lelik
Rookie Solder Flinger
Posts: 16
Likes: 2
|
Post by lelik on Oct 6, 2024 1:53:06 GMT -5
It looks like your diagram will work, but I'd do a few things differently. I don't have expertise in any wiring software, but I can explain it pretty easily. If you aren't set on a 250k volume pot, a 500k pot would allow for some more tunability of a few toggle switch positions. I'd wire the tone pot off of whichever switch positions you need it on rather than before the switch so you don't need to adjust it for every switch pos. The following trim pot value suggestions are based on the volume pot being 500k. I'd definitely go with a 1nF cap for the ~4H Area T for the P90 and the alternate Q-filter sound. That will give a peak in the 1.5~2.2kHz range, depending on the R load. Rather than include the tone pot on those positions, I'd wire a 200k trim pot from switch lugs 3 and 4 to ground so you can adjust the peak levels to taste without affecting the depth of the mid-dip. Use two 200k trim pots if you want different peak levels for each Q-filter position. I think you can fit 4 trim pots in a Tele control cavity. I'd use double-sided foam tape to attach them to the back of the tone pot, and label them in a way that makes sense to you. Rather than use the tone pot on pos 1, you could wire a 200k trim pot from lug 1 to ground to tune the full pos 1 pickup sound to taste, and then wire a 1nF cap from lug 2 to the 250k tone pot to ground for a versatile tunable pos 2 P90 sound. Conversely, instead of the tone pot on pos 2, use a 200k trim pot from lug 2 to ground, and wire a 10-22nF from lug 1 to the 25ok tone pot to ground. I think the first option is more useful. If you find the initial ~2kHz peak too high for the pos 3 Q-filter sound, I'd go directly down to ~1kHz with a 4nF cap value. You can temporarily wrap another 1nF & 2nF (or a 3nF) over the 1nF for that. Then try removing just 1nF or 2nF to see what you prefer. More than 4nF will start to sound like the 10-22nF, but it's your choice. If you want the tone knob on both pos 1 and 2 with different caps for each, omit the trim pots and wire a 1o-22nF cap from lug 1 along with a 1nF cap from lug 2 to the 250k tone pot to ground. You'll then need to adjust the tone knob for those two positions if you want a P90 sound and an open sound. Regardless of where you use the 250k tone pot, I'd ground the open outer lug so the pos 2 P9o-style ~2kHz peak isn't too strong. The Z of a typical 7~9H Fe core P90 at 2kHz is ~100k Ohms or so vs ~25k Ohms for a typical AlNiCo core pickup (including the Area T). Even with 500k pots, there may be no significant peak with a Fe core P90, and the bass is slightly emphasized due to the eddy-current losses. You may then want to wire another 200k trim pot over pos 2 to reduce the peak more, but try it without at first. Rather than source different trim pots, you might try getting something like this: www.amazon.com/dp/B07WDCVGJV/ref=pd_sim_hxwPM1_sspa_dk_detail_0?There are also capacitor and resistor packs like that. Incidentally, you can use the second set of switch lugs as an "insert" to use two caps for different purposes for each switch pos if you leave the two common lugs unconnected. FI, you could wire a 1nF cap from lug A2 to B0. B2 could then go to the 250k tone pot, or to a trim pot, or a trim pot going to the Q-filter. All of which would go to ground. A4 could then go to a 1o-22nF cap to B0, and B4 can go to...wherever you like. The same applies for the other A side lugs. Each lug on the B side can go out to anywhere. I owe you a huge thank you for the information and effort on my project! To be honest, my head is exploding now, and it will take me some time to digest all the instructions and suggestions, and to translate them in layman's terms and into a diagram... but it's a nice and interesting challenge. About the inductor, actually I ordered this one you found out: www.aliexpress.us/item/3256801281563699.html? |
|
lelik
Rookie Solder Flinger
Posts: 16
Likes: 2
|
Post by lelik on Oct 6, 2024 2:35:01 GMT -5
FI, you could wire a 1nF cap from lug A2 to B0. B2 could then go to the 250k tone pot What is the function of this 1nF cap? Is it just a low cut filter? My idea was (but I could for sure change my mind following your fantastic tips) that I'd prefer to keep a general tone control. But at the same time, I'd like - if it'll be necessary when I try to play this "system" - to fine-tune each position of the switch with additional low- or high-cuts and/or additional resistors to reduce the volume in case the volume of each position is very unbalanced. Thanks to your idea, I guess I could use the "B" slugs to do that work... or maybe not?!? |
|
|
|
