Onboard transformer for passive bass secret sauce?

[NKBassman]

There's much ado about transformer coloration in signal chains these days. Some claim that something like the Lightning Boy 2020 passive 1:1 transformer in a pedal is just the secret sauce they needed. Others say they can't hear any improvement even running two of them. Other pedals like the Hudson Broadcast are incorporating transformers into the audio path to replicate the sound and saturation of old consoles. Mixing blogs are all about bouncing tracks through transformer boxes to add subtle coloration.

I had an errant thought last week about whether adding a small 1:1 audio transformer onboard a passive P bass would provide any desirable coloration direct off the output of the bass. Unfortunately, I don't know the first thing about spec'ing a transformer, and would appreciate some guidance from the TB Braintrust.

Dumb idea? Almost certainly.
Impractical? Probably.
Worthwhile? Doubtful.
Possible? You tell me.

The obvious candidate is my passive Fender Hwy 1 Precision Bass. I'd be looking for a really small onboard transformer that I could tuck in under the pickguard, immediately before the output of the bass.

• I'm not necessarily looking to lower the impedance for buffering purposes, so I understand I'd be looking for a 1:1 ratio transformer. However, please educate me on what the effect of stepping up or stepping down the ratio would do at the output. I'm curious and would like to understand this better.
• The main point would be to impart a little bit of je ne sais quoi coloration on the output, so probably something with steel laminations rather than nickel (from my understanding).
• Should be small enough that it would impart color at passive bass signal levels.

What else do I need to know? I'm no luddite, but I am kinda dumb when it comes to electrical stuff specifically, so speak slowly and in plain english as much as possible. I think I'd be experimenting externally with alligator clips off the output before making any actual wiring changes to the bass. My first thought was to place it post-volume and tone, but maybe right off the pickup would be better?

I guess what I'm looking for is a knowledgeable person to chime in and either detail hypothetically how this could be done, or just tell me to scrap the whole idea and get on with my life.

 

[johnh89]

Look up the thread of the Epiphone Jack Casady bass . They have a transformer for low impedance output . May give you some ideas . I have one and love it to bits .

 

[NKBassman]

Look up the thread of the Epiphone Jack Casady bass . They have a transformer for low impedance output . May give you some ideas . I have one and love it to bits .

A few threads on the Epi Jack Cassady basses had come up when I tried searching for this topic. I guess I should dive deeper into a few of those.

 

[Dadum]

https://www.jensen-transformers.com/wp-content/uploads/2014/08/Audio-Transformers-Chapter.pdf

 

[NKBassman]

lol I was hoping that would be a mouser product page.

 

[Passinwind]

lol I was hoping that would be a mouser product page.

"Really small" does not work in your favor in this case, sadly.

 

[Dadum]

It will be easier to work "after" the preamp as the voltage output is usually higher. Essentially, make your own effects box. If it is away from the guitar, you can decide on active electronics or an all passive arrangement. Passive could include transformers like -> 1:3 then sound changers -> 3:1 -> output. If you want audio changes, you are filtering and distorting. Potentiometers and variable capacitors will be quite large but would help you find some unique sound.

The reason for two transformers above is to increase the number of modifying steps.

 

[NKBassman]

"Really small" does not work in your favor in this case, sadly.

As in, a minimum physical size of transformer would be required to pass audio in an appropriate bandwidth? ... which may or may not be small enough to hide under a P bass pickguard?

It will be easier to work "after" the preamp as the voltage output is usually higher. Essentially, make your own effects box. If it is away from the guitar, you can decide on active electronics or an all passive arrangement. Passive could include transformers like -> 1:3 then sound changers -> 3:1 -> output. If you want audio changes, you are filtering and distorting. Potentiometers and variable capacitors will be quite large but would help you find some unique sound.

The reason for two transformers above is to increase the number of modifying steps.

The idea was specifically to hide this inside a passive bass. no preamp. bypass switch for in-out switching, but that's it for controls or variability. Kinda similar to using diodes for onboard passive distortion i guess.

