First Wiring Design for Strat - Ready for Review

[axedoctor]

Okay ... upon entering the fall season, I decided to parlay my electronics background into a project to reconfigure a neglected Stratocaster Clone gathering dust in my basement. Since then, I have poured through quite a bit of on-line data and was thrilled to happen upon this forum with its wealth of information and avid participants. After reviewing a bunch of archived postings and playing with the GF & DIYLC tools, I am ready to post my initial idea for an overhaul of the electronics "beneath the pickguard".

I have attached a pdf containing a schematic of the proposed circuitry, sans component values as I am most interested in feedback regarding the architecture, and a chart detailing the operation and functionality of the design. Your comments are hereby elicited.

respectfully submitted,

Dr A

PS - I do have some additional questions regarding value targets for the components, but I will wait on that until the initial responses are in.

Guitar-1C.pdf (894.9 KB) 

[newey]

I'm reposting axedoc's schematic so we can all see it without scrolling, etc.




No time to vet this at the moment, bedtime calls . . .

But someone will be along.

[newey]

And, just for starters, it would be easier to discuss this if the various switches were numbered in some fashion. Also, are we to assume that the treble and bass cut switches are on-off-on types?

[axedoctor]

newey et al - 

color-coding within schematic and summary should help identify each switch and its type, but here you go

pickups connect to standard 2-pole 5-way selector 

series/parallel blender connections are established with a push/pull volume control potentiometer as indicated in the summary

bass cut and treble cut switches are both 2-pole 3-way on-on-on (up, ctr, dn) to achieve the three desired states

I have chosen to implement the no-load setting of the treble tone control with a dedicated switch 
so that the potentiometer might be of a push/pull variety, enabling some future feature


hope this helps
 

[newey]

It does help, not obvious from the chart that the switches were center-on types. I'm still tracing through he series/parallel switching and blender; the bass and treble cut switches look OK, although I can't help wondering if leaving the treble pot, resistor and cap hanging when in the center position might not induce some noise. It would be "cleaner" (although equivalent electrically) to use the common poles of the DPDT to switch the wiper in/out of the circuit in the center position, IOW, put the pot after the switch and caps instead of before it.. Also, I'm not clear on what R2 is doing there.

I'm at work now, so the rest will have to wait until later . . .

[JohnH]

I think the series/parallel blender is very tricky. I never found an arrangement that does a nice smooth blend in both modes, keeping all the available treble sparkle. The best passively blended tones seem to be when one pickup is fully on and the other is faded up from 0 to max. Any case where both are partly running trough pot resistance is not quite as nice as a sim0le switched blend.

[axedoctor]

feedback is always good (unless it comes from your mics being too close to your monitors)

agree with newey that putting the no-load disconnect before the pot is a better approach ... will implement this change

including R2 in series with VR2 is an attempt to eliminate the mid-range peak that occurs when the tone control pot is totally closed ... should also shift the effective breakover point of the dual slope audio taper

given the recent glowing tributes, I opted to utilize ChrisK's series/parallel blender but perhaps there have been no successful implementations of this Design Module ... I will defer to experience here but will kick around a few other ideas in attempts to achieve something more interesting than simple series/parallel connections

will post again next year ... until then please have a fun but safe New Year's celebration

[axedoctor]

back again with the latest version of my Strat overhaul ... abandoned implementations that were questioned during the previous review, but was still able to obtain an interesting (I think) palate of pickup combinations and tone-shaping options

the schematic :
 

the feature set : 



Volume Control   VR1 : 250kΩ audio taper                                    
Middle Pickup Phase Swap   PP1 : DPDT push/pull switch

Treble Control   VR2 : 500kΩ audio taper (R2=25kΩ, R2P=499kΩ)
Parallel/Series Mode   PP2 : DPDT push/pull switch

Blend Control    VR3 : 500kΩ linear taper with no-load

Pickup Selector    SW1 : 2P5T lever switch Treble Compensation (R1=150kΩ, C1=1nF)

Treble Cut Mode   SW2 : DPDT 3-way toggle switch (on-on-on)        
Treble Tone Options   (C2U=8.2nF, C2D=33nF)

Bass Cut Mode     SW3 : DPDT 3-way toggle switch (on-on-on)      
Bass Tone Options     (R3U=250kΩ, C3U=1.8nF, R3D=500kΩ, C3D=4.7nF)



the wiring diagram :




once again, your feedback & comments are coveted

axedr