tonyw JR-1M Comprehensive Build Diary

[DrNomis_44]

I'll be interested in see how this build goes.

[tonyw]

A few more dribs and drabs, its nothing you cant fix by swearing at it

Hims fit Mr Wok

Middle cut away top shot

Neck no fit, neither did my Warmoth, get the sanding block on the sides. Whats that filler or Mr MaGloo?

Shiny Dingo Luthier Fret job very nice

Headstock well its a headstock

[wokkaboy]

looks good Tony, cheers for the bridge check, I'll see if my bridge is different and compare to the JR-1DC kit I have

[tonyw]

Clarence has been working on the neck

Pickup slotted in nice, will try my own P90 later

I think this is going to come up nice with all the different grain patterns


I will sand the neck 1st its a bit grubby from Clarence working on it

When sanding the neck i use the sand paper moulded to the shape of my hand, after all its me going to be playing it.

[tonyw]

Checked the pickup Inductance and resistance, a typical P90 would be about 8kΩ and the inductance on a vintage P90 would be somewhere around the 5.3-5.9Henries.

I dont pay much attention to capacitance other than it tells me i have a complete coil, and why dont i use capacitance? because DC resistance is NOT a power rating; it is the resistance of the wire in a pickup's coil at zero hertz, something that only occurs when the guitar isn't played. But people always ask me how many KΩ a pickup has calling it output etc so i quote it. To quote the late Bill Lawrence who i admired immensely and who i could ask all the questions in the world, and he would always reply with advice, may he RIP.

"DC resistance (Rdc) tells you as much about a pickup's tone and output as the shoe size tells you about a person's intelligence!


Now why am i waffling on with all this? i just put this Chinese P90 clone through its paces and was astounded to discover.

We have a 6kΩ reading for resistance so that puts it in low Strat/Tele territory, i like to wind a telecaster Bridge that reads about 5.75-6kΩ it give me that Roy Buchanan type of thing with an inductance of about 2.7H


So i check the Inductance and whoa


Without hearing it i would say this is going to be one nasty toppy, shattered champagne glass, fingers down the blackboard pickup with no grunt.

When i get time i will strip it down and have a further peek inside. A typical P90 will have A3or A5 mags both south facing on to the slugs and about 10000 turns.

[dingobass]

Clarence has been working on the neck

Pickup slotted in nice, will try my own P90 later

I think this is going to come up nice with all the different grain patterns


I will sand the neck 1st its a bit grubby from Clarence working on it

When sanding the neck i use the sand paper moulded to the shape of my hand, after all its me going to be playing it.

That Clarry is a grubby bugger

[tonyw]

I have been all over the fret and neck job, beautiful work by DB cant fault it. I might add the rosewood fret board is very nice.

I think i might round those bouts off a bit as well.

[tonyw]

Back to the weak P90 style pickup, time to field strip it

Take out the 2 plate screws which will also release the earth


The magnets were glued onto the plate and the bobbin, no keeper bar, magnets just hard against the poles


Hard to release from the bobbin with the glue


Correct orientation of the magnets both north facing meaning they repel each other.

The magnets are set up to repel each other so as to create a heart-shaped magnetic field around the polepieces

[tonyw]

The Chinese love their Mr Magloo


4 winds of thick black tape and less than half the bobbin wound.


Put it back together and chuck it in my crappy parts bin.

Now i need to test the pickup route and see if i have some sanding to do.

[wokkaboy]

nice tutorial Tony of the PBG P90 pulled apart.