker outs is less than 2mv, so the 5.5mv I have now is bothersome.

Since the hum is equal on both side, I'm checking the circuitry around the input tube.  

I'll try to post pictures later tonight.

Mike B
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