Mid cut with passive circuit

[lelik]

I'm building a single pickup guitar (using the Area T 615 from Dimarzio in the bridge) and I'd like to get more types of sound from it.
I'm very interested in adding a passive mid cut switch for this reason to simulate (just a little) a kind of position 2 or 4 of a Strat guitar or just to get more flexibility.

I'm in Italy and the shipment of the commercial stuff is rather expensive; no second hand parts are available and typical Mouser inductors suggested in some posts aren't available locally.

Before ordering any commercial expensive part, I wonder if anyone has some experience and comparisons about something like:
- Rothstein RG500d
- Bill Lawrence Q-filter (bass or guitar version)
- THD Quintet Tone Curve module
It seems they all could be a good choice. I'm also open to any other suggestions in case (except for building an inductor by myself, I'm afraid I can't...). The THD module seems to be very interesting with its "presets" but I don't even know if it uses an inductor and the only demo I found on YouTube is pretty awful.
Thanks!

[gckelloch]

They are all a bit overpriced for what they are, IMHO. I have a BL Q-filter set up as a "Q-tone" and it works great. Not sure about the others, but the Q-filter is very low Z with only a few hundred winds. The inductance value is achieved by compressing the coil within two pieces. The highs are not damped down as with a high Z device, and there's also no significant added noise.

It's impossible to know how much R you'll want in front if you use it on a switch. You might mount it on a P/P pot as a Q-tone, or experiment with a few trim pots. Trim pots are linear taper. I'd try a 100k or 200K and one around 20k or 30k for a deeper setting. A 3-pos switch might be nice in that case. You could also use individual cap values for each position, and either bypass the tone knob on the Q-filter settings or use another 200k trim pot before the tone pot cap to take the edge off. I have a tone knob with the Q-filter, and I find turning them both down about the same works very well. It's all personal taste.

[lelik]

Sept 29, 2024 15:28:30 GMT -5 gckelloch said:

They are all a bit overpriced for what they are, IMHO. I have a BL Q-filter set up as a "Q-tone" and it works great. Not sure about the others, but the Q-filter is very low Z with only a few hundred winds. The inductance value is achieved by compressing the coil within two pieces. The highs are not damped down as with a high Z device, and there's also no significant added noise.

It's impossible to know how much R you'll want in front if you use it on a switch. You might mount it on a P/P pot as a Q-tone, or experiment with a few trim pots. Trim pots are linear taper. I'd try a 100k or 200K and one around 20k or 30k for a deeper setting. A 3-pos switch might be nice in that case. You could also use individual cap values for each position, and either bypass the tone knob on the Q-filter settings or use another 200k trim pot before the tone pot cap to take the edge off. I have a tone knob with the Q-filter, and I find turning them both down about the same works very well. It's all personal taste.

Thank you for your information, it's very interesting for me.
By the way: did you use the guitar or bass version of q-filter?
I see this post: guitarnuts2.proboards.com/thread/8288/bill-lawrence-filter-analysis
by Antigua about the higher inductance of the bass version that could be useful for guitar pickups too.

Thanks also for your tips about using pots or trimmers to find out the best sound.
My target is really to fine-tune the system, and then to use a switch for a quick passage from one "preset" to the other(s) with fixed resistors and caps.

Considering that the shipping costs from BillLawrence - Wilde Pickups is $33 (more than the price of each inductor), maybe I'll get two pieces, one standard and one bass version so that I can try them, or even use both to get two different "presets".

[gckelloch]

I can see getting one of each Q-filter to try. My understanding of when it's wired with a cap in series is the cap and pickup values determine the corner freq below the mid-dip, while the high freq peak is determined by the pickup, filter and cable C (Capacitance) values. The 3H filter would then have a lower freq peak with a given cable C. Assuming the DiMarzio T 615 is ~3.2H, the L (Inductance) would only go down to ~1.6H with the Bass filter. That can give highs in the 8kHz range with a low C cable. The guitar filter could offer highs in the 10kHz+ range, which is good for acoustic guitar sounds. Can't say which you'd prefer, but the cap value should give the same corner freq with either filter. A low C cable can also smooth out the high freq peak-- particularly if the T 615 has very low internal C, which it likely does.

