NBD 1967 Sunburst Starfire II

14K sounds right, 137 is 10x too high. Check again with all the knobs on full and with the suck switch in both positions. If still that high check the pickup itself right at the pickup leads. Making progress!

It's the suck switch. For sure. The same thing happened with my m-85. Even when it's not engaged it can suck all the tone out of the bridge pickup. You can either remove the coil or run a bypass wire from the front to the back of the coil.

if a volume pot or the coil/switch is suspect or not working correctly the only true reading of the pickup has to be after it's been removed from the circuit. Otherwise you are also reading whatever is connected within the circuit.

bklynbass said:

It's the suck switch. For sure. The same thing happened with my m-85. Even when it's not engaged it can suck all the tone out of the bridge pickup.

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the bridge pickup or the neck pickup? Wow the plot thickens. Starting to wonder if some of these were done incorrectly at the factory when new...I know some electronic issues have been reported with the 60s Polara guitar new from the factory. And the bass suck switch was a very new thing, at the time.

when I purchased my 68 SF2 bass, it was advertised that the suck switch had been disconnected, but was all there if I wished to re-connect it. Then when I got it, the suck switch seems to me to be fully functional, doin what it was designed to do- to the neck pick up. It sounds to me like the bridge pickup is not affected by it, but it's the only bridge Bisonic I've ever heard. Still, everything is connected and there is a lot going on with a SF2 bass. The suck switch "effect" is much more transparent on a SF1, you know what it's doing and when it's doing it. You shut it off and the bass sounds normal. On the SF2 I can say the same but to a slightly lesser extent. What is my point? Removing the suck switch no matter what, on both models...is a fantastic idea. But apples to apples if I had one of each I'd remove it from the SF2 first. It is beyond pointless in that instrument, on several levels. Seems to really mix things up

Thanks guys. Having never soldered anything, Im a bit apprehensive about doing this myself. As any disconnections I make will need too be resoldered, correct?

Can someone show exactly where the pickup should be measured when it is in the circuit and when it is out of the circuit. Furthermore do I only need to cut one wire to achieve this or a specific wire?

Finally, if it is a blown pot how do I access them? It seems like it would be pretty difficult to get it out and back in.

wisconsindead said:

Having never soldered anything, Im a bit apprehensive about doing this myself....
Finally, if it is a blown pot how do I access them? It seems like it would be pretty difficult to get it out and back in.

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O.k., I only can give you some advise here. It's great that you admit where your limits are. That helps.
If you never soldered any electrical connection before, a Guitar is the worst thing where you can learn it. Just don't bring a soldering iron near it. Seriously. Don't try.
Also, if you never changed a pot in an archtop guitar, don't try. It's a lot of work and you can damage a lot in the process if you don't know how the wiring circuit and the grounding circuit works and where everything belongs.
My advise: Find a good luthier who does work on electrical guitars and who knows what to do. Whatever you will try will make things worse.
If you want our help, let us know in which area you are and one of us might know a luthier you can trust in that area.
Ralf

right on Ralf. I went to a pretty reputable guitar shop and the tech wasn't working. I will probably take it to him for a look through this week.

Question...

Does this seem right?
~800 ohm for neck pup with suck switch on
~13.3 kohm for both neck and bridge pup on

I really have no idea what I'm talking about, but based on something I read that Curtis Novak posted, I will say 13.3k appears to be an accurate measurement. I THINK his reissue is 14.5k; or at least one version of it is. So to me 13.3k is close to that. Lots of variables though...just get it to sound good!

All bets are off with the suck switch on, as it's adding a coil to the circuit, which changes the resistance, but I have no idea what it does to the impedance (which is resistance as it changes with respect to frequency). 13.3k is very much in the right ballpark for these kinds of pickups. But, at this point, without taking the pickups out of the circuit and measuring them that way, it's hard to tell exactly what's going on.

thanks guys. 13.3 kohm would be right with the pickups connected in parallel and the resistances of each pick up as previously stated (14.4 and 137 kohm for bridge and neck). Thus I think with both pups on the resistance should measure around 7 kohms (if things are as they should be). Anyone with an SFII willing to check this out for me? I still plan to take it into the shop to at least get the suck switch out but Im having a hard time with the thought of having to play my squire P :frustrating:

Got a measurement of 8 kohms on the leads of neck pickup and 14 kohms for the bridge pickup, also at the leads. They were still connected to the wires. Any thoughts on why this may be?

