Old Blood Noise BL-37 Reverb

The Old Blood Noise Endeavors BL-37 Reverb is a reverb pedal in the company's BL line, a series built around a variable Clock control that warps the timing of the whole circuit. Old Blood Noise describes the BL-37 as featuring modulation at two points in the reverb trail, which gives it what the maker calls "a wandering, lush reverb unlike any of our other reverbs," delivered with a deliberately simplified control set¹.

The pedal's defining feature is its diagonal Clock fader, which moves the sound from a quick, tile-bathroom echo out to a dark, lo-fi-stretched reverb. MusicRadar reported that set long, the pedal produces what the maker calls "a dark, lo-fi stretched reverb, unlike any space in existence"². The BL-37 launched in July 2023 as the third pedal in the BL line, after the BL-44 Reverse and the BL-82 Chorus/Delay³.

What it does to your sound

The BL-37 is a modulated reverb: modulation is applied at two points in the reverb trail rather than one, which is what gives the trail its wandering, lush movement. The Clock fader then stretches the whole system's timing, from a short, snappy room-like response at one end to long, strange, lo-fi tails at the other¹.

Delicious Audio's write-up called the Clock fader "a deviant 'size' knob" that determines both the length of the reverb's tails and their character, with the lo-fi quality increasing at higher Clock settings³. MusicRadar's Jonathan Horsley covered the launch and noted the pedal's spaced-out character, reporting the maker's description of the long setting as a reverb "unlike any space in existence"².

The controls: Clock, Feedback, Mix and Volume

The control set is intentionally simple: one diagonal fader and three knobs. Here is what each one does, as described by the maker and the press that covered it.

The Mix control deserves a note for ambient players: because it sweeps the full range from 100% dry to 100% wet, the BL-37 can run as a fully wet reverb, with none of your dry signal in the output³. Feedback is the control that shapes how far the trail goes, and it also deepens the modulation character as you push it, so decay length and the wandering quality of the trail move together¹.

Power and bypass

The BL-37 runs on a 9V DC center negative power supply through a 2.1mm jack, drawing 110mA. The supply is not included with the pedal⁴. That current draw is shared across the BL series: the BL-44 Reverse and BL-82 Chorus carry the same 9V DC, 110mA requirement⁵⁶.

Bypass is true bypass, handled by a soft-touch footswitch designed for minimal switch noise⁴. Both Delicious Audio and MusicRadar confirmed the true bypass design in their coverage of the launch³².

The third pedal in the BL series

The BL-37 arrived as the third pedal in the BL line, after the BL-44 Reverse and the BL-82 Chorus/Delay³. The series concept is the variable Clock control: each pedal pairs the diagonal fader with a small knob set, and the Clock control behaves differently in each circuit. In the BL-44 Reverse it shapes a reverse delay, while in the BL-82 Chorus it works on chorus and delay timing, with the Feedback knob there setting chorus intensity or delay repeats at high Clock settings⁷.

Gearnews described the BL-37 as the latest in the series that also includes the BL-44 Variable Clock Reverse and the BL-82 Chorus⁸. The BL-37's artwork is by Brandy M Patterson, who handled the pedal's art for the maker¹.

Old Blood Noise Endeavors has since marked the BL Series as a 2022 to 2026 run, with the BL-37 and the BL-44 Reverse both listed as Sold Out on the maker's product pages⁴⁸⁹.

Price

The maker's list price for the BL-37 was $179.00⁴. At the time of the launch, Gearnews reported an MSRP of USD 179 / EUR 209, and a retail price of $194.00 / £175.00 / 199.00€ at Thomann⁸.

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