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How do you perceive SE34I.3 "hum" NEARFI (Read 3354 times)
Rizlaw
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How do you perceive SE34I.3 "hum" NEARFI
03/10/13 at 17:13:58
 
My new Rachael hums through my Omega Super 3E speakers (94db efficient 8ohm speakers). The amp in centered on my desk, 2 feet from my chest. The speakers are at the desk's corners and approximately 3 feet from my ears. Steve and I have ruled out all other hum inducing factors. The hum is clearly being caused by the amp. The amp has been back to Steve for repairs but that's not what this post is about. I'm also not talking about the mechanical hum from the amp which is now very low and inaudible when music is playing at any level.

Question 1:

What I'd like to find out from other Rachael owners, who may be listening nearfield to similarly efficient speakers, is what they hear or don't hear concerning amp hum from their speakers.

Steve tells me that with a 94db speaker I should near no hum from the speakers unless I put my ear right up to the speaker cone.  In my case, that's not true and it's very distracting during low level music. I also can not use the amp's line outs to my powered subwoofer because it makes the hum worse.

Question 2:

Also, the "hum/noise" rating of the different Decware amps are inconsistent in description:

Mono Torii = -90db
Torii III     = -90db
Mini Torii   = Too low to hear
SE34I.3    = less than 1.5mv
Super Zen = less than 1.5mv

What does "less than 1.5mv" mean and why isn't it spec'd to a -xx db number like the two top amps; or, given a word description like the Mini Torii?

I've been trying to reach Steve since March 6th about this but I can't. I just found out this morning from a forum post by "Longbowbbs" that he's at Axponia from March 8-10, but his answering machine doesn't tell you that he's away and the shop is closed.
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« Last Edit: 03/10/13 at 17:28:06 by Rizlaw »  

System 1: Computer/Linux OS > Audiophileo 2 > W4S DAC-2 > Woo WA-2 / CSP3 > Taboo III > Omega 3E / LCD-2.1/ Beyer DT-990/DT-1350
System 2: Yamaha PX-2 (Shure Ultra) / Oppo DV983H > Classe CAP2100 > Thiel 7.2
System 3: Fisher:R200/X202B > Magnapan MMG
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opnlybafld
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Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #1 - 03/10/13 at 18:39:55
 
If you have the amp hooked to the speakers with no source plugged in you still have hum?
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Rizlaw
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Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #2 - 03/10/13 at 19:18:34
 
Openlybafld,

The answer is YES, I did mention that in the original post where I wrote: Quote:
Steve and I have ruled out all other hum inducing factors.


This is not a source, tube or ground induced hum. It's a hum, apparently, inherent in the amp. It is made obvious when you are using a single driver, high efficiency, crossover-less speaker (Omega Super 3E). If I connect the Rachael to my MMGs, which have crossovers and are significantly less efficient, the hum is so low as to be virtually inaudible. However, I didn't buy this amp for MMGs. Of course, this doesn't change the hum I hear in my subwoofer through the Rachael's line outputs.

What I'm trying to determine, is whether this hum is, for example, greater in the SE34I.3 than any of the Torii amps and why. Perhaps I'm wrong about this, but it seems that such a simple SET circuit should be very quiet compared to more complex circuits like the Toriis.

Nothing I read about the Rachael on the website, in the manual or discussed with Steve before purchase, suggested I would experience this type of hum issue in my desktop nearfield setup. For me, the hum significantly detracts from my use and enjoyment of the amp. It's not what I expected. Nevertheless, since getting the amp back from Steve, apart from a new mechanical issue that has surfaced with the input selector switch, I love the way it looks and sounds.

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System 1: Computer/Linux OS > Audiophileo 2 > W4S DAC-2 > Woo WA-2 / CSP3 > Taboo III > Omega 3E / LCD-2.1/ Beyer DT-990/DT-1350
System 2: Yamaha PX-2 (Shure Ultra) / Oppo DV983H > Classe CAP2100 > Thiel 7.2
System 3: Fisher:R200/X202B > Magnapan MMG
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opnlybafld
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Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #3 - 03/10/13 at 19:36:32
 
The reason I asked is because you said hooking up a powered sub with ICs made it worse, which would indicate a ground issue.

Are your MMG's in another room?
I had a ss class A amp that hummed in a spare bedroom system, but when connected in my larger main room it was not noticeable.
Apparently it was a combination of something amiss in the electrical circuit and a 60hz room resonance in the smaller room.

Would it be possible to take your system over to a friend's house?

Lin
PS I have a pair of Omega Super 3i's with the new drivers. Amazing!
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« Last Edit: 03/10/13 at 19:40:57 by opnlybafld »  
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Rizlaw
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Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #4 - 03/10/13 at 20:15:37
 
It's positively not a ground issue and the sub only made it worse in the sense that it added its own hum to that of the Omegas; it didn't make the Omegas hum more. It's simply a question of the Rachael passing the hum via the speaker connections and the line out connections. As Steve explained it to me, the line outs are connected to the output transformer just like the speaker outputs are, so the same sound (hum included) is passed to both the main speakers and any other component connected to the "line outputs".

