Im Hooked - an SF-2 tale

[echo008]

OK not a tale its just another SF2 thread ....
I just recieved an SF2 as part of a trade deal!
its the second one I have been very fortunate to have owned ...
I would just like to ask since it has been awhile ... I have a GK700RBII and I am using the SF2 in the effects loop.
MONO
Send > Channel A In on SF2
Return > Channel B Out
OK thats easy enough but I could not get both channels working that way so I connected another patch cord from the
Out of Ch. A to the In of Ch.B
and now I have both sides working.
 
Yes I have read the past threads, But I wanted to see how people were currently hooking up there SF2 and what they liked about the way they are doing it.
 - Tom

[bob]

Congratulations, Tom, I can imagine how much you must have missed having one.
 
Puzzling... your connections seem to be correct, I even dug out my manual to check (since I'm currently running in stereo mode).
 
From what you describe, it almost sounds as if your Mono/Stereo switch isn't functioning properly. Just to be clear,
- you added a patch cord from A Out to B In
- you left the switch in the MONO setting
- you have nothing plugged into the front panel instrument jack, but are just sending the input from your effects loop into A In.
 
With the patch cord in place as you describe, you should now be running the filters in series... but only if you had the switch set to STEREO (unless I'm more confused than I think).
 
One way to help confirm this would be to describe what each of the four Gain knobs actually does. If you are really still in MONO mode, then I think if you turn the leftmost knob all the way down, you should get no output (i.e., this would be sort of a master volume, in three way mixer mode).
 
I would suggest removing the patch cord, and switching the MONO/STEREO setting a few times, just in case it's a little gunky or something, then see if MONO behaves as you expected.
 
Running the two filters in series (as I suspect they are now for you) can be interesting, but it's trickier to use because of the interactions between the various gain controls. Three way mixer mode is a lot easier to use, and generally recommended unless you have something very specific in mind.
-Bob

[echo008]

Hi Bob,  
Thanks for the info.
Yes I added the patch cord from A out to B in.
The switch is in Mono.
And nothing plugged in to the front instrument jack.
 
You are right about the left most Gain control acting as a master volume when I turn it down or up it controls the overall level.
 
I will remove the patch cord and give it a try again, maybe it is something as simple as switching it up and down a couple of times. Ill report back as I am about to go out.
 
What is Series mode most used for?
 
again thanks!
 - Tom

[echo008]

OK I just checked...
Removing the patch cord...
Channel B will not work in Mono mode.
 
Again Im running this through my effects loop  
Send = Ch A In
Return = Ch. B Out
 - Tom

[David Houck]

Series might be useful if you were wanting to attenuate both the high end and the low end of the frequency range; i.e. running the high pass after the low pass.  You could probably get some interesting curves running the band pass after the low pass, again attenuating both the high end and low end.  And thinking about it some more, running the low pass and low pass in series and applying liberal amounts of the damping control could produce interesting results.
 
Hopefully, Bob's suggestion of moving the switch back and forth several times will fix the problem.

[David Houck]

In mono parallel mode you essentially have three channels.  The input gain on the far left is the master gain control.  The Channel A filter gain is the gain control for the first filter.  The direct gain near the center of the panel is the gain control for the unfiltered channel.  The Channel B filter gain is the gain control for the second filter.
 
So when you are saying that Channel B is not working, then you are saying that turning the Channel B filter gain doesn't do anything?
 
What about the direct gain for the unfiltered channel?  Does turning it do anything?

[David Houck]

A couple other things just occurred to me.  Does changing the filter type switch on Channel B do anything?  I.E. is it not working in all three modes?
 
With your power amp off or very low, try turning the Channel B filter gain back and forth thirty or forty times.  And just so you can say you tried everything, do the same thing for all the knobs and switches.

[echo008]

Alot of good ideas there Bob and Dave.
well I have moved the mon/stereo switch back and forth alot! and I still have only channel A working.  
 
Ch. B filter gain does not do anything
Nor does the Ch B. Direct Gain  
I have tried to hear a difference switching between Hi/Band/Lo and there is no change in tone again on channel B
 
any other ideas or should I just run this in Series until I can get it looked at> or maybe Ill open it up and have a peek if I know what to look for?
Thanks guys your help is appreciated
 - Tom

[David Houck]

I wouldn't know what to tell you to look for, but yes, open it up and at least look for anything obviously wrong like a loose wire or burned cap.  If you know a really good tech (i.e. someone who knows not to use cheap replacement parts), I would go ahead and take it in and have it looked at.
 
Also, since you just received this in a trade, have you called the previous owner and asked if there were any problems?  Was the previous owner running it stereo, mono parallel, or mono series?
 
Oh and just to get more info, try running it in stereo mode and see what happens.

