F2B before DI is noisy, why?

[Rusty The Scoob]

I love my F2B and I really want to get it into the signal chain that I send to the front of house, it's a key part of the sound I want.  Unfortunately it's very noisy through a DI, I've tried a few and had no luck so far, there's a constant and obnoxious hiss.    Lifting the ground doesn't help, and turning the internal trim pot (as suggested by my much smarter friend who is the one who replaced all my dried up caps, etc) doesn't have any effect.  Has anyone run into this?

My test setup: https://i.imgur.com/GUayKkx.jpg

[StephenR]

Hey Dan... welcome to the club. Nice looking rig!

I can't think of one sound engineer I work with who would want me to send my preamp signal to FOH but your situation may be different. If I want the sound of my stage amp to be in the mains I ask to have it miked.

Is your F-2B dead quiet at volume when you use it through your rig with no DI connected? Have you tried a different tube? Someone here recently had noise issues with their F-1X and in the process of swapping tubes discovered that the contacts in the tube socket were a little dirty and not making proper contact.

http://club.alembic.com/index.php?topic=24423.0

[elwoodblue]

I'll second StephenR's approach.
Do have some DeOxit?

[cozmik_cowboy]

Well, I don't have the knowledge to answer your question, Dan - but Stephen, you can count me as a sound engineer who loves to get the bassist's preamp signal.

Peter

[StephenR]

Peter... I will remember that if I ever get to work with you

[Rusty The Scoob]

I know some will object so I plan to give them a pre-F2B signal as well, but I'll strongly encourage them to use the post-F2B.  I'm in a JGB tribute band and Kahn's Dual Showman is a crucial part of his tone, especially the bright switch and sometimes the mid-scoop you get when you turn all three EQ knobs all the way up.   I don't really like to have my cab mic'd, I like to use it in weird ways for my own stage use, sometimes high-passing it or shutting it off entirely for a song or two to hear how the bass is behaving in the room.  No one else on stage even notices, believe it or not.

I've been running a DI before the F2B for years with no noise problem at all and inserting it into the chain doesn't add any noise to the feed to my poweramp.  So I think the unit itself and the tubes are fine, both channels sound great with no particular noise.

[edwin]

Hey Dan! Great to see you here!

I always provide a post preamp (usually F-2B) signal to FOH. I think it's possibly a gain thing. DIs are expecting to see instrument level and output mic level. A preamp provides something that's closer to line level. I would make sure that you're feeding it a good healthy level and if it's too hot to FOH, pad the DI, instead of turning down the preamp. The power amp doesn't output noticeable hiss because it's expecting different gain than a mixing board and your speakers are probably not reproducing the frequency range where hiss is most prominent compared to the lower frequencies they are putting out. A full range cabinet would probably reveal some hiss. Or maybe not.

I've never gotten a complaint about hiss from my preamp, using DIs from Radial (ProDI and JDI Duplex), my own Reichenback xformer based DI, an IN-2, or various active DIs. There is a bit of hiss in the background, but once I'm playing, it's pretty much inaudible.