Post by gckelloch on Oct 6, 2024 2:39:38 GMT -5
That transformer should work, and I like how informative the description is. It seems really honest. I had recommended a few others after that one that have coil taps. Maybe it's not too late to cancel and order one of these Z11 SiFe alloy transformer pairs that have the inductance written on each coil: www.aliexpress.us/item/2255800936817835.html?Let me know if you need anything cleared up in my suggested wiring options. Going to sleep now, though. |
|
|
|
Post by gckelloch on Oct 6, 2024 3:33:49 GMT -5
FI, you could wire a 1nF cap from lug A2 to B0. B2 could then go to the 250k tone pot What is the function of this 1nF cap? Is it just a low cut filter? My idea was (but I could for sure change my mind following your fantastic tips) that I'd prefer to keep a general tone control. But at the same time, I'd like - if it'll be necessary when I try to play this "system" - to fine-tune each position of the switch with additional low- or high-cuts and/or additional resistors to reduce the volume in case the volume of each position is very unbalanced. Thanks to your idea, I guess I could use the "B" slugs to do that work... or maybe not?!? The 1nF cap from lug A2 to B0 is just the cap wired in parallel to the pickup for the P90 sound. The signal going through it would come out of lug B2 to a 250k pot or to a 200k trim pot. However, I was mistaken about using the same Cap for different positions along with a trim pot wired from any of the A lug sets to ground. You'd still need individual caps from each A lug set, but wiring them over to the B0 lug may offer anchoring points for components wired directly after the caps. I haven't suggested any bass reduction other than the 5-10k resistors on the Q-Filter position, but I actually think you should omit those resistors. A bridge position SC pickup wound with 42AWG wire is already pretty thin sounding. Reducing the bass would just make it that much thinner sounding. The trim pot (or pots) I suggested to wire over the Q-filter switch positions to ground are to adjust the peak levels. Any perceived loudness loss from the midrange dips can essentially be compensated for with those trim pots. You may just need to bring the 2kHz peak down a bit. The other two positions also allow for peak-level adjustment with either the tone pot or a trim pot. The bass level will be the same for each position. It should be good. |
|
|
|
Post by gckelloch on Oct 6, 2024 20:05:41 GMT -5
Once again, I had to correct something I wrote. I don't think there's any advantage in using the B lug set as cap inserts. Whichever caps are shared by any A lugs will also be shared with any trim pots wired from those A lugs to ground. The trim pots could be kept separate off a third lug set, but there isn't one. In short, forgo my cap insert idea for this project.
Luckily, you should have enough hard points for every solder joint, but you will need individual caps for each sound that involves a cap-- each of which will come from the designated A lug to the input of the designated trim or full-size pot, or to ground. The open outer lugs of the trim pots should not be grounded, but I'd ground the outer lug of the full-size 250k pot.
If you don't ground anything to the back of each full-size pot, you could probably tape 4 trim pots on the back of 1, and as much as 2 on the other to leave enough space to fit the transformer between the pots. For my wiring recommendation, you'd need 2 trim pots wired after the individual caps going to the Q-filter, and at least 1 wired over that signal path to ground, but 1 for each Q-filter option would be better. You'd then need just 1 more wired to ground from the remaining A lug that the tone pot is not on. I don't see how you'd need more than those 5 trim pots unless you want to add bass reduction caps, which I don't recommend.
|
|
lelik
Rookie Solder Flinger
Posts: 16
Likes: 2
|
Post by lelik on Oct 7, 2024 16:46:16 GMT -5
Maybe it's not too late to cancel and order one of these Z11 SiFe alloy transformer pairs that have the inductance written on each coil: The day after my order of the first inductor pairs you mentioned, I got the message that they were already sent. So, I can't change my order. No problem. When I get them I'll try to measure their inductance and then I'll ask a little more help... |
|
|
|
Post by gckelloch on Oct 7, 2024 19:36:17 GMT -5
I think the one you ordered is not a pair. Should be fine, though.
You could use 300k or 500k trim pots wired over the Q-filter positions to allow for stronger peaks. I doubt you'd want either one turned down much lower than to 200k, but you'd have the option of strong peaks without any drawback. Again, leave the outer lug open.
