WT550 + Warwick Thumb (weired thing)

KNURRR · #1 01-15-2011, 05:21 AM

So hopefully you can explain a thing to me i'm really concerned of.. here is the case:

I got my WT550 back from Repair and yesterday was the first time i played my Thumb through it. While setting the level (plugging the B string, waiting for the green light to flash) i noticed something i cannnot explain:
everytime the "Set Level" light flashed there was a silent farting sound coming through both of my cabs, although i set the mastervolume to 0 (!)
Interestingly the "farting-sound" doesn't get louder when highering the mastervolume (and ofc is drowned that way)

I don't have this phenomenon with my passive Lakland JO5.

A maybe importand sidenote is that the Thumb (in active mode) is also "farting" through my Korg Pandora PX5D and headphones.

Can someone imagine how this thing comes up? i really do not have any clue!

Thank you for your responses!
Cheers, KNURRR

Jaco who? · #2 01-15-2011, 05:35 AM

You'll need to clarify what you mean by a silent farting sound, but maybe the battery in your thumb is dead.

KNURRR · #3 01-15-2011, 06:07 AM

really, i dont know how i can clarify the weird sound more then "silent farting" ...it sounds very similar to the farting when the battery is dead, but thats not the case (i checked it).

But anyway let's say the battery is dead, why would there come a sound out of my cab when the mastervolume is 0, and why is it coaccidental to the "Set Level" light flashing? and why is it not amplified when turing up the volume?

KNURRR · #4 01-15-2011, 06:18 PM

seems to be a mistery.... not only for me

*insertcoolname · #5 01-15-2011, 06:22 PM

Turn down the volume some on the Thumb and see if the farting happens. Might just be the higher output of the Thumb is leaking through ever so slightly even when your amp's master is at 0. If that's the case then there shouldn't be anything wrong and I'd run it a full volume.

prd004 · #6 01-15-2011, 06:23 PM

The preamp on your thumb may be too hot, just a guess. My preamp has an atenuator, and if it's all the way up it will overdrive just about anything.

Good luck

IntrepidCellist · #7 01-15-2011, 06:24 PM

Try pulling out the "Enhance" knob to bypass the compressor. I used to get the same issue with my Dingwall in series mode (hugely powerful) and it would make a clipping noise with the compressor engaged through the tweeters in my cabs.

JTE · #8 01-15-2011, 08:14 PM

I'm still trying to understand "silent sound". By definition, if it's silent there isn't any sound...

OK, you're hearing something through the cabinets when the master volume is at 0 on the WT-550, and you hear it with the Pandora/headphones? Sounds like something in the Thumb is spiking. Is there a trim pot inside the Thumb's pre-amp? Do you have the EQ on the bass pushed? It could be enough to trigger the compressor as IntrepidCellist says, so see what happens if you pull out the "Enhance".

Otherwise, you'll probably have to just keep the Thumb at a lower level.

John

eastcoasteddie · #9 01-15-2011, 10:21 PM

"silent farting"

silent......but deadly.

KNURRR · #10 01-16-2011, 08:31 AM

Ah okay, i got the point JTE. By typing "silent" i mean a sound with low volume. Sorry for this confusion, i guess this is provoked by heritage.

Thanks for the explanations so far. *intercoolnamehere's thesis is quite comprehensible for me, but what still stays unclear for me is the fact that the "excess-output" of the thumb is not amplified when turning up the volume.

BassmanPaul · #11 01-16-2011, 11:47 AM

I'm still confused by what you are meaning, SBDs notwithstanding. Are you talking about your speaker cones moving a lot but not making much sound??? If so this is caused by sub-sonics that cannot be heard but just waste power and can possibly damage your speakers.

BassIan · #12 01-16-2011, 12:32 PM

I know that in my Thumb neck-thru there is a trim pot within the preamp. It is an overall gain pot, and when adjusted too high allows the bass' preamp to distort. At the recommended setting (indicated by a factory mark on the pot), lots of low-end boost can provoke the same response.

If the issue follows the bass, I'd check this with a fresh 9V battery first.

It's typical for a small amount of audio to "leak" through when the master volume is at zero. It is not a switch, so at "zero" it is simply attenuating as much as it can. I've noticed this with Tuner Mutes that simply switch in a large resistor as well.

Son of Bovril · #13 01-17-2011, 01:11 AM

Quote:

Originally Posted by BassIan

...It's typical for a small amount of audio to "leak" through when the master volume is at zero. It is not a switch, so at "zero" it is simply attenuating as much as it can. I've noticed this with Tuner Mutes that simply switch in a large resistor as well.

+1 the mute function is often just an attenuator that cuts the volume significantly but if your bass is sending a really strong signal you can still sometimes hear it slightly... you wouldn't hear this "extra" strong signal when un-muted as it would just sound like normal except you would probably be running your gain on the amp slightly lower.

KNURRR · #14 01-17-2011, 10:56 AM

okay, this sounds very plausible. i guess this phenomenon is not harmful, isn't it?

KNURRR · #15 01-23-2011, 11:52 AM

It worries me. I experience the same issue with my Lakland.

Everytime the "Set Level" Light flashes there is this farting-sound (Mastervolume set to 0). This can't be right or do you WT550 users experience the same?

I think this weird thing did not occured to me before the "repair".

T. Brookins · #16 01-23-2011, 08:22 PM

The general consensus is that your high gain setting is heavily using the compressor (turn GAIN down and MASTER up). It is just the way the WT400 and 550 compressors are. You can pull the ENHANCE knob out to defeat it. I have a steel chassis WT400 with the defeat switch wired in reverse.