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ZP3 phono pre hum problem! (Read 6178 times)
marky
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Re: ZP3 phono pre hum problem!
Reply #30 - 12/05/12 at 19:18:54
 
The Isotek mains sub has 6 inputs so as the ZP3 is earthed anyway through the plug there should be no need to use the earth jack in the unit. Next step is to try it in different sockets in the Iso. They are rated for different power requirements so, tomorrow...
Yes Lon...wonder if RM has spoken to Steve.
I tried to explain soon after I received it through online chat.
Theres an earth wire with a spade coming from through the decks arm/phono loom. It`s onyl a couple of inches long. I`ve never used it and cant think where it goes. I linked it up anyway with the rest of the earths.
Come in RM, it`s a solveable puzzle.  :)

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rmcfee
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Re: ZP3 phono pre hum problem!
Reply #31 - 12/05/12 at 19:43:24
 
Hey Marky. I did talk to Steve. See my previous post.
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marky
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Re: ZP3 phono pre hum problem!
Reply #32 - 12/06/12 at 00:17:42
 
Ah, yes. Thats a pity, it`s a very open sounding amp.
My upgraded Roksan worked ok with my old phono.
I cant beleive the TT is the cause, it`s quite standard.
What I`m thinking deep down is that when my other
Decware amps arrive there should be more compatability.
My minimax pre/power are good but maybe there is an imbalance
with the signal going in.
In the meantime the small hum isn`t really noticable to be
anywhere near offputting.
Sugar, thats unfortunate for you.

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« Last Edit: 12/06/12 at 00:19:25 by marky »  
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rmcfee
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Re: ZP3 phono pre hum problem!
Reply #33 - 12/06/12 at 02:27:44
 
 A bit irritating actually. And costly.
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marky
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Re: ZP3 phono pre hum problem!
Reply #34 - 12/06/12 at 21:08:22
 
You`re dead right it`s irratating trying to find it, you pay your money you want silence, you cant get it, only option is to return it, what can I say.
First thing I thought when I took a breather playing with the earths, was no way would Decware sell noisy amps, it`s not going to happen.
I tried most things, swopped out the e/stats for my more efficient higher ohmed Focals. Anyway to cut a long story short, I realised that the ZP3 is a big lump of gear, 5 valves and sounds so open and bass powerful that I realised there were no filters on the output. The hum, is going through the amps and so coming from the phono, so in my way of thinking, the pre amp couldn`t handle it. What to do.
Now the hum is so quiet that you couldn`t hum to yourself more quietly at the levels I use that I would have been more than happy with it as it was. I can turn it up when it`s playing etc. And I`ve got the c/heating boiler in a cupboard that sometimes you can hear very quietly  when the music stops. So...
I was so pleased with it that I ordered the pre and power, which will be more at home wih the ZP3.
Different route to you, I should think everyone here feels a little.

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Lon
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Re: ZP3 phono pre hum problem!
Reply #35 - 12/06/12 at 22:08:33
 
Definitely feel for you r, the long wait, the frustration, the loss of duty money and shipping. . . . Sorry that you had this problem, and don't understand why as I don't have a problem.

Best of luck with your next component!
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Decware:ERR,HR-1,ZP3,CSP2+(2),Torii Mk III, PS Audio PWT+PWD MkII,PowerBases,PPP,AC-12 pcs, Denon DBP-A100, Denon DCD-A100, Rega RP3 +TTPSU,white belt+Exact2, VooDoo Cable IC: Evo and UL, Mapleshade:Double Heiix Samsonv2+v3 and 4"platforms,Herbie's IsoCups+Tendft
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marky
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Re: ZP3 phono pre hum problem!
Reply #36 - 12/07/12 at 16:19:03
 
There is one last test I havent done.
My pre amp usually stays around 7-8 o`clock with my cassette, cd, and old phono. With the ZP3 it reaches around 10-11 o`clock for the same volume, so the extra headroom would exaggerate any tiny hum, maybe not audible.
Would changing the 0a3, voltage regulator, for another value which I have seen used here, make a difference to the output ?
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Lon
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Re: ZP3 phono pre hum problem!
Reply #37 - 12/07/12 at 16:27:19
 
Well, the OA3 is I think the "hottest" of the types. I find that the straight shouldered ones have a bit more "oomph" than the coke bottle shaped ones, but I'm not sure that translates into more voltage output. . .

I've tried OB3s in my ZP3 and for me the bass output is too soft and the dynamics restrained. . . not sure there was less output, but there wasn't more. That should be even more pronounced so to speak with the OC3 and OD3 tubes.

Have you tried different 12AU7 and pairs of 12AX7 tubes, have you determined that it's not particular tubes or a particular tube that is contributing to the hum? (I bet you have, I just haven't seen you specifically mention trying a number of tubes).
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Decware:ERR,HR-1,ZP3,CSP2+(2),Torii Mk III, PS Audio PWT+PWD MkII,PowerBases,PPP,AC-12 pcs, Denon DBP-A100, Denon DCD-A100, Rega RP3 +TTPSU,white belt+Exact2, VooDoo Cable IC: Evo and UL, Mapleshade:Double Heiix Samsonv2+v3 and 4"platforms,Herbie's IsoCups+Tendft
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marky
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Re: ZP3 phono pre hum problem!
Reply #38 - 12/07/12 at 17:49:02
 
Thanks Lon. I`ve tried just that. I put all the stocks back in because I remembered that sylv ax7`s were put in before the stocks.
The volume is back where it should be now, and the hum is, well i`ts not really a hum more like a quiet warmth which I would expect with valves amplifying valves. Now at the normal volume it`s quiet. When I lift the needle and turn it right up it past 12 o`clock it`s annoying, but at that volume people down the street would be knocking.  :)

I suppose thats a lesson learned ! Put the stocks in that were shipped with it first as they were tested with the unit in situ.


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Lon
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Re: ZP3 phono pre hum problem!
Reply #39 - 12/07/12 at 19:19:17
 
Whew! Happy to hear that. Now you know to look for tubes that are tested to be very quiet if you are looking for other tubes. Hope you can settle in and really enjoy some listening.
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Decware:ERR,HR-1,ZP3,CSP2+(2),Torii Mk III, PS Audio PWT+PWD MkII,PowerBases,PPP,AC-12 pcs, Denon DBP-A100, Denon DCD-A100, Rega RP3 +TTPSU,white belt+Exact2, VooDoo Cable IC: Evo and UL, Mapleshade:Double Heiix Samsonv2+v3 and 4"platforms,Herbie's IsoCups+Tendft
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marky
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Re: ZP3 phono pre hum problem!
Reply #40 - 12/07/12 at 23:18:13
 
You got it Lon !
I`ve been busy putting the tree up this evening but am looking forward
to a good session when time permits.  :)
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