it was a Boss Phase 90...
That would be MXR Phase 90. I bought my first one in 1974. It finally died on me (I had made a simple mod for an external power suply which worked great but in the end something took the pedal out in the early '90s. I eventually bought a replacement a couple years ago. They sound great with bass.
I thought the Phase 90 worked fine for bass BTW.
It did and still does for me.
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When I was gigging I rarely used any pedals except in my Top 40/Diss-Cho-Daze® in the mid to late '70s (I had the Phase 90, an MXR Distortion+, and Morley Wah/Volume pedal.
Now, in my non-gigging days I have a Strymon Flint, the Phase 90, Sansamp GT2, Cave Passive Pedals B-Drive Mk II, and a tc electroninc MOJO
MOJO. I always use the Flint and swap out the other pedals as needed/desired.
I have had other pedals over the years; a Heathkit wah pedal that I built, EHX Micro-POG, tc electronics Stereo Chorus-Flanger (the big, square one that ran on AC power only), and a Bass Big Muff Pi.
In my Rare Blend days I use the tc SCF, a Voodoo Lab Tremolo, VT Bass pedal, and Ernie Ball VP Jr.
When I had my 1966 7ender BandMaster head I used the tremolo sometimes. Same with the 1974 Traynor YSR1, and the 1962 7ender Concert (4-10) combo amp.
Oh yeah, I also had two Aphex 661 Expressors, an orange-box Aphex Punch Factory, and a Universal Audio LA-610 Mk II.
Other that that, I don't use pedals.