[Russtafarian]

I’m 44 and I live with mild tinnitus, a result of mixing lots of rock concerts when in my 20’s.  I’ve learned what kinds of noises and sound pressure levels will get my ears ringing, and as long as I’m careful to avoid those situations or use earplugs, I’m fine and it usually doesn’t bother me. 

Here’s my question.  I have two different power amps that I alternately use in my system.  One is an EL34 based tube amp and the other is a Hypex based Class D amp.  The tube amp has that wonderful “lit for within” magic midrange and a fluid, organic sound quality.  But other than that, the Hypex amp sounds better in just about every other way.  It has a smooth, effortless presentation, has way more resolution, is much quieter, has tighter, deeper bass and clear extended highs, etc, etc.  I really like both amps, but all things being equal, like the sound of the Hypex amp more except…

After listening to the system with the Hypex amp, my tinnitus gets aggregated and my ears ring for the next day or so.  This does not happen when I listen to the system with the tube amp. It’s not simply a SPL issue. I listen at the same levels regardless of the amp I’m using. 

So I’m curious to know what’s going on here.  Why does the Hypex amp set my ears off while the tube amp doesn’t?  Any ideas?

Russ

[DaveC113]

Sorry I can't be of much help, but thats not the first time I've heard that about class D amps. 

Can your amp use kt88 or 6550 power tubes? You may like them more than the el34s....

Dave

[*Scotty*]

Russ,have you verified via an spl meter that you are in fact listening to the two amps at the same volume level.
Scotty

[awe-d-o-file]

Sure, it could be the odd order harmonic vs even order harmonic thing. Tube amps produce much more even order, SS odd order. Also as to Tinnitus look at diet as caffeine and other things can make it worse. Take a look at this site for some pointers: http://www.ata.org/

Also here is a diet for tinnitus article: http://www.tinnitusformula.com/infocenter/articles/treatments/diet.aspx


                                                          ET

Avoid ototoxic medicines. Aspirin is ototoxic as are many prescription meds. Call the ATA at their "contact us" phone number and they will fax or email a list of ototoxic meds


Here is a link to OTC anti-tinnitus formulas - http://www.tinnitusformula.com/

[andrewbee]

Check the levels (SPL).
With the Class D being "cleaner" you may tend to listen at higher levels with that amp whilst not realizing it.

[sts9fan]

Also check placebo effect.

[konut]

Like you, I did live sound in my 20s. I do now, as I did back then, use the lowest distortion amps I can/could afford. While many disparage SS amps, the vast majority have several orders lower distortion than the vast majority of tube amps. If you check the distortion specs of both amps, you will see that this is the case. Its the distortion, however pleasing it may sound, thats causing your problem.


Edit: Brain fart. The posts following mine have the logical explanation.

[dyohn]

And FR.  The class D amp will probably have a much wider FR than a tube amp... and also it could potentially be introducing ultrasonic switching noise depending on the filter design.

[Brian Cheney]

russtafarian:

If you are indeed listening at equivalent levels to both amplifiers, you may be experiencing a reaction to the supersonic artifacts of switching amplifiers, which can "fold down" into the audio range and irritate some listeners.  

I myself find most class D amps unpleasant for this reason.

I am amazed no one has published scope photos of a typical switching amp output waveform, with its multiple oscillations, noise and HF parasites. Many audiophiles would be shocked.

B Cheney, Pres
VMPS Ribbon
www.vmpsaudio.com

[Russell Dawkins]

This subject interests me a lot, as I have mild tinnitus, too, and am currently making decisions between amps, but all of them are class D.

Until now I was prepared to choose based solely on apparent sonic quality, but this may throw yet another "Spaniard in the works", as John Lennon would say.

I am a little confused on one point, though - are all "class D" amps switching amps, even if their power supplies are non-switching or linear, as in the Hypex variety?

[dyohn]

This subject interests me a lot, as I have mild tinnitus, too, and am currently making decisions between amps, but all of them are class D.

Until now I was prepared to choose based solely on apparent sonic quality, but this may throw yet another "Spaniard in the works", as John Lennon would say.

I am a little confused on one point, though - are all "class D" amps switching amps, even if their power supplies are non-switching or linear, as in the Hypex variety?

Yes, all Class D amps are switching amps, although not all of them exhibit ultrasonic noise.  It depends on the quality of the output stage low-pass filter.

[Gordy]

It's been reported that taking vitamin E can increase tinnitus irritation in some cases.  As Vit. E is fat soluble, it could take up to 2 weeks to notice an improvement once you stop taking it.

[Occam]

I am amazed no one has published scope photos of a typical switching amp output waveform, with its multiple oscillations, noise and HF parasites. Many audiophiles would be shocked.
.............

Image 1: Amplifier A, Differential Mode. 500us/div, 200mV/div.


Image 2: Amplifier A, Common Mode. 500us/div, 1V/div.

From -
http://www.audioholics.com/education/amplifier-technology/switching-amplifier-class-d-basics/switching-amplifier-class-d-basics-page-2

The vendor of that amp shall remain nameless, to protect the less than innocent....
Please note that the article was written by Bruno Putzeys, developer of the Hypex switching modules. Not all switching amps are created, or rather, implemented equally.

[Russtafarian]

Great input folks.  I’m going to check out some of those resources regarding tinnitus.  Thank you.

