Jetstar II STEREO wiring.

[DukeAlbert]

Hello all, I recently purchased this mangled corpse of a JS-II in need of A LOT of work! It needs to be rewired and appears to have the choke switch AND stereo option! So my questions are 1, is it worth it rewiring it and keeping that stereo option or just bypass it and include the switch for someone in the future to rewire if they desire? Also, if it IS worth maintaining does anyone have any wiring diagrams or schematics including the stereo and choke switches?

 

[Happy Face]

Wow, a stereo option. Fretless to boot. It seems like it has been pretty seriously modded already so you may as well for it.

Attention Mellow One!

 

[fronobulax]

I'm not seeing evidence of a stereo option but that could be my fading eyes.

Guild called it the "Deep/Hard-Switch" although choke is certainly more accurate than phase.

This is a mono Starfire II but the JS and Starfire were pretty much wired the same. I can get hand drawn schematics from a JS II if that will help.



We could probably find ways to wire it stereo for you but unless you are going to split and use multiple amps or a stereo amp, will you really be gaining anything useful?

There are definitely some parts in that bag that I cannot relate to anything on my JS II.

For clarity that body style is usually called JS not JetStar so it is not confused with the 60's solid body JetStar.

 

[fronobulax]

Forgot I had this. JS II with "choke" presumably from an official source.

 

[mavuser]

I am seeing the Stereo switch, and the pickup switch, but not the Deep Hard (choke) switch. The Stereo switch has an S+M for Stereo and Mono.

Also if you want a nice deal on a pair of Guild reissue Bisonic (Dark Star actually) pickups for that, hit me up! Those HB-2 pickups look crazy without the chrome covers.

 

[fronobulax]

I am seeing the Stereo switch, and the pickup switch, but not the Deep Hard (choke) switch. The Stereo switch has an S+M for Stereo and Mono.

OK. That raises the question - did a Stereo JS II also have the Deep-Hard switch? I can make a case a Stereo bass should not have the switch - one less hole to drill and it is not clear that changing the tone on one PU is useful in a true stereo setup.

What I recall about output jacks is that the jack is wired for stereo but whether you get stereo or mono depends upon the cable that is plugged in. Did Guild have some kind of "collar" around the output that said "Stereo"?

Time for some catalog digging.

 

[lungimsam]

Here’s one with normal looking controls but a stereo trc:

https://reverb.com/p/guild-js-ii-walnut-1974?hfid=80860482&utm_source=google&utm_medium=cpc&utm_campaign=18040569733&utm_content=campaignid=18040569733_adgroupid=143121795794_productpartitionid=1720203842862=merchantid=5343949641_productid=80860482_keyword=_device=m_adposition=_matchtype=_creative=616435425577&gad_source=1&gbraid=0AAAAADRxZYUy4amuAbhHJIkQeYPmPJ4LW&gclid=Cj0KCQiAyoi8BhDvARIsAO_CDsBDCeZiWnqHA3O3nHUO9LGM4EHoMo2RXlLAuo4Zq5DIaBNzRw6TWfkaAlUqEALw_wcB

 

[lungimsam]

But the jack looks normal. Wonder how Guild designed the stereo.
BTW, love those small diameter tuning shafts. They look much nicer than the huge diameter tuning shafts the NS basses have.

 

[fronobulax]

But the jack looks normal. Wonder how Guild designed the stereo.

Normally you won't be able to tell the difference between a stereo jack and a mono jack until you take it out of the bass or otherwise expose the whole thing. Counting lugs will tell you if the jack is capable of stereo but you will actually have to look at the wiring to see whether it is actually wired for stereo.

At some point my recollection is that it was common to use a stereo jack whether you needed it or not and connect the extra lugs together for mono. Reduces noise I believe.

As for wiring I don't recall that Guild was ever very innovative in how it wired basses so you could probably come close to what Guild did with a generic wire two pickups in stereo schematic.

 

[lungimsam]

As for wiring I don't recall that Guild was ever very innovative in how it wired basses

One thing is for sure; in all the vintage Guild bass cavity pics I’ve seen around LTG, Guild’s wiring looks nice and neat and simple and tidy.
Rickenbacker 4 control basses are a rats nest and hard to trace when I look at them.

 

[DukeAlbert]

I'm not seeing evidence of a stereo option but that could be my fading eyes.

Guild called it the "Deep/Hard-Switch" although choke is certainly more accurate than phase.

This is a mono Starfire II but the JS and Starfire were pretty much wired the same. I can get hand drawn schematics from a JS II if that will help.



We could probably find ways to wire it stereo for you but unless you are going to split and use multiple amps or a stereo amp, will you really be gaining anything useful?

There are definitely some parts in that bag that I cannot relate to anything on my JS II.

