Trying to recreate Yamaha Passive Boost

[frets]

Hi Guys,

I this some time ago but wanted to revisit it in order to get input on how to fix it.   It is intended to be a passive boost like Yamaha’s.   You can see that it does not work.  

I was wondering if anyone had any thoughts on this issue?  
As always, thanks😺

[JohnH]

Hi frets, what do we know about Yamaha's system? I hadn't heard of it.

[mikecg]

Hello frets,

It looks like you have the push pull switch incorrectly wired. Here's a link to the original post on this topic:


guitarnuts2.proboards.com/thread/9930/revstar-new-tone-control?page=1


And here's the original schematic (unverified):





This shows that that both poles of the push-pull switch and one end of the inductor should be connected to ground. The other end of the inductor should be connected to the tone cap and the switch lugs marked 1 & 4. The remaining switch lugs 3 & 6, are not connected. In fact you only need to use one pole of the push-pull switch, as both poles and lugs are wired in parallel.

I hope this helps!

[sumgai]

Jun 11, 2024 13:17:35 GMT -5 frets said:

I was wondering if anyone had any thoughts on this issue?  

Yeah, I have a thought.... it's to quote Robert A. Heinlein, who famously said:

TANSTAAFL

IOW, There Ain't No Such Thing As A Free Lunch. Which translates to No, you don't get something for nothing. If you could do so, don't you think that EMG (and every other pickup manufacturer) would be all over this, and not using active electronics?

Your circuit above is nothing more than a switchable filter, and from that one might obtain a small band of frequencies that could be said to be resonating (but it would be a quite small band).  Resonance appears as an increase in strength greater the nominal signal level. Often this is, incorrectly, interpreted as an increase in gain.  But regardless of the interpretation, it comes at the cost of losing most of the signal strength outside of that resonating band of frequencies.  After all, that is the purpose of a filter in the first place, to remove, or filter out, unwanted frequencies.  Those of us with functioning ears usually label such a sound as highly lacking in tonal quality. Substitute the equivalent plain language description of your choice here.

Sorry, didn't mean to pee in your Cheerios, but that's the nitty-gritty of it.

HTH




sumgai

[frets]

John,

I don’t know a lot about the wiring, I have just heard from folks about this passive boost and that it works well. Other than the diagram Mike posted, there is no other wiring documentation to be found. I just think it’s an interesting proposition and really want yo try it.
So, thank you Mike for posting the diagram.
Sumgai, I hear what you’re saying but I’ve got customers that say it’s great. So maybe it’s worth spending some time on.
I don’t use boost but a lot of guys do. You know me, anything weird and I’m interested in it.
Mike, I will try the schematic you posted.