The Q-filter doesn't offer the same sound as two pickups in parallel because it doesn't produce the comb-filtering effect that cancels different freq sets for each string, but I would suggest trying a 1.5~2nF cap value for one of the switch options. I'd think that would be more like a pos 2 sound than with a much higher value cap that dips the entire 1.5~2kHz range. I think a lower cap value like that also boosts the corner freq for very good clarity while reducing the harsh 3-3.5kHz range.

You can still use a 5-10k R in parallel with the cap and both in series with the filter. That reduces the bass a bit at lower knob settings as well as keeps the peaks from being very sharp. 10k would reduce bass a bit more. If you don't want any bass reduction but do want smoother peaks and prefer to reduce the part count, you could just try grounding the other outer lug of each trim pot.

BTW, I think a 100k linear trim pot would be more useful than a 200k for the more shallow dip setting. You'd want to use the 20~30k trim pot with the lower cap value to get any corner freq boost.

[lelik]

Sept 30, 2024 18:46:02 GMT -5 gckelloch said:

I can see getting one of each Q-filter to try. My understanding of when it's wired with a cap in series is the cap and pickup values determine the corner freq below the mid-dip, while the high freq peak is determined by the pickup, filter and cable C (Capacitance) values. The 3H filter would then have a lower freq peak with a given cable C. Assuming the DiMarzio T 615 is ~3.2H, the L (Inductance) would only go down to ~1.6H with the Bass filter. That can give highs in the 8kHz range with a low C cable. The guitar filter could offer highs in the 10kHz+ range, which is good for acoustic guitar sounds. Can't say which you'd prefer, but the cap value should give the same corner freq with either filter. A low C cable can also smooth out the high freq peak-- particularly if the T 615 has very low internal C, which it likely does.

The Q-filter doesn't offer the same sound as two pickups in parallel because it doesn't produce the comb-filtering effect that cancels different freq sets for each string, but I would suggest trying a 1.5~2nF cap value for one of the switch options. I'd think that would be more like a pos 2 sound than with a much higher value cap that dips the entire 1.5~2kHz range. I think a lower cap value like that also boosts the corner freq for very good clarity while reducing the harsh 3-3.5kHz range.

You can still use a 5-10k R in parallel with the cap and both in series with the filter. That reduces the bass a bit at lower knob settings as well as keeps the peaks from being very sharp. 10k would reduce bass a bit more. If you don't want any bass reduction but do want smoother peaks and prefer to reduce the part count, you could just try grounding the other outer lug of each trim pot.

BTW, I think a 100k linear trim pot would be more useful than a 200k for the more shallow dip setting. You'd want to use the 20~30k trim pot with the lower cap value to get any corner freq boost.

Thanks a lot for your terrific suggestions! 🙏

In the meanwhile, after writing a message to THD, asking more information about the circuit of their module, I got this simple reply: "The Quintet has 6 capacitors, 4 inductors, and no resistors". It's interesting, but it's a pity I couldn't find any sound samples or video demos.

[frets]

Hi Lelik,

I just wanted to say that you might want to think about the Rothstein for your mid cut. I think it’s easier to put in the guitar and I prefer it to the Wilde filter. With it you just pop the pot into one of your tone positions. Simple to wire up. Plus, I think it might be cheaper (although I haven’t checked prices). And with the Rothstein, you get a two sided effect rolling to 0 or 10. Just a thought.

[gckelloch]

Oct 1, 2024 11:57:07 GMT -5 frets said:

I just wanted to say that you might want to think about the Rothstein for your mid cut. I think it’s easier to put in the guitar and I prefer it to the Wilde filter. With it you just pop the pot into one of your tone positions. Simple to wire up. Plus, I think it might be cheaper (although I haven’t checked prices). And with the Rothstein, you get a two sided effect rolling to 0 or 10. Just a thought.

