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Rock Bass Revival!!


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Back in 2012 I did an Epiphone 1993 Rock Bass project.  The Rock bass is a Fender Jazz bass copy.  New tuners, new pickguard, new Seymour Duncan Bass Lines J Set .  The action was a high so I took it to my tech for a set up and he told me he could not get the truss rod to move any further and the relief was at over 0.025".  I put it back into my rack and it sat there until today, about 9 1/2 years.  I decided I needed a 4 string bass with round wound strings tuned to Eb so I pull the Rock bass and put it on my bench to see if I could salvage the bass.

The 5mm truss rod nut was tight. I de-tuned the strings. and with some umph and prayers, bam! It tightened !  I kept going and it would tighten with a pop but it was still OK.  Re-tuned, check relief.  Finally after 5 iterations I had the relief set at 0.012" per Fender's spec (capo at the first fret, press down on the last fret, and measure at the 8th fret).  Set string height, checked intonation, and pickup height.  All good!!!

I then plugged it in and played & it sounded like crap.  Scratchy pots and the tone/vol pots had no range - the tone pot would go almost all the way down before the tone darkened.  The volume pots did the same.  I opened up the electronics plate and discovered that the pots were all 500K linear factory pots.  The Fender Jazz bass specs calls for 250k audio taper pots and a 0.047 capacitor.  Fortunately I had a number of 250k audio split shaft pots on hand to use.  I replaced the tone pot first with an A250K Alpha pot and tested the factory cap.  It showed .047 on my cap meter so I used it again.  I then tested the tone pot.  Smooth with a much longer tone swing.  I then replace the two vol pots with 250k audio taper pots and now the bass plays like it should.

Why Epiphone would put 500K linear pots in a single coil pickup design that called for 250K audio taper I do not understand. So if your Epi bass doesn't seem to sound right, check the pots!

I got this 1993 Rock Bass back up  and playable.  I might just replace the bridge now that the neck is where it should be.  A great revival as it saved me doing another bass project.



rock bass body.jpg

Rock bass done.jpg

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