Arkham Sound Club

[labeledbass]

You can ID the hum with something like EQ or high slope HPF. Noise due to other gear, near the oracle, will generally be 120 hz, noise from a ground loop or faulty lug somewhere will be 60 hz. Also make sure it's not environmental, emf noise, this will show when "pointing" the bass in a specific direction, and usually 180 degrees in the opposite way.

You could try another tube, a 5751 is 30% less gain/mu, will work, but he designed the oracle around the 12ax7. Unless the current tube is faulty, you shouldn't need to lower (or replace) the gain factor. Same goes for EQing an issue out, only in rare instances where someone has pushed gain, before or after the Oracle, would this honestly be appropriate.

Try to identify the type of noise first, and go from there. Micah uses very good components, that in turn yield great noise filtering

 

[J.Wolf]

This is helpful thanks. I’ll put it thru my para eq and see if I can figure out where it lives

 

[labeledbass]

I was going to suggest, a paraEQ works the best for narrowing problems frequencies. Keep the band narrow as possible and sweep away. Once dialed in you can make the band broad and it should increase in volume (the target hz)

 

[rickdog]

Does it hum with nothing plugged into it? I'm just guessing here - but the Oracle might just be higher input impedance and thus more sensitive to noise picked up by the bass and cable.

 

[Joshua]

I'll put a better ear on it next practice, but I've never specifically noticed any undue noise from mine. And my usual practice space is fluorescentpalooza.

 

[Cdnbassnut]

Hello all.
I'm curious if the Di and pre out levels are determined by the master volume. I'm on the fence between the Oracle and Zepher.

Thank you.

 

[labeledbass]

I think the transformer is coupled, I remember both gain and master affected each output. I can't remember if the TS output is padded or not though.

 

[J.Wolf]

OK someone needs to help me out here. Here is the board.... IEC from the power supply and IEC from Oracle go into separate inputs on isolated Furman power conditioner.

With a passive P bass:

When I plug into just the oracle, there is a little bit of hum and buzz, not bad but a little noticeable.

When I plug into the board and bypass the oracle (taking it out of the chain, between the flint and the Empress buffer loop in), the board is dead silent.

When I run it as pictured, with the oracle in the chain just before the Empress buffer (which I mainly use as a solo boost and a patchbay), aforementioned bothersome level of noise.

If I turn the treble knob down on the oracle, it becomes manageable.

Seems odd that 1+1 = 4 somehow in this scheme, with the IEC power running into seperate isolated power conditioned inputs.

Thanks for any advice here.

 

[Joshua]

Can you just try running bass-Oracle-amp-cab to see if the noise is still there? IE remove the Oracle from the whole chain of pedals and then test?

And have you ever changed the tube?

Just throwing out guesses of course...

 

[J.Wolf]

Hi, yes, that first scenario I’m just plugging into the Oracle and then the amp. I am still getting a small amount of buzz. Not nearly as bad as with the whole board, but definitely noticeable.

I have not had a chance to swap the tube yet. Will try that today.

 

[J.Wolf]

3 good 12AX7's later, still hearing it pretty noticeably.

 

[rickdog]

With a passive P bass:

When I plug into just the oracle, there is a little bit of hum and buzz, not bad but a little noticeable.

A real puzzler! Here are some things I'd be looking at if I were having this problem:

Is the hum and buzz only when the bass is plugged into the Oracle? If you unplug the bass from the input of the Oracle, does the noise stop?

What is the amp? Where is it getting its power? (I was in an impromptu home studio yesterday, awful buzz from the preamp out of the amp into the mixer, fixed it by powering the amp from the same power conditioner as the mixer. Sketchy power wiring in a 70-year-old house.)

When you are testing bass -> Oracle -> amp, is the Oracle completely disconnected from everything else on the board, or are you using Out2 to the amp while Out1 is still connected on the board? And is the IEC for the board power supply still connected?

