My EHX Black Finger basically, which is a tube driven optical compressor that runs its tubes at proper high 300V plate voltage.
It's an always on pedal placed towards the end of my signal chain in both my bass and guitar setup, dialed in to a quite minimal compression, set with such a high threshold that the compression basically never kicks in, but with a high input gain setting to run the tubes just on the verge of breakup when I dig in the hardest, adding a beautiful touch of nice tube warmth and subtle tube compression, just making everything that is send through it sound great and rounding off any harshness from my signal ever so slightly, without in any way dulling it or effecting my playing dynamics, as this pedal is basically an optical compressor circuit placed between the input and output stage of a tube preamp.
Actually... Just about any pedal in my bass setup can be said to be used for just 1 sound, as they are all dialed in to a fixed setting that I use all the time (or that is every time the given pedal is active), that is except for my Zoom G1Xon, which I, beside the always on subtle plate reverb patch, use for 4 additional reverb patches, the Zoom MS-70CDR that I use with an always on equalizer patch, that has a lush Church Reverb fixed at the end it, which can be kicked on or off as desired (still you could argue that all this, if not exactly being 1 sound, then at least being fixed settings as well), and then my NUX Tape Core Deluxe, which I use the build in tap tempo function of to change the delay time, though I suppose it's still the exact same delay tone, and even the same amount of repeats, really just being the delay time changing.
My entire "amp-less" pedal setup looking like this (except I have swapped out the Valeton Aquaflow Vintage Chorus with a TC Electronic Shaker Mini, loaded with a customized chorus toneprint) :
(the white goo is hot glue used to fix the settings of some of the pedals)
My entire signal chain explained in written form :
(*pedals listed in
[ red/bold/underline text ] are "always on" effects*
)
4 string 28,6" scale Ibanez GSRM20 neck + GSRM20B body Mikro Bass (equipped with an EMG Geezer Butler P pickup, wired directly to the output jack socket, and strung with gauge .090 - .072 - .054 - .040 D'Addario XL nickle plated roundwound hex steel core strings, tuned in F# standard tuning, 2 half steps above regular 4 string bass E standard tuning) ->>
TC Electronic SpectraComp (always on 3 band parallel compression, adding extra punch, snap and bite, but without really affecting my playing dynamics) ->> TC Electronic Sub'N'Up Mini (always on digital polyphonic octaver, used as an 1 octave up effect mixed with clean bass signal, giving an effect similar to that of an 8 string "octave" bass, with pairs of respectively bass and octave strings) ->> Boss LS-2 [A+B Mix <-> Bypass] (always on parallel effect loops mixer/switch) ={ [Loop A Send] ->> Joyo Orange Juice (always on low gain overdrive, really primarily used to enhance harmonic content, [Tone] set at about 11 o'clock, [Voice] set to boost a wide curve around a 800Hz center frequency about +3dB pre gain stage, always mixed with clean {bass+octave up} signal from parallel effects [Loop B]) ->> [Loop A Return] ->||<- [Loop B Send] ->> (empty effects loop for clean {bass+octave up} signal blend with Orange Juice in effects [Loop A]) ->> [Loop B Return] ([Loop A] + [Loop B] mixed at an about 50/50 ratio)
}=>> Boss LS-2 [A+B Mix <-> Bypass] (parallel effect loops mixer/switch) ={ [Loop A Send] ->> Behringer SF300 Super Fuzz (Boss FZ-2/Univox Super Fuzz clone, octave fuzz, always mixed with clean {bass+octave up} signal from parallel effects [Loop B]) ->> Mosky Black Rat (RAT clone, in Turbo RAT, LED diode clipping, mode, quite raunchy, fuzz-esque, high gain distortion, always used mixed with the Metal Zone distortion in parallel effects [Loop B]) ->> Behringer VP1 Vintage Phaser (EHX Small Stone clone, used in the high feedback and deep sweep mode, always used boosted by the Hotone Trem in front of it, and almost always used mixed with flanger in parallel effects [Loop