I'm all for saving money and time. The only consideration about the Rothstein, which is ~$100, is it looks like an off-the-shelf audio transformer for the inductor. The Z might be so high that the high freq peak is damped down a lot. No way to tell unless someone posts an example SPL, which can generally be sampled with white noise through an earbud, placed over a pickup, and into a computer with SPL graph software. Details of the guitar electronics should also be provided.

The SPL graph of the THD Quintet module shows some damping, but not enough component details are provided to know how much damping would occur with your setup. At least the Volume pot value and pickup specs would have been helpful. FI, how do we know the SPL is not taken with a very low L AlNiCo core pickup and a 1M Volume pot? Why they have the two lowest freq peaks right in the harshest range is beyond me, but that will depend on the pickup inductance. At least we can see that peaks in that range do indeed have significant amplitude. Much higher or lower cap values would not show as much boost, as is seen in the higher freq peaks.

[unreg]

Oct 1, 2024 18:14:51 GMT -5 gckelloch said:

Why they have the two lowest freq peaks right in the harshest range is beyond me, but that will depend on the pickup inductance. At least we can see that peaks in that range do indeed have significant amplitude. Much higher or lower cap values would not show as much boost, as is seen in the higher freq peaks.

Your words above are difficult to piece together, partly since lots of your sentences lack direction. What higher frequency peaks, at the end of my last of your quoted sentences, are you talking about?

You are obviously in an entirely different ballpark than me. You know what you are thinking, but you hardly try to help me connect your dots. I guess, if I know what you are talking about too, I should be able to connect the dots myself?

Simply, I can appreciate frets’ words, but your reply leaves me lost wondering about what you are attempting to say.

I also don’t usually understand ChrisK, but his words are usually fun for me to read since he usually provides some direction.

[gckelloch]

Not sure what you mean by my words lacking "direction", unreg. Do you mean they don't point toward a definitive conclusion, or that I don't provide enough clear info for you to follow?

Hopefully, this will help: I referred to the other initial freq peaks just above the ~3kHz peak produced by each switch pos on the THD Quintet module SPL graph, which are progressively lower in amplitude. I guess I didn't make that clear.

I may not be as entertaining as some other members, but I generally expect some compensation for my entertainment services. I'll be here all week. Two shows a night, and please remember to tip your wait staff and bartenders...ladies and gentlemen.

[lelik]

Oct 1, 2024 11:57:07 GMT -5 frets said:

I just wanted to say that you might want to think about the Rothstein for your mid cut. I think it’s easier to put in the guitar and I prefer it to the Wilde filter. With it you just pop the pot into one of your tone positions. Simple to wire up. Plus, I think it might be cheaper (although I haven’t checked prices). And with the Rothstein, you get a two sided effect rolling to 0 or 10. Just a thought.

Did you have the chance to try and compare the Rothstein against something else?
The Rothstein and the THD circuits are interesting because they are already "complete" products, even if at the same time they could offer less flexibility and adjustment and they are also more expensive!

The cost of these things to be sent to my Italy are rather high unfortunately. 
This is what I see (with shipment to Italy, and not including the Italian VAT of 22%, yet, on top of all the costs including shipment)

Rothstein RG500D Midrange Shaper: USD 160
(90+70 shipping cost)

THD Quintet with 6 position switch: USD 135
(99+36 shipping cost; it seems that if I buy it from the Australian dealer I could save a little)

Bill Lawrence Q-Filter (2 pieces: 1 bass + 1 guitar): USD 98 
(64+34 shipping cost) or USD 66 if I get just one piece

[frets]

Lelik,

That’s a big price differential. I would go with the cheapest.

