Mark I Reissue tone potentiometer value

[Michael Italia]

What is the tone potentiometer value for a Mark I reissue as I need to replace a broken middle pot and missing knob? Best place to buy one? Thanks

 

[mark1406]

Which pot in particular are you referring to?

Treble bass or middle pot?

Regards

Mark

 

[Michael Italia]

Which pot in particular are you referring to?

Treble bass or middle pot?

Regards

Mark

Middle tone pot.

 

[mark1406]

Middle tone pot.

There are options there. You can get a log taper (10%) 10K pot, if you are adventurous you can put a 100K log taper pot like the Santana Mark 1 model. It would work like a normal middle control from 0 - 5 and from 6 - 10 is would disengage the tone controls. If you use a foot pedal to turn the boost on and off then I would stick with a 10K log pot.

Regards

Mark

 

[Michael Italia]

There are options there. You can get a log taper (10%) 10K pot, if you are adventurous you can put a 100K log taper pot like the Santana Mark 1 model. It would work like a normal middle control from 0 - 5 and from 6 - 10 is would disengage the tone controls. If you use a foot pedal to turn the boost on and off then I would stick with a 10K log pot.

Regards

Mark

OK Thanks! I'll look into getting a 10K pot.

 

[mark1406]

A CTS pot with a solid shaft and a log taper should be fine. I prefer CTS to Alpha as the CTS look like they are made better. The Alpha pots work fine, I’m not fond of the coating on the back of them which you can’t solder onto.

Regards

Mark

 

[Michael Italia]

A CTS pot with a solid shaft and a log taper should be fine. I prefer CTS to Alpha as the CTS look like they are made better. The Alpha pots work fine, I’m not fond of the coating on the back of them which you can’t solder onto.

Regards

Mark

Thanks again for your input! I did happen to receive a reply yesterday from Mesa Boogie indicating it's a 250K linear pot, which they sell online.

 

[mark1406]

Thanks again for your input! I did happen to receive a reply yesterday from Mesa Boogie indicating it's a 250K linear pot, which they sell online.

The mid pot definitely isn’t a 250K pot, it’s a 10K pot. Suspect the 450S is the one that you are after. Have a look at the specs for both pots in the link and see what you should have. The 250K pot info from Mesa Boogie is definitely wrong.

The treble and bass pots are 250K have a look at the diagrams.

Original Mark 1 circuit

Boogie 270S 10K pot

Boogie 450S 10K pot




Regards

Mark

 

[electric mayhem]

Boogie 450S 10K pot

This 598379 is the one Kris emailed someone on behalf of MB for the mid on a IIB- 10k linear.

598380 is a 10k audio, 10% log.

The 450S is the same 24mm pots in there.
270S is a smaller 16mm form.

 

[Michael Italia]

This 598379 is the one Kris emailed someone on behalf of MB for the mid on a IIB- 10k linear.

598380 is a 10k audio, 10% log.

The 450S is the same 24mm pots in there.
270S is a smaller 16mm form.

OK This is helpful as it's been a little confusing. The # is 591278 0515 on the broken (shaft) middle tone pot on my MKI, if that helps. Anyway, Kris at MB responded that it is a 250K, but per your schematic, I see that it's a 10K. I actually had ordered some pots, handles, and a cover from MB yesterday, but they didn't have any knobs in stock. I'll just order the 10K and knobs from Amplified parts today. Thanks very much for your help!

 

[mark1406]

No problem Michael, happy to assist you. Using a log pot, at “5” the wiper will be at 1K ohms. This means the bass control has the most effect. The higher the mid control the less the bass pot does. With a linear pot, at “5” the wiper is at 5K ohms.

Whether you chose a log or linear pot, it depends on what pot taper that you find meaningful. I personally like the log taper, which is what I believe Fender used.

Regards

Mark

 

[electric mayhem]

The # is 591278 0515 on the broken (shaft) middle tone pot on my MKI, if that helps.

This is a 10K linear they've left up on the site but have no stock. So if you like it you like linear.
As mark1406 said you could use log and he gave an example of 10% but you can also use 30% log (or 20%) which as I understand it puts you at 3k ohms for '5'. More dramatic sweep than linear but not as much as the 10%.