Welcome, Guest. Please Login or Register
Decware Audio Forums
07/19/24 at 12:13:15 




Most recent 50 posts

Pages: 1
Send Topic Print
TRANSFORMER HUM HOW TO ELIMINATE (Read 13107 times)
Steve Deckert
Administrator
*****


If the 1st watt
sucks why continue?

Posts: 6299
TRANSFORMER HUM HOW TO ELIMINATE
09/07/19 at 02:28:53
 
Quote:
Hi Steve!  

You’ll be interested in the latest developments with my very noisy Torii Jr transformer.  First of all, except for a 60 watt solid state amp made by a mad scientist (this guy very much reminds me of you) in Great Britain that I bought a couple of years ago, I have used tube gear exclusively for the past 30 plus years, and most were the SET variety.  Unfortunately, every tube power amp I’ve owned had very noisy transformers, but none quite as loud as the big transformer on my Torii Jr.  Many years ago I considered purchasing a PS Audio Humbuster, thinking that it might solve my possible DC-on-the-AC-line problem, but I didn’t want to take a $350 chance, and, I was still feeding 3 hungry teenagers and finances were tight.  

With your suggestion a few weeks ago that I might have a DC offset problem, I decided to check out Emotiva’s website to see if their $129 CMX-2 DC offset eliminator was currently available.  It was, so I ordered one a week or so ago.  It has been sitting on the floor in the box since last Monday because I’ve been afraid to try it thinking that it would do nothing to solve my noisy transformer problem.  I finally took it out of the box today and hooked up my Torii Jr to it.

After the Jr had been on for about 30 seconds I started to panic, thinking that some new
problem was occurring, because the amp was absolutely dead silent.  Well, it has turned out that I had a severe DC offset problem, as the amp operates flawlessly now with no vibrating, humming, or buzzing—literally, none at all.  If I put my ear within an inch of the transformer, I can hear a faint buzz, but I’ve gone from being able to hear the noise from 30 feet away down to barely hearing it at 1 inch.  Here’s the other thing; it became instantly clear when I began playing music that the DC issue was causing numerous other problems........significant distortion, very weak and unstable bass response, veiled treble response, what I can only describe as compression of the music, and even more issues that I would have difficulty describing.  

I am now having 2nd thoughts about selling the Jr to buy a Mystery amp, as the Jr now appears to have far more power than I previously thought.  Maybe I should simply have your 25th anniversary mods applied to the Jr to match my CSP3-25.  

So, that’s where I have landed of today.  I will be plugging the CSP3 into the Emotiva unit later today.  Who knows....maybe I’ll see another big improvement in sound.  I’ll let you know.

Thanks for everything!
Back to top
 
 
WWW   IP Logged
Lonely Raven
Seasoned Member
****


Jack of all Trades,
Master of None

Posts: 3567
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #1 - 09/10/19 at 00:33:31
 

Ha, just reading the title before I clicked on the thread, I'm thinking to myself this sounds like DC riding on the AC and wondering where it might be coming from...then I open the thread and I'm like Ha! One point for the Raven.

It's good that the device eliminated that DC, but I'd like to find the source. IMHO, I usually find it's coming from a cable connection. Disconnected the main coax line to the house and suddenly your problem goes away. The hard part is getting them to fix it!
Back to top
 
 
WWW Lonely Raven   IP Logged
Lon
Seasoned Member
****


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

Posts: 24114
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #2 - 09/10/19 at 01:09:18
 
I've found the cable to be the culprit as well in the past. You can buy a transformer to put in the cable line that eliminates it and does no harm. Several make them, Jensen makes a nice one, amazon sells these type of things.
Back to top
 
 

HR-1,ZBIT,ZROCK2,SEWE300B,CSP3-25mod; Rega RP3 all GrooveTracer mods;PSAudio:PST+DSD, DAC Mk II, P15,NPC,PowerBases,AC-12 pwr cbls, Reference spkrcbls; Mapleshade SamsonV3; VooDoo:Cremona+Amati interconnects, IsoPods; headphones: Sennheiser HD800S,ZMF Ori,Oppo PM1
  IP Logged
dank
Seasoned Member
****


pair of dual 18
Imperials

Posts: 421
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #3 - 09/10/19 at 14:05:25
 
Don't know about all digital multi-meters, but mine will read any DC that is on the AC line.  Just set it to DC volts and plug the leads into the AC socket, being careful not to electrocute yourself of coarse  :)

The higher voltage ranges, 40 and 400, work fine.  The lower range, 4, reads "over" all the time.  The way to test is with a hot air gun, or a hair dryer.  My hot air gun puts .34 vdc on the line in low and 1.7 vdc in high.  My cheap $5 Harbor Freight meter also works, but does not read 0 when there is no DC, but rather flickers between 0, .1, and .2 (200v scale which seems to have the least flicker) so you might interpret this as a false positive.

