My Parker P36/P38 hybrid project.

[JACK G]

Hello Guys,

I have had a lifelong interest in guitars since scratch building a Stratocaster copy in 1963.

Check out following links for full story.....................

https://www.squier-talk.com/threads/res ... -1.179759/

https://www.squier-talk.com/threads/res ... -2.179760/

I have always fancied a Parker but they are hard to find in the UK. However, I have just bought a Parker P38 body and a Parker P36 neck as a starting point for a project.

The all-Maple neck which is NOS was never an option on the P38 so a nice combination with the Sunburst body. In addition to the body I have the pickguard and rear hatch covers plus the Fishman bridge which may not be working. The neck is complete with the tuners.

I'm guessing parts will not be easy to find and ideally I would like to find a complete P38 loaded pickguard. Alternatively a set of Parker pickups, a wiring loom and the three black volume and tone knobs. Whilst looking for parts I am going to install a set of aftermarket HSS Strat pickups from a loaded pickguard I have purchased. At least it will be up and running.

I'm looking forward to learning a lot more from the forum.

Greetings from London, Jack

[mmmguitar]

Welcome, @JACK G! Looking forward to any headway we can help you make with this.

The bulk of what you need falls under that umbrella of generic strat faire (I’m pretty sure everything under the hood in the P series was Chinese OEM pots, switches, and pickups you’d find in many brands produced at the time). You can order replacement elements for the Powerbridge VS-50P Wilkinson trem through a Fishman dealer, should that end up being an issue.

[JACK G]

Thanks for the information - very useful.

[JACK G]

Just a quick update.

Temporarily fitted a wiring loom and a set of pickups from an aftermarket pickguard. This currently gives me a five way pickup selector switch, master volume control and two tone controls, the second one for the humbucker.

Yesterday I tested the Piezo bridge as the guitar was sold as a non working Piezo. I just wired it straight to an amp lead and it all worked fine except for the low E which had a broken connection to the PCB. I managed to solder this back on so all now OK.

Next I need to sort out wiring the Piezo into the volume and a tone control.

As the temporary pickups are passive no battery connection required yet.

Still looking for parts.

[mmmguitar]

Thanks for keeping us updated, @Jack G. Looking forward to seeing the completed project.

[JACK G]

Thanks @mmmguitar.

I will post some pics when there is something worth taking - all very temporary and sketchy at the moment.

[JACK G]

As previously mentioned, I am trying to rewire a standard Strat loom to incorporate a piezo bridge. My experience of piezo bridges is limited ie. no experience at all and I understand that they usually have to run with a battery in the circuit. I do not have a battery in the circuit and although the piezo bridge is working this may be the cause of my problems.

In order to give the piezo its own volume control I have rewired the Strat loom to use one of the tone controls for this a volume control. I have adjusted the wiring on the 5-way selector switch so that all 5 positions use the same tone control.

I have sort of got it all working but with problems. Firstly, there is a variation in interference depending on which room I am in and the interference gets worse if I hold my hand about 3" above the controls and bridge area with the guitar flat on the floor.

This is where I am and I am wondering if I am trying to do the impossible?

Magnetic pickups on - piezo bridge off.

Neck pickup only.

Slight background hum.
Loud humming noise when strings, bridge, 3-way selector switch or 5- way selector switch screws touched.
Volume hums loud as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.
Tone works OK but hums slightly as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.

Neck/middle pickup.

No background hum.
Loud humming noise when strings, bridge, 3-way selector switch or 5-way selector switch screws touched.
Volume hums loud as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.
Tone works OK but hums slightly as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.


Middle pickup only.

Very slight background hum.
Loud humming noise when strings, bridge, 3-way selector switch or 5-way selector switch screws touched.
Volume hums loud as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.
Tone works OK but hums slightly as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.


Middle/bridge pickup.

Very slight background hum
Loud humming noise when strings, bridge, 3-way selector switch or 5-way selector switch screws touched.
Volume hums loud as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.
Tone works OK but hums slightly as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.


Bridge pickup only.

Very slight background hum.
Loud humming noise when strings, bridge, 3-way selector switch or 5-way selector switch screws touched.
Volume hums loud as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.
Tone works OK but hums slightly as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.

Magnetic pickups and piezo bridge both on.

The magnetic pickups all respond as listed above in the five positions.

In addition.

The master volume control turns down both the piezo and magnetic pickups but hums loud as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions. This also turns down the piezo pickups at the same time.
The piezo volume control hums slightly as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions. This also turns down the magnetic pickups at the same time.
Tone works OK but hums slightly as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.

Piezo bridge on - magnetic pickups off.

No background hum when I stand away but loud hum if I hold my hand about 3" above the controls and bridge area with the guitar flat on the floor. .
Loud humming noise when strings, bridge, 3-way selector switch or 5-way selector switch screws touched.
The piezo volume hums slightly as turned down as I have my hand on the knob but is quiet if hand removed in intermittent positions.

