[Freo-1]

 OK, here's today's question:

Will a isolation transformer, such as Tripp Lite ISO 1000 provide sonic improvement if the audio equipment (amp/preamp/cd player) were plugged into it vice straight from the wall?

This is assuming a 60 WPC tube amp, like a citation II, or an MC 275. I would think that it should reduce hum by a fair amount.

The following is the blurb on this unit:
 
"Tripp Lite Isolator series isolation transformers offer complete line isolation, continuous noise filtering and enhanced common mode surge suppression. Internal low-impedance isolation transformer component with Faraday Shield offers 100% isolation from the input AC line. Secondary neutral to ground bonding eliminates common mode noise, providing an isolated ground reference for sensitive equipment and an inexpensive alternative to the installation of dedicated circuits and site electrical upgrades. Removes EMI/RFI noise, utility switching transients, background spikes generated by other on-site loads and utility or lightning related surge conditions. Additional surge suppression components placed at both the line input and transformer output combined with full line isolation offers continuous line filtering of a full range of power line noise in all modes. Active transformer filtering with no wearable parts is uniquely able to reduce surges in the worst of power environments to harmless levels. Reduces 6000V IEEE587 Cat A&B ring wave and combination wave test surges to only 0.5V common mode."

So, It seems to me that the net result would be a cleaner power supply, hence cleaner audio.


What's your experience with using these types of devices?


"What this country needs is a good 5 watt amplifier!" (Paul Klipsch)

[dweekie]

I have 3 Tripp Lite Isolators.  I can say that I can't tell a difference if they are connected or not.  They reduced hum on some amps when I used them in a different home, but in my home, it doesn't make any difference to my equipment.  I guess that really reiterates the fact that the line quality and other devices determine how effective these power isolators or filters really are.  I still like having these isolators around, even if they don't help me directly in my setup. 

[JoshK]

I think the only way they could really reduce hum is if you had DC on your line, then the isolator would bear the DC load instead of your equipment, but if you had a ground loop before you'd still have a ground loop after.  If you had filament or electro-mechanical choke/transformer hum, you'd still have it after. 

Its not that it doesn't do its job, it just doesn't do miracles.  Isolation transformers really only isolate your equipment from other equipment on the same line as I understand it.  So they present a high impedance to hash put on the line from other sources in your house, so it doesn't get into your system.  If you don't have any such hash you'd be hard to notice a difference. 

I'm sure someone could add more color then what I've said, but that is how I understand them.

[HumanMedia]

Isolation transformers are great on front ends and low current preamps.  They may well be toxic for your power amps and limit attack and dynamics.  Power amps should generally be plugged straight into the wall anyway.

I have a DIY iso transformer and it is wonderful for my CD player. Makes it sound smoother and relaxed.
Tried my preamp on it and it also sounded better connected straight to the wall, but thats probably because mine uses valves and has relatively high current draw compared to most transistor preamps.

[TheChairGuy]

I have a DIY iso transformer and it is wonderful for my CD player. Makes it sound smoother and relaxed.
Tried my preamp on it and it also sounded better connected straight to the wall, but thats probably because mine uses valves and has relatively high current draw compared to most transistor preamps.

Bingo - and what JoshK said, too My isolation transformer only worked on my CDP.  I'm no sure it directly benefitted the CDP directly, or blocked the leakage of digital grunge back into the lines so that my other components sounded better...but, either way, it's a perfect compliment to my CDP.

Can't help you on the hum issue.  It does make my turntable AC motor quieter, however.....hum wasn't it's issue, it's just on the loud and boisterous side of things.

John

[doug s.]

i have found the best use for isolation transformers is to use a separate one on your cdp transport, and a separate one on your dac.  it seems these digital electronics are most likely to send noise into your system; using iso trannies here will lower the noise floor.  you can also use them on other equipment - even amps - if they are sized large enough.  caveat being that mondo iso trannies are wery heavy, and can hum...

ymmv,

doug s.

[Glen B]

IMO . if your electrical supply is already clean, you are likely to notice no difference with line conditioning.  If your electrical supply is “dirty” then line conditioning may help.   

Even better than a standard isolation transformer like the Tripplite is a balanced isolation transformer.  The neutral on the secondary side of a standard isolation transformer is connected to the incoming ground, the same as when you plug directly into the wall.  Noise riding on the ground will contaminate the secondary side to some extent.  A balanced isolation transformer has its secondary center tap also connected to ground BUT, the center tap is at 0V (the 60Hz cycle crossing point) where there is no electrical flow and therefore no noise.

