[TX inside] The Original, the Clone and the Perpendicular

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

clintrubber

Well-known member
Joined
Jun 3, 2004
Messages
5,982
Location
The Netherlands
Let's do some pics for fun.

Had some hum in a multi-guitar-amp setup.

After having verified that using an isolation-TX box (Behringer HD400) does indeed solve it,
I figured I'd best go for a more sturdy type (Ebtech Hum Eliminator), which is most likely also
the inspiration for the Behringer clone.

The HD400 uses what seems to be those cheap but usable kind of TXs as for instance also in the Geofex-splitters.
As long as you drive them from a low impedance, the bandwidth extends enough for guitar.

Having seen the Ebtech was bigger, I was curious to which kind of TXs they used - couldn't find any info or gut shot beforehand - and Ebtech didn't give any max level spec & conditions (only a bandwidth & recommended source & load impedance).

So here goes, see pics below, fwiw...

* the Behringer uses SMD, the Ebtech uses thru-hole components. Some loading resistors and a Zobel
* the circuits are (about) identical: either TS or TRS is converted into either TS or TRS. Simple elegant straightforward circuit
* the Behringer spends an additional cap to connect to the (otherwise) isolated metal case 
* last but not least & interestingly, the TXs in the Ebtech are placed perpendicular w.r.t. each other.
Wouldn't expect any direct need for that, but appearently this avoids any interaction between channels. ...or better safe than sorry?
 

The HD400 works fine, didn't notice any change in sound (for gtr).
Just had the Ebtech in, so soundwise haven't compared them side by side yet.
But I'd rather have some hum than have an unsupported PCB-mounted connector give me an intermittent connection at a gig, so I went for the more sturdy Ebtech. Which is a pain to open though, US-made it may be, but some of the screws don't fit too well.
 

I guess that's all there is to say about them!  :)

Feel free to chime in about the perpendicular placement, otherwise let's live on without hum.

Bye
 

Attachments

  • TX-01_TX-05.jpg
    TX-01_TX-05.jpg
    358.6 KB · Views: 41
Back
Top