For clarity that body style is usually called JS not JetStar so it is not confused with the 60's solid body JetStar.

It is missing the additional switches, which necessitates the rewiring, but that is what that extra drill hole is for based off of complete examples such as this:

 

[DukeAlbert]

I am seeing the Stereo switch, and the pickup switch, but not the Deep Hard (choke) switch. The Stereo switch has an S+M for Stereo and Mono.

Also if you want a nice deal on a pair of Guild reissue Bisonic (Dark Star actually) pickups for that, hit me up! Those HB-2 pickups look crazy without the chrome covers.

I was able to get ONE chrome cover so far. Looking hard for a second one!

 

[lungimsam]

Here’s a stereo model with serial number on back of headstock for data point. Alleged to be originally black.

 

[fronobulax]

OK. I got it. The Stereo-Mono collar looks to have been moved to the location of the Deep/Hard switch and the original location of the Stereo-Mono switch is empty. I thought the empty hole was just a ding until I blew the picture up and pressed my nose to the monitor.

 

[mavuser]

OK. I got it. The Stereo-Mono collar looks to have been moved to the location of the Deep/Hard switch and the original location of the Stereo-Mono switch is empty. I thought the empty hole was just a ding until I blew the picture up and pressed my nose to the monitor.

ahh. missed that! Deep Hard switch probably
more useful than the stereo feature. but who knows what the resulting/modded circutry is on this bird. just get it to sound good, and don't worry about how it got there. nice work on the chrome cover. don't see those too often, maybe it is original to your bass! #2 is out there...keep us posted

 

[lungimsam]

Forgot I had this. JS II with "choke" presumably from an official source.

WOW!!! Linear taper volume pots and audio taper tone pots! Neat!
Looks like the deep/hard switch either engages or bypasses a .0033mf cap depending on which way you switch it.

 

[fronobulax]

WOW!!! Linear taper volume pots and audio taper tone pots! Neat!
Looks like the deep/hard switch either engages or bypasses a .0033mf cap depending on which way you switch it.

Feel free to search LTG. I once made some assertions about the DH circuitry. They seemed correct to me but they were wrong because I was applying things I had learned about digital circuits to an analog one. I was very precisely and politely corrected.

 

[lungimsam]

Feel free to search LTG. I once made some assertions about the DH circuitry. They seemed correct to me but they were wrong because I was applying things I had learned about digital circuits to an analog one. I was very precisely and politely corrected.

Ha! I was just reading that thread. As interesting as that deep electronics dive was by everyone on there, I found that this post of yours (post #40) cleared up the mystery of the switch for me :
You wrote-

“For historical reference, I found the original hang tag from my bass describing the switch.

"UP position, toward pickup: Normal tone. Full, rich bass.
DOWN position: Tone changes to a hard, more treble sound."”

 

[mavuser]

The deep hard switch, at least the way it was wired on my prior JS-1, was very useful. You could go from 70's power trio mud thundar (deep), to upright bluegrass tones (hard), and even dial in some fender flavors in the hard position. One thing I would I change is the location of the switch is not good, too easy to hit when you play, and the unintentional change in tone and vol would be drastic. If you could make that a footswitch somehow instead, that would be the ticket!

I have limited experience with the JS-2. @fronobulax 's seemed to function differently than my JS-1. But it was not a fair (or long) trial. Some of those JS and SF w the hums from the 70's sound quite good. there was definitely variation in circutry and pickup values.

good catch on the different type of pots. i'm no expert, but they may have been trying to tame the humbuckers however possible. if linear taper is quieter, or louder less fast (ha), than audio taper...that would make sense. I can never remember which is which. I feel like the audio taper sounds more linear? suppose that can't possibly be right

 

[mellowgerman]

Stereo mini-toggle switch should be pretty simple here. Assuming they went the simplest route for this kind of wiring, my guess is that it's s spdt mini-toggle added to the circuit after the neck pickup controls, which either routes the signal from the controls (1.) to the 3-way pickup selector or (2.) to the ring of the stereo jack. That would allow you to either send both pickups to the tip for normal mono operation with a standard cable OR when utilizing the ring of the jack, stereo operation with a stereo cable.

I'm hesitant to speculate about the potentiometer choices in this schematic, since we know that Guild wiring diagrams weren't always consistent with the actual wiring used for each instrument within a given model designation, but also that these pickups have such a massive ohm resistance, it's a little bit outside of most of the general ranges I've experimented with over the years. Pickups are weird and there are a lot of factors at play, ohm resistance just being one of them. I'm a self-taught tinkerer, not formally trained in electronic stuff, everything I know came from hands-on trial and error. Additionally, please take everything I say with a grain of salt, because a lot of weird things have happened since I started my experiments almost 2 decades ago.