And does anyone know how to effectively disconnect the suck switch? The tech I took it to said he'd have to take everything out to get an idea as to whats actually going on with that circuit. $$$$$

"Is that a transformer!?!! I've never seen that before, why is that there" - Tech
shrugged shoulders - Me

wisconsindead said:

"Is that a transformer!?!! I've never seen that before, why is that there" - Tech shrugged shoulders - Me

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mgod wrote: "Its not a transformer, its a choke, its the heart of "suck-tone"."
Here's a picture fixit took:



Have a read here: http://www.letstalkguild.com/ltg/showthread.php?173150-Question-for-the-Starfire-Bass-Gurus-(Long)
And especially read mgods post there (post #12): http://www.letstalkguild.com/ltg/sh...Gurus-(Long)&p=1543782&viewfull=1#post1543782

Ralf

SFIV1967 said:

And especially read mgods post there (post #12): http://www.letstalkguild.com/ltg/sh...Gurus-(Long)&p=1543782&viewfull=1#post1543782

Ralf

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Good memory, Ralf! Thanks.

Thanks Ralf. Still on the hunt for a solution. Other than gutting and rewiring the entire thing.

Does 1-2 hours of labor from a luthier sound about right for this kind of job (complete rewiring)?

wisconsindead said:

Does 1-2 hours of labor from a luthier sound about right for this kind of job (complete rewiring)?

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Not sure why you want to do a "complete rewiring"? Just take the choke out and connect the two cables I would say. But yes, if you speak "complete rewiring" and mean taking out the harness, cleaning the pots,...that is a multiple hour work! I would guess even more than 2 hours! Mind all needs to go through the F-holes!
Just to give you a feeling how such kind of work looks like:



Ralf

So you're saying remove the choke and connect the black wires which went in and out of the choke?

That would surely bypass the choke which might sound great. I think there are other resistors and things in the circuit, though, right? At it's age, though, and because it's a nice instrument and it's worth it, you should probably have a tech go through it and make sure that everything is clean and properly wired. I'd think a pro could do it in 2-3 hours. Me, I'd make a day out of it!

grisezd said:

That would surely bypass the choke which might sound great. I think there are other resistors and things in the circuit, though, right?

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I am no bass expert but I doubt there is anything else beyond that choke and the switch in that bass. Unfortunately we don't have any photos of the choke and the connected bridge pickup from wisconsindead, so don't even know what he has in the bridge pickup cavity. We would need to see which wires are in there and which wires go to the choke and which wires go to the pickup. Who knows if there were modifications done in the past? So we can propose many things but without knowing what is going on in the bass of wisconsindead it is difficult or impossible...
Wouldn't the suck switch be connected in a way that one setting has the pickup directly connected and the second brings in the choke? So what was the main issue with other basses? Did the switch fail over time? So in theory the failure is not the choke but the switch itself? Fixit didn't report further in the thread what exactly he changed in twocorgis bass.
Ralf

Well we have somewhat of an update.

I pulled out the pickups to swap spots to see if the neck pickup was the issue and it seems that it is not. In the process I removed the transformer/choke/coil from the circuit. This caused the output to be zero when the suck switch is engaged, no sound. So it seems that the real problem is likely the entire wiring of the suck switch. This is still pretty odd as the neck pickup when removed entirely from the circuit measure 9.3 kohms and 15.1 kohms for the bridge pup. The only other thing that I can think of would be that the distance from the strings is causing the output to be so drastic. However, that is unlikely.

Thoughts appreciated and I'll keep yall posted as further developments are made.