[mikecg]

Hello lelik,

These three links may be of interest:


guitarnuts2.proboards.com/thread/4309/inductors-passive-guitars


www.ebay.co.uk/sch/i.html?_dkr=1&iconV2Request=true&_blrs=recall_filtering&_ssn=kellingsound88&_oac=1&_nkw=varitone


www.ebay.co.uk/itm/196572683706?_skw=mid&itmmeta=01J97GNAYY9BS5R3V8CBJ7JY2E&hash=item2dc4a51dba:g:OGoAAOSwX-BflhmI

[unreg]

Oct 2, 2024 13:16:52 GMT -5 mikecg said:

www.ebay.co.uk/itm/196572683706?_skw=mid&itmmeta=01J97GNAYY9BS5R3V8CBJ7JY2E&hash=item2dc4a51dba:g:OGoAAOSwX-BflhmI

This version of that link also works for me: www.ebay.co.uk/itm/196572683706

The ? and everything following can usually be removed since that ? usually only specifies browser specific info.

[gckelloch]

Say, I was way off on the L of the Area T 615. Antigua did a full analysis of it here: www.tdpri.com/threads/dimarzio-area-t-analysis.1013907/

The 1.8H Q-filter could bring the Area T to as low as 1H, while the 3H filter could bring it to 1.8H. Unless you want acoustic guitar-like ~10kHz highs (which are well above the range of almost every guitar speaker), just a 3H filter might be fine-- allowing a high peak in the ~6kHz range when fully in parallel, and using a low C (~200pF) cable. I'd get such a cable if you don't already have one. It will give the Area T better articulation without the tinny harshness. A decent 3-pos switch, trim pots and some low-value caps might cost another $20~30, but at least you'll know the highs will be audible when you engage the Q-Filter.

Those cheaper options with transformers as inductors are tempting, but there's no telling what the Z is in the higher freqs. Z measurements are generally given at 1kHz. The Z could be much higher at 6kHz, and taking the tone pot R from the circuit won't bring the peak up much at all. It could be down ~6dB or more at 6kHz depending on the transformer core alloy. I don't know if Gibson even understood that when they designed the Varitone. BL did once tell me they didn't know bunk about electronics when he took over as chief engineer in the late 60s.

The other option is to order a Ferrite pot core and try winding and compressing your own low Z inductor, but that would end up costing about the same as a Q-Filter, and I wouldn't know what size wire would be ideal to achieve the desired L, and you'd need a decent LCR meter to measure it.

~$100 is a lot for such a simple function when an active 3-band eq can be had for ~$25+, or another pickup could be even less.

[lelik]

Oct 2, 2024 21:19:09 GMT -5 gckelloch said:

Say, I was way off on the L of the Area T 615. Antigua did a full analysis of it here: www.tdpri.com/threads/dimarzio-area-t-analysis.1013907/

The 1.8H Q-filter could bring the Area T to as low as 1H, while the 3H filter could bring it to 1.8H. Unless you want acoustic guitar-like ~10kHz highs (which are well above the range of almost every guitar speaker), just a 3H filter might be fine-- allowing a high peak in the ~6kHz range when fully in parallel, and using a low C (~200pF) cable. I'd get such a cable if you don't already have one. It will give the Area T better articulation without the tinny harshness. A decent 3-pos switch, trim pots and some low-value caps might cost another $20~30, but at least you'll know the highs will be audible when you engage the Q-Filter.

Those cheaper options with transformers as inductors are tempting, but there's no telling what the Z is in the higher freqs. Z measurements are generally given at 1kHz. The Z could be much higher at 6kHz, and taking the tone pot R from the circuit won't bring the peak up much at all. It could be down ~6dB or more at 6kHz depending on the transformer core alloy. I don't know if Gibson even understood that when they designed the Varitone. BL did once tell me they didn't know bunk about electronics when he took over as chief engineer in the late 60s.

The other option is to order a Ferrite pot core and try winding and compressing your own low Z inductor, but that would end up costing about the same as a Q-Filter, and I wouldn't know what size wire would be ideal to achieve the desired L, and you'd need a decent LCR meter to measure it.

~$100 is a lot for such a simple function when an active 3-band eq can be had for ~$25+, or another pickup could be even less.

I'm very grateful for all the information and attention to my question.