Audio by VanAlstine (www.avahifi.com) also makes a DC blocker, the HumDinger, that sells for $140.  They have sold quite a few and have had very few, if any, returned under their 30 day money back satisfaction guarantee.
https://avahifi.com/collections/used-demo-and-quick-ship/products/humdinger-dc-l...


Dan
Back to top
 
 
  IP Logged
Geno
Seasoned Member
****


Without music, life
would be a mistake.

Posts: 2097
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #4 - 09/10/19 at 15:26:54
 
I have a Zstage in my phono setup that still has just enough hum to be aggravating. It gets worse the more I increase the volume. I've done all manner of troubleshooting, but cannot get rid of it.

I wonder if this product would help with that?
Back to top
 
 

(2)SE84UFO(Balanced Monoblocs) OR Sansui AU-222/Zbit
Cambridge Audio CXN(ModWright)
Crown XLS-1002 Sub Amp
SL-1210MK5(KAB Mods) Soundsmith Aida MKll cart • Darlington Labs MP-8b
Otari MX5050-Bll2 R2R
ZLC Power Cond.
Lii Audio PT-10/W-15 in Open Baffles
  IP Logged
dank
Seasoned Member
****


pair of dual 18
Imperials

Posts: 421
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #5 - 09/10/19 at 15:55:49
 
Correction:  The hot air gun puts much more DC on the AC line when its in LOW.  Typically a diode is used to to block half the AC to the heater in low and this causes a large imbalance and hence the large DC component on the AC line.

Geno:  Try plugging a hair dryer in the same circuit as your Zstage and turn it on/off.  You can use a long extension cord to get the hair dryer in another room if its too loud.  If your hum changes noticeably as the hair dryer is turned on/off it will tell you that your Zstage is sensitive to DC.  If there is no change in hum your Zstage is relatively immune to DC and the blocker probably won't do much good.

Dan
Back to top
 
 
  IP Logged
Geno
Seasoned Member
****


Without music, life
would be a mistake.

Posts: 2097
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #6 - 09/10/19 at 16:31:45
 
Thanks, Dan. I'll try that and see what happens.
Back to top
 
 

(2)SE84UFO(Balanced Monoblocs) OR Sansui AU-222/Zbit
Cambridge Audio CXN(ModWright)
Crown XLS-1002 Sub Amp
SL-1210MK5(KAB Mods) Soundsmith Aida MKll cart • Darlington Labs MP-8b
Otari MX5050-Bll2 R2R
ZLC Power Cond.
Lii Audio PT-10/W-15 in Open Baffles
  IP Logged
Doug
Seasoned Member
****




Posts: 283
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #7 - 09/14/19 at 15:37:45
 
So, I’m the guy that had the DC offset issue for years, and that’s my note that Steve posted a few days ago.  Over the years, I tried several possible solutions, really thinking that the problem was anything other than DC on my AC, although, the DC offset issue was always in the back of my mind.  Installation of dedicated AC lines, heavily shielded AC power cables, shielded IC cables, careful positioning of all equipment and cables, weights on transformers, using isolation transformers that themselves hummed, even attaching clamps directly to transformers and tightening them down, were some of the things I tried.  Some had some affect, but none solved the problem.

