[Freo-1]

If one REALLY wishes to improve the overall performace of your audio or HT rig, this is a product that delivers the goods:

http://www.jensen-transformers.com/ci2rr.html

These transformers will get rid of ALL residual hum and ground loops.  The improvement in sound will depend on your system, but I would dare say that ALL systems will see some benifit from the use of these. 

A lot more bang for the buck than some tweak-o too expensive interconnects, to be sure.

[Freo-1]

Unlike so called claimed improvemets with cables that cannot actually be verified, use of these transformenrs can be verified via  test equipment.  (no to mention an audible reduction/elimation of hum and noise).

Given the modern digital inputs, these things become more important than ever.  Sat and Cable TV really wreak havoc with grounds, noise, etc.   

Anyone else use these?

[TheChairGuy]

A less expensive fix for a common enough problem in A/V systems: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=180-075&vReviewShow=1#reviews

Given that both these solutions add extra joints (and lengths) to the actual signal....they cause degradation in signal quality. 

An isolation transformer, for at least the line level components (as amps and some preamps may exceed the capabilities of all but the largest types) would likely cure any attendant hum in the system and wouldn't cause degradation the signal quality.

Something like this: http://www.macconnection.com/1/1/43599-tripp-lite-1000w-full-isolation-transformer-120v-4-5-15r-outlets-is1000.html

John

[Freo-1]

Good recommmendations, John.

The possible problem with the dayton isolation xformer is that for a lot of SAT and Cable applications, they don't work, as 2 way connectivity is required.

The isolation transfoormer is good, but they can limit the amps output, espcially if you have a couple of 200WPC in your rig

The Jensens are used in pro audio applications.  As long as the interconnects to the amp are 3 feetor less, would argue that there is an enhancement is sound quality as opposed to any degragation (assuming of course, one is using a quality inconnect).  This can actually be verified by test equipment.

I agree that the Jensens are not all that cheap (140.00), BUT, considering the prices audiophiles pay for interconnects that results are dubious at best,  would argue this gives a good return on investment. 

[Ethan Winer]

I agree that the Jensens are not all that cheap (140.00), BUT, considering the prices audiophiles pay for interconnects that results are dubious at best,  would argue this gives a good return on investment.

Just to be clear, adding a transformer to the signal path can only degrade the quality, and never improve it. I'm a huge fan of Jensen transformers! But the only reason to get an audio transformer is if you have a problem with hum. So it's not a "tweak" in the usual sense. It's really a problem solver.

--Ethan

[*Scotty*]

As much as I dislike agreeing with any of  Ethan's statements outside the field of acoustics,I have to agree with his stance on adding a transformer to the analogue signal path. The problem with adding any transformer to the signal path is that you have also added Hysteresis distortion to the signal in addition to any other distortion that may also be present. See explanation at this Google books link   http://tinyurl.com/23lhsaf

The presence of hysteresis distortion added to the signal is what creates the characteristic sound associated with a transformer. High enough levels of added hysteresis distortion will compress the perceived dynamic range,blunt the edge of transients and shrink the size of the sound-stage. The magnitude of the distortion is also related to the signal level. The higher the signal level is the more distortion
you have,this is why it particularly damages transients because they rapidly rise above the average signal level.
As a commentary on the relatively sad state of currently available preamps, many people prefer the sound of a TVC preamp,even with its built in levels of distortion, to that of preamps with active circuitry.
Scotty

[Freo-1]

Just to be clear, adding a transformer to the signal path can only degrade the quality, and never improve it. I'm a huge fan of Jensen transformers! But the only reason to get an audio transformer is if you have a problem with hum. So it's not a "tweak" in the usual sense. It's really a problem solver.

--Ethan

And that, Ethen, is my point.  Many modern systems (espcially ones where there is a SAT or cable TV input) often have some hum level included as part of the analog signal.  It's worse now than ever.

I guess my point is that the Jensens will HELP most modern systems more than they will degrade the sound.  Thus the net effect is that the overall sound improves.  Besides, if one carried that out, no tube amp would sound as good as a solid state. amp.

