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Hum (Read 8452 times)
Lacee
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Hum
03/29/11 at 15:25:37
 
I was wondering if anyone has experienced hum from their amp?

I have isolated it down to just  the amp and speaker wires with nothing else connected except the power, it's not a power cord,grounding issue, I've done all that there is to do in this respect.

It's not a big issue, but just because it's there,it bothers me.

Could something concerning the transformer be the problem, because that's what it sounds like, but just thru the speakers, it's not buzzing from the amp chassis.

Is a bit of hum just one of those things or could there be a problem that can be fixed?

Other than this I am 100% pleased,just concerned if this is my problem or if it's shared by others and accepted.

Thanks.
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Lacee
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Re: Hum
Reply #1 - 03/29/11 at 15:46:28
 
I just looked into other threads and see that I am not alone, although the thread is about the non select amp that I own.

I should also post some more info about system and set up.

I run two 20 amp dedicated lines, the amp is powered with a Shunyata PythonCX, into a Shunyata Hydra two and now into a Furman IT 1500 balanced power conditioner and into a short 10 ft 10 guage run to the panel.

I tried the the furman just recently to see if this would help.
It didn't.

I have run other amps in the same power set up and no hum, so it has to be just in the Decware amp.

I will try moving the breakers around and see if this helps.

I listen about 9 feet away from the speakers(Ref 3A Grand Veena,Nordost Heimdal speaker wires,IC,Manley Steelhead, Audio Aero Capitole CD, Rega P9, Hydra 8, Shunyata Annaconda Helix power cords ).

The hum is not heard from the listening position, but it's there if you put your ear to the speakers.

The asnwer is if it hurts when you do this don't do it, but,, any noise is bad noise and I know it's robbing me of something.

I am glad I looked at the posts for the other DecWare amp and feel more reassured that this isn't just my problem with my amp.

I thought i would post this again so that others would see that an isolation or balanced transformer and extensive power conditioning won't solve the problem.

I believe it to be internal not external, and so far the fellow with the cap mod might be onto something of a fix for these amps .

If that's the case, maybe a quick fix is all that's needed, but I don't want to destroy my warranty by having it done outside of the company.

I hope this helps, and I hope someone has the answer.
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4krow
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Re: Hum
Reply #2 - 03/29/11 at 18:50:53
 
I must say, that many years ago, I owned two mono amps made by Forte'. They were among the best I ever had in my system just because of the synergy that they had with the system. They had a slight hum, and I tried to correct it with many 'fixes'. I later sold them. My point here is that to this day, I miss them. Few, if any other amp since has possessed the magic that they gave to the musical experience. I hope this doesn't become the case for you. You say that the hum is not audible from your listening position. Having said that, it well may not affecting your musical pleasure. If there was a way to 'a/b' the situation with and without, probably you would not be able to guess either way.
 Before I forget, have you disconnected all sources from the amp to see if the hum comes from one of them? Or even if the amp is in a magnetic field where it sets? From the sounds of it, you probably have tried these things, and many more. Good luck in alleviating this imp.
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Decware 34I.3 integrated amp/Forte' 3 bass amp/Velodyne SMS-1 bass mngmnt system/Decware ZOB speakers/BESL subs/Emotiva ERC3 CD player/BPT 3.0 power cond. PS Audio P500
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Lacee
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Re: Hum
Reply #3 - 03/29/11 at 20:27:26
 
Thanks 4K, I have done everything and it comes down to just the amp.

Even wallplugging the amp doesn't diminish the hum, and neither does any of the other power conditioning and power cords.

I should mention that the hum is the most pronounced from my mid range driver, and not from the tweeters or the two bass woofers.

Now this may be specific to my speakers in that this very same driver is direct connected to the power amp by it's design , no crossover, it's full range, and then a simple crossover kicks in for the bottom end and the tweeter and super tweeter.

I may experiment sometime and take the amp to a friend and see what happens, but I don't think his old Spendor 2.3 are a very nice match to the Zen.

Anyways I have nothing but praise for the sonics of the amp, I really like it.It has bested quite a few amps more expensive than it is.

The only drawback is the hum.
My other amps, a pair of Red Dragon Mono blocks are dead silent.

If I had experienced the same hum with other amps in my system I wouldn't be concerned, and just accept it as a fact of life.

But in this case after isolating all components and not connecting anything to any of the two inputs on the amp, with only the speaker wires connected to the amp(plus power cord) the hum persists.

And only from the mid driver which is connected directly to the amp, not from the bass driver or tweeters.