 

[J.Wolf]

A real puzzler! Here are some things I'd be looking at if I were having this problem:

Is the hum and buzz only when the bass is plugged into the Oracle? If you unplug the bass from the input of the Oracle, does the noise stop?

equal amounts of buzz with the bass plugged in and not plugged in

What is the amp? Where is it getting its power? (I was in an impromptu home studio yesterday, awful buzz from the preamp out of the amp into the mixer, fixed it by powering the amp from the same power conditioner as the mixer. Sketchy power wiring in a 70-year-old house.)

Glockenklang bass rig, dead quiet in my home studio otherwise. Also dead quiet with the remainder of my pedal board sans oracle.

When you are testing bass -> Oracle -> amp, is the Oracle completely disconnected from everything else on the board, or are you using Out2 to the amp while Out1 is still connected on the board? And is the IEC for the board power supply still connected?

oracle completely disconnected from everything else. Bass > oracle > out 1 > amp

 

[J.Wolf]

Also, according to my para eq there is some 60 cycle hum but it’s marginal and the rest of what I’m hearing is broad wide frequency buzz in the upper mids and treble

 

[rickdog]

equal amounts of buzz with the bass plugged in and not plugged in ...
oracle completely disconnected from everything else. Bass > oracle > out 1 > amp

That narrows it down quite a bit.

Also, according to my para eq there is some 60 cycle hum but it’s marginal and the rest of what I’m hearing is broad wide frequency buzz in the upper mids and treble

I don't think it's conclusively proven - but it seems pretty likely there's a problem in your Oracle that makes it unusually susceptible to picking up high frequency noise. Maybe it's time to talk to @Arkham Sound about whether it needs to go in for a checkup?

 

[Joshua]

I'll put a better ear on it next practice, but I've never specifically noticed any undue noise from mine. And my usual practice space is fluorescentpalooza.

I'll confirm all but zero noise from mine. Last night was Suhr Classic J > Oracle > Berg IP112/EX112 and I had to put my ear up to the stack to hear the slightest noise.

 

[labeledbass]

Also, according to my para eq there is some 60 cycle hum but it’s marginal and the rest of what I’m hearing is broad wide frequency buzz in the upper mids and treble

Do you have a headphone amp? Or something similar (I use a broughton messenger with HP out), or even an interface you get a headphone signal from? Try to set it up basic as possible, bass>oracle>headphones and see if it's still there. If that setup is mobile, maybe even try different rooms, more importantly different circuits in your home (or whatever local you're in). You can even eliminate the bass and just have the 1/4" instrument cable.

Which also reminds me, switch out the cables linking each variable as well, damaged cables and insulation can cause this

You've already had Micah look at the oracle correct?

 

[J.Wolf]

Do you have a headphone amp? Or something similar (I use a broughton messenger with HP out), or even an interface you get a headphone signal from? Try to set it up basic as possible, bass>oracle>headphones and see if it's still there. If that setup is mobile, maybe even try different rooms, more importantly different circuits in your home (or whatever local you're in). You can even eliminate the bass and just have the 1/4" instrument cable.

Which also reminds me, switch out the cables linking each variable as well, damaged cables and insulation can cause this

You've already had Micah look at the oracle correct?

yeah he looked at it back in the spring and it was fine. It’s actually fine all by itself it’s just interacting poorly on the board, so it’s probably another pedal or cable that’s causing the oracle to act up. Now for the elimination process to try to find the culprit….

 

[labeledbass]

Consider yourself lucky then. Finding a problem outside of the gear is easier than the alternative, inside the dang thing..

 

[J.Wolf]

Consider yourself lucky then. Finding a problem outside of the gear is easier than the alternative, inside the dang thing..

totally. Just a little time consuming.

I'll confirm all but zero noise from mine. Last night was Suhr Classic J > Oracle > Berg IP112/EX112 and I had to put my ear up to the stack to hear the slightest noise.

fantastic rig Im sure. How's that Suhr J? Been eyeing one of those.