Clearcom Hum in custom assembly

[Anonymous067]

So I have a little custom headset rigged up that I use for my shows that I run.

We use a party line/two channel clearcom system. I purchased a CC-27 headset. It is a lightweight headset with a boom mic and little CHEAPO ipod style earbud. First thing I did was chop it off and add an 1/8" jack, then I plug my custom ears into that.

Problem, I get a nice little fuzz in the background. Now, it does go away in your head after you listen to it for hours on end, and it doesn't bother me too much, but how do I make it go away completely? Is there an adjustment I can make?

My reasoning has always been because the in ears are a higher sensitivity that they just amplify that signal that isn't there, which is the fuzzy noise.

 

[Chris15]

So I have a little custom headset rigged up that I use for my shows that I run.

We use a party line/two channel clearcom system. I purchased a CC-27 headset. It is a lightweight headset with a boom mic and little CHEAPO ipod style earbud. First thing I did was chop it off and add an 1/8" jack, then I plug my custom ears into that.

Problem, I get a nice little fuzz in the background. Now, it does go away in your head after you listen to it for hours on end, and it doesn't bother me too much, but how do I make it go away completely? Is there an adjustment I can make?

My reasoning has always been because the in ears are a higher sensitivity that they just amplify that signal that isn't there, which is the fuzzy noise.

I suspect it's a combination of the noise floor of the party line system (it's unbalanced audio running around after all) and the noise floor of the beltpack. You could try powering up the beltpack directly and seeing if that reduces things, in which case you have a cable noise somewhere, good luck with that. If the hum is the same, then you MAY be able to adjust the pack to reduce the noise but by the same token, I wouldn't put money on it.

If you had a Riedel system then your headset would likely be much quieter... As it is I suspect it's just one of the joys of analogue...

 

[Cameron]

I agree with Chris, that it's a S/N issue. Out of curiosity, how open/loud is your belt pack(1/8th turn, 1/16th)? There is always some hiss or hum with analog comm systems that is always going to be there, and I think it is exacerbated by the custom buds. Usually with a muff headset, the hiss is pretty well covered up within the enclosure.

Get an attenuator to throw in-line and improve your S/N ratio. UE and Shure make them, plus a few other consumer companies.

 

[SHARYNF]

Clearcom headphones typically use a 4 pin connection

# Pin 1: mic common
# Pin 2: mic hot
# Pin 3: headphone common
# Pin 4: headphone hot

How did you wire this to a 1/8" jack? most 1/8" are 3 connection?
Sharyn

 

[Anonymous067]

Only two of the wires are used. Two of them still go to the mic part of the headset, and the two speaker ones go to the 1/8", with the L/R inside the trs jack bridged together. It's just a mono signal. so the speaker + goes to tip and ring, and the speaker - goes to sleeve. :]

 

[fx120]

What headset are you using now? Brand and model would be helpful.

If you're running to low of an impedance, it's possible that the driver circuitry of the pack is trying to deliver more current and running hotter than normal, which will degrade the SNR.

 

[Anonymous067]

What headset are you using now? Brand and model would be helpful.

If you're running to low of an impedance, it's possible that the driver circuitry of the pack is trying to deliver more current and running hotter than normal, which will degrade the SNR.

As specified in the original post, a CC-27 from Clearcom...

 

[fx120]

As specified in the original post, a CC-27 from Clearcom...

No, what "custom ears" are you using?

 

[gcpsoundlight]

Possably you have a ground issue as you have altered it, and you might have broken the shielding

 

[Anonymous067]

Ultimate ears. I didn't alter the ears, just the headset connector. The headphones never used a shield though...it was just two of the four wires in the cable. The shield wasn't connected anywhere in the original makeup either.

 

[fx120]

Again, I ask which model.

Let's take the standard CC-27 earphone which uses a single ~90 ohm driver, while the Ultimate Ears 700 uses two ~40 ohm drivers.

Now if you wired them up in parallel or "split" the mono signal coming from the pack you have dropped the impedance down to ~20 ohms, which is a very tough load for most dedicated headphone amplifiers to drive, let alone whatever low cost IC clearcom is using in their packs to handle the task. Likely the IC driving the earphones is running hot, raising the noise floor.

 

[Chris15]

I'd been thinking impedance issues too...

Now that I take the time to look it up, Clearcom spec the minimum impedance for the RS601 beltpack as 50 ohms (with a max of 2k).

Now I know that this don't make sense at first, but try rewiring your 3.5 socket to connect the tip and ring to the comms system and ignore the sleeve.

What you're doing is placing the 2 drivers into series and so based on the impedances tossed around, you're then up to an 80 ohm load which ought to make the beltpack behave more betterer...

 

[Anonymous067]

Is what I'm doing now putting my ears in jeopardy of blowing or breaking?

I use UE-5.