I hooked up a cable from one of my tuner's two outputs into the DI11 and get a hideous loud hum from any of several guitar amps.
After some troubleshooting, even if I have just the SCA unit connected to nothing, the tuner or another non-isolating splitter (just parallel I assume), and guitar amp it still does the same thing.
If I need to buy a DI unit to isolate the signal from the guitar amp's input chain, then there is no sense in having the DI11 so I'm pretty baffled?
I have little use for plugging an instrument into ONLY the DI11, is this the only way it can be used?
How to split signal from guitar?
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How to split signal from guitar?
by LamontGrady » Sun Jan 03, 2010 9:30 am
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by tpryan » Sun Jan 03, 2010 11:09 am
Try:
*Jumper across J1 and J2 as shown in step 31
*Move the jumpers at J3 and J4 to their alternate positions as described in steps 32 and 33
*Plug the guitar cable into the upper jack
*Connect a second guitar cable from the lower jack to the amp input
*If you still get hum, try powering the amp and CH01 from the same outlet strip. If the amp has a ground lift switch, try it.
Let us know what you find.
*Jumper across J1 and J2 as shown in step 31
*Move the jumpers at J3 and J4 to their alternate positions as described in steps 32 and 33
*Plug the guitar cable into the upper jack
*Connect a second guitar cable from the lower jack to the amp input
*If you still get hum, try powering the amp and CH01 from the same outlet strip. If the amp has a ground lift switch, try it.
Let us know what you find.
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by LamontGrady » Mon Jan 11, 2010 4:49 pm
It wasn't really an SCA problem. Unfortunately, I don't know how the issue got resolved. 
It was a really bad hum from the guitar amps (any of several tried) plugged into same outlet or not, w/ either the sca unit's D11 or my profire 2626's DI inputs or any other similar device. I changed a zillion things when troubleshooting and could not figure it out. No matter how I split the guitar signal, any connection from my guitar to the amp to 2/3 of the DIs I had handy had the same mad hum.
A few days went by, then I took apart the sca to change the jumpers as per your suggestions and put it back together and the hum was gone. Then I changed it so the only thing different from the earlier state was one ground lift jumper lifted. Then I could see if that was the solution. No hum on EITHER input. So I put it back the way it was.
No hum
Anyway, I hate it when an issue ends with no real information so the real answer to my question ends up being some other products.
A third solution I had handy through this that did NOT hum was an mxr bass di. It has an xlr di output that works swimmingly in all occassions I've tried. So I figured I'd still have to rely on that.
Today I got a Peterson Strobostomp and it has a nice DI that is only very slightly different from the mxr. They both sound very good and very similar to each other by my ear.
The Boss TU-2's tuner output into the SCA D11 into Profire 2626 mic preamps had quite a bit of hissy noise. NOT saying it's the D11 there are several other factors and long messy cable runs at this point.
Tim you should sell kits of some of the jensen reference designs, there's a huge need.
You could make them super flexible.
Put two transformers on a board w/ i/o. A pair of the 1:1 or a pair of the 1:12 or maybe one of each.
I built one of these recently and it's wonderful. I might try to somehow put it in the sca chassis.
http://www.muzique.com/lab/patent1.htm
http://www.jensen-transformers.com/datashts/dbe.pdf
http://www.jensentransformers.com/as/as013.pdf
It was a really bad hum from the guitar amps (any of several tried) plugged into same outlet or not, w/ either the sca unit's D11 or my profire 2626's DI inputs or any other similar device. I changed a zillion things when troubleshooting and could not figure it out. No matter how I split the guitar signal, any connection from my guitar to the amp to 2/3 of the DIs I had handy had the same mad hum.
A few days went by, then I took apart the sca to change the jumpers as per your suggestions and put it back together and the hum was gone. Then I changed it so the only thing different from the earlier state was one ground lift jumper lifted. Then I could see if that was the solution. No hum on EITHER input. So I put it back the way it was.
No hum
Anyway, I hate it when an issue ends with no real information so the real answer to my question ends up being some other products.
A third solution I had handy through this that did NOT hum was an mxr bass di. It has an xlr di output that works swimmingly in all occassions I've tried. So I figured I'd still have to rely on that.
Today I got a Peterson Strobostomp and it has a nice DI that is only very slightly different from the mxr. They both sound very good and very similar to each other by my ear.
The Boss TU-2's tuner output into the SCA D11 into Profire 2626 mic preamps had quite a bit of hissy noise. NOT saying it's the D11 there are several other factors and long messy cable runs at this point.
Tim you should sell kits of some of the jensen reference designs, there's a huge need.
You could make them super flexible.
Put two transformers on a board w/ i/o. A pair of the 1:1 or a pair of the 1:12 or maybe one of each.
I built one of these recently and it's wonderful. I might try to somehow put it in the sca chassis.
http://www.muzique.com/lab/patent1.htm
http://www.jensen-transformers.com/datashts/dbe.pdf
http://www.jensentransformers.com/as/as013.pdf
- LamontGrady
- Posts: 11
- Joined: Thu Apr 09, 2009 9:38 am
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