Upgrading pots and caps on a new Guild Starfire 2 bass.

[BillyB33]

Greetings, first post.
I just got a Guild Starfire II bass.
I wanted to know the tone caps in them but can't find any info.
Does anyone know?
Is it worth swapping out the pots for 500kCTS and get 0.22 oil in paper caps?
Also, does anyone play this bass with flats? Any suggestions?
Are they short scale?
Thanks
BillyB

 

[RVBASS]

Hi BillyB33, welcome! I don’t know about your caps question, but I use Pyramid Gold flats on mine, short scale and have to trim back the silk at the nut on some of the strings. I have also tried TI jazz flats, short scale, but they are lower tension than the Pyramids.

 

[fronobulax]

Welcome.

I have never torn my Starfires apart. But if I wanted advice I'd check with @lungimsam who shielded his Starfire I as described here.

Lots of string discussions. The Starfire and the JS have the same scale length so you might glean some ideas from here. The one piece of advice is don't assume that what the string makers calls "short scale" will actually fit.

I've used rounds and flats on my vintage, only flats on the Newark Street. The sounds are different but which is better depends upon my mood. For whatever reason I am finding flats easier to play at the moment so if I were getting new strings I'd continue with them. But I don't think the Starfire reacts differently to rounds vs. flats than any other instrument where I have made the comparison, if that makes sense. You can make the choice, not the bass.

Schematic with values for a Newark Street SF I.

Fuzzy schematic with values for a SF II. Not sure of the era. Might be pre-68 (because of the master volume and no tone switch) but I really don't know.

So, why would you swap? Lots of guitarists have bought into the idea that changing caps and pots makes a difference (and sometimes it does) but often, when I ask, what do you expect to hear that is different after the swap, I get crickets or some anecdote that turns out to be about capacitors in a 1950's tube amplifier. I understand that cheap pots can sound scratchy and contact cleaner doesn't help. I understand that the pot's taper changes the way the controls respond. I understand that changing resistance changes output levels. But what is there about the new to you bass that needs to be fixed or can be improved by swapping components? And could I hear it?

I am kind of assuming that you are talking about a recent Newark Street bass and not something from before 2013. My comments don't really change with the answer but might be less relevant

 

[DeArmond Hammer]

Welcome, Billy! As frono wrote, don't assume you need short scale strings, because the Starfire Bass has some distance between its bridge and the string anchor. Medium is the correct length for LaBella strings, I don't know about other brands.

 

[lungimsam]

My personal opinion, which isn't important, but may be something to consider:
(Caveat: everything below comes from experience with my Newark Street 2013 Starfire I)

Electronics:
If I were going to go to all that trouble to remove the harness and change components on a semi-hollow body like a Starfire, I would want more tone options the just one cap change could give for the trouble.

I would (and did) pull the harness, ditch the caps and resistors and tone pots and replace with Stellartone ToneStyler Bass 10 tone pot. That way you get 10 significantly different tones on each pickup from each ToneStyler pot, from really bassy to extremely bright and true bypass, all in one tone knob selector as you click thru the filters, or whatever is in there that changes the tones of each click. The voice of the instrument will also change slightly as you click thru the 10 settings, which is really fun to hear. This change is what makes it different from a normal tone pot. Plus it sweeps way bassier and way brighter than a normal tone pot. You can even use their Guitar 10 pot on a bass if you prefer a brighter bass and don't need the ultra bassy tones of the first few clicks on the Bass 10 pot. They recommend Bass10 on the neck pup, Guitar 10 on the bridge pup. But using either will get the bass from super dark to super bright on each pup. There is a cool Pbass demo with a Bass 10 on YouTube.

I would also shield the harness up as described in the link Frono provided. Gonna be a little tougher with 4 pots, but it is a royal pain to work on semi-hollow body electronics so you might as well do it all in one shot, especially if your Starfire is noisy, like mine was. Others report theirs were not noisy from the factory.

Plug in and test everything before reinstalling the harness in the bass, of course.

Strings:
Bass scale length is: 30 7/8" in real world measurement on my bass.
String scale length is 34" minimum, 35.5" maximum from ball end to string silks on my bass.
LaBella medium scale strings fit.
Chromes medium scale strings fit.
However, I now use Chromes ECB80 longscale Flatwounds on the Starfire. No problems so far. Short scale will be too short because you must measure from ball end to silks and bridge to nut to see what will fit.

 

[fronobulax]

Bass scale length is: 30 7/8" in real world measurement on my bass.