The Omegas have been connected to my recently overhauled 50+ year old tube Fisher X202B (got it as a gift when I was a wee lad and have kept it ever since) and to a Classe CAP-2100 (100w SS) on the same  dedicated 20 amp electrical circuits (4 separate and dedicated 20 amp AC lines specially installed for my audio system when I was into this hobby big time). Same results in all cases. Both the Fisher and Classe were/are dead quiet (no hums, buzzes, etc.) with the Omegas. As for going to a friends house, that, in my circumstances, is out of the question.

And yes, the new Omegas are exceedingly good and Louis is a super fantastic fellow to deal with IMO.

P.S. I forgot, the MMGs are in the same room as the Omega, behind me in the middle of the room so to speak. I use them for casual listening to conserve tube hours on the Rachael and Fisher. Actually, as watt sucking as they are, they are driven amazingly well by the Rachael (and with little or no hum). I didn't notice any clipping on the Rachael's meters on the few Diana Krall tracks I played while troubleshooting the hum issue.
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« Last Edit: 03/10/13 at 20:23:48 by Rizlaw »  

System 1: Computer/Linux OS > Audiophileo 2 > W4S DAC-2 > Woo WA-2 / CSP3 > Taboo III > Omega 3E / LCD-2.1/ Beyer DT-990/DT-1350
System 2: Yamaha PX-2 (Shure Ultra) / Oppo DV983H > Classe CAP2100 > Thiel 7.2
System 3: Fisher:R200/X202B > Magnapan MMG
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opnlybafld
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Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #5 - 03/10/13 at 20:51:15
 
I assume Steve had no problems with hum when he had it?
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Rizlaw
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Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #6 - 03/10/13 at 21:31:13
 
It's dangerous to assume. Have you ever heard the saying:
Quote:
When you ass-u-me it makes an "ass" out of "U" and "me".


Not that either one of us is an ass.  :) To answer your question. He did find hum as I described when he duplicated my setup in his shop (albeit with different speakers). He was able to reduced the hum by about half by isolating the transformer with washers and re-routing some wiring. He also said the hum was "within normal limits". I don't understand what that means since I have no high and low limits to go by. That's why I'm asking other owners about their experince with hum or lack thereof in the nearfield with high efficiency speakers.

Remember, according to Steve, on a 94db speaker, there should be no audible hum at 3 feet; only when your ear is up against the speaker should you hear any hum/noise. By that test, my SE34I.3 is not within normal limits while my Fisher X202B and Classe CAP2100 are.

I don't hear the reduction by half on the Omega speakers in my 3 foot, desktop, nearfield setup. The amp chassis itself sounds a less hummy than before.
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System 1: Computer/Linux OS > Audiophileo 2 > W4S DAC-2 > Woo WA-2 / CSP3 > Taboo III > Omega 3E / LCD-2.1/ Beyer DT-990/DT-1350
System 2: Yamaha PX-2 (Shure Ultra) / Oppo DV983H > Classe CAP2100 > Thiel 7.2
System 3: Fisher:R200/X202B > Magnapan MMG
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busterfree
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Posts: 142
Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #7 - 03/10/13 at 22:10:07
 
I am listening near field with the Decware Trapeziums (89 db). I just took out the MT to try the Rachael, and my Rachael is definitely quieter than the MT. My Super Zen is equally as quiet as the Rachael.

I often think about sending the MT back for a check up and upgrade, but I keep on listening to it.

I am confident that you will get the issue resolved.
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busterfree
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Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #8 - 03/10/13 at 22:13:20
 
How do like the Omegas? I have thought about trying the Omega 3T Desktop against the Trapeziums, but I do not "need" another set of speakers
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Rizlaw
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Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #9 - 03/11/13 at 00:50:16
 
Busterfree,

So your Rachael is quieter than your Mini Torii, and the Mini Torii's hum/noise rating is "Too low to hear".  That reinforces my opinion that my Rachael is not as quiet as she should be and that's why I still hear hum. On the other hand, 89db Trapeziums are 5db less efficient than Omega Super 3Es, nevertheless you still perceive the MT to be noiser than the Rachael on your speakers.

