Lots of hum with my ToneHammer

[christiaan_01]

Hi guys,

My new ToneHammer just arrived, with power supply.
I play it through a fender jazz, through an old fashioned analogue mixing desk, and then a headphone. Normally I plugged my jazz directly (without DI) into that mixing desk, and I had never experienced any sign of hum.

Now I put the Tonehammer in between, and now there is loads of buzz/hum. If I switch from using it as a DI, or just using the normal line output, the hum is the same. Pressing the engage switch doesn't help it, the AGC button only adds hum (which is logic I guess). The ground/lift button doesn't reduce the hum as well.
The only thing I can do to reduce the hum is by turning the tone pot on my jazz down.
But it doesn't seem that the hum comes from my bass, since it doesn't give any hum without the TH.

It's really annoying to play with so much hum, so anyone has got some ideas?

[dido__15]

Sounds like it could possibly be the cables. I'm not an expert but IME cheap cables cause noise, especially if coiled. Try keeping the cable straight, and maybe buy some better cables if you absolutely can't live with it. Also check you're not crossing over the instrument cables and power supply/power cable.

[Toasted]

I'm giving 10:1 on ground loop.

[NoHomework81]

Originally Posted by Toasted

I'm giving 10:1 on ground loop.

+1 and in which case, you'd use the Ground Lift feature on the TH's XLR out.

[fightthepower]

Originally Posted by NoHomework81

+1 and in which case, you'd use the Ground Lift feature on the TH's XLR out.

Originally Posted by christiaan_01

"..the AGC button only adds hum (which is logic I guess). The ground/lift button doesn't reduce the hum as well.
The only thing I can do to reduce the hum is by turning ..."

Morehomework!

[christiaan_01]

It really sounds like the TH adds a lot of hum. When I play together with some music, it isn't really annoying me, but it definitely is when playing alone.

I checked the thing about crossing the cables, but it wasn't the sollution.
My cables are perfectly fine, because there's no hum without TH, it cannot be the cables, since I checked both XLR and regular jack cables.

It is really the sound of shaving your beard with an electronic shaver.

Edit: the groundloop can easily be solved by the ground/lift button at the back of the TH, right?

[JohnDavisNYC]

what is the mixing console? are you running the TH off of 48v phantom power?

if the desk is old, it could be wired pin3 hot instead of pin2 hot, and if the output on the TH is servo balanced, instead of transformer balanced, they could have not planned for older gear... dunno.

john

[katri]

Lift the ground on the TH. Is there hum when the TH is bypassed?

[christiaan_01]

Originally Posted by JohnDavisNYC

what is the mixing console? are you running the TH off of 48v phantom power?

if the desk is old, it could be wired pin3 hot instead of pin2 hot, and if the output on the TH is servo balanced, instead of transformer balanced, they could have not planned for older gear... dunno.

john

It's an old one.
This is almost the one (just a little bit different, but the same brand and type)


I don't really understand about the phantom power, pin 3 hot, servo balanced, but I'm just running it in this order:

Bass --> Aguilar Tonehammer (line-out) --> Inkel mixing desk --> Headphone

[christiaan_01]

@ Katri: When I bypass it (engage: on - off), the hum stays the same

[christiaan_01]

I just tried a modern mixing desk, and it works perfectly fine now! No hum at all!!!
Thanks very much for that suggestion!

[JohnDavisNYC]

my guess is the pin hot layout... You could either make a cable that flips the polarity, or buy a polarity reverse 'barrel adapter'

John.

[NoHomework81]

Originally Posted by fightthepower

Morehomework!

DOH!