The pickup I plan to get for my single pickup guitar is slightly different from the one analysed by Antigua - that was DiMarzio DP418, on the contrary I will get the DP424 - but the difference is really small; I think that their induction will be very similar.
At the end, I was also thinking to order just the "bass" version Wilde q-filter and experiment a little with it using different caps and resistors (including trimmers/pots) and taking note of the values I like.

My ideal target would be to use a Tele 4 position switch (plus a volume and tone control with treble bleed, too), and I'd like to wire it in order to get:
- the standard pickup connection
- the pickup with a resistor and a cap in parallel to get a kind of humbucker (or maybe P90) sound
- two different sounds from the q-filter (using different caps/resistors) or from the mid-scoop circuit I'll get

Actually I really don't know if it is possible using a normal Tele-like selector or if I should use a 5 position switch (I mean the "super" version that is more flexible) or something else. Maybe I'll have to go out of my comfort zone and beyond my knowledge to study a little more this project and I'll ask some more questions in this forum since you are all so knowledgeable and so kind!
But it will take a lot of time; I'm not ready with my guitar build, yet.

By the way, you're right: using a second pickup could be easier, less expensive, and even more flexible... but I like a new challenge and a weirder guitar configuration, considering that it will be a rather original body shape (a kind of "offset Telecaster" or a "Jazzmaster" with a shorter body, and with the new strange VT2 tremolo from Vega Trem). And nobody says that at the end I couldn't add the second pickup anyway!

[gckelloch]

You can get all those settings with a 4-way Tele switch. Just wire the components you want off the second set of lugs. FI, wire the tone pot from whichever of the second set of lugs you want > the cap value you want > ground. Wire the second lug > a 1~1.5nF cap & a 200k trim pot > ground. Wire the third lug > a 1~1.5nF cap & a 5-10k R > a 20-30k trim pot > the Q-filter > ground. Wire the fourth lug > a 10~22nF cap & a 5-10k R > 100k trim pot > the Q-filter > ground. Don't include the 5-10k R's if you don't want any bass reduction. If you don't include the tone knob on the Q-Filter positions, you might want to add a 500k trim pot from those two lugs > ground so you can control the high freq peak level.

If you order a Wilde Q-Filter, you might save money by including a Wilde L290TL. It's more punchy and has higher output than the Area T, yet has low string pull. It's 4.2H with a mid-60s Tele-type sound. Maybe use a 500k volume pot for more 4kHz+ chime when the tone knob is up. I'd go with 250k for the tone pot. I think the L298TL is ~5H. It also has the highly permeable/low conductivity 400 series pole pieces that don't roll off the highs, but has AlNiCo 8 side magnets instead of C5, and the coils are shorter and fatter. It's not quite as clear sounding or as loud as the L290TL. I think the L200TL is 4H. It has AlNiCo 2 poles with Ferrite side bars. It's thinner sounding with the tallest coils of the three to produce a midrange dip and lower output than the others. You don't need the mid-dip with the Q-Filter. I'd go for the L290TL. It's the most versatile of the three. I believe you can specify a flat or modern pole stagger in your order. The default is flat.

[frets]

Another option is to buy from Mouser a 42TL019 10K Ohms 3.75 Henry transformer for $5.

We have to remember it’s all about the sound produced. We can get involved in the technical details about the inductor but how it sounds is “what matters most.” And I can say there is not much difference between a 1.5H and a 4H - “sound wise.” Personally, a 1.5H sounds the best to me.

Buying the transformer from Mouser will probably be the cheapest alternative. I think they ship overseas. And they are simple to wire. I believe there are diagrams on how to do it on the forum.

[gckelloch]

Oct 3, 2024 15:25:20 GMT -5 frets said:

Another option is to buy from Mouser a 42TL019 10K Ohms 3.75 Henry transformer for $5.

We have to remember it’s all about the sound produced. We can get involved in the technical details about the inductor but how it sounds is “what matters most.” And I can say there is not much difference between a 1.5H and a 4H - “sound wise.” Personally, a 1.5H sounds the best to me.