The results of using the Emotiva CMX-2 DC offset eliminator go far beyond silencing extremely noisy vibrating transformers.  Steve told me that it would be like listening to my Torii Jr for the first time, and of course, he was right!  To my great surprise and delight, every aspect of music reproduction has improved!  A huge perceived increase in power was immediately noted.  The deeper bass and incredible control over my eight 15” OB woofers is simply hard to believe.  I thought I had a very clean sounding system prior to buying the CMX-2, but only now do I realize that there was significant distortion.  Treble sounds have completely opened up, as if I added tweeters to my system.  Sound staging/imaging have improved too, but in unexpected ways—the apparent spaces and silence between instruments and singers is now spooky good.  It’s all truly better than what I’m writing.....I just don’t know how to describe it.  And here’s the biggest surprise of all; not only are all of these things true when driving my PAP Quintets with my Torii Jr, the improvements are even bigger when using my LFD solid state amp that has a huge toroidal transformer.  This transformer was dead silent before using the CMX-2, so I was expecting little to no enhancement of sound.  Man, was I wrong!

I will be purchasing another $129 Emotiva DC offset eliminator and plugging my CD player into it.  Will I see more refinement in sound?  Based on what has happened so far, my guess is yes, but if not, it’s only $129 and it certainly won’t hurt anything.  I’ve read on various forums that DC offset filters cause overall compression of music reproduction, but my experience has been the exact opposite.  There has been a substantial increase in dynamics, especially on the low end.  My OB woofers now have as much tight slam as my corner bass horns (Klipsch copies) loaded with Altec 515B’s.  I am one happy guy today!
Back to top
 
 

Jay’s CD2T-Mk3
Denafrips Pontus II
ZROCK2 25th Mods
CSP3 25th & Custom Mods
PAP Quintets with Voxativ 1.6
First Watt J2 or Cary 300SEI
driving Voxativs—no crossover
LFD NCSE driving 15” Woofers
  IP Logged
Archie
Seasoned Member
****




Posts: 2731
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #8 - 09/14/19 at 17:56:51
 
Doug, your post reminded me to ask whether plugging my ZLC into a Emotiva CMX-2 would allow me to run all of my components off of just a single CMX-2 rather than using multiple units.  I can't say I have a DC problem but based on your success, it might be worth trying one anyway.
Back to top
 
 

ZLC
Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
Homemade Big Betsy Speakers (F15s)
Silver Cabling
DIY Isolation platforms under amps & TT.
  IP Logged
Doug
Seasoned Member
****




Posts: 283
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #9 - 09/15/19 at 22:30:33
 
Archie, I think that’s a question for someone with far more technical expertise than I possess, but my question is this.  Are any of your larger transformers audibly vibrating/humming beyond your expectations?  The smaller transformer on my CSP3-25 was nearly dead silent prior to purchasing the CMX-2, and I have been unable to sense any improvement in sound quality with it plugged into to the CMX-2.  So, it seems to be the pieces with very large transformers that are negatively impacted by DC offset.  Maybe Steve or the guys at Emotiva can give you some advice.
Back to top
 
 

Jay’s CD2T-Mk3
Denafrips Pontus II
ZROCK2 25th Mods
CSP3 25th & Custom Mods
PAP Quintets with Voxativ 1.6
First Watt J2 or Cary 300SEI
driving Voxativs—no crossover
LFD NCSE driving 15” Woofers
  IP Logged
Archie
Seasoned Member
****




Posts: 2731
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #10 - 09/15/19 at 22:54:18
 
Thanks Doug.  My ZMA transformers must be my biggest and they are very quiet.  I was just trolling for an inexpensive improvement.  

If your CSP3 didn't improve with the CMX-2, why do you think your CD player might?  It was based on that idea that I thought it might be a magic pill.  And if I could have it in front of everything, a cheap magic pill to boot!
Back to top
 
 

ZLC
Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
Homemade Big Betsy Speakers (F15s)
Silver Cabling
DIY Isolation platforms under amps & TT.
  IP Logged
Doug
Seasoned Member
****




Posts: 283
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #11 - 09/19/19 at 12:23:42
 
Same thinking here......maybe it’s the missing link to creating the perfect chain!
Back to top
 
 

Jay’s CD2T-Mk3
Denafrips Pontus II
ZROCK2 25th Mods
CSP3 25th & Custom Mods
PAP Quintets with Voxativ 1.6
First Watt J2 or Cary 300SEI
driving Voxativs—no crossover
LFD NCSE driving 15” Woofers
  IP Logged
Lon
Seasoned Member
****


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

Posts: 24114
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #12 - 10/25/19 at 12:40:37
 
