[dBe]

It seems to me that an isolation transformer is always going to have some losses and the voltage will sag under load. Even a large one will have a few percent voltage drop when used with a large power amp and can significantly lower the power available. If you don't need to isolate the ground due to noise problems why use one on a power amp?
   Low level devices are a better fit IMO. The current demands are lower and don't vary much with signal level and the supplies are regulated.
   I work in a large laboratory. From 1985 to maybe 2000 it was pretty standard practice for instrument manufacturers to include an OneAC brand line filter/isolation transformer with new instrumentation. These units were very good at preventing EMI from causing glitches in the operation of this instrumentation. Lately every instrument is supplied with a UPS unit which normally filters as well as backs up the power. Newer equipment is much better engineered and we rarely have any power related problems now.
 Oh! I'm rambling again.


Brian

Core losses can eat up any advantage of a small iso TX.  Why turn power into heat unless there is a really good reason?  A loss of around 3% is considered to be an average loss IIRC and having a bunch of smaller transformers to provide isolation is OK with constant current loads like preamps and other line level gear, but amplifiers are far from a constant load.  I've had good results using a large isolation TX for tube amplification due to the characteristics of tubes, but they just don't cut it for solid state.

Ramble on..

Dave

[jdbrian]

Dave

 I think the issue with the instrumentation was ground to neutral noise. In a large 8 story building with a lot of heavy loads and a convoluted distribution system there was a lot of potential (pun intended) for problems and we experienced many battles with manufacturers over this issue.
  The major fault was with computers embedded in the instrumentation going off the rails for no apparent reason. In the early days of computer based instrumentation many engineers did not understand the line noise issue. These days it is not an issue at all. Better training, testing and regulatory standards.
   There continues to be a problem with audio equipment being built with poor and inconsistent grounding practices. With balanced connections there is the pin1 problem. The solution to this is well known at this point but there does not seem to be a will on the part of manufacturers to standardize grounding practices so you can connect different brands of equipment and have a hum free system. An isolation transformer may offer a solution in some cases.

Brian

[dBe]

Dave

 I think the issue with the instrumentation was ground to neutral noise. In a large 8 story building with a lot of heavy loads and a convoluted distribution system there was a lot of potential (pun intended) for problems and we experienced many battles with manufacturers over this issue.
  The major fault was with computers embedded in the instrumentation going off the rails for no apparent reason. In the early days of computer based instrumentation many engineers did not understand the line noise issue. These days it is not an issue at all. Better training, testing and regulatory standards.
   There continues to be a problem with audio equipment being built with poor and inconsistent grounding practices. With balanced connections there is the pin1 problem. The solution to this is well known at this point but there does not seem to be a will on the part of manufacturers to standardize grounding practices so you can connect different brands of equipment and have a hum free system. An isolation transformer may offer a solution in some cases.

Brian

What is up with the pin 2/3 hot thing anyway?  Never could figure that one out.  I think it was Mark Levinson (maybe) that configured pin 3 hot just because he could. The TRS standard just never made it to XLR in a consistent manner.  I've always wired pin 2 hot because that is the way 'most' gear is done.  There is always that one odd piece of gear though.

Grounding in audio should be very easy, but I think that the advent of printed circuit boards (the cheap ones - where manufacturers don't want to pay for copper) really hosed the audio community.  I build tube guitar amps with AC heaters and seldom have hum as an issue.  I guess the wildcard in all of this is digital and analog on the same board.  I don't know enough about PCB design to know what is good and what isn't. 

Now look who's rambling...

Dave

[Rocket]

Hi Dave,

I have Ampzilla monoblocks and one of the amps is experiencing fairly loud transformer hum and occasion buzzing. 

Are you able to tell me when you new product will be available and ballpark figure that it will cost me?

Thanks

Rod

[dBe]

Hi Dave,

I have Ampzilla monoblocks and one of the amps is experiencing fairly loud transformer hum and occasion buzzing. 

Are you able to tell me when you new product will be available and ballpark figure that it will cost me?

Thanks

Rod

Hi, Roy.

My hum eliminator is a ways off - several months.  Pricing will be determined at that time, but 'should be' in the $150.00 - $175.00 range.

PS Audio's Humbusters work very well.  If you are in a hurry I would say that they would be a great choice, especially if you can find one used and not abused.

I wish I could have mine ready sooner, but this guy has a VERY full plate.

Thanks,

Dave 

[jtwrace]

What's the deal with the other new products?  FridgeBuss and such. 

[dBe]

What's the deal with the other new products?  FridgeBuss and such.

FridgeBUSS betas go out next week.  Power cables are in the mill and part of what is consuming my time right now.  I had a development last week that has caused me to rethink the direction of the cabling.  You know how 'epiphanies' can derail this old man. 

I'll be in touch.

Dave