It's a low 60 hz type of hum that neither gets louder or softer in volume when you fool with volume pots.

It takes a few seconds for the hum to begin,I guess as the amp charges up, but it doesn't stop as the hours go by.It only ends when the power is turned off on the amp.

I may try some different rectifier tubes,but it was there with the stock tube and the amp is still only a few months old.

I've lived with it this long, and it's not a deal breaker, but if I could find a way to rid myself of the hum, I would be 110% satisfied.

It was small comfort to find out that I am not alone in the hum situation.
I am curious to find out what systems set ups are hum free.

Maybe it would be nice to hear from all the hum free folks and find out what gear they have been successful with.

I wonder if there is anything I can do at my speaker end to fix the problem.

I have tried running a ground wire from the screws on my speaker's connection plate to no avail.

I tried lifting the ground at the amp with a cheater to no avail also.

So I am open to all suggestions, short of selling either the amp or speakers.

Thanks again.


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Lon
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Re: Hum
Reply #4 - 03/29/11 at 20:48:36
 
I've always had a bit of hum in my system, and sometimes more than a little bit of hum. When there's just the tiniest bit I don't feel I'm missing anything musical and I just don't stress about it. I know that's not always possible.

When I had the loudest hum it was traced to a tube. Was not what I was expecting!
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Decware:ERR,HR-1,ZP3,CSP2+,Torii Mk III,PS Audio PWT+DS,
PowerBases,PPP,AC-12 pcs, Denon DBP-A100, Denon DCD-A100,Rega RP3 +TTPSU,white belt+Exact2, VooDoo Cable:Evo,Ultra Linear, Iso-PodMapleshade:Double Heiix Plus.Samsonv2+v3 +4" platforms,Herbie's Iso-Cup
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4krow
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Re: Hum
Reply #5 - 03/29/11 at 22:30:52
 
Lon,

 That is a great idea about the tube. Something like that often gets by me when I am tracking down a problem. My system also has a little hum, and it is all solid state for the time being. The reason that this worries me is that I have on order the FRX drivers, and with them being very efficient(like ZENs), the hum will only increase. I'll keep ya posted.
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Decware 34I.3 integrated amp/Forte' 3 bass amp/Velodyne SMS-1 bass mngmnt system/Decware ZOB speakers/BESL subs/Emotiva ERC3 CD player/BPT 3.0 power cond. PS Audio P500
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Lacee
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Re: Hum
Reply #6 - 03/30/11 at 19:30:11
 
Just a little more info.

There is a slight hum from the tweeters, and very little from the woofers, the most pronounced is the direct coupled mid range speaker.

I have an assortment of 5U4 rectifier tubes that I will try tonite and if any of them make an improvement, then that will settle it for me.
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MarkBlair
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Re: Hum
Reply #7 - 04/01/11 at 19:19:34
 
I still haven't solved my SE84C+ hum problem (another thread on the SE84C+ forum), but I just started another thread on the General forum asking if anybody's had success with isolation transformers, power regenerators, etc.

But my hum level isn't a show-stopper at all.  However, it would be nice to know if there's something external to the amp that could reduce the level of hum somewhat.

Mark Blair
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Lacee
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Re: Hum
Reply #8 - 04/01/11 at 19:35:00
 
Hello Mark so far I haven't found an external fix, I've used a Furman IT 1500 balanced power and Shunyata Hydra 2, and straight into the wall and floating the ground and trying to ground the amp with a piece of wire.

I have also tried a few different rectifier tubes that didn' fix the hum.

I think it's just one of those things that we somtimes have to put up with.

I think we are so happy with how good the amp sounds, that anything less than complete silence upsets us.

Nothing is perfect,but this is so close except for that hum.
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Lacee
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Re: Hum
Reply #9 - 05/28/11 at 17:04:33
 
Well I thought I would try a different tube for the input .

I replaced the very good Russian tube with an older gold pin Seimans 6922.

I believe the hum is not as pronounced,but again it's win some loose some.

The bass has bit less puch and impact, but in return, the mids and highs and the overall clarity of the amp has improved.

This amp is a source of wonder for me.

It's like a chameleon.

Do some tube swapping and change the sound.

My advice to anyone who is thinking they need a change  and are contemplating selling their Decware, is to just do some tube rolling.

The rectifier and the input was where I started to notice differences.

I wonder if switching to EL 84s would be a step forward or back?
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Lon
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Re: Hum
Reply #10 - 05/28/11 at 17:09:37
 
If your amp has the CCE/Hazen Grid mod, I'd think it's a step back.

