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Post by gckelloch on Oct 20, 2024 21:06:46 GMT -5
gckellochI like it. It's illuminating and clears up much ambiguity. Thank you very much for that work. Looks like that software worked out well for you. Mid dip: which frequencies get cut and by how many dB? I know this kind of depending on the resistor, value of the transformer, whether the transformer pot is at 10, 7. 3, 0 or whatever, etc, but I just want to to get a initial feel so I could 'nudge' it one way or another. I'm thinking Strat pickups don't have many mids anyway, but the concept could be really useful with thicker sounding pickups (P-90s maybe) or it quite likely I'm just missing the point here, that mid-dip is actually thicker in the mids (dipping heavily into mid but cutting higher frequencies, not suppressing them). Maybe a quick and dirty graph would clear that up for me. Transformer: do the P and S on the drawing have any meaning (parallel/series maybe?)? I see the connections are just to the outside terminals (on just one side) Low value caps: I'm with you on the values. It backs up what I've found in my experiments. Also having individual ones makes sense (especially for the bridge which needs the extra help). As far as the 2 and 4 position having the caps in parallel increases 'seen' cap value so even more highs are cut, so I'm not understanding what you said, "using one cap for each pickup not only makes 2 & 4 have virtually the same peak as the single pos's". I'm thinking the peak frequencies for 2+4 are going down, but maybe because the 2+4 are more 'thin' sounding it brings them back down? Anyway let me know how I should think about this. SC pickups: I presume the 1-3nF range for the low value caps is for the normal and low wind Alnico 5 type", is that right? I also have to work on a lot of Chinese ceramic SC with DC 5-6K, sometimes more. I suspect these same value apply but may be tempered as some say ceramics are less bright (I have done no testing) but sometimes find them annoying bright other times not so at all, but more mid strong. AlNiCo SC's don't really have less mids than P90's or other Fe core pickups. They just don't have rolled-off highs. There might be something about the wider coil and/or higher impedance of a P90 that affects the mids, but it's probably just the lower than AlNiCo V flux that tends to sound "fatter" along with less high-end. AlNiCo 2 SC's tend to sound sweeter/fatter than V. Fe core P90's already tend to roll-off by ~2kHz due to the much higher inductance - usually 7~9H - so the next lower peak to determine the cap value for would be ~1kHz. How deep the mid-dip goes will depend on the transformer (inductor) and pickup (also an inductor) values, but it should be more than you'd ever want when the knob is at 0. You could use a ~10k trim pot after the mid-dip pot if you are concerned about how it will feel at lower knob settings. Otherwise, I'd try a ~5k or ~10k R if you feel you need any R there at all. Trim pots are pretty cheap. The P and S on the transformer stand for Primary and Secondary. The Primary is usually the lower inductance side. The dip freq is just above the peak and determined by the cap value in series with the transformer, and the secondary high freq peak is determined by the combined transformer & pickup inductance. FI, the dip freq should be at 3~3.5kHz with ~1.5nF on a ~2.5H pickup. Reducing 3-3.5kHz produces a sweeter, more syrupy sound that gives the impression of being fatter because the less harsh midrange below it becomes more evident as the knob is turned down and a ~2kHz peak starts to come up. The lower midrange is untouched. The dip freq should be down at 600~800Hz with a 22nF cap. The mids below that range will also be untouched. That tends to sound more like an acoustic guitar-- not at all thin. With this mid-dip network, the secondary peak freq on a ~2.5H pickup should be as high as ~6kHz with a ~3H transformer, or ~8kHz with ~1.5H. That peak will be even higher in pos's 2 & 4 because the total pickup inductance in the circuit is ~1/2 of each when combined in parallel. Although the distributed pickup capacitance also doubles, it won't be high enough to bring the secondary peak freq down to where it was with just one pickup. Those secondary peaks will be a bit lower in both freq and amplitude with Fe core P90's. The "primary" peaks will be about the same in pos 2 & 4 with individual ~1nF+ caps of roughly the same value over each pickup. Although cap values sum in parallel, the total pickup inductance will be roughly half. 1.5~3nF is for AlNiC0 core SC pickups wound to ~6k with 42AWG wire, or with whatever wire gauge DCR value that produces ~2.5H, which is a classic Strat pickup inductance value. Chinese Fe core SC's wound with 42AWG wire to 5-6k should be in the 3~4H range. 