B]) ->> Hotone Trem (Tremolo with rate and depth at 0, always used to boost the Behringer phaser placed behind it and make it a bit brighter, since it's a few dB above unity gain when engaged and got a tone control) ->> [Loop A Return] ->||<- [Loop B Send] ->> Joyo Orange Juice (lower gain overdrive with a somewhat grindy character, always used either stacked into the Metal Zone in front of it, and then mixed with the Rat distortion in parallel effects [Loop A], or as a dirty slight "clean" boost mixed with clean {bass+octave up} signal from parallel effects [Loop A]) ->> Boss MT-2 Metal Zone (distortion, used with a relatively low gain setting, always used with the Orange Juice behind it stacked into it, and always used mixed with the Rat distortion in parallel effects [Loop A]) ->> Monarch MFL-22 (flanger, most often used mixed with phaser in parallel effects [Loop A]) ->> [Loop B Return] ([Loop A] + [Loop B] mixed at an about 55/45 ratio)
}=>> Behringer UT100 Ultra Tremolo (almost always used staked into the Shaker chorus in front of it) ->> TC Electronic Shaker Mini (vibrato functioning as a chorus, loaded with a Boss CE-1/EHX Small Stone fusion -esque Toneprint, almost always used with the Behringer tremolo staked into it) ->> Artec SE-EQ8 (always on 8 band graphic equalizer, settings as follows: [Freq=100Hz LoShlv[/I] Boost=+1dB ; Freq=170Hz Q=wide Boost=+1dB ; Freq=280Hz Q=narrow Boost=+3dB ; Freq=500Hz Q=narrow Boost=+2dB ; Freq=800Hz Q=narrow Boost=+1dB ; Freq=1.4kHzHz Q=narrow Boost=+2dB ; Freq=2.3kHz Q=wide Boost=+3dB ; Freq=5kHz HiShlv +/- 0dB]) ->> Zoom G1Xon (Always on subtle plate reverb, and additionally used for 4 other reverb patches, which respectively are as follows: Plate Reverb->HD Hall Reverb->Tape Delay, more prominent reverb :-: '63 Spring Reverb->Analog Delay (set to a slapback type delay), lush splashy spring reverb :-: 63 Spring Reverb ->Tape Delay (set to a slapback type delay), brighter sounding lush splashy spring reverb :-: Plate Reverb->HD Hall Reverb->Tape Delay, extremely thick lush reverb, used as a reverb pad effect with volume swells) ->> NUX Tape Core Deluxe (Roland Space Echo tape delay emulation) ->> Zoom MS-70CDR (Always on "160 Comp" (emulating a DBX 160A compressor), set to a quite subtle compression -> always on 2 x 2 band parametric EQ : [Freq=63Hz Q=4 Boost=+1dB ; [I]Freq=250Hz Q=4 Boost=+1dB ; Freq=400Hz Q=4 Boost=+1dB ; Freq=1kHz Q=4 Boost=+1dB] -> always on faux, EQ based, cab sim, consisting of a 2 band parametric EQ set as follows: [Freq=12kHz Q=1 Cut=-18dB ; [I]Freq=20kHz Q=0.5 Cut=-20dB], and additionally used for a lush Church reverb that can be switched on/off, which is often used combined with the other reverb effects of the G1Xon[/I])
->> Joyo American Sound (always on clean preamp (gain set to ever so slightly break up when digging in the hardest), a Tech 21 Blonde clone, analog emulation of a Fender type amp, with a wide curve around the center frequency of 400Hz boosted about +3dB, and an about +3dB pre gain stage boost to a wide curve around the center frequency of 800Hz)
->> EHX Black Finger (always on tube driven optical compressor, used primarily as a tube preamp stage) ->> ART Tube MP Project Series (tube preamp, with HPF fixed @ 40Hz)
// ->> Band rehearsal/jamming/gigging // ->> Home practice // ->> Home recordings // :
// ->> Band rehearsal/jamming/gigging ->> [Effects Return] (poweramp input) of Peavey Solo Special 112 (160W, solid state guitar combo, with the build in 4 Ohm 12" speaker unit disconnected and instead hooked up to a The Box PA 502 PA speaker) ->> The Box PA 502 (full range PA speaker with 1x 15" woofer/mids driver + 1.7" high frequency tweeter horn) // ->> Home practice ->> Behringer Eurorack UB1202 (mixer) ->> Sennheiser HD 380 Pro (headphones) // ->> Home recordings ->> M-Audio Fast Track (sound interface) ->> Reaper (DAW) //
I guess though this really only counts as of currently and as far as my bass setup in this context goes, at other times in other contexts I might very well use some of these pedals differently, and as such not keeping them only for that 1 sound.