I know, it can be totally mind-blowing what a tube roll can do in these amps. I've stepped back from it because I had lost my reference point a few years ago and it was driving me MAD!
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Decware:ERR,HR-1,ZP3,CSP2+,Torii Mk III,PS Audio PWT+DS,
PowerBases,PPP,AC-12 pcs, Denon DBP-A100, Denon DCD-A100,Rega RP3 +TTPSU,white belt+Exact2, VooDoo Cable:Evo,Ultra Linear, Iso-PodMapleshade:Double Heiix Plus.Samsonv2+v3 +4" platforms,Herbie's Iso-Cup
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Juan Antonio
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Re: Hum
Reply #11 - 07/09/11 at 14:15:01
 
It's normal to have always a slight hum. The main reason must be the input tube. There's also the design of the amp. As far as I know, a SET amp is going to have more hum than a push-pull amp or an amp which has negative feedback.
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Pale Rider
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Re: Hum
Reply #12 - 07/10/11 at 03:06:38
 
Quote:
I still haven't solved my SE84C+ hum problem (another thread on the SE84C+ forum), but I just started another thread on the General forum asking if anybody's had success with isolation transformers, power regenerators, etc.
I just added a PS Audio Power Plant Premier power regenerator to my setup. Perviously, I have had a Monster AVS-2000 (which really does generate rock solid 120v), with The Monster HTS-5100MkII, as well as a Transcendent Balanced Power Supply. I haven't listened enough to be sure, but on measurements alone, the PSA unit delivers a quieter supply of power, cutting THD by over 2/3. I read somewhere recently, during my decision-making to pick the PS Audio unit, that isolation transformers can introduce problems of their own. Don't know, but I have decided not to go down tha path.
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« Last Edit: 07/10/11 at 16:55:53 by Pale Rider »  

Decware: Ultra | Torii MKIII [2] | SE84ZS | Taboo MkIII Sources: Synology 1812+ | Baetis Revolution | PWD DAC MKII | Lumin Network Player | Mytek 192 | Oppo 105 DSP: DEQX Mate | Emotiva Outputs: ERR [6] + Servo Subs | LCD-2 & other cans
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Lon
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Re: Hum
Reply #13 - 07/10/11 at 14:42:07
 
Glad you're enjoying your Premier! I've had mine two weeks now and it's transformed my listening. I have really bad power here. It's more dramatic a change than tube-rolling. I obviously have been experiencing my system at far less than "all it can be."

I've not yet used the Premier without an isolation transformer, but the isolation transformers I've used have really improved my sound and I've seen no indication it's doing anything detrimental to my sound with the Premier. I've seen cautions to not use computer related isolation transformers/uninterrupted power supplies, but haven't heard of problems with audio-suitable isolation transformers as long as they can provide enough power for the system.
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« Last Edit: 07/10/11 at 14:45:05 by Lon »  

Decware:ERR,HR-1,ZP3,CSP2+,Torii Mk III,PS Audio PWT+DS,
PowerBases,PPP,AC-12 pcs, Denon DBP-A100, Denon DCD-A100,Rega RP3 +TTPSU,white belt+Exact2, VooDoo Cable:Evo,Ultra Linear, Iso-PodMapleshade:Double Heiix Plus.Samsonv2+v3 +4" platforms,Herbie's Iso-Cup
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Pale Rider
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Re: Hum
Reply #14 - 07/10/11 at 17:04:02
 
Lon, the distinction between computer-oriented isolation transformers and others makes sense. I was not suggesting that any of these are inherently deleterious, only that I had decided to stay away from them.

Which way do you chain the isolation transformer and the PPP? I will probably add another Balanced Power Supply to my rig, but am curious. I will probably plug my BPS into one of the IsoZones on the PPP, and then plug either my main Torii or my Oppo into the BPS. If that doesn't keep its digital noise out of the other units' power, I don't know what will.

Plugged my several Noise Harvesters into my listening room. No surprise, they blink. Whether they do anything remains to be heard. I plan to cut the drywall for my Solo Power Port Premier plugs later today.
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Decware: Ultra | Torii MKIII [2] | SE84ZS | Taboo MkIII Sources: Synology 1812+ | Baetis Revolution | PWD DAC MKII | Lumin Network Player | Mytek 192 | Oppo 105 DSP: DEQX Mate | Emotiva Outputs: ERR [6] + Servo Subs | LCD-2 & other cans
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