1nF caps on each should then produce primary peaks in the 1.5~2kHz range-- well below the harsh 3-3.5kHz range. I'd at least use a 500k volume pot if not all 500k pots with those pickups. Annoyingly bright could be with all 500k pots and a cable C that puts the circuit peak in the 3-3.5kHz range. High cable or preamp input C will substantially affect the peak freq produced with a low-value cap. I'd limit cable C to ~200pF, especially with those higher H-value Chinese pickups. ~300pF is OK with ~2.5H AlNiCo pickups, but I prefer ~200pF or a bit lower. I'll post SPL graphs of my Wilde Q-filter later this week with all the relevant specs listed, and then some more SPL graphs when I get my Z11 core transformers. In the meantime, look at the results of a ~2H (tampered with 1.8H) Q-filter wired in a few different ways here. You can see the dip is as much as ~30dB if the 10k R over the cap is not included. There's more bass reduction than I expected with the 10K R in place, and the Cap looks almost completely bypassed when the knob is at 0. guitarnuts2.proboards.com/thread/8288/bill-lawrence-filter-analysis?page=1&scrollTo=85456Considering the flexibility trim pots offer, you might as well use a 20k after the mid-dip pot to keep the mid-dip from going too deep, and the peaks from being too strong when the pot is at o. There's no way to wire a trim pot over the caps to just the mid-dip knob with this wiring, but it shouldn't have a significant effect on the tone knob sound unless it's set below ~20k. I'd use a 50k for that one. Here's my revised diagram:  |
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Post by ssstonelover on Oct 22, 2024 17:10:59 GMT -5
AlNiCo SC's don't really have less mids than P90's or other Fe core pickups. They just don't have rolled-off highs. There might be something about the wider coil and/or higher impedance of a P90 that affects the mids, but it's probably just the lower than AlNiCo V flux that tends to sound "fatter" along with less high-end. AlNiCo 2 SC's tend to sound sweeter/fatter than V. Fe core P90's already tend to roll-off by ~2kHz due to the much higher inductance - usually 7~9H - so the next lower peak to determine the cap value for would be ~1kHz. How deep the mid-dip goes will depend on the transformer (inductor) and pickup (also an inductor) values, but it should be more than you'd ever want when the knob is at 0. You could use a ~10k trim pot after the mid-dip pot if you are concerned about how it will feel at lower knob settings. Otherwise, I'd try a ~5k or ~10k R if you feel you need any R there at all. Trim pots are pretty cheap. The P and S on the transformer stand for Primary and Secondary. The Primary is usually the lower inductance side. The dip freq is just above the peak and determined by the cap value in series with the transformer, and the secondary high freq peak is determined by the combined transformer & pickup inductance. FI, the dip freq should be at 3~3.5kHz with ~1.5nF on a ~2.5H pickup. Reducing 3-3.5kHz produces a sweeter, more syrupy sound that gives the impression of being fatter because the less harsh midrange below it becomes more evident as the knob is turned down and a ~2kHz peak starts to come up. The lower midrange is untouched. The dip freq should be down at 600~800Hz with a 22nF cap. The mids below that range will also be untouched. That tends to sound more like an acoustic guitar-- not at all thin. With this mid-dip network, the secondary peak freq on a ~2.5H pickup should be as high as ~6kHz with a ~3H transformer, or ~8kHz with ~1.5H. That peak will be even higher in pos's 2 & 4 because the total pickup inductance in the circuit is ~1/2 of each when combined in parallel. Although the distributed pickup capacitance also doubles, it won't be high enough to bring the secondary peak freq down to where it was with just one pickup. Those secondary peaks will be a bit lower in both freq and amplitude with Fe core P90's. The "primary" peaks will be about the same in pos 2 & 4 with individual ~1nF+ caps of roughly the same value over each pickup. Although cap values sum in parallel, the total pickup inductance will be roughly half. 1.5~3nF is for AlNiC0 core SC pickups wound to ~6k with 42AWG wire, or with whatever wire gauge DCR value that produces ~2.5H, which is a classic Strat pickup inductance value. Chinese Fe core SC's wound with 42AWG wire to 5-6k should be in the 3.5~4.5H range. 