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JohnH

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  1. A parallel treble bleed circuit will move the taper towards what youd like and also maintain more consistent tone. 150k in parallel with 1nF if you have a 500k pot, od use 120k with a 250k pot
  2. You might be interested to add a simple buffer stage after the pickup, then you can drive the 100k pot with no loss. You can build that with a bout $1 of components, being a resistor, a capacitor and a Junction Field Effect Transistor. have a look at the one built into a cable here: http://guitarnuts2.proboards.com/index.cgi?board=schem&action=display&thread=3150 If you build it into the guitar instead of a cable and box, you could omit R2 R3 and C3 if you wish the output would go to your volume pot and amp. Maybe make C2 about 1uF. J
  3. just on my post above - I cant seem to edit it today. The last part about coil cutting, I got the B and N wrong way round when I was talking about which centre connection gets grounded to where, since I see it is the neck pup that you want to have different coils cut to. I hope its almost clear - but the theory should be OK! J
  4. Agreed - and I just wanted to add that its just a basic Tele switch, so easily obtained. On a Tele, the other half of the switch comes into play to get the B,B+N,N.
  5. I reckon its all possible. the key to getting all the phasing to happen on one switch is to note that you never wish to have more than two pickups at a time. So, use the superswitch to select any two pickups Pickup1 Pickup2 Neck none Neck Middle Neck Bridge Middle Bridge none Bridge One pair of switch poles select pickup1, one pair selects pickup2. In each pair, one pole selects the ground side, the other the hot side of the humbucker or single-coil middle. So you end up with not three but two virtual pickups. Put the phase switch on 'pickup2' For coil cuts, use a dpdt to connect the series links in the centre of the humbucker coils to actual ground for the bridge pup and to the cold side of the neck pickup (ie where it usually is grounded. Now, to get position 3, select the neck and bridge pickups in reverse - hot to ground and cold to output. Due to the above coil cuts, the bridge coil slected will reverse but the neck single coil will remain. Both puops are reverse phase so overall phase is OK. Youll get phasing in all settings of two pickups. Also,if you select bridge only and pull the phase switch,you get to hear the other bridge coil. What Im talking about is similar to this HSS design: http://guitarnuts2.proboards.com/index.cgi?board=schem&action=display&thread=5624 You only need to change a single coil neck to a humbucker, and use the other half of the coil-cut switch as above to get your result. My design also has overall series/parallel, which you could omit. John
  6. Hi bob - Ive done pretty much what you are working on. Its all written up on Guitarnuts2: http://guitarnuts2.proboards.com/index.cgi?board=schem&action=display&thread=3718 John
  7. Pete - thanks for pointing to my GN2 thread I also initially had huge subsonic pulses to deal with, so that if you pressed the bridge the signal would die for a second or more. The thing is, when you press a piezo, it makes a charge, and if you press it alot, its a significant level, larger than the music signal and swamps it. The nature of it is like the piezo is acting as a capacitor, and generating charges across its plates. I think the best way to control these unwanted very low frequency signals is to bleed them off, by lowering the input resistace of the preamp. My piezo (based on a buzzer) has a capacitance of 20nF, so 150k gives a roll off from about 50Hz and below. Other values would apply for different piezos. This fixed the problem in my case and has no effect on the low musical notes. So I think that the idea that very high input impedances are always needed for piezos is not always true. It would only be so if he piezo capacitance is very small. John
  8. This one of mine might be of interest: http://guitarnuts2.proboards.com/index.cgi...amp;thread=4571 Based around an LP, with its 2V and 2T, I have a standard way of wiring the pickups to their individual tone and volums, then six options for switching it all together, one of which is a rotary. Ive built one of them (though not the rotary scheme), so I know the idea is OK John
  9. I put a piezo element into my Ibanez Strat, placed between trem block and back of body, so that all the vibrations from the block need to go through the piezo. It worked out pretty well, after I had put together a suitable preamp to EQ it and mix with the mag pickups. Its all written up with photos and sounds clips here: http://guitarnuts2.proboards.com/index.cgi...amp;thread=3718 John
  10. You can mostly picture how it works from looking at it. Most probably, the two centre lugs are the poles and get joined together and go to the volume pot. The three outer lugs on each end are as the three other lugs on each side of the wiring diagram. Or another way to look at it. Number lugs 1 to 8 left to right 1 and 2 go to bridge pup 4 and 5 go to volume pot, 7 and 8 go to neck pup With lever pushed to the right, it will be selecting neck only It doesnt matter which side of the switch you are looking at when you read the above. John
  11. A mini-toggle will do it fine, just a single pole one with 3 lugs. Wire the centre lug and one outer lug between hot and ground, to shunt the output to ground. This way its dead quiet, better than just disconnecting the output leaving it floating, which causes noise. As a variant, these mini-toggles can also come with three positions, being on, centre off, on, with one of the on positions springing back to the centre. I reckon that could make it easier for those staccato effects, and use the other on for kill switch between songs. You would use all three lugs, wiring the two outer lugs together John
  12. It could easily be done, but Im not going to tell you
  13. So it would be three positions, Bridge, Bridge + Neck, Neck? That will work fine. your rotary switch will probably have 4 inner lugs, one for each pole, and 12 outer lugs being 3 lug connections for each pole. You should identify which lugs connect to each pole, visually or with a meter. They should be the 3 nearest outer ones for each inner pole. call the inner poles 1, 2, 3 and 4 call the outer lugs 1A, 1B, 1C, 2A, 2B....etc corresponding to three switch positions A, B and C You only need two poles, so ignore half the switch Wire your pickups: ground to guitar ground, bridge hot to Pole 1 and neck hot to Pole 2 run a wire that connects these four outer lugs, 1A to 1B to 2B to 2C and then to the volume control for output thats it! John
  14. Are you getting enough overall volume? The standard opamps such as 741 have an output resistance of 75 Ohms. Headphones, such as used with mp3 players have quite low resistance, mine measure 16 Ohms, or 8 ohms if both sides are being driven. So the chip cant drive the phones to more than about 10% of the available voltage swing, which is about a 20db loss. A couple of transistors in a push/pull configuration to drive the output might help.
  15. If its a dual-gang blend pot, where on one half the left lug is ground and the right is hot, and vice-versa on the other half, then a good candidate for the answer is that the ground and hot lugs are the wrong way round. You can try swapping the pickup and ground connections that you have from the inner half of the pot to the outer half, and outer to inner. Keep the diagonal X across the outer lugs. The thing is, if its what Im thinking of, these pots have 50% of their track (say from left to centre) of very low resistance, and 50% where it builds up the reisistance to change the volume(say right to centre). The inner and outer halves are reversed left to right. So if you wire it right, in the middle position, both pups have a low resistance to hot and a high resistance to ground, and so both work. But if its the wrong way round, then the middle eposition gives both pups a low resistance to ground and high resistance to hot, hence no sound there, which is what you are describing. John
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