I  would also argue the negative audible effects of a transformer such as a Jensen would not be heard by people, but they sure as hell would hear the dead quiet background and clear transients.

[Nuance]

Just to be clear, adding a transformer to the signal path can only degrade the quality, and never improve it. I'm a huge fan of Jensen transformers! But the only reason to get an audio transformer is if you have a problem with hum. So it's not a "tweak" in the usual sense. It's really a problem solver.

--Ethan

Agreed.  Rather than risk money on power conditioners, which isn't guaranteed to fix the problem, I always recommend people pick up a Jensen instead. 

[Occam]

Agreed.  Rather than risk money on power conditioners, which isn't guaranteed to fix the problem, I always recommend people pick up a Jensen instead.

Horses for courses. A mains power conditioner, whether isolation transformer based or not, does nothing to eliminate ground loop caused hum or noise.

[Freo-1]

Ground loop problems are more common now than ever.   The one thing that I know gets rid of it is the Jensen transformers. 

[Ethan Winer]

Many modern systems (espcially ones where there is a SAT or cable TV input) often have some hum level included as part of the analog signal.

I've never had a problem with hum from my cable box, but I understand there are RF transformers you can buy that break the loop without having to add anything to the audio signal path. Anyway, my point wasn't to indict transformers as much as point out that you need one only if you have a hum problem. I had minor hum with my previous subwoofer, and a Jensen transformer fixed it.

--Ethan

[JRace]

Ground loop problems are more common now than ever.   The one thing that I know gets rid of it is the Jensen transformers.

The other thing is proper grounding of the offending component.
9/10 it is your cable TV feed. Easily fixed by grounding and of the splitter boxes in the line to your main house ground.

[Regalma]

When I rearranged my gear and ended up with an AC hum I tried all sorts of things. The Jensen transformer was the only thing that worked. But I was never happy having it in signal path, though I can't say I heard a difference. Then I came across the Ebtech Ground Hum Exterminator. You plug your AC line into it. It works perfectly and nothing is added to the signal path. Plus, at $90 it is less expensive than the Jensen.

[Freo-1]

The other thing is proper grounding of the offending component.
9/10 it is your cable TV feed. Easily fixed by grounding and of the splitter boxes in the line to your main house ground.

Yes, but easier said than done.  I tried the usual tricks, but no joy.  The in line RF transformers with the SAT box do not seem to work (not sure why, may have something to do with the ability of the SAT box to ping back via the splitter).

[Freo-1]

When I rearranged my gear and ended up with an AC hum I tried all sorts of things. The Jensen transformer was the only thing that worked. But I was never happy having it in signal path, though I can't say I heard a difference. Then I came across the Ebtech Ground Hum Exterminator. You plug your AC line into it. It works perfectly and nothing is added to the signal path. Plus, at $90 it is less expensive than the Jensen.

Thanks, good to know.


I'm not sure that the Jensen transformer really does add any mesaureable distortion, or degrade the sound in any way.  For goodness sake, it's used throughtout the pro audio community.  McIntosh STILL uses output autoformes in their best amps, and I'm sure it's not to degrade the sound

It's all about trade offs.

[NewBuyer]

I greatly trust the members posting here, but I'm left considering: Could the above advice (on avoiding line-level transformers) possibly not be the whole story here?

For instance, I've used such Jensen transformers with what certainly seemed (to me) as excellent transformative sonic improvement, in many situations over the years - including situations when no audible buzz or hum was present. 

I've previously wondered, how is this possible (besides the always-possible, and ever-present, placebo effect)?

For reference - On Jensen's website they advise: "Jensen transformers improve signal quality by removing hum, buzz and interference signals of other types (such as radio frequency interference) from the audio signal. The Bessel low pass filtering effect also removes ultrasonic distortion products generated by previous amplification stages from the audio signal. These ultrasonic distortion products create additional intermodulation distortion products when amplified by succeeding stages. These signals are folded back into the audible frequency range, generating an audio modulated, non-harmonically related noise floor. This type of noise is characterized by listeners as a "veil" in front of the music. The term "Spectral Contamination" was coined for this effect..."