Say, I'm curious to hear more about the guitar specs. I assume it's the new Warmoth body.
|
|
|
|
Post by perfboardpatcher on Oct 8, 2024 0:50:24 GMT -5
I think the one you ordered is not a pair. Should be fine, though. I've read that you had to order 2 to receive the circuit board. But you have to take the data provided with a pinch of salt. The following was stated on the web page for the item lelik purchased: Note: In order to broaden the frequency response and reduce the leakage inductance, the secondary pole of the transformer is not a conventional parallel winding method. The copper resistance of the two ends of the coil center tap will be different and have errors, and the error is large. This is due to the internal and external layer winding method of the transformer. The copper resistance error caused by the inconsistent circumference size does not affect the balance use, and the perfectionist is required to be cautious when used for balance! ! ! Note: There are errors in the measurement of size, inductance, and resistance. Transformers are mainly based on inductance value, and the inductance value is selected for sale. |
|
|
|
Post by perfboardpatcher on Oct 16, 2024 1:13:42 GMT -5
Sorry Lelik, guys, The item I bought was exactly what I didn't need. It was pretty hard to find the resonance frequency, -5 dB notch in stead of -20 dB..( Depends on signal level.) Iron core. Eddie current losses.  The inductances based on my measurements were around 3.6 H (both sides) as advertised. Do not purchase for this particular application! I guess I have to find a new use for this high quality transformer for microphone. |
|
lelik
Rookie Solder Flinger
Posts: 16
Likes: 2
|
Post by lelik on Oct 16, 2024 7:10:26 GMT -5
Sorry Lelik, guys, The item I bought was exactly what I didn't need. It was pretty hard to find the resonance frequency, -5 dB notch in stead of -20 dB..( Depends on signal level.) Iron core. Eddie current losses. The inductances based on my measurements were around 3.6 H (both sides) as advertised. Do not purchase for this particular application! I guess I have to find a new use for this high quality transformer for microphone. Thanks for the information! Anyway I ordered this: www.aliexpress.us/item/3256801281563699.html?and sooner or later I'll get it and try to put together my special circuit. For sure I'll post again at that moment because I'll need a little help... |
|
|
|
Post by frets on Oct 16, 2024 13:27:54 GMT -5
Lelik,
It looks like you will have to connect these transformers in Series. They might already be; but looking at it, it looks like they are isolated. Maybe the board connects them. I think you bought the right choice.
|
|
|
|
Post by gckelloch on Oct 16, 2024 16:13:10 GMT -5
Sorry Lelik, guys, The item I bought was exactly what I didn't need. It was pretty hard to find the resonance frequency, -5 dB notch instead of -20 dB..( Depends on signal level.) Iron core. Eddie current losses. The inductances based on my measurements were around 3.6 H (both sides) as advertised. Do not purchase for this particular application! I guess I have to find a new use for this high quality transformer for microphone. What are you trying to do with it? From the diagram and the description, coil 3-4 may be wrapped around coil 1-2, and 7-8 around 5-6. Either way, I'd try using just coil 1-2 or 3-4 in series with a cap if you want to use it as a passive midrange-cut/mid-dip. You won't get much of a high freq peak if you use two coils in series with an Fe core pickup. You should get more midrange cut with one coil, but the high freq peak still won't be very strong with an Fe core pickup. EE25 is supposed to be Ferrite. It is non-conductive and should not cause eddy currents. Ferrite is very cheap ceramic-based stuff. I doubt they'd substitute it with Iron. |
|
|
|
Post by perfboardpatcher on Oct 17, 2024 6:20:00 GMT -5
EE25 is supposed to be Ferrite. It is non-conductive and should not cause eddy currents. Ferrite is very cheap ceramic-based stuff. I doubt they'd substitute it with Iron. The core material is shiny, it conducts electricity, it's laminated. It must be iron. |
|
lelik
Rookie Solder Flinger
Posts: 16
Likes: 2
|
Post by lelik on Oct 17, 2024 16:31:45 GMT -5
|
|
|
|
Post by gckelloch on Oct 17, 2024 18:37:00 GMT -5
I think it depends on the freqs at which the LCR meter measures the inductor. It might give somewhat high readings if it starts at 1kHz. Mine generates freq's starting at 140Hz. Maybe it takes an average at various freqs or something. I touched the leads to a guitar cable to the Hi-Z input of my audio interface and could see the freq's on an SPL graph in my PC. You might try that. It might even show whether there is any high-end roll-off if you run it through the transformer. Either way, it looks like you have something close to what you want. 2~3H should be good. You could also connect the outer two lugs on that side to take a parallel reading. I guess it should show ~1.5H.
|
|
lelik
Rookie Solder Flinger
Posts: 16
Likes: 2
|
Post by lelik on Oct 20, 2024 9:32:17 GMT -5
I touched the leads to a guitar cable to the Hi-Z input of my audio interface and could see the freq's on an SPL graph in my PC. You might try that. Terrific idea! I did it... and I see that my tester generates a 274Hz peak and its harmonics (with less power gradually).  |
|
