Has anyone had trouble with hum in these amps?  It is as loud as the quiet passages in any album making it unusable.
 I tried grounding the tonearm to the Zen, grounding the Zen to the amp, grounding both to the amp or no ground.
  I gave the Zen a dedicated outlet instead of the isolation transformer I usually use.
   I replaced the Decware interconnects with shielded ones.
    I tried swapping tubes in case a tube had a problem.
  Still a loud hum.
  Any advice would be great since I really wanted to like this amp. Thanks.

 When I disconnect the ZP3 the noise goes away so it is not the table/tonearm.
   When I turn the ZP3 off it is still making a faintly audible hum through the channel.
   The previous preamp (Rega Fono) was dead silent so it is not the channel on the amp. Very frustrating.

I may have to send it back which would suck after waiting so long to get it!

rmcfee wrote on 12/02/12 at 05:58:16:


I agree that would suck. I waited three months for mine and have had it just over two weeks, I love it and would hate to send it back.

You should both call Steve!

Great news!

There are two oher things you could try.
1) Use a cheater plug on the ZP3. Thay may remove the ground loop.
This is not the best solution but it may work.

2) I cured my hum problem by grounding the motor on my VPI Scoutmaster. I took a thin wire and ran it from the mounting screw on the motor assembly, wrapped it around the bearing assembly , then attached it to the phono grounding post. Why a stand alone motor not even attached to the turntable causes a hum is a mystery.

  One thing I forgot to mention - the rectifier tube supplied was a different one than listed in the manual (5Y3GT) It was an equivalent 5U4G.
    Also the other tube OA3 looked different than the pic in the manual - it looked like a rectifier bottle shape.
   If I installed them in the wrong place the amp wouldn't work at all would it?

rmcfee wrote on 12/02/12 at 21:17:55:


I would try running a ground wire from the ground lug by the RCA connections to the ground lug on the ZP3, as well as the wire coming out of the table.

Don't go crazy here. If we can't help you solve this call Steve Deckert. He is the final authority on these things.

Haha! Thanks. I won't go crazy yet. I will talk to Steve tomorrow or whenever he has time.
  The system is:  a Tripp Lite Isolation Transformer to plug everything into. It is plugged into a dedicated outlet.
  The amp is a Bryston B100 SST integrated. Also a Bryston crossover so I can send the lowest stuff to a subwoofer (HSU UL15)
   The table is a VPI Scoutmaster 2.  The speakers are Mirage OM-7s.
   Thanks for the help, by the way.

A Scoutmaster 2 -very nice . What cart. are you using?
I grounded mine by attaching the wire to the silver ring that goes around the top of the motor. I poped off once and the diff in the sound is very easy to hear between cuts or during quiet parts.
I am using the speed controller so maybe that is cuasing my problem.
John

Talk about with friends

Awesome Marky! Glad that has been taken care of.

I hope rm has been able to talk to Steve?

Oops. Well, hope you can get this squared away. Have you tried calling Steve?

Really sorry to hear that. I have a Rega RP3, a new but pretty common gear, and have no issues at all so I'm surprised.

Glad that this has at least been exhaustively worked out.

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.  :)

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.

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.

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 ?

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.

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.  :)