[echo008]

opened it up and it looks very clean. no blown anything in there ....
 
trying to run it in stereo mode
very low output from ch.B  
 
Ill run it in series mode for now I do not know what could be wrong with it, but I think maybe I have someone who can take a look at it.
 
any other advice is welcome!
thanks
 - Tom
 
(Message edited by echo008 on December 09, 2006)

[bob]

Sounds like you have a problem, but I guess you already knew that :-)
 
Stereo mode was going to be my next suggestion. Switch in Stereo, use one channel at a time in the effects loop (e.g. just use A In/A Out), and see how they behave with identical settings.
 
Sounds like you have probably done that, and that something funky is going on with channel B, right?
 
The weird thing is that, to run in series mode, the switch should be in Stereo. I'm not quite clear on what you tried, but with the patch cord in place and the switch in Stereo, how does it work?
 
I might test this configuration by having both of the Direct Gain knobs at full, both Filter Gain knobs at zero, both filters set identically, and then take turns using one Filter Gain or the other (but one always at zero). I'm pretty tired tonight, but I think this should produce identical sound regardless of which channel you use.

[echo008]

Hmmm
OK just to summarize this
so when I use Ch A in/out only I get the Input gain working and nothing else no other knobs on Ch A do anything nor the Hi/Band/Lo
 
Plugging into Ch. B in/out works normally everything works as it should
 
So ... when I hook it up in three way Channel Mixer mode as is usual for my situation I only get Ch A working.
 
I can run a Patch cord from ch. A out to ch. B in and get it running in Series mode. everything works that way.
 
Bob when I run it in Stereo in series mode, there is  slight lift in volume and even the tone changes a bit. I suspect its just re-reading the setting on the filters and this is not a problem?
 
Dave can we maybe move this to troubleshooting now? at your discretion of course.
 Thanks guys
 
any more advice is welcome
 - Tom
 
(Message edited by echo008 on December 10, 2006)

[David Houck]

Ok; I'll just move the whole thread over.

[bob]

so when I use Ch A in/out only I get the Input gain working and nothing else no other knobs on Ch A do anything nor the Hi/Band/Lo.
 
Plugging into Ch. B in/out works normally everything works as it should
 
If the switch was set to Stereo, then this suggests you have a problem with Ch A.
 
However, if Mono then I believe this would be normal - not how you are supposed to use the input/outputs in this case, but the behavior would not be surprising.
 
I assume you did this test in Stereo, but just want to be clear.
 
So ... when I hook it up in three way Channel Mixer mode as is usual for my situation I only get Ch A working.  
 
I can run a Patch cord from ch. A out to ch. B in and get it running in Series mode. everything works that way.
 
Assuming the switch was in Mono here, both of these sound wrong and puzzling to me. The first comment seems to conflict with your earlier test, in that it now sounds like you have a problem with Ch B, rather than A. And to patch it into Series mode, the switch is supposed to be in Stereo (though I guess I don't know for sure it wouldn't work in Mono).
 
when I run it in Stereo in series mode, there is slight lift in volume and even the tone changes a bit
 
At least this part sounds normal. You can actually get more total gain, by applying one filter after the other, depending on what settings you use, and the tone will also likely change.
 
One of the best discussions I've seen about using Series mode is here.
 
any more advice is welcome
 
I think it's time to seek professional help :-) If I am understanding you correctly, it seems like there's some problem in how the signal gets routed (or not) from Ch A to B, which might be due to a problem with the switch, or perhaps some magic that happens internally that I don't really understand.
 
One other test you might try would be to take your preamp out of the picture. Plug the instrument into the front panel jack, run Ch B Out directly to your amp.
 
With the switch set to Mono, you should have a 3 channel mixer.
 
With the switch in Stereo, you could do either of two things. Use either Ch A or B Out (just one at a time) to your amp, and they should behave identically. Or, patch Ch A Out to Ch B In to run in Series mode, using Ch B Out to your amp.
 
Maybe this will somehow help to clarify where the problem is, but I certainly won't be able to tell you how to fix it. I'm pretty much out of ideas here.

[echo008]

Thanks Dave
 
Hi Bob
 If the switch was set to Stereo, then this suggests you have a problem with Ch A.
However, if Mono then I believe this would be normal
 
I had it set to mono....
 
Assuming the switch was in Mono here, both of these sound wrong and puzzling to me. The first comment seems to conflict with your earlier test, in that it now sounds like you have a problem with Ch B, rather than A. And to patch it into Series mode, the switch is supposed to be in Stereo (though I guess I don't know for sure it wouldn't work in Mono).
 
This was how I set it to begin with this was the only way I could get both channels working and I had it set Mono.
 
I am going to read through the thread you posted and Ill try your last suggestion as well
I sincerely appeciate you trying to help!
 - Tom