My Tribute bass pot is very scratchy. I started looking for a metric replacement that is a 1Meg reverse audio taper and there is not much out there. The G&L store is out of the Tribute 1MegC variety to make things worse.
So I looked at the circuit and realized that the bass pot is only used with the cw and wiper terminals. Since the ccw terminal is not being used, the pot can be replaced with a different value without impacting the circuit behavior. You will just be limited in how much adjustment range you have.
When the bass is "full on" the wiper to cw resistance is zero and as you rotate for bass cut, the cw to wiper resistance increases from 0 to 1Meg. Given this is a reverse audio taper, the first 50% of rotation from the "full on" position is seeing the shallow side of the reverse log taper. I usually do not rotate the 1Meg bass cut anywhere beyond the 50% point which is in the ballpark of a 100K resistance.
So I ran some PSPICE simulations to see how the 250K linear would stack against the stock 1Meg reverse audio taper. These simulations are for a passive mode model which assumes a 1000pF cable capacitance, volume full on, tone pot full on, and one MFD coil (SC).
The 0-100% settings in the plots are for pot position. I used a mathematical estimation for the resistance seen by the circuit at each position. I then did the simulation again using a 250K Linear Taper Pot. I think I will prefer the finer adjustment exhibited by the 250K linear in the -4 to -6 dB cut range. And I don't think I need more than -6dB of cut.
I also found a CTS made "metric" pot that should be a direct replacement for the metric pots used in the Tributes with the smaller mounting hole (I had to drill a bigger hole for the push pull pot I put in the volume position that uses the more standard US 3/8" bushing).
CTS Metric 250K Linear Pot
Alternative Metric 250K Linear Pot
I am somewhat surprised by these results. I see no reason to chase down a 1Meg reverse audio taper pot. And why has G&L gone through the trouble of sourcing this odd ball part for the last 35+ years? This makes me question if I have done the math right. I think I am going to order a CTS metric 250K linear pot and see if it works as advertised.
Edit: I am posting new plots that hopefully don't truncate like the originals.
1Meg Reverse Taper Stock
250K Linear Taper Mod