EMG systems normally use lower-value pots, while East UK passive tone circuits are generally designed around passive pickups.
East UK uses the same capacitor values for the tone roll-off, so the maximum tone effect is similar, but the rotation versus effect will not feel the same.
With EMGs, the tone change may occur more toward the darker end of the control rotation.
A small amount of mechanical movement in stacked pots is normal, especially on push-pull versions.
The movement is mainly caused by the compact switch mechanism. Replacing the pot with a new one of the same type will usually feel similar.
This does not normally affect the electrical performance of the preamp.
To compare Active and Passive levels, first set the internal pickup gain presets fully backed off.
On a standard pre-shape unit, Active mode may still have a slight lift in the lows and highs. On a Flat Response unit, the levels should be very similar.
The standard Pre-Shape version has a gentle built-in lift in the low and high frequencies. This gives a slightly fuller and brighter starting point.
The Flat Response version is intended to retain the original pickup response when the EQ controls are set neutrally, apart from the buffering effect of the preamp.
Both versions can produce a wide range of sounds. The difference is the starting point.
Even with a flat response circuit, the pickups are buffered by the preamp.
Buffering reduces the effect of instrument cable capacitance, which can otherwise roll off some high frequency content from passive pickups.
For this reason, Flat Response can still sound slightly more present than a purely passive cable-loaded signal.
East UK preamps are handmade in small quantities in the UK rather than manufactured in very large batches overseas.
The price reflects UK labour and overheads, imported specialist components, dealer margins where applicable, and the decision not to reduce the signal path quality simply to cut cost.
The design priority is performance and reliability rather than lowest possible manufacturing cost.
An active preamp can generate much higher signal levels than a passive bass, especially with EQ boost added.
Using full volume with a lot of boost can reduce headroom and may overload the preamp output, pedals, DI input or amplifier input.
Set the amp level from Passive mode first, then switch to Active, set the EQ, and adjust the bass volume to suit. Treat the preamp volume more like a mixer channel fader than a passive bass volume control.
First check the spacing between the upper and lower knobs. The upper knob can be loosened with a 2mm hex driver, raised slightly and retightened. The lower knob can also be lowered slightly if needed.
Make sure the upper knob is level when tightened, as it can rock slightly.
If the clearance changes as the knob turns, the inner shaft may be slightly bent from an impact.
A slightly bent inner shaft can sometimes be straightened, but it must be done with great care.
Remove the knobs and identify where the inner shaft is touching the outer shaft. Using larger pliers, gently apply firm pressure in the opposite direction.
Do not make sharp movements. The shaft can shear if forced. If unsure, return the unit for service.
On many East UK preamps, the treble control includes a Pull for Bright function.
This adds extra high-frequency lift or presence without needing to overuse the main treble control.
It is especially useful when a little extra top-end detail is needed, but the exact result depends on the bass, pickups, strings and amplifier.