Perhaps the isolating and impedance-balancing effects of high-quality line-level transformers, when used properly (i.e. not producing high-levels of hysteresis), can indeed improve matters more than they could harm them?

I'd be interested in related comments here from those that use Jensen line-level transformers in their products.  For example, Wes Miaw (Neko Audio) posts on this forum; to achieve signal isolation and avoid using opamps/transistors, his D100 DAC uses Jensen line-level transformers for audio signal output.  I'm believing he must have considered hysteresis when designing the D100(?), but still it would be good to hear from Wes on this...

Edit: Sent request to Wes, in case he wishes to comment...

[NekoAudio]

Perhaps the isolating and impedance-balancing effects of high-quality line-level transformers, when used properly (i.e. not producing high-levels of hysteresis), can indeed improve matters more than they could harm them?

I'd be interested in related comments here from those that use Jensen line-level transformers in their products.  For example, Wes Miaw (Neko Audio) posts on this forum; to achieve signal isolation and avoid using opamps/transistors, his D100 DAC uses Jensen line-level transformers for audio signal output.  I'm believing he must have considered hysteresis when designing the D100(?), but still it would be good to hear from Wes on this...

The "improve matters more than they could harm them" is why I am using transformers. But it's sort of a different situation in my case.

From what I gather, the original discussion is whether or not to introduce an audio transformer into your signal chain to address a problem. Obviously if there is no problem, adding a transformer can in the best case do nothing and in the worst case introduce a problem. RFI is certainly a problem which one might want to address.

I use a transformer in the D100 because I have to use something. Using nothing is not an option. Output transformers are the solution I picked to provide optimal sonic performance and I publish measurements to back this up. (I'm particularly proud of the multitone THD+N graph. ^_^)

You can always look at a audio transformer datasheet to determine what the manufacturer has measured for its distortion versus frequency. The distortion will rise as the frequency goes low, relative to the input signal amplitude, but shouldn't rise in the audio spectrum's high frequencies.

Although, for a finished product, it's still much more useful to look at the product measurements as you can't really tell what the result will be just from a single component.

[NewBuyer]

...RFI is certainly a problem which one might want to address.  ... Output transformers are the solution I picked to provide optimal sonic performance and I publish measurements to back this up... The distortion will rise as the frequency goes low, relative to the input signal amplitude, but shouldn't rise in the audio spectrum's high frequencies...

Hi Wesley,

Thank you (very much) for your comments.    Per your measurements, the output transformers seem outstanding as applied in your D100 DAC - and I see for example in your measurements the comment, that the rise in distortion below 60Hz is due to limitations in the test equipment.  Although the test equipment was limited, could measurable hysteresis distortion possibly be occurring in those lower frequencies as well (and does it matter / is it audible)?

Also, the D100 DAC (version 1) has a maximum output voltage of about 1 volt - does this also serve to keep potential hysteresis issues fully controlled?

Thanks in advance. 

[NekoAudio]

Per your measurements, the output transformers seem outstanding as applied in your D100 DAC - and I see for example in your measurements the comment, that the rise in distortion below 60Hz is due to limitations in the test equipment.  Although the test equipment was limited, could measurable hysteresis distortion possibly be occurring in those lower frequencies as well (and does it matter / is it audible)?

Also, the D100 DAC (version 1) has a maximum output voltage of about 1 volt - does this also serve to keep potential hysteresis issues fully controlled?

You can look directly at the Jensen transformer data sheets to see its THD measurements as a function of frequency and amplitude (input voltage). You will see from those data sheets a rise in THD as frequency decreases or as voltage increases.

But the Audio Precision gear I used had 60Hz and harmonics even without a real "device under test" (DUT) which is why I added the comment to the graphs.

Since the transformer distortion does increase as the input voltage increases, I kept the transformer input voltage lower to minimize distortion. The lower voltage level also helps with the DAC chip linearity.

The D100 Mk2 has the same transformer input voltage. The higher output voltage is achieved through the transformer windings.