The sushiboxfx Slampegg Bee Pre is an analog tube preamp pedal that also works as an overdrive and equalizer. according to RockBoard's PedalPedia, it is based on the preamp of the legendary Ampeg B-15N, the bass amplifier known for its gritty warmth and luscious low-end, and the pedal is built to deliver that character without the amp1. It sits in the wider field of preamp pedals and overdrive pedals, and bass players looking at this territory may also want to see the bass pedals page.
The B-15N circuit and its tube
The Slampegg Bee Pre takes its circuit from the Ampeg B-15N preamp. To fit that circuit into a pedal, sushiboxfx used a 12AX7 tube, the same tube found in the modern B-15, rather than the bulky 6SL7 of the older units. RockBoard's PedalPedia says this swap allows a little more drive while keeping the same main circuit, so the pedal is not missing the gritty warmth and luscious low-end that bassists have come to expect from the B-151.
Tonestack and the Ultra-Lo and Ultra-Hi switches
The pedal carries a standard Baxandall/James two-band tonestack, the classic two-knob bass and treble arrangement used in the original amplifier1. On top of that, it has two switches that shape the extremes of the frequency range:
| Control | What it does |
|---|---|
| Baxandall/James tonestack | Two-band bass and treble EQ1 |
| Ultra-Lo switch | High-cut: a strong rolloff of high content to emphasize the fat lows and low-mids1 |
| Ultra-Hi switch | Hi-boost1 |
The Ultra-Lo switch is the one that leans hardest into the B-15 character, pulling the top end down so the lows and low-mids carry the sound, while Ultra-Hi pushes the top end up when a brighter voice is needed1.
Power
The Slampegg Bee Pre runs on 9V DC, center negative, and draws 400mA1. That current draw is well above what most compact pedals need, so it is worth checking what your power supply can deliver on a single output before adding it to a board.
With a 400mA draw at 9V DC1, the Slampegg Bee Pre needs a supply output that can deliver that current. A weak or shared daisy-chain output may not be enough.
Where sushiboxfx fits
sushiboxfx builds a range of pedals beyond this preamp, including the sushiboxfx Dreamcatcher and the sushiboxfx Elementary1.
Videos
Monteforte Valerio
Kevin F
Questions
What tube does the Slampegg Bee Pre use?
The Slampegg Bee Pre uses a 12AX7 tube, the same tube found in the modern Ampeg B-15. The maker chose it over the bulkier 6SL7 used in older B-15 units to keep the pedal compact, while keeping the same main circuit and allowing a little more drive.
What does the Ultra-Lo switch do?
Ultra-Lo is a high-cut switch. It rolls off high content strongly to emphasize the fat lows and low-mids, which is the classic B-15 bass character. Its counterpart, Ultra-Hi, is a hi-boost switch.
How much current does the Slampegg Bee Pre draw?
The Slampegg Bee Pre draws 400mA at 9V DC with a center negative supply, according to the maker's product information. That is a high draw for a pedal, so a dedicated supply output rather than a shared daisy chain is worth considering.
Is the Slampegg Bee Pre analog?
Yes. The maker lists the circuit type as analog, with a real 12AX7 tube in the signal path.
Sources (1)
- Slampegg Bee Pre by sushiboxfx, RockBoard PedalPedia, 2026
