# The Perfect Treble Boost - Help me build it!



## daeg

Range Masters have been my thing lately and I've come up with what I think is the perfect Treble Boost circuit. It's a RoG Omega with an AMZ Pickup Simulator and a couple of cool tricks.


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## cooder

So have you breadborded this or built it already and how does it sound?


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## daeg

Let me walk through it.

The Buffer, Transformer and 'Edge' control are all there to counteract the shrillness you get when putting a Rangemaster downstream from a buffer.
- We're only using half of the Transformer, so it behaves as an Inductor to 'simulate' the response of guitar pickups. It's far from accurate simulation, but it gets the job done. Read More.
- The switch allows you to switch between half and full inductance, which moves the resonant peak and corner frequency of high rolloff. AMZ describes it like a single-coil vs humbucker response, and that isn't a huge stretch either.
- 'Edge' is your tone control that goes from icepicky highs clockwise to dulled highs counterclockwise. It's interactive with the transformer as well as the low-Z HPF circuit that follows it, but since we're making analogies, think of this as your cable length.

A couple of changes have been made to the RoG Omega as well.
- The 'Clarity' control gradually allows a Ge diode clip the signal. Turning it counterclockwise adds some reminiscence of a the grittyness of a Germanium Transistor if you're looking for that. The clipping is asymmetrical and unfiltered. It loads the Transistor, limits headroom a bit and _does not_ sound like an overdrive. Turning it fully clockwise gives you the loudest, most clear, punchy signal. You'll be surprised how well it works. (Check out the Electrosmash article to see how the original unit gently clips.)
- The added trimpot (R8) is a nice-to-have. It helps you fine-tune the output of Q2, while changing the bias point of Q3. At center there is no change from the original circuit. Adjust to taste to make your circuit a little hotter or cooler.


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## daeg

cooder said:


> So have you breadborded this or built it already and how does it sound?



It's on bread board right now and think it sounds great.

Of course, Rangemasters do not sound good on their own, so their 'sound' revolves how well they get along with your guitar and already distorting amp.


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## daeg

So, I created the thread because... my building skills suck.

Before PedalPCB, I mostly used perf, my own layouts and things were always... messy. Things would work for a few months then start getting intermittent issues, often have noise problems, yet I was too stubborn to buy PCBs.

Now I'm ready to assemble this thing, but ... how should I put this all together?


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## BurntFingers

Easy, layout the PCB and get it made. Jlcpcb will do you 5 for $2.


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## Chuck D. Bones

That INDUCTANCE switch is not wired correctly.  If you short a winding, or any part of a winding in a transformer, the inductance goes down to nearly zero.  You can use the switch to select between full winding and 1/2 winding.  With half of a the winding, the inductance is not cut in half, it's divided by four.  That's because inductance is proportional to the square of the number of turns.  Not the same as tapping a Humbucker because the coupling between the bobbins is nowhere near 100%.

Not sure that Ge diode does anything.  The way you have it facing, it will never go into forward conduction.  If you turn it around, it will always conduct.

Thanks for pointing me to the ROG Omega.  I thought I had all of their schematics, but that one got past me.  Gotta build me one o' dem!


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## music6000

I had one of these around 11 years ago, Never checked it out internally as I did not know what I was looking at back then!
I know it sounded better than this video but it has a clever switching system I thought worth showing.


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## daeg

Chuck D. Bones said:


> With half of a the winding, the inductance is not cut in half, it's divided by four.  That's because inductance is proportional to the square of the number of turns.


Thank you, I was totally unaware of that.

Here it is fixed.


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## daeg

Chuck D. Bones said:


> Not sure that Ge diode does anything.  The way you have it facing, it will never go into forward conduction.  If you turn it around, it will always conduct.



Good eye Chuck. It most definitely does work... I just forgot to put the capacitor on the schematic. Fixed it.


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## daeg

BurntFingers said:


> Easy, layout the PCB and get it made. Jlcpcb will do you 5 for $2.



Taking a look at this. I had no idea this was so affordable.

I've wasted _so much time_ making perf layouts and builds that never hold up.

Any recommendations on how to get started?


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## Chuck D. Bones

daeg said:


> Good eye Chuck. It most definitely does work... I just forgot to put the capacitor on the schematic. Fixed it.
> 
> 
> View attachment 7382



Let me know if that works, because the only way for C6 to get any charge on it is from D1's leakage current.  You might need to put a resistor in parallel with D1 to ensure there is enough leakage current.  Something like 100K maybe.