Please check out the wiring pic - as it's a work in progress it is not yet neat and tidy!

I'm hoping there is a very straightforward and easy solution as I hate to admit defeat.

Apart from the wiring it's begining to come together.........................

[mmmguitar]

Thank you for the concisely detailed text and photos, @Jack G - This thread of yours will be a valuable resource to others who find themselves troubleshooting such issues.

The issues you’re describing are common; and tend to have a simple cause - Though of course have a way of also being incredibly frustrating: You seem to be describing a grounding issue in which you’re chasing gremlins in circles because every solder point looks great. I and every guitar tinkerer hates that feeling of taking the time to do every solder joint in a passive circuit “right”, only to plug the guitar in and find symptoms of a failure point that seemingly comes from nowhere.

I’m afraid you’re going to need to use a multimeter to check for ground continuity between components (including the pickguard foil) - Its possible that your ground wires between pots and switches are redundant to the foil on the pickguard; and turning the assembly into an antenna. For whatever reason, the bulk of the signal noise being picked up by the single coils and the pots/switches aren’t being passed along the signal chain to the output jack’s ground connection.

I love that you’re using wire nuts to connect the pickguard-mounted circuit(s) to the guitar, but there could be a failure point there (I don’t know if you tested the nuts carrying grounding for continuity during assembly).

If it was me, I’d isolate the mag circuit of the guitar and make sure everything was tip-top before incorporating the piezo signal (despite the elements themselves not picking up mains ground hum, I’ve previously encountered head scratchers where the strings failing to ground through the bridge for whatever reason managed to turn the piezo lead wires into an antenna when combined with the mag circuit - the diagnosis typically requires isolating the parallel circuits after first pulling all my hair out).

What's the commons layout of your 5 way switch? It looks like you have one of the contacts going to ground - Is it just bent out of the way? I also see a strand of wire that may bridging to something? It also looks like you have two lead wires (red and white) coming from the output of the mag/piezo switch and being combined at the wire nut?

[JACK G]

Thanks @mmmguitar for taking the time to respond in such a helpful manner.

The concisely detailed text and photos are a result of my lifelong OCD!

Carefully looking at my pic of the wiring (which seems easier than looking at the actual wiring) it looks like there is a ground missing from the back of the piezo volume pot - I will add one and see if that makes a difference.

I will then disconnect the piezo and check out the mag pickups as you suggested.

There also seems to be some ground wires that are unnecessary and I will remove these.

Not sure why I put two lead wires (red and white) coming from the output of the mag/piezo switch and being combined at the wire nut - I will remove one of them.

I will also check out ground wires and stray wire (?) on the 5-way switch and the connections of the wire nuts.

Unfortunately I don't have a multimeter but this may be a good time to invest in one.

I will post again when above completed.

[mmmguitar]

I will post again when above completed.

Best of luck. I’m still a bit confused about the internal switching of the pictured five-way - With one tone control, you could use just one “side” of four contacts (neck, middle, and bridge inputs, and the one common/output lug to volume pot), then solder the tone control input wire to the input or output lugs of the mag volume pot. The way the selector switch is currently wired, with the tone pot input wire jumpered between what appears to be a particular pickup’s contact and the switch’s output to the volume pot, makes me think something is amiss there - But I don’t know if the internal switching for the 8 contacts is laid out like I imagine (e.g. 1-2-3-0-0-3-2-1).

Were you trying to wire the selector switch the way it appears in the P-38 diagram with the cortek switch and coil splitting when the humbucker and middle pickup combo are selected?

[JACK G]

Thanks again @mmmguitar.

I have managed to sort it out!!!!!!

Firstly I rerouted some of the ground wires but this made no difference and then I started to isolate the circuits from each other and disconnected the live feed and ground from the main circuits. With these wires completely disconnected the amp was still humming.

And then it dawned on me - would you believe I made a really stupid and rookie error - I wired up the jack socket the wrong way round!!!!!!

Can't believe I did this after all the years I have been playing around with guitars.

So all is now well.

Responding to your question regarding the 5-way switch wiring this is how it came. I did put the short black jumper wire on to give me tone on mag bridge pickup and this works OK.

I now have master volume and tone on all 5 positions when using mag only.

With mag plus piezo I have master tone on all 5 mag positions plus master volume which turns down both the mag and the piezo volume. Don't know if this is how it should work as I have never tried a complete P38.

With piezo only the secondary small volume control works OK. The large master volume control does not turn down the piezo.

So all in all I am now happy.

What I don't understand is how I have worked this on a simple wiring loom with no battery in the circuits. I suppose I need to compare with a complete P38.

Thanks again for your interest.