Buying the transformer from Mouser will probably be the cheapest alternative. I think they ship overseas. And they are simple to wire. I believe there are diagrams on how to do it on the forum.

I agree the inductance may not make that much difference. It's the Z (impedance) at higher freqs that matters. It may be very high at 6kHz depending on the core alloy. Might be worth trying it first. The 1.5H should have a higher Q so the high freq peak will be a bit stronger.

[lelik]

Oct 3, 2024 2:47:40 GMT -5 gckelloch said:

I'd go for the L290TL. It's the most versatile of the three. I believe you can specify a flat or modern pole stagger in your order. The default is flat.

It's an excellent suggestion! And I checked immediately the Wilde shopping site, finding out that if I add a pickup (to the order of the q-filter) the shipping costs go from 30 to 60 $ because the only option is DHL express (and I have always to consider the Italian sales tax +22% and the custom duties, everything is calculated on the shipping costs, too; and over Eur 150 there is also a tariff duty!).
I'm afraid it doesn't make sense, unfortunately.
No final decision for now, but my favorite choice is still Q-filter (bass version) from Wilde, and then Dimarzio DP424 bought locally.

[newey]

lelik-

I appreciate your difficulties with duties, taxes and so forth. In the past, we Nutz here have, on occasion, been able to make "other arrangements".

For example, would all of those duties, taxes and so forth be applied if someone from the US were to send you a birthday present?

Second, when is your birthday?

[gckelloch]

I'm sure the Area T is fine. BTW, I changed my recommendation of a 1.5~2nF cap value to 1~1.5nF because I was initially basing my values on pickups I have in the ~3H range. I'd start with 1nF for a ~4H pickup for the P90 and the alternate Q-filter option. That will give it a peak in the 1.5~2.2kHz range, depending on the R load.

I was thinking you might want to leave switch pos one without any components but just a 500k trim pot> ground to tune the full pickup sound. You could then use a 1nF cap on the 250k tone knob for pos 2 for a tunable P90 sound. It offers a lot of usable sounds if you don't need a very dark tone. With a 500k volume knob, the most "mellow" tones should be between 4~6 on the knob. P90 sounds will be below 4. You might find ~2.5 to be the most P90ish. This is all assuming you plug into a 1M Ohm input.

[perfboardpatcher]

Sept 29, 2024 1:49:04 GMT -5 lelik said:

I'm building a single pickup guitar (using the Area T 615 from Dimarzio in the bridge) and I'd like to get more types of sound from it.
I'm very interested in adding a passive mid cut switch for this reason to simulate (just a little) a kind of position 2 or 4 of a Strat guitar or just to get more flexibility.

I'm in Italy and the shipment of the commercial stuff is rather expensive; no second hand parts are available and typical Mouser inductors suggested in some posts aren't available locally.

Before ordering any commercial expensive part, I wonder if anyone has some experience and comparisons about something like:
- Rothstein RG500d
- Bill Lawrence Q-filter (bass or guitar version)
- THD Quintet Tone Curve module
It seems they all could be a good choice. I'm also open to any other suggestions in case (except for building an inductor by myself, I'm afraid I can't...). The THD module seems to be very interesting with its "presets" but I don't even know if it uses an inductor and the only demo I found on YouTube is pretty awful.
Thanks!

I have been looking for something cheap. The problem is that most of the time the essential information is missing. The ones I purchased earlier on the Conrad website were really cheap and came together with a datasheet that provided me with information e.g. 1350 turns, 6 Henry minimal, DC resistance 670 ohms, impedance 5000 ohms minimal. In reality these inductors proved to have an inductance between 11 and 16 Henries. Unfortunately not available anymore. Conrad was selling a 2.5H version.

I came across this one. audio transformer ee25 microphone audiosignal
I myself ordered 2 of them. I cannot confirm if this is available in Italy. I changed nl into it and destination into Roma and got a price of 0.93 euro and no shipping costs. Very unlikely! You need to check it out for yourself if you're interested.

