MUSICMANBASS.GLOBAL
MUSICMANBASS.GLOBAL 

Formerly MUSICMANBASS.ORG

 

SR4 PUPs AND PREAMPS 

Pre-EB & EB (Part 2)



EB 3EQ PREAMPS (1987 - Current)

Beginning of 1987-Circa 1990 (3 band).

Pic of a 1988 3EQ Preamp.

 As opposed to the 2EQ with its"treble" & "bass" controls, the 3EQ has an extra "mid" control in addition to the volume control. A "TL062" chip is used whereas the 2EQ uses a "LM4250CN" chip.

 

The 3EQ was introduced as an option to the 2EQ preamp at the beginning of 1987. However, it was standard for the new SR5 introduced latter in 1987 and the dual pickup SR4HH and SR4HS Basses introduced in 2005 (no optional 2EQ for the SR5 and dual pickup Basses).

Note that, although the two outer pots have lugs for hook-up wiring, the two inner pots are soldered directly to the circuit board with pins attached to the pots. Note also that the preamps are dated with a round sticker on the rear of a control pot from 1988 onwards. Prior to this some were dated with a black marker pen on the rear of the control plate. 

Reproduced with permission. Schematic wiring for 3EQ
preamps from circa 1987 up to circa 1990.

Circa 1990-October 2006 (3 band).

Pic of a 1994 3EQ preamp.

Just like the 2EQ, the 3EQ circuit board also changed from rectangular to a crescent moon shape. Note that the two outer lug pots on the previous 3EQ version (above) are now soldered directly to the board. The circuit still remains the same as do pot resistance values.

Reproduced with permission. Schematic wiring for 3EQ preamps
from circa 1990 to Oct 2006.

October 2006-July 2018 (3 band).

Pic of an Oct 2006 3EQ preamp.

The circuit remains the same and continues to use the TL062 chip. Although pot resistance values remain the same, the previous larger pots are replaced by smaller "Noble" pots.

July 2018-current. New revoiced 18 volt 3EQ.

With the next generation SR4 Special light weight, introduced July 2018 and replacing the regular SR4, the 3EQ preamp above is replaced with a new revoiced 3EQ 18 volt preamp. The control plate is now aluminium (chrome or black). The pickup now has Neodymium pole pieces rather than Alnico. The older 3EQ 9 volt preamps and Alnico pickups are not an option.

 

Back to Part 1: HERE