I have been using DIY balanced isolation transformer based conditioning for the past 4½ years and had excellent results.  I’ve experienced a lowering of the noise floor of an already very quiet system, increased detail and transparency, and sense of greater low frequency weight and extension. 

An isolation transformer provides a lower impedance source versus direct into the wall.  As long as the transformer is appropriately sized for the load, there should be no current limiting.  Also in my experience with DIY and various techniques of isolating outlets and employing supplementary noise filtration, degraded sonics was the result of the EMI/RFI filters I tried.  I use separate isolation transformers for my digital and analog equipment, including my amp.  Each was carefully chosen for best sonics, immunity to power line DC and lack of mechanical noise.

[Eric]

What about some of the bigger transformers like Topaz?

[Wayner]

Remember that transformers are like mirrors in a way. They will pass on what ever is in the primary onto the secondary, only in different ratios as the winding dictate. The good news is that (as previously stated by Josh, is that a ground loops on the primary can be isolated from the secondary.

Clean voltage is like clean clothes, why wash them if they aren't dirty, you won't be able to tell the difference.

The equipment protection of the Tripp-lites are worth the cost, IMO, as I just met a guy that had all of his electronics fried by the power company by a mistaken stepdown transformer that put 480 into his house.

Wayner

[Quiet Earth]

I don't have a Triplite or a hum issue, but I have a small Equitech and a BPT. My first experience was with the Equitech, which is only a 1000W balanced power transformer. I had the exact same experience as Glen :

I’ve experienced a lowering of the noise floor of an already very quiet system, increased detail and transparency, and sense of greater low frequency weight and extension.

I plugged the entire system into the Equitech and got those results. My AC requirements are relatively low and I had no hum issue to begin with. My amplifiers are biased class A so if they are on they are on. The rest of the components draw around 25W each for a total system draw of around 325W. There is no dynamic restriction noticeable.

I upgraded to a BPT for even better results and now I use the Equitech on the TV junk in the family room.

[jdbrian]

Hi

  I have to disagree with your statement that an isolation transformer provides a lower source impedance than the direct line connection. The opposite is true for a conventional (non regulating) isolation transformer. The transformer regulation can never be better than the source that is feeding it and in most cases will be quite a bit worse. However, this may not be an issue with low power devices. Also the ground is connected directly to the neutral on the outgoing side of the transformer eliminating ground to neutral noise.
   For many years the Oneac brand isolation transformers were standard equipment for instrumentation installed in our laboratory. They prevented power related software glitches by doing some filtering and spike protection as well as preventing ground to neutral noise. These days they are no longer needed as the power supply designs are much better at ignoring poor power quality.

Brian


Quote
I have been using DIY balanced isolation transformer based conditioning for the past 4½ years and had excellent results.  I’ve experienced a lowering of the noise floor of an already very quiet system, increased detail and transparency, and sense of greater low frequency weight and extension. 

An isolation transformer provides a lower impedance source versus direct into the wall.  As long as the transformer is appropriately sized for the load, there should be no current limiting.  Also in my experience with DIY and various techniques of isolating outlets and employing supplementary noise filtration, degraded sonics was the result of the EMI/RFI filters I tried.  I use separate isolation transformers for my digital and analog equipment, including my amp.  Each was carefully chosen for best sonics, immunity to power line DC and lack of mechanical noise.

[Occam]

Remember that transformers are like mirrors in a way. They will pass on what ever is in the primary onto the secondary, only in different ratios as the winding dictate.

No, an appropriately designed isolation transformer for the task is also a low pass filter, where the capacitive coupling of high frequencies is attenuated by either separation of primary and secondary winding(s) and/or the imposition of a grounded shield between to shunt noise to ground.

The good news is that (as previously stated by Josh, is that a ground loops on the primary can be isolated from the secondary.

Whatever impedance exists on the ground legs (the cause of ground loop hum/noise) prior to imposition of galvanic isolation is simply reestablished when neutral is re-bonded to safety ground. A properly implemented isolation transformer, unless its a system wide balancing split phase[technical] transformer does not address ground loop issues.

Clean voltage is like clean clothes, why wash them if they aren't dirty, you won't be able to tell the difference.

That is simply an excuse for your lack of empirical curiosity and/or a rationalization for not changing your underpants..... Frankly, you're not someone who comes to mind as an appropriate judge of either. 

[Wind Chaser]

That is simply an excuse for your lack of empirical curiosity and/or a rationalization for not changing your underpants..... Frankly, you're not someone who comes to mind as an appropriate judge of either. 

That's too funny!  I knew someone who thought that theory of relativity also applied cleanliness, thus his justification for wearing the same pair of socks every day for six weeks.