If the image on smartphone was hard to read, according to the information offered this item appears to have 2 coils of 3.6 H or even 4 coils of 1.8 H.

[gckelloch]

Aha! Here's one with a Permalloy core and a 200 Ohm 2.5-3H primary for $10. Permalloy is more expensive than cold rolled Steel but has low eddy-current loss for much better high freq response. BL did mention Permalloy when designing his Micro-Coil pickups. It looks like it might come as a pair. I assume you could wire the two primaries in parallel if you want ~1.5H.

www.aliexpress.us/item/3256801281563699.html?

[lelik]

Oct 4, 2024 9:55:19 GMT -5 gckelloch said:

Aha! Here's one with a Permalloy core and a 200 Ohm 2.5-3H primary for $10. Permalloy is more expensive than cold rolled Steel but has low eddy-current loss for much better high freq response. BL did mention Permalloy when designing his Micro-Coil pickups. It looks like it might come as a pair. I assume you could wire the two primaries in parallel if you want ~1.5H.

www.aliexpress.us/item/3256801281563699.html?

Wow, this is very interesting, and I'm really tempted to try 
Once more: thanks for the tips and the help with my project!

[gckelloch]

Whoa! Here are two low-Z symmetrical isolation transformer pair options with coil taps, each offering at least three L (inductance) values. Z11 Silicon Steel is cheaper and also has low-eddy current loss, but might be slightly higher or lower L than the EE19 Permalloy. The L values are not given, but I'd assume the 600 Ohm path is about the same 2.5-3H as the first 600 Ohm Permalloy transformer I linked to. Just one coil tap should then be ~1.8H, and both in parallel might be ~0.7H. You might even be able to wire both sides in series for a total of ~6H, but I'm not sure how the interaction through the core would affect the guitar signal. It might produce some reinforcing hysteresis distortion (which might even go into oscillation), the EE19 Permalloy possibly distorting smoother than the Z11 Silicon Steel. Wiring both sides phase-reversed might cancel the distortion and any coil noise and/or the entire guitar signal or just the signal above the Capacitor value peak? I'm not sure how that all works. Might be a fun experiment with all that.

www.aliexpress.us/item/2251832612123777.html?

www.aliexpress.us/item/2251832624162267.html?

[mikecg]

Hello lelik,

Here's another interesting old thread on the Gibson Varitone that you may have overlooked:

guitarnuts2.proboards.com/thread/7477/gibson-varitone

[lelik]

Oct 3, 2024 2:47:40 GMT -5 gckelloch said:

You can get all those settings with a 4-way Tele switch. Just wire the components you want off the second set of lugs. FI, wire the tone pot from whichever of the second set of lugs you want > the cap value you want > ground. Wire the second lug > a 1~1.5nF cap & a 200k trim pot > ground. Wire the third lug > a 1~1.5nF cap & a 5-10k R > a 20-30k trim pot > the Q-filter > ground. Wire the fourth lug > a 10~22nF cap & a 5-10k R > 100k trim pot > the Q-filter > ground. Don't include the 5-10k R's if you don't want any bass reduction. If you don't include the tone knob on the Q-Filter positions, you might want to add a 500k trim pot from those two lugs > ground so you can control the high freq peak level.

I'm not sure if I understand it all. I tried to put down the circuit diagram. Is it really that simple or am I missing some important bit?
(I didn't study electronics: forgive my form, in case!)

Tele 4-way switch:
1) standard single coil (bridge) pickup
2) modification of pickup resonant peak to get a sound closer to P90/humbucker
3 and 4) two different "presets" using the same inductor

[lelik]

Oct 3, 2024 19:56:18 GMT -5 newey said:

Oct 3, 2024 19:56:18 GMT -5 newey said:

when is your birthday?

Eh...eh... my birthday is very close... that's (also) the reason for my attempt to get me a new special custom guitar.
But considering my time and pace, this could probably become my birthday present next year! 

[gckelloch]

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.

[gckelloch]

lelik, please reread my previous post again when you can. I made several changes since you gave it a like it some 3 hours ago.