I tried one of these Emotiva units and I'm not using it. . . . I primarily bought it to use it's line condition readout capabilities and it helped me identify an outlet that had the hot and neutral reversed. I'll put it up for sale soon as it didn't provide a sonic benefit for me, I don't seem to have a DC offset issue, but it's an impressive bit of kit.
Back to top
 
 

HR-1,ZBIT,ZROCK2,SEWE300B,CSP3-25mod; Rega RP3 all GrooveTracer mods;PSAudio:PST+DSD, DAC Mk II, P15,NPC,PowerBases,AC-12 pwr cbls, Reference spkrcbls; Mapleshade SamsonV3; VooDoo:Cremona+Amati interconnects, IsoPods; headphones: Sennheiser HD800S,ZMF Ori,Oppo PM1
  IP Logged
maddog07
Seasoned Member
****


seeker of truth

Posts: 587
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #13 - 10/30/19 at 19:57:43
 
+1 on the Emotiva DC eliminator.  I have kept one around for years - they work if/when you encounter the problem.  I don't have a DC offset problem in my current setup/listening room.  But I carry the CMX-2 around with me to my audio buds house in case we encounter that dastardly beast when swapping gear around.  If you have DC offset, you can also see it displace the cones on your speakers drivers(mids and woofs) from their neutral resting positions when you hook your amp to the speakers.
Back to top
 
 

Decware Torii MK3, Wyred4Sound DAC2, Theta Digital Miles, Emotiva XMC-1, Emotiva XPA-5, Aesthetix Calypso, Wyred STP-SE, Martin Logan Vista, Audio Nirvana 12" Alnico's, PS Audio PW P5, Goertz, Kimber, Nordost and DIY wires, PSA pwr cords, Cary SLI-80, DM945's.....
  IP Logged
Carlsbad
Seasoned Member
****




Posts: 202
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #14 - 04/17/22 at 03:51:54
 
Well, based on this thread I thoroughly investigated DC offset and found no indication of it.  I have a dedicated line from breaker panel.  10 awg.  

So I opened it up.  found the center fuse under the rectifier blown.  I'll further investigate which pin on the rectifier goes through this fuse but it apparently still makes some very nice music without it.  However it causes transformer hum.  UPDATE:  This tube has 2 anodes, this is one of the anodes out.  So was running on 50% and unbalanced power.  Yes, I think it regained some magic when I replaced the fuse.

Transformer seems to run much cooler now too.  

I didn't have a 500mA fuse so I put in a 315mA.  So far it hasn't blown and probably won't. but I'll order some 500mA for Monday delivery.

And I assume that wire by the on-off switch (bottom of photo) isn't supposed to be hooked up to anything.  It comes from the transformer.

https://share.icloud.com/photos/042ASun4LEoEoqO7PzqP_-y3Q
Back to top
 
 

Decware SE84UFO w/20th mods
Grimm MU1 Streamer
Lampizator Golden Gate 3 DAC
Tekton Encore Speakers
  IP Logged
Nick
Verified Member
**




Posts: 1
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #15 - 10/29/22 at 18:58:01
 
I just wanted to thank Carlsbad for sharing his story. In my case, with a SE34I.5, I suspected a DC Offset issue, based on posts here on the forum, and I tried the iFi DC Blocker without any improvements and then I decided to check the fuses and one was blown (the one on the right). Once replaced the hum was gone. Too bad that there is no access to them via the bottom and you need to open it up. I hope this information will help others.
Back to top
 
 
  IP Logged
Carlsbad
Seasoned Member
****




Posts: 202
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #16 - 10/29/22 at 20:38:21
 
I no longer have the SE34I.5, sold it and upgraded to a ZMA. (FYI, it is currently for sale on audiomart.  Seller says he is going back to UFO, hooked on Decware).  

If I still had the amp, I would replace these fuses with copper jumpers.   I believe the fuses protect the transformers. But I'd be willing to replace whatever components might get damaged in eschange for power unencumbered by a fuse.  We spend thousands of $ on power components and cables as big as our wrist, then we strain the electrons through a fuse with a filament the size of a human hair.