1nF caps on each should then produce primary peaks in the 1.5~2kHz range-- well below the harsh 3-3.5kHz range. I'd at least use a 500k volume pot if not all 500k pots with those pickups. Annoyingly bright could be with all 500k pots and a cable C that puts the circuit peak in the 3-3.5kHz range. High cable or preamp input C will substantially affect the peak freq produced with a low-value cap. I'd limit cable C to ~200pF, especially with those higher H-value Chinese pickups. ~300pF is OK with ~2.5H AlNiCo pickups, but I prefer ~200pF or a bit lower. I'll post SPL graphs of my Wilde Q-filter later this week with all the relevant specs listed, and then some more SPL graphs when I get my Z11 core transformers. In the meantime, look at the results of a ~2H (tampered with 1.8H) Q-filter wired in a few different ways here. You can see the dip is as much as ~30dB if the 10k R over the cap is not included. There's more bass reduction than I expected with the 10K R in place, and the Cap looks almost completely bypassed when the knob is at 0. guitarnuts2.proboards.com/thread/8288/bill-lawrence-filter-analysis?page=1&scrollTo=85456Considering the flexibility trim pots offer, you might as well use a 20k after the mid-dip pot to keep the mid-dip from going too deep, and the peaks from being too strong when the pot is at o. There's no way to wire a trim pot over the caps to just the mid-dip knob with this wiring, but it shouldn't have a significant effect on the tone knob sound unless it's set below ~2ok. I'd use a 50k for that one. Here's my revised diagram: The explanations make sense, and thanks for covering all the bases from Alnico 2, 5 to steel rod ceramic SCs and P-90 was welcomed. I do like the idea of the trim pots as well. Bringing in adjustability makes sense and I do enough rear mounted control cavities (for S-type guitars) that adjustments later are are simple and just a screwdriver away plus I have an amp right by the workbench. Sorry for the delayed response, I had to take care of some housework business yesterday (2 toilet installations) |
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Post by gckelloch on Oct 23, 2024 12:41:51 GMT -5
No problem. It gave me time to edit my post to be my best recommendation. I've installed/repaired 3 comodes in my 61 years, and am about to make it 4. As Danny Glover said in the Lethal Weapon films: "I'm getting too old for this sh!t" (pun intended). The tone and mid-dip options could be shared by the same knob, but being able to set a knob b4 switching to it could be useful. One could easily add another DPDT switch (and a 300~500k trim pot) to disable both knobs, giving quick access to the full pickup sound and setting the other switches AND both knobs b4 switching back to either one. Granted, 3 switches would be much harder to switch at once, but the option might be useful to some. I think this diagram is correct. I just had to swap the wire going to the 50k trim pot to the first common lug on the 5-way so it would be out of the circuit when the tone knobs are disabled.  |
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Post by gckelloch on Oct 31, 2024 18:49:14 GMT -5
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Post by ssstonelover on Nov 3, 2024 13:39:13 GMT -5
I just reverse the male/female individual banana plugs. Therefore the plug might be male on the hot jack side and female on the pickguard side, whereas the ground plug orientation would be flipped for the male/female combo on jack/pickguard side. Also the color codes on the wire are different. Also the tremolo claw will have a banana plug (different color wire to avoid confusion) so you can walk aorund the would with the pickguard off the guitar pretty easily and w/o delustering anything I've been tempted to use the JST SM connectors as you could bundle all three wires together (hot/ground/claw), or do a pair and then a single connector for the claw. I've never used one however and but this connecter does require a crimper, something probably good to have around anyway. |
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Post by gckelloch on Nov 3, 2024 13:56:53 GMT -5
I forgot about the trem/bridge wire. Guess I'll use one plug set without the cover for that.
Got my Z11 transformers today. The series DCR labels of each side are correct, but the listed L is way off. ~12H is listed for each side, but I get ~1.75H for each coil, and ~2.9H in series on each side. That's much closer to the advertised specs, and it makes sense that the stacked coils are less than 2x the value of each coil. Will get to wiring things up soon.
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