Fixed Tube Pre Noise

200man

Power User
It WAS working...but something weird happened tonight.
1-I had a cool jazz patch setup with the tube pre...sounded good!
2-unrelated...but...updated to Mac sierra...updated to Logic Pro x
3-went to take new logic for a spin...set up a track to record a little audio
4-I can hear noise...sporadic...sounds like scratchy ground noise
5-try several instrument cables...no change
6-try several guitars...no change
7-check cables between the axe and an rme audio interface...no change
8-test the rme unit...no change
9-throw hands up in the air...change to a different patch...noise gone
10-I have 2 patches with the tube pre...both have noise
11-reset the block...no change

this one is baffling...any ideas?

If this is the wrong area to post this issue...please accept my apology
 
Check the sample rate of the Logic project matches the Fireface? Also How are you running Logic if the computer is off??
 
Thank you for responding!
Latest firmware...
not running Logic...not running the Mac...only the axe.
When I bypass the tube pre block the noise goes away.
But any other amp block...and the noise issue is non-existent
 
This problem is worse than I feared, so I needed to record it so you folks don't think I'm crazier than I am. ;)

Turn on the computer, open Logic and record away....

First be careful because I recorded these samples hot to better hear the noise floor.

The first sample is the tube pre. But not only do I have this noise issue...listen to the tail of the sample.
As the volume fades, there is this synthesized zipper noise as well...that is even worse.

The second sample is a patch that uses the fender double verb silver face.
There is zero noise before and the tail is great.

On both patches there is no noise gate anywhere.

Okay here's the bad sample:
www.200man.com/audio/noise.mp3

And here's the good sample, recorded exactly the same:
www.200man.com/audio/nonoise.mp3
 
Last edited:
The root cause is because you've got so little gain and then you're making it up with tons of gain after amp. You've got the amp block level control at +20 dB and then another +20 dB in the graphic EQ after the amp and then another +12 dB in the output block, etc. So you've got at least 52 dB of gain after the amp!!! And that's not including the gain you've got in the compressors.

Regardless, I've adjusted some things that will prevent it for the next firmware release.
 
He beat me to it! Figured it must be related to all the gain post amp. Man I kinda like that alien fuzz as effect though ;-)
Nice sounding preset by the way!
 
Thank you sir.
Sorry to have placed so much gain...what should I have done?
after the tube pre....should I have included a power amp?
before the tube pre....should I have added some type of gain block?
It hurts sometimes showing off my newbie status. :(
 
Back
Top Bottom