Jerry
Back to top
 
 

Decware SE84UFO w/20th mods
Grimm MU1 Streamer
Lampizator Golden Gate 3 DAC
Tekton Encore Speakers
  IP Logged
Tony
Seasoned Member
****


"Life without
..music is
inconceivable"
A.Einsteln

Posts: 664
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #17 - 10/31/22 at 04:58:17
 
Ditto with Nick. I tracked down my hum in a Torii MKIV to a blown a fuse. Once replaced,  no perceivable hum from the listening position.
Back to top
 
 

SE84UFO25 | Ic0n4 Passive Preamp | ZBIT | Sonore opticalRendu | Denafrips Pontus II | Denafrips Gaia | Decware I/Cs | Decware Pwr Cbls | ZWIRE Speaker Cbls | Omega SAHOM & KEF KC62 | Furman Cond l GIK Room Trmt
  IP Logged
markmiller
Verified Member
**




Posts: 2
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #18 - 07/06/23 at 08:07:24
 
I am grateful for this website because it makes our job easier
Back to top
 
 
  IP Logged
Rensselaer
Verified Member
**




Posts: 10
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #19 - 05/26/24 at 13:56:04
 
I am waiting for a Sarah, hence my presence on this site, but currently using a Soundgate Ongaku copy (copper instead of silver however), and it hums.

230 Volts 50 cycle AC, shielded discrete power source with upgraded sockets and power cords. There are hum adjustment screws that have been adjusted to get the lowest hum, but still present. Tried the vertexaq JoRez ameto DC buster and filter, but no joy.

The hum from bass speaker (Altec A7 voice of the theatre) is about 50 cycles and volume increase increases heard hum. The transformers are Tango. The power transformer hums audibly at the same frequency that I hear over the speakers. I tried sorbothane pads under the feet and they might of helped a little, so I ordered some BrightStar IsoNode feet for the amplifier, the phono stage and each SUT. One YouTube video has some old electrician saying that if I place a sheet of wool felt between that transformer and the chassis it will go, but with voltages exceeding 1000 volts inside, I daren't fool with it.

My speakers are sensitive and the amplifier (at twenty watts) is probably too powerful for them. I am hoping the Sarah will be a better (quieter) fit. In the interim, I just barely crack the volume and the music covers the hum fairly well.
Back to top
 
 
  IP Logged
charles hidalgo
Seasoned Member
****




Posts: 504
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #20 - 05/29/24 at 22:42:32
 
For me the power of the amps/tube has never mattered. I have a 100wpc ARC amp, 160wpc Sonic Frontiers monoblocks, and you cannot tell they are on with 103db speakers. I have a Sarah and I love it. It has traveled the country with me in a pelican case and has been in over a dozen systems in 5 states. It has left channel hum in EVERY system. It's NOT hum pot related hum, (That is as quiet as the circuit can get in my opinion) . Also as suggested jumping terminals did nothing. It has been to Steve for a checkup even though at the time it was only three months old. Steve has given it a clean bill of heath yet the hum is still there. I have owned over a dozen Decware amps alone since around 2007 and most except three were quiet and acceptable. Acceptable is the key word for me as the Sarah so far is the only amp in my 45 years with tubes that I have tolerated with a hum of its type. Once the music starts it all goes away. I wish it did not exist. Others wish the same after hearing it. It's what I have chosen for now to accept. I have a bottlehead 300b that is again dead quiet so much so that I have to make sure it's on if I do not look.
Back to top
 
 

SEWE300B #004
HDTv2
Zbit
Schiit Freya+
Schiit Loki Max
EverSolo Streamer/DAC combo
Custom AT turntable
Softone phone stage
TEAC and Otari tape machines
SVS Pro 1000 subs
Nordost cables
WWW   IP Logged
Steve Deckert
Administrator
*****


If the 1st watt
sucks why continue?

Posts: 6299
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #21 - 05/30/24 at 01:20:42
 

Have you swapped all the tubes on the right channel with the ones on the left channel to see if the hum changes sides?  (You will probably have to set the hum pots again when you swap the 300B tubes left for right.)