As for how I like my Omega Super 3Es. I think they are exceptionally good. At first I didn't care for them, but now with over 100 hours, I've made a 180 degree opinion turn. They are very fast (almost electrostatic fast). On a smaller scale, they remind me alot of my old Acoustat, Beveridge and full Levinson HQD (Two 24" Hartley Subs, four Quads in custom stands, and two Decca Ribbon Super Tweeters) systems. On the plus side for the Omegas, they won't self-destruct every week (if you've owned these electrostats you know what I mean). The Omegas are articulate, smooth from bottom to top and have an exceptionally good 3D soundstage for a small point source monitor. I imagine they would sound even better in a more "non nearfield" setup. More room to sonically blossom. With the Rachael, the bottom end is surprising powerful down to 50Hz and maybe a little lower. Not so when connected with my more powerful Classe SS amp or even my Fisher X202B. The top end is smooth and sweet as far as I can hear (to about 15k for my old ears). The crossover-less single full range speaker concept also imparts a subtle, but noticable continuity/body to instruments (if that makes any sense to you). Instruments that span a wide frequency range, and would normally use 2 or 3 speakers to reproduce their sound, just sound more fleshed out and whole. Low level listening, one of the main reasons I selected this speaker and amp combination, is wonderful. A lot of speakers/amp combination just can't play well at low levels. Details and clarity go missing. This, I believe, has much to do with Steve's "first watt" motto. "If it sucks why continue?" Well the Rachael/Omega combo don't suck! They shine.  It's the first time I've owned this type of single full range cone speaker and it has made a positive impression on me. Finally, the build quality is really something to behold, especially Level 3 finishes like Bubinga (an African rosewood)veneer. I'm fairly certain you'd have to pay 2-3 times as much to get this level of craftsmanship from one of the big name speaker companies.

Sorry for a rambling, incoherent, mini-review. They are two great products. I just wish my Rachael would tone down on the humming. Cry


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System 1: Computer/Linux OS > Audiophileo 2 > W4S DAC-2 > Woo WA-2 / CSP3 > Taboo III > Omega 3E / LCD-2.1/ Beyer DT-990/DT-1350
System 2: Yamaha PX-2 (Shure Ultra) / Oppo DV983H > Classe CAP2100 > Thiel 7.2
System 3: Fisher:R200/X202B > Magnapan MMG
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Fireblade
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Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #10 - 03/11/13 at 01:14:33
 
FWIW, my Mini does not make any noises that I can hear, even with my ears significantly closer to the speakers than the std reference of 3 ft.  My speakers are DM945's, at 94 dB @ 4 Ohms.

Therefore, in my case, the Mini's noise is indeed 'too low to hear.'
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Laptop-Foobar2K-ASIO Direct//WD 2.0Tb HDD//Audio Gd USB cable//Audio Gd NFB 3 (2014) DAC//Decware Silver Ref IC's//Decware Mini Torii SE//Kimber Kable spkr cbls//Decware DM945's//Velodyne DLS 3500//BJC SUB Cbls//Tripp Lite 500 Isolation Trnsf.//Jellyfish Pwr Cord
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Lon
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Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #11 - 03/11/13 at 01:18:11
 
Are you certain the hum is not from elsewhere?
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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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Rizlaw
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Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #12 - 03/11/13 at 01:33:50
 
Lon,

Yes, unless there's a ventriloquist in the room with me. Grin

As I said before, Steve heard it too and claims to have reduced it by half with a few tweaks noted in my posts above. The hum is coming from the amp into the speakers and it has nothing to do with sources, tubes or grounding. I'm not ruling out poltergeists.

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System 1: Computer/Linux OS > Audiophileo 2 > W4S DAC-2 > Woo WA-2 / CSP3 > Taboo III > Omega 3E / LCD-2.1/ Beyer DT-990/DT-1350
System 2: Yamaha PX-2 (Shure Ultra) / Oppo DV983H > Classe CAP2100 > Thiel 7.2
System 3: Fisher:R200/X202B > Magnapan MMG
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Lon
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"Love without
guts is
worthless!"
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Posts: 7490
Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #13 - 03/11/13 at 01:35:37
 
OK, I didn't read the whole thread.

Every time that I've had a hum like this. . . it was a tube. Every time.
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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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Rizlaw
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Posts: 82
Re: How do you perceive SE34I.3 "hum" NEARFI
Reply #14 - 03/11/13 at 01:45:46
 
You'd think so. But the first thing I did was swap out all the tubes. Steve even sent me one of his own primo 5u4gB rectifiers and a new set of 6np1-ev's. No difference. Same for the power tubes (EL34 and Treasures).  Even put Herbies Halo III Titanium dampers on every tube along with silicone ring dampers Steve sent with the 6np1-evs. Also tried 6922s and  NOS Philips 5R4GYS
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System 1: Computer/Linux OS > Audiophileo 2 > W4S DAC-2 > Woo WA-2 / CSP3 > Taboo III > Omega 3E / LCD-2.1/ Beyer DT-990/DT-1350
System 2: Yamaha PX-2 (Shure Ultra) / Oppo DV983H > Classe CAP2100 > Thiel 7.2
System 3: Fisher:R200/X202B > Magnapan MMG
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