Here’s what prompted the question.  For the past six months I’ve had the tube amp in the system, and it has been so long since listening to my system had triggered the tinnitus that I’d forgotten about it.  The Hypex project amp had been on the shelf despite its great sound due my past tinnitus reactions to it. 

This past weekend I finally found the time to put together a +/- 28 VDC battery PS for the two Hypex UCD180 modules.  I put it in the system Sunday afternoon and listened Sunday night and last night for a few hours each time.  The sound of this amp with the battery PS is just phenomenal.  I’m absolutely in love with what I was hearing.  But the tinnitus ringing returned and frankly caught me by surprise.  Could it be volume related?  It’s possible.  Maybe I was listening to the Hypex amp louder than usual.  If I was it wasn’t by much, maybe a few dB.  But I’ve listened to the tube amp for much longer and much louder many times without the tinnitus reaction.

I'm not trying to bash Hypex, I'm just trying to figure out why I react to the amp the way I do.  Hypex based amps by Channel Islands, Exodus, and others have been very well reviewed and acknowledged as great sounding amps by lots of folks, including me.  My guess is that Bryan Cheney is on to something regarding the supersonic artifacts of the amp and because of my tinnitus, I’m more sensitive to it than most people.

Russ

[Kevin Haskins]

Giving you a definitive answer is pretty tough due to the number of variables.   I try not to give subjective advice based upon individual feedback because a sample of one is always a poor sampling. 

I'd say the ultrasonic noise is a non-issue.   The noise created by the switching is WAY out of the bandwidth of the device.    The switching noise is more of an issue with other electronics and the interaction that can occur rather than being audible in of itself.   

There are just too many variables in your situation in order to be able to give you a definitive answer.    I'd say keep experimenting and see if it really is an amplifier difference that is setting it off, or if it is just normal physiological variables.   

[SET Man]

Hey!

   Hmmmm.... interesting

   Personally I cannot stand these type of amp, Class-D, T and etc also. No, not that I have bad tinnitus... although I think it beginning a bit in my left ear.

  Anyway, I've never found any type of these amp that I think I could live with. I've have heard a few lower power ones in my own system. And many more in others system.

  They always make me feel unease about the sound and some to almost teeth grinding annoying feel.  Especially in the high I couldn't listen to them for extended pepriod of time.
 
  On the other hand I feel fine listening to my SET amp. These amp suppose to have extension up to 30khz I think and I do have supertweeters in my system that goes up to 50khz.

  But! Here is something interesting. I do own a JVC RX-F10 receiver of which based on these type of amplifier technology of which I use it in my TV/second system. I have no problem listen to this.  But I do use it with a 3" fullrange speaker of which don't really extend much above 18khz. Still I don't really listen to it for long period of time like my main system.

   I found this subject to be very interesting. No I'm not bashing Class-D amp I'm sure they sound great for some. But personally they are not for me. If I have to use these type of amp than it is likely I will use them as sub amp.

  Anyway, Russ have you heard other Class-D, T and etc amps beside the one you have now?  How do you feel about them?

Take care,
Buddy

[JoshK]

I'd try to verify your prior about levels being equal when listening to the two amps.  Like the above poster mentioned, the lower the distortion the quieter it subjectively sounds.  This can cause one to believe they are listening at lower levels then they really are.

[ted_b]

I agree with all the posters who say you need to make sure you aren't fooling yourself about the equivalent levels.

My amp is Class D, a Spectron Musician III Mark 2.  I have what seems to be, and has been diagnosed as slight tinnutis in my left ear, although I still  claim that it might be something foreign, too, cuz I get pressure issues with it at weird times, as if something moves around.  I was hammering in a nail into my fence outdoors the other day, and the pressure from the hammer sound was really affecting my left ear...not a ringing at all...but a feeling of pressure like it was blocked.

Anyway....sorry to ramble.  My Spectron is a truly wonderful sounding thing, and as published on their website has ulrasonic noise at 500kHz (the carrier frequency).  As Spectron's Simon says, if you can hear that you are a bat.  Me, I find the Spectron to be the best amp at NOT aggravating any tinnutis for me (but then, maybe I don't have true tinnutis..  ).  It has the least amount of listener fatigue I've ever experienced.  Good reading here about distortion, amplifiers and listener fatigue:
http://www.enjoythemusic.com/magazine/manufacture/0708/

[Russtafarian]

Anyway, Russ have you heard other Class-D, T and etc amps beside the one you have now?  How do you feel about them?

I have had a 100 wpc Tripath and a Panasonic XR55 receiver in my system in the past.  Both drove me from the room screaming and really aggravated my ears.  I really like listening to the Hypex.  It's the after-effect that bothers me.  I've heard ICE, Spectron and Nuforce amps in other systems, but not long enough to know if they would bug me in the same way.

This is a curiosity issue for me, not a crisis issue.  I'm more than happy sticking with the tube amp and enjoying the music.  Going forward, I will note listening levels with the two amps to see if there's a significant difference.

[mfsoa]

From a post of mine from Jul '07:

And for one last thing - Has anyone noticed an overall sence of being ill-at-ease whan listening to UcD amps? I can't put a finger on it, but I would find myself kinda clenching my jaw, even when listening to the tuner. Not in response to anything directly audible, but just that feeling of tenseness. This feeling is completely gone with the VAC.

Maybe similar to what you describe?
-Mike