Anyway, time to move on to the next stage.

[JACK G]

I have had a further go at this with another Strat wiring loom.

The aim is to try and get the two volume controls to work independantly when mag and piezo pickups are both on.

I have tested the new loom with mag pickups/no piezo and piezo/no mag and they are both performing OK.

Previously I had ..................

Mag plus piezo with master tone on all 5 mag positions plus master volume which turns down both the mag and the piezo volume. The small piezo volume control turns down mag and piezo pickups too.

Now I have...............

Master volume turns down mag and piezo as previous but piezo volume is working independantly and just turns down the piezo and not the mag pickups which is good. It does not turn the piezo volume completely down to silence but is a step forward.

Pics below of the revised Strat loom and hopefully one of you guys can advise how to achieve two independant volume controls.

Please note that for this set up I am using a 4th mag pickup and not the piezo as I do not want to disturb the first loom. Also I have not wired in the three way switch but joined all wires as if the switch was in the middle position.

I hope this all makes sense.

[mmmguitar]

Very cool. Can’t wait to see how it looks installed (and hopefully hear how it sounds).

I somehow missed your previous post about reversing the jack connections. I’ve certainly been down that rabbit hole before.

The worst one was a customer bringing me a Gretsch Electromatic I had previously replaced a selector switch in. He said that there was a new buzz that went away when he touched the switch I had replaced; and wanted me to determine what the issue was. I pored through what I thought was everything, before I thought to check the barrel jack’s stereo connections (wired for mono): I found out afterward that the customer’s brother had caused a classic broken connection at the jack by stepping on the cable while it was plugged in, then “repaired” it by swapping and bridging a few solder points until the guitar kind of worked.

I put the wires back in the proper place, and refused to charge the guy out of embarrassment for how much time I had wasted taking for granted that the jack was still in order from the last time I’d worked on it (he thanked me with continued business and referrals). Such memories are what reminds us with a wince to check the output jack first during subsequent troubleshooting (and I still manage to miss the obvious, sometimes - I swapped the ground connection of a Fly jack three or four times before I realized the issue was being caused by the ground wire at the trem being adhered through a bit of melted insulation and not by the wire core).

[JACK G]

Thanks @mmmguitar and I'm glad it's not just me!

In a previous post I mentioned that I didn't understand how I got this far without a battery in the circuits as used by Parker.

My understanding now is that an original Parker wiring loom has a Fishman Powerchip hence the need for a battery to be connected to the circuit to power this. As far as I can see the only advantage of the Powerchip is that with a suitable cable you can run the guitar as stereo. This setup also requires a stereo jack input and as I cannot see myself ever using the stereo facility I will not try to replicate this.

[mmmguitar]

@Jack G, the function of the missing preamp, in this case, is essentially to ensure that the summed signal generated by the individual piezo elements is amplified to a voltage comparable to what’s being put out by the magnetic pickups. You can run a “raw” piezo signal in parallel with a magnetic pickup signal (as you seem to be doing in your setup), but the signal levels aren’t necessarily going to play nice with one another, and may even be out of phase. The other functions of the Fishman preamp (EQ, stereo routing, buffering across longer lengths of cable, etc.) are quality-of-life features which I don’t use, either.

This old discussion from 2012 gets more into the meat and potatoes of what onboard piezo preamps are actually doing:

https://www.diyaudio.com/community/thre ... ls.210566/

What I like about that thread is that I can read until my curiosity is satisfied, then ignore the rest.

[JACK G]

Thanks once again @mmmguitar.

The link was interesting and as you intimated needs more than one quick read!

I'm begining to think that with the amount of time I am spending on this I should just buy the powerchip and stereo jack socket which comes with it and wire the guitar up properly. Seems a little defeatist but I have learnt a lot from this excercise and it seems I will never get it right going down my current route so I will give this some thought.

[JACK G]

Woohoo I've done it!

I decided to alter the wiring loom in the style of a Les Paul - that is volume and tone for each circuit and treat the three mag pickups as one humbucker and the piezo as the other. The piezo does not have a separate tone control as not enough knobs on the pickguard.

I changed or removed quite a lot of wires (see pics) but when completed it made no difference until..........................I remembered that on a Les Paul if you turn one of the pickup volume controls all the way down to off it also turns off the other pickup too. I then turned the master volume down all the way and then rolled it back just a little and there it was mag pickups silent (well 99%) and the piezo volume OK just what I was trying to achieve.

So now I have...............

Master volume turns down mag pickups but piezo volume is still working independently.

With the master volume on I can turn down the piezo volume control and the mag pickups are not affected. The piezo volume does not turn down to complete silence which is why the mag pickups continue to function.

In addition, the tone control works on both the mag pickups and piezo - together or independently.

My next job is to replace the 4th mag pickup with the piezo and see if all is still OK.