Dear Electro-Harmonix, fellow members!

This one is going to be a long essay so I’d rather start with summarizing my topic as a single question, hope You can decide early on wether You are interested or not:

“Why is my SB+ able to unite the signals of two instruments in order to send them both to one amp but doesn’t manage to mix 2 signals of the same instrument previously split by another SB+?”

---

INTRODUCTION:

I hereby declare, the way I was willing to use the product was not included in the official product description therefore I can not expect the pedal to work just like that and blame it on EXH in any way.

My plan was:
– connect a bass (Rockbass Corvette basic, 2006, two active single coil J-pickups, gain knob at full, kills almost any hum) with 1st SB+ (input), set to A+B
– preserve a clean channel with Output A
– run an overdrive/distortion and optionally a compressor on Output B signal
– instead of using 2 amps/combos, plug in both A and B channels into a 2nd SB+, in Output A and Output B
– passively mix the signals with its A+B feature and run the united signal from its Input with only one cable into one combo (Carlsbro Bass Baby BC2110, only one input, one channel)
– both channels could be boosted or EQ-ed independently so I don’t have to be afraid of getting too much distorted sound if I only want to boost the clean
(please note: currently both my instrument-and patch cables are mono)

---

RESULTS:

Results were the following:
– in A/B mode on 2nd SB+, I could switch between both channels without an issue, no hum, no noise, both preserved their tone, dynamics, volume and character which is cool because I can add any subtle extras to the clean channel (eq or compressor) inbetween without forcing it onto the B effects loop as well, this is another reason for arranging my channels like that, so far it works like a wonder

– in A+B however, only the clean signal is present, the B channel effects cannot be heard but instead, there is a a certain loud sound like holding down a fully clean synth key endlessly (with some weak background distorted noise as well, doesn’t resemble my original overdrive pedal tone and does not follow my bass playing), it is ranging from mid tones to piercing whistling sounds, (depending on me messing with the gain knob on my bass, lower setting of the knob makes louder and higher noise) or the drive/voice knobs of my overdrive pedal on channel B, higher setting results in higher-louder
-each pedal has its own “synth-noise”, they differ both in volume and tone
-it does only go away if I either turn them off, set the knobs on even lower level to the point where using my pedals becomes pointless anyways, still only the clean channel is present, even with matching volume set on the fx pedals.

---

TROUBLESHOOTING:

I did some testing:
-power the effects both with batteries and power cables, without positive results
-switch the jacks in A and B channels on the second Switchblade+, still the clean sound dominates completely, the noise is present on (the previously) channel B as well
-since overdrives and compressors are the most vulgar source of noise in a pedal rig, I replaced one of them with an octave up (Hotone Harmony), laughed my ass off: clean sound (A) present, fx-ed sound ( kept its noise like before, it is now a bit more silent however the noise now has an octave up!! (yet it still does not follow my bass playing)
-cross tested both Switchblades the same ways:
1.) one instrument into one SB+, channel A out to one practice combo, clean, channel B into another combo (with pedals in the signal chain), works well, no synth-noise, not even any hum with active pickups, and Royalbloody AF!
2.) with two instruments into one SB+ into one combo (using only clean signals so far), both A+B and A/B feature: A channel with my bass, B with a passive epiphone (double humbacker) guitar, both features were working fine without the issues mentioned above, so you can play two instruments the same time and they both can be heard fairly well with one combo (quite useful for later)

This second cross-test especially made me wonder:
“Why is my SB+ able to unite the signals of two instruments in order to send them both to one amp but doesn’t manage to mix 2 signals of the same instrument previously split by another SB+?”

---

QUESTIONS:

Browsed some similar topics regarding the product, my brain still doesn’t completely process the hints and explanation of more experienced people, my main questions are the following:

-is it because of the passive circuits of the Switchblades?
-should I use stereo cables at some point in the signal path?
-does the combo has to have stereo input or should I lend a pro amplifier with two inputs?
-does it have something to do with the pedals being 9V AC powered, is this standard still compatible with all Electro-Harmonics products?
-shall I insert a preamp or a DI box or a buffer or such in one of the signals before the 2nd SB+ so the switch will react like the signals would come from two different instruments?
-should it be working, is it simply caused by hardware defect? (doubt it accoring to other test results)

It would be sweet if it worked tho…

---

I am open for harsh criticism as long I learn something useful along the way and also hope nobody died of boredom and my tests spawned some new ideas.
Take care!

Your loyal EHX fan
Dave

ps.:

Still keep my new Bass Soul Food in firing position and it rather seems to be the winner until next gig.

Simply love the image design on the 9V battery which came with the Switchblade+, made my day!