How are you measuring? Nut to 12th fret and double or something else? Nut to saddle gets interesting but will vary with which string and how the intonation is set. I use the face of the nut closest to the bridge and the crown/high point of the fret. That might not be correct but I do get the vintage factory spec (30 1/2 ") on all of my Guilds when measured that way

 

[lungimsam]

Inside of nut (fretboard side) to center of the metal of the 12th fret x 2 = 30 7/8"

 

[franko D]

New user here.
I have a one month old 2020 green Starfire II which I love.
I like to modify basses and everything else.
I will not change anything on this bass, not even the strings at this point.
I think the flat Chromes and GHS pressure wounds are great choices.
I've learned a lot on this forum and in particular thread.
Thank you for posting the diagrams of the volume tone circuitry.
After some initial confusion, I figured out the functionality of the volume/tone controls.
I found out the following with both pickups switched on.
The volume controls are coupled and interact with each other.
When the volume controls are maxed, the individual tone controls lose their independence.
When the volume controls are less than max, the tone controls regain their independence.
I use the volume controls between 5 and 7 and max out one tone control on one PU and min on the other PU.
I hope I explained this ok.
I noticed huge differences in the sound depending on where one is plucking.
Anywhere between the bridge and the neck joint, a lot more than my other basses.
I find that I sit and play/practice a lot longer than I intend to.
This thing wants to be played.

 

[lungimsam]

They are interesting basses. I find myself using lotsa varied techniques on my SFI that I usually don’t use on my other basses. It helps bring out creativity somehow that way.

Congrats on the new bass!

 

[fronobulax]

After some initial confusion, I figured out the functionality of the volume/tone controls.
I found out the following with both pickups switched on.
The volume controls are coupled and interact with each other.
When the volume controls are maxed, the individual tone controls lose their independence.
When the volume controls are less than max, the tone controls regain their independence.
I use the volume controls between 5 and 7 and max out one tone control on one PU and min on the other PU.
I hope I explained this ok.

I noticed huge differences in the sound depending on where one is plucking.

My experiences with the controls on a vintage JS II are different. If my bass worked like that I think I might have it checked out. Since we are talking about different instruments from different decades my observation might not mean anything relevant to your bass.

Moving the plucking hand between the bridge and the neck (and even plucking over the fretboard) is a common technique for varying tone so your discovery is to be expected.

 

[franko D]

Thanks for the circuit diagram frono.
I'll post a larger one that seems clearer.
All pots are 500k ohm and caps appear to be .05 ufd.
The Starfire bass I have appears to operate in accordance with the circuit diagram.
For any needing pots, I ordered some pots that look good from Best Bass Gear.
The site calls them Noll pots.
They look to be sealed, well constructed, and pricey.
When I got them, they say MEC on the backside, which I think is a good thing.
I'll do a PJ bass upgrade after the holidays using them.
I'll report back with results.

 

[lungimsam]

I don’t see how the ground wires from v and t pots connect to ground in these drawings. What am I missing, Don’t they have to connect, along with bridge ground (not pictured) to the ground lug of output jack?

 

[Nuuska]

The symbol of ground is drawn right on the pots where the leads end.

 

[SFIV1967]

What am I missing, Don’t they have to connect, along with bridge ground (not pictured) to the ground lug of output jack?

A complete ground circuit is normally never shown in wiring diagrams, only what Nuuska said. Otherwise you would create chaos in a wiring diagram! So yes, ground from the pickups and from the bridge and from the output socket and from the pots connect but one has to be careful not to create unwanted ground loops! (like some people connect all four pots with one wire in a closed ring which is not good at all!) Just google for "ground loop" in guitars or read the following:

Understanding Guitar Grounding

Guitar Grounding can be an elusive subject, but it doesn't have to be. Learn from Fralin Pickups the best practices for Guitar Grounding.

www.fralinpickups.com

Ralf

 

[lungimsam]

Ah, that explains it.
Thanks. I never learned to read wiring diagrams.
Tricky with the MV. I guess They could pigtail the T,T,MV, and bridge grounds, then a wire from them to output jack lug. I don;t think I can finger trace any loops that way. And I thought messing with a SFI harness was tough...

 

[franko D]

Thanks much Ralf and everybody.
The Fralin explanation was great and clear.
Some thoughts...
When I was working, our equipment had two grounds, always kept separate, with a single point where they connect.

Chassis ground - in our case, the back of the control cover and the control cavity. Hopefully metallic, conductive paint, or copper foil covered.

Signal ground - that would be the return wire from the pickup and any wire that carries the return signal.

These grounds connect at one point and one point only. probably the ground connector at the output jack.
Main point is that you don't want the chassis ground carrying any signal ground current.

I wish all pickups used a shielded cable with two wires inside the shield.
The shield would be at chassis ground.
The inside wires would be the signal wire and its return wire. This return wire would be at signal ground.
This would make for a lot less noise in the control area.
Pickup shielding is a whole other discussion.....argh.

For me, an ohm meter is essential, especially for testing pots.
Something to test is the pot mechanics also.
All pots are not the same.
The cover on the back of the pot may not have a good electrical connection with the rest of the pot where the threaded part and knob shaft is.

Sorry for the long wind here but I want to contribute what I've experienced.
Just in case any weirdness happens after an upgrade.