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Wacky Transformer Idea


ShadowSpectre
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Hey i had a wierd idea (keep in mind that i know very little about induction and transformers): Transformers saturate faster at lower frequencies.... So doesnt that mean if an electric guitar signal was passed through a 1:1 winding ratio transformer that the bass would be rich, full, and packed with harmonics as if overdriven, but the midrange and treble would remain clean? If it does, how would i have to build a transformer to fit in a guitar to do this (or possibly blend this effect in with a knob? Actually while i'm at it, could a transformer not be used as an alternative to a preamp (requiring a battery) to lower the impedance to counter the effects of cable capacitance and loading?

Thanks

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Hey i had a wierd idea (keep in mind that i know very little about induction and transformers): Transformers saturate faster at lower frequencies....

Well...

To get a transformer to saturate, you would need to drive it near the edge of its ratings (I would think). This might happen in a tube amp with an undersized OT when it's cranked up. So for example you might get this effect with an underpowered interstage transformer within a tube amp. But think about it... your initial guitar signal is in the range of hundreds of millivolts and very little current (since the pickup is pretty high impedance). I doubt that any transformer would do what you think you want with such a tiny signal dribbling through it.

So doesnt that mean if an electric guitar signal was passed through a 1:1 winding ratio transformer that the bass would be rich, full, and packed with harmonics as if overdriven, but the midrange and treble would remain clean?

I doubt it. Assuming you could get a lame enough 1:1 transformer to give out when slammed with a 500mv guitar signal, I don't think you would get bass such as you describe. In my limited experience, when bass F's distort thru a less-than-adequate OT, you get a mushy, squishy sound. Pretty cool if that's what you want, but NOT (to my mind) "rich, full and packed with harmonics".

If it does, how would i have to build a transformer to fit in a guitar to do this (or possibly blend this effect in with a knob? Actually while i'm at it, could a transformer not be used as an alternative to a preamp (requiring a battery) to lower the impedance to counter the effects of cable capacitance and loading?

Thanks

Winding transformers is a whole science/art unto itself (from what I've read). It would be simpler to buy a teensy isolation transformer, but I don't think that's what you want.

No, the transformer won't work like that. A 1:1 transformer will give you the same Vout as Vin, and (I believe) the same impedance. Now, an OT in a guitar amp takes a 5k-some impedance and makes it into ~8ohm impedance (for example), but I don't see how you could apply this to a tiny guitar signal. Certainly it would need some kind of driver or gain makeup. I imagine it's much simpler to build a small solid-state buffer if you need to lower the impedance of your signal.

I know very little about transformers and inductance, but I imagine if you read up on everything, you'll see why this has never been done. I don't think it will do what you want. If you want to distort your bass signal, build something that seperates your signal into frequency bands and distort the lower band. I could give you some advice for a tube circuit like this but not solid-state...

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Hey i had a wierd idea (keep in mind that i know very little about induction and transformers): Transformers saturate faster at lower frequencies.... So doesnt that mean if an electric guitar signal was passed through a 1:1 winding ratio transformer that the bass would be rich, full, and packed with harmonics as if overdriven, but the midrange and treble would remain clean? If it does, how would i have to build a transformer to fit in a guitar to do this (or possibly blend this effect in with a knob? Actually while i'm at it, could a transformer not be used as an alternative to a preamp (requiring a battery) to lower the impedance to counter the effects of cable capacitance and loading?

Thanks

Welcome to PG ShadowSpectre

No, like many you expect too much from a passive signal in the pursuit of avoiding active electronics. An example in the reverse of what you propose are lace alumitone pickups...

alumitones.jpg

These have effectively a single turn (the aluminium part) so are exceptionally low impedance, but to bring it up to a high impedance level it has a small transformer beneath.

No, I don't think your desires are possible and so much more could be done with active electronics. Your other post leans more along these lines, but while possible, is probably not as desirable as you may assume.

Les Paul's signature recording guitar also has a transformer, but again low impedance pickups that he still uses today.

A small buffer or preamp uses extremely low power, a 9v could last a year easily with a lot of simple designs. I am kind of surprised that someone hasn't designed very efficient tiny preamps that could run from a button cell, perhaps even rechargeable.

The other thing is the art of pickup design itself, some of these "effects" are touted from a pickup design itself...afterall, a pickup is very much like a transformer itself.

still, food for thought...

pete

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A small buffer or preamp uses extremely low power, a 9v could last a year easily with a lot of simple designs. I am kind of surprised that someone hasn't designed very efficient tiny preamps that could run from a button cell, perhaps even rechargeable.

Pete, the major limiting factor in button cell powered preamps is the voltage. Many cells are 1.5V or 3V, which doesn't really provide enough headroom to make a good preamp, even though the button cell has enough energy to power the preamp for a good amount of time. The voltage could be boosted with a small switching supply (and these days, highly integrated low voltage switching supplies are easily available), but I think that's just beyond the level of complication that most preamp makers are interested in. The MIMF preamp runs on 3 coin cells, though. It's a neat little preamp, too. Check it out at the MIMF library if you haven't seen it before.

As to the original question: transformers don't do anything for "free." Voltage gain varies by the turns ratio, and impedance is transformed by the inverse of the square of the turns ratio (as seen from the primary side looking into the secondary). This makes transformers somewhat unsuitable for boosting high impedance signals like a guitar's. You can use a transformer to increase the impedance seen by the pickup, but it costs you some output. Also, real world transformers have inductance, which may negate any signal brightening effects you might otherwise achieve (though not necessarily -- it's a design problem). Transformer saturation is probably not going to get you much, either. While you can produce some distortion by saturating the core, you would need to drive it pretty hard to get a very noticeable effect -- something you probably won't be able to do without an amplification stage before the transformer.

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There is nothing wacky about using transformers to match pickups to amplifiers. The telecommunications world used them for just that: match equipment to transmission lines when everything was still analog and electronics expensive. As solid state devices became more plentiful and cheap they were replaced by solid state. Then everything went digital and became a whole different set of issues.

Keith

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lol. it was just something that occurred to me at like 3 in the morning when i had been designing and redisigning the most switch/knob efficient way to get all the sounds from H-S-H. lol. its basically impossable BTW.

Nothing is impossible!

switchpot1.jpg

I built the above switch pot that has a dpdt push pull function and a 4pdt twist function, plus it works as a conventional pot!

antiKISSwiring1.jpg

However...be careful what you wish for...my guitar still looks like this through over ambition!

hehehehe

Chck out guitar nuts forum or the amazing dgb studio site for ideas if you dare!

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