Back to top
 
 
WWW   IP Logged
charles hidalgo
Seasoned Member
****




Posts: 504
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #22 - 06/08/24 at 18:50:59
 
[quote]Have you swapped all the tubes on the right channel with the ones on the left channel to see if the hum changes sides?  (You will probably have to set the hum pots again when you swap the 300B tubes left for right.)/quote]

If this wasn't meant for my comment I apologize. If it was ...... Yes I have switched ALL tube positions and I have three complete sets of tubes with 300b's from WE, Cryotone, and the Chinese tube kit that Decware offers. I tried all other options before I sent it in, and after as well. No change. I still have the same Hum that the original owner had (found that out after purchasing) in the same left channel that gets louder with volume increase. He was told it was fine and being new to tubes accepted it. I on the other hand have changed my mind as of late and do not think I can live with it. I am very saddened that there has been no fix for this. Again it is NON hum pot related. That different hum is totally under control with the very sensitive hum pots.
Back to top
 
 

SEWE300B #004
HDTv2
Zbit
Schiit Freya+
Schiit Loki Max
EverSolo Streamer/DAC combo
Custom AT turntable
Softone phone stage
TEAC and Otari tape machines
SVS Pro 1000 subs
Nordost cables
WWW   IP Logged
Tony
Seasoned Member
****


"Life without
..music is
inconceivable"
A.Einsteln

Posts: 664
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #23 - 06/08/24 at 20:21:50
 

Hey Charles, as a future Sarah owner, this is very unsettling to hear. If I remember correctly, you sent your amp back to Steve, and it was returned with adjustments made to eliminate this problem—do I have that right? I'm sure that Steve will have a solution, but I'm sorry to hear that you are struggling with this issue.

Tony

Back to top
 
 

SE84UFO25 | Ic0n4 Passive Preamp | ZBIT | Sonore opticalRendu | Denafrips Pontus II | Denafrips Gaia | Decware I/Cs | Decware Pwr Cbls | ZWIRE Speaker Cbls | Omega SAHOM & KEF KC62 | Furman Cond l GIK Room Trmt
  IP Logged
charles hidalgo
Seasoned Member
****




Posts: 504
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #24 - 06/13/24 at 07:37:19
 
It truly is sublime once music starts playing.  :D
Back to top
 
 

SEWE300B #004
HDTv2
Zbit
Schiit Freya+
Schiit Loki Max
EverSolo Streamer/DAC combo
Custom AT turntable
Softone phone stage
TEAC and Otari tape machines
SVS Pro 1000 subs
Nordost cables
WWW   IP Logged
Steve Deckert
Administrator
*****


If the 1st watt
sucks why continue?

Posts: 6299
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #25 - 06/13/24 at 18:43:44
 
Hi Charles,

If the hum is getting louder as the volume increases, then the issue is related to the 12AU7 input stage and we know that the output tubes and corresponding driver tubes are OK.

Also, this is not transformer hum, as the thread is titled.  This is hum coming from the speakers, and it is 103dB speakers.  We test the amps on 100dB speakers so you are hearing 3dB more hum than we would no matter what.

I agree the hum whatever it is should be the same on both channels provided the input tube has matched sections and the noise spec is the same on both sections.  

You are welcome to send the amp back in, or the input tubes that you have to be tested for noise, left for right sections of the tube.

All of this is assuming that you are making this test without any interconnects hooked to the inputs of the amplifier to rule out cables or upstream components.

-Steve : )
Back to top
 
 
WWW   IP Logged
charles hidalgo
Seasoned Member
****




Posts: 504
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #26 - 06/18/24 at 02:23:57
 
Yes no interconnects and several several several tubes all ran through it. Like I mentioned I have three sets with thousands invested in tubes alone (not to mention over 10,000 tubes including brand new ones all tested fine and quiet in other amps using the same tubes.. All same results. Again sorry if this hum incident isn’t the same as the original OP’s post.
Back to top
 
 

SEWE300B #004
HDTv2
Zbit
Schiit Freya+
Schiit Loki Max
EverSolo Streamer/DAC combo
Custom AT turntable
Softone phone stage
TEAC and Otari tape machines
SVS Pro 1000 subs
Nordost cables
WWW   IP Logged
Steve Deckert
Administrator
*****


If the 1st watt
sucks why continue?

Posts: 6299
Re: TRANSFORMER HUM HOW TO ELIMINATE
Reply #27 - 06/18/24 at 18:02:44
 

Contact Sarah for an RA and lets get to the bottom of it.   Both channels measured identical when it was here so lets see what happened and fix it.

-Steve : )
Back to top
 
 
WWW   IP Logged
Pages: 1
Send Topic Print