The BP1 and BP1 Compact are superb bass guitar preamplifiers: they deliver slightly different audio performances but both are of the highest quality and suitable for live and/or studio use. Like all Caveman Audio products, they follow Steen Skrydstrup’s principle that the signal leaving a guitar should reach the input of its amplifier without any additional noise being added, and I discussed this philosophy in detail in my AP1 review in SOS September 2022.
Other than the Compact’s steel chassis being 41 percent narrower than that of the BP1, there aren’t massive differences in appearance between the two. Both front panels feature a Mute footswitch and a pair of detented, chickenhead knobs for Gain and Level. Although both pedals possess a serial effects loop, only the BP1 has a footswitch to activate it.
On both units’ rear panels, you’ll find a high‑impedance instrument input (labelled Cable I/P on the BP1, and merely Input on the Compact); a transformer‑balanced XLR DI out; and quarter‑inch jack sockets for the effects loop send and return, and for the amp and tuner outputs. The BP1 possesses additional rear‑panel space for the optional (€80 extra) transformer‑balanced XLR Radio (wireless system) input; a 9V DC output to power an attached tuner; indicator lights that display the health of attached cables; a ground‑lift switch; and an IEC mains connector for the onboard switch‑mode power supply. Power to the BP1 Compact comes courtesy of an external, owner‑supplied 12V DC centre‑negative PSU. There is one invisible internal difference between the two units in that the tuner output of the BP1 is transformer‑balanced, whereas that of the Compact is not.
Unsurprisingly, the BP1’s interior, despite its greater volume, looks rather more congested than that of the BP1 Compact. After all, its input and outputs (save those of its loop and amp out) are transformer balanced, it carries an additional footswitch, it has to leave room for an optional Radio input, and it runs on an internal power supply! However, as you’d expect from Caveman Audio, the circuit boards, all‑discrete componentry, wiring and construction in both products are all of a very high quality indeed.
Electronics‑wise, the BP1 features the 5MΩ input impedance buffer found in the company’s Custom Shop systems, together with the 1073‑inspired preamplifier and output circuitry of the company’s rackmount flagship BASC1 Bass System. Although the Compact’s input buffer is a slightly redesigned version of the BP1’s, it retains the 5MΩ input impedance and components. The Compact also features the 1073‑inspired preamp, though its output stage is an original Skydstrup design. The circuit alterations in the Compact have resulted in a very slight difference in sonic delivery between it and the BP1.
Both units’ latching footswitches feature ‘silent switching’, which eliminates switching transients when activating the Mute function or, on the BP1, the effects loop (which is always active on the Compact). Both pedals’ effects loops sit after their respective input buffers, with both the loop send and loop return presenting output and input impedances optimised to interface with effects pedals. With this arrangement, your bass guitar’s pickups are correctly loaded by the buffer, you get the best out of your pedals, and the result is a considerable improvement over an unbuffered, pre‑input pedal chain. The amp out and tuner out in both pedals work perfectly as advertised, and also offer additional options in studio settings.
Powered up and connected, via their DI outputs, to the microphone inputs of my RME audio interface, both the BP1 and the Compact were essentially silent in normal operation at my normal 85‑95 dBA monitoring level, illustrating perfectly the efficacy of Steen Skrydstrup’s approach to maintaining signal integrity.
Playing bass through the BP1 for the first time was a revelation, the pedal delivering a crisp, clear definition to every note that I played, most notably in the bass and low midrange, without ever sounding harsh. Turning up the gain on the BP‑1 brought an increasing level of saturation and a sense of weight that became quite addictive. The Compact, despite its electronic differences, delivered the same clear definition and gain‑driven saturation in what I felt was a slightly warmer presentation which, to me, was very attractive in its own right.
Playing bass through the BP1 for the first time was a revelation.
The Caveman Audio BP1 and BP1 Compact are both superb bass guitar preamplifiers that deliver sonic performances which completely justify their price. Returning either of them, but especially the BP1, is going to be a wrench. If you’re in the market for a pedal‑format bass preamplifier of the very highest quality, then I highly recommend that you check them out.