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## daeg

Chuck D. Bones said:


> Let me know if that works, because the only way for C6 to get any charge on it is from D1's leakage current.  You might need to put a resistor in parallel with D1 to ensure there is enough leakage current.  Something like 100K maybe.


Just tried it. The 100k resistor definitely makes a difference -- lower headroom, more squashed.

I might yet prefer it without, as it cuts less volume and is more of a crackly grit as opposed to a squished farty sound. I'll play with it on breadboard for a few days.


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## BurntFingers

daeg said:


> Taking a look at this. I had no idea this was so affordable.
> 
> I've wasted _so much time_ making perf layouts and builds that never hold up.
> 
> Any recommendations on how to get started?



I use eagle for the schematics and for PCBs, then just export the gerber files as a zip which is uploaded to jlcpcb. 2 weeks later I have the PCBs. 

Any software that allows exporting of gerber files is all you really need. I think pedalpcb uses diptrace.


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## Nostradoomus

Yeah DipTrace is pretty slick and newbie friendly.


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## cooder

Another vote for Diptrace, I find it much more intuitive and user friendly than Eagle, which I have been using before.


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## daeg

Anyone have templates for PedalPCB-esque boards (125B, top-mounted jacks)?


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## Nostradoomus

Download the rullywow DipTrace library, it’s got enclosure outlines so you can size your board cutout properly.


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## Robert

daeg said:


> Anyone have templates for PedalPCB-esque boards (125B, top-mounted jacks)?



I don't use a template, each one is created manually.

For a 125B using the standard drill template here you can go to up 2.35"W x 2.4"H, assuming the lugs for the top row of pots is 0.125" from the top edge of the board.   This puts the board right against the edge of the 3PDT.


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## daeg

Nostradoomus said:


> Download the rullywow DipTrace library, it’s got enclosure outlines so you can size your board cutout properly.


I don't see it on the Rullywow site. Could you point me to it?


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## perfboarder

daeg said:


> I don't see it on the Rullywow site. Could you point me to it?


Dont know the latest version.


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## mdc

Just curious how hard it would be to change the SPDT switch to a 3-position so that you could bypass the buffer and AMZ stage? It might be useful to be able to take advantage of the low-z input in the absence of buffers upstream and wire it off/"single"/"hb." 

I'm also really curious how well that AMZ circuit works compared to either a passive trim pot (like the catalinbread katzenkonig) or a series resistor (a common fuzz face/wah mod, I think?) or even a fixed, passive bandpass filter on the input. I remember reading a bunch of anecdotal info about the pickup simulator and opinions were definitely mixed. I think a few folks said they got equivalent results by simply wiring whatever single coil pickup they had laying around in a parts box into an enclosure with a couple of jacks attached. 

I love tone benders but also the boss LS-2 for switching so I'm always interested in reports from the frontline of the low-z vs buffer war.


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## mdc

And of course kudos on working out the circuit and sharing it!


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## daeg

mdc said:


> Just curious how hard it would be to change the SPDT switch to a 3-position so that you could bypass the buffer and AMZ stage? It might be useful to be able to take advantage of the low-z input in the absence of buffers upstream and wire it off/"single"/"hb."



Funny you should ask...

The center-tap position on the transformer wasn't doing anything noticeable, so I repurposed the switch for buffered / unbuffered. Bypassing something completely takes 2 poles, so no DPDT On/On/On magic is possible.

This is what I have on breadboard right now.



I'm using a new schematic software (LibrePCB) and don't have the suggested libraries imported, so the symbols are a little off, but it's all there. The pots labeled VR are intended to be external while the pots labeled R will be trimmers. The buffer is fully bypassable, the single Ge diode clipper works great, noise is low-ish, gain is medium and overall I'm very happy with it.


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## daeg

mdc said:


> I'm also really curious how well that AMZ circuit works compared to either a passive trim pot (like the catalinbread katzenkonig) or a series resistor (a common fuzz face/wah mod, I think?) or even a fixed, passive bandpass filter on the input. I remember reading a bunch of anecdotal info about the pickup simulator and opinions were definitely mixed. I think a few folks said they got equivalent results by simply wiring whatever single coil pickup they had laying around in a parts box into an enclosure with a couple of jacks attached.



We're thinking alike. What you wrote above is exactly what I've been contemplating this past week.

While the circuit is coming along nicely, I need to tackle these 2 issues to tackle before calling this done.

1.) When unbuffered, C4 will load pickups and shift the resonant peak...
2.) The LPF formed by VR2 and C4 seems to make the inductor obsolete. You get icepicky highs at full CW and a dark grunty sound when fully CCW. I'm leaning towards omitting T1.


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