From ted@speakeasyvintagemusic.com Tue Apr 10 13:25:06 2007
Subject:Re: OT: 60hz hum

An open letter to those who have been experiencing hum with our Vintage
Tube Preamps:

Hum in audio gear can come from a number of sources. Earth ground can
often be seen as the "problem" when in fact it actually isn't.

First a foremost, the earth ground is a *Safety* ground. I think most
of us can recall the stories (some possibly urban legends, but never the
less) where a musician touched and instrument and then a microphone and
BAM! - he was on his butt, if he was lucky.

The idea of this "HUMX" as I understand it, is a good one - ditch the
noise and keep the safety. Those that cut off or otherwise defeat the
ground prong as a solution are flirting with disaster.

Ok - enough with the PSA, now some practical help.

One solution for ground loops is isolation, using transformers to couple
the audio in an unbalanced system to keep the audio grounds from seeing
one another.

http://www.rane.com/note110.html is an excellent article on the issue.

As another list member mentioned, earlier model preamps from Speakeasy
did have a certain degree of hum which was found to be exposed in
certain settings (IE sometimes there, sometimes not or sometimes worse
than others) We corrected this in later models.

ALL SPEAKEASY OWNERS SHOULD REMEMBER:

We offer FREE updates on ALL our preamps. You only pay the shipping cost.

You do need to contact us by phone, so we know what's going on, but once
that is done, you can send in your preamp and have it updated to the
last revision for it's type.

And keep in mind that we are constantly looking for better ways to
improve even the OLDEST of our preamps. We don't obsolete our older
models in favor of newer gear, we look for ways to improve our products
will maintaining support for everything we ever made.

I know these days it's almost to good to be true (and I know some of you
are hard pressed to part with your Speakeasy for even a week or two) but
Speakeasy does not abandon it's customers or ignore them. If it's wrong
not only will we fix it, we WANT to fix it. In fact I'd say that if it
weren't improper I'd DEMAND to fix it.

Our customer's satisfaction is the absolute TOP priority.

So, get the info, check your gear, and if it looks like something is
amiss in our preamp - SEND IT IN!

(BTW - even if you broke it, our gear has a lifetime labor warranty - so
all you pay for is the parts needed to fix it + shipping, EVEN IF YOU'RE
NOT THE ORIGINAL OWNER. Your preamp is your receipt, we don't care who
you bought it from. See if the "other boys" will do that.)

Cheers!

Ted Thompson
General Manager - Speakeasy Vintage Music

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* PH: 717.292.0814 *
* Main Site: http://www.speakeasyvintagemusic.com *
* Media Site: http://media.speakeasyvintagemusic.com *
* Support: http://support.speakeasyvintagemusic.com *
* MOSweb: http://www.mosweb.com *
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jpittas wrote:
> I don't have a HUMX, but there was a discussion about it on another
> forum. It apparently minimizes ground loop hum by filtering the ground
> line. It's the same result as lifting the ground, while still
> maintaining a safe ground. So if you've tried lifting the ground with
> no success, then the HUMX might not help. But if you try it and it
> does work, please let us know. I also have a humming Speakeasy preamp.
>
> Regarding whether it would be safe to plug a power strip into a HUMX,
> that should be safe (it's rated to 15 amps), but potentially not
> effective since it wouldn't be eliminating ground loops between
> devices on the same strip.
>
> JP
>
> --- In CloneWheel@yahoogroups.com, "Ryan Stroup" wrote:
>> I honestly can't remember if it was on this list that I posted a topic
>> about a 60hz hum coming out of the Leslie. I would've been several
>> months ago. In any case, after some trial and error, it was determined
>> that the hum was coming from the Speakeasy Vintage preamp. I have some
>> other equipment with the same hum, but not as intense. I've tried one
>> of those ground plugs (3 prong to 2 prong adapter) but it did not
>> solve the problem. I was wondering if anyone has had any experience
>> with the Ebtech HUMX Voltage Hum Filter. This sounds exactly like what
>> I need to eliminate the problem. A question I do have about this
>> device though...would it be safe to plug a power strip into this unit
>> so the hum will be eliminated in all affected gear? Or would that
>> overload or damager the device?
>>
>> --
>> Ryan
>>
>
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