 

[Dadum]

If you don't get enough feedback here, try this other site. They are already discussing similar things. After you figure it out, report back here. Tell them you are working on a bass guitar and passive only.

Guitar signal isolation transformer *component*

It's a much more techy site.

 

[NKBassman]

Paging @Wasnex and maybe @micguy ? I think I saw one or both of you posting in some of the Jack Casady bass threads. Any thoughts on this hair-brained idea?

 

[micguy]

Paging @Wasnex and maybe @micguy ? I think I saw one or both of you posting in some of the Jack Casady bass threads. Any thoughts on this hair-brained idea?

There are reasons to use transformers. There are reasons to avoid them. If you're going to use one, you have to understand the circuit around it, and the levels involved, to make sure ugly things don't happen. The kinds of "nice things" that transformers do to audio are things that happen on "the edge". If you go a little too far, (saturating the core) this leads to the very ugly side very quickly. If I want warm, almost but not completely clean sounds, there are several other places I'd look to before I'd use a transformer in one of my basses. My pedalboards do have passive transformer DI's, but I'm not using them to make the audio "transformery", I do it because, with the right transformer, it is the simplest thing that works, and therefore, the most reliable. The transformers I use have enough headroom that you never really get close to the limits - they are used for what transformers do well, not what they do when pushed.

A magnetic pickup (like almost all the pickups in our instruments) place near the strings has a nice non-linearity to it - the kind of thing you might look to a transformer for. But the non-linearity in your bass pickups doesn't go over the cliff and make ugly noises at low frequencies like a transformer that's saturated. If you want more non-linearity, raise your pickups a bit.

 

[NKBassman]

How ugly are we talking?

 

[micguy]

How ugly are we talking?

We're talking "sounds normal throughout most of the range, but on your lowest notes, when you play hard, it's an ugly raspy sounding fuzz". Not cool sounding, but "something is broken" sounding.

 

[Kenan]

Couldn't you just rip the guts out of a Lightning Boy 2020 and put that in a bass? Probably some routing needed, but not much more than a battery box would be.

 

[NKBassman]

Couldn't you just rip the guts out of a Lightning Boy 2020 and put that in a bass? Probably some routing needed, but not much more than a battery box would be.

I could if I had one and if Lightning Boy was still making them. But I also didn't want to spend $100+ for a fully packaged pedal just to rip it apart. Also, based on the reviews I've read, the 2020S is pretty subtle unless it's being driven by pedals.

 

[Honkey tonk]

A transformer will isolate and balance the signal
they put transformers in most all dynamic microphones it seems to me instruments were sorta short changed since birth.
Ever wonder how Rupert Neve would design a guitar ?

 

[Coke Kane]

Radial Dragster let's you adjust the input impedance that your pickup sees. Not sure if that is what you are asking, but it's small, cheap and adjustable.

 

[kumimajava]

The first thing that came to mind after reading your post was the Yamaha 'Revstar' guitar, which uses an onboard transformer as a boost feature:



Not a bass & not 1:1, but it does seem that an onboard transformer is not an impossible idea

In your case - if the transformer is 1:1, I was wondering about is whether it would get rid of 'grounding' issues etc.. If so, that might be another positive side-effect.

Curious to see what other views on this issue emerge

 

[Aidenn7]

The first thing that came to mind after reading your post was the Yamaha 'Revstar' guitar, which uses an onboard transformer as a boost feature:



Not a bass & not 1:1, but it does seem that an onboard transformer is not an impossible idea

In your case - if the transformer is 1:1, I was wondering about is whether it would get rid of 'grounding' issues etc.. If so, that might be another positive side-effect.

Curious to see what other views on this issue emerge

Prolly grounded it the body.. Maybe

 

[Andy Marshman]

Personally I don't see why anyone wants this. But, to be helpful - regular DI boxes contain a small transformer. You could pick one up cheap (used) and take the tranny out of that. The transformers in the ones I've seen are about 1.5" x 5/8" (going from memory). What I would do is just plug into the DI box and not route the P bass. You'd need an adapter cord XLR to 1/4" from the DI box output.