How effective are hum eliminators for unbalanced to balanced conversion?

[canidoit]

I tried the Art DTI Dual Transformer Isolator, didn't seem to do anything. I compared it with straight through and I still have the-same hum/noise on the reel to reel and cassette player.

DAW balanced out > long balanced cable > DTI XLR in/DTI TS out > unbalanced rca cable > X5000 line in

I did notice that using the DTI boosted the signal from the DAW going into the Reel to Reel by about 6db but either ways, the Reel to Reel really cannot handle these sort of levels.

Might have to accept the hum/noise as part of the sound of these devices.

Thank you all for the replies!

 

[JohnRoberts]

When troubleshooting hum, you need to confirm that the source is clean and that the hum is being introduced by the interface. If possible can you listen to the feed with headphones ? If the headphones have hum the that source must be addressed separately from the interface.

JR

 

[canidoit]

When troubleshooting hum, you need to confirm that the source is clean and that the hum is being introduced by the interface. If possible can you listen to the feed with headphones ? If the headphones have hum the that source must be addressed separately from the interface.

JR

Hi JR, you are right, I should check if it is from the interface but I do get hum/noise from the reel to reel and cassette deck when I feed audio from the interface. The hum/noise are different on both cassette and reel units. The reel to reel gives me that low hum sound whilst the cassette deck gives me a combination of slight low hum and static, with prominent white noise.

 

[ccaudle]

Hi JR, you are right, I should check if it is from the interface but I do get hum/noise from the reel to reel and cassette deck when I feed audio from the interface. The hum/noise are different on both cassette and reel units. The reel to reel gives me that low hum sound whilst the cassette deck gives me a combination of slight low hum and static, with prominent white noise.

The first step to developing a solution is to make sure you have properly identified the problem.
Bill Whitlock (MisterCMRR on this forum) created a very good presentation on system grounding and shielding several years ago. The Indiana section of the AES still makes it available on their web site:
Whitlock grounding and shielding seminar

A section on troubleshooting begins on page 101.
Everything makes sense to me in that section, but I have a background in electrical engineering and have read a lot of Bill's writing in the past, so I have kind of absorbed it by now. You can come back here if you get stuck on a step and something isn't making sense.
You will need some connectors to make some "dummy" adapters, so read through all of the troubleshooting section first and round up the connectors and resistors you need for those to start.

The starting testing step is shown on page 108, basically make sure you tape machine is quiet by itself. It is certainly possible that the power supply caps are way out of spec, and the device just has a lot of power supply noise now that makes it hum no matter what is attached (or if nothing is attached).

I tried the Art DTI Dual Transformer Isolator, didn't seem to do anything.

Starting on page 132 of the presentation is a section on all the ways to poorly design an "isolator" to make them kind of useless. Perhaps the Art device is one of those poorly designed isolators, or perhaps your tape recorders are just noisy on their own and need to be fixed first. Start on page 108 and work through all the combinations.