Reverend Style Bass Contour wiring?

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borntohang
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Re: Reverend Style Bass Contour wiring?

Post by borntohang » Thu Apr 14, 2016 3:28 am

garyptaszek wrote:
arri93 wrote:Image

After extensive googling I made this..
If anyone who actually understands electronics could weigh in on my attempt.
Would this work without a tone pot?
As in instead of a tone pot? Yes, it'll work.

The cut cap will also work fine without a pot like in the diagram I showed up there, but it's better running in front of a volume pot as the effect it has works on the impedance of another component and if you put it last in the circuit that will be the front end of your amp. That might work for you, might not! I found a great post on talkbass explaining this in more detail but I can't seem to dig it up now.

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Re: Reverend Style Bass Contour wiring?

Post by garyptaszek » Thu Apr 14, 2016 12:52 pm

borntohang wrote:
garyptaszek wrote:
arri93 wrote:Image

After extensive googling I made this..
If anyone who actually understands electronics could weigh in on my attempt.
Would this work without a tone pot?
As in instead of a tone pot? Yes, it'll work.

The cut cap will also work fine without a pot like in the diagram I showed up there, but it's better running in front of a volume pot as the effect it has works on the impedance of another component and if you put it last in the circuit that will be the front end of your amp. That might work for you, might not! I found a great post on talkbass explaining this in more detail but I can't seem to dig it up now.
So what would a diagram look like for 2 JM pickups, 3 way toggle, volume and bass contour?

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Re: Reverend Style Bass Contour wiring?

Post by borntohang » Fri Apr 15, 2016 12:21 am

garyptaszek wrote: So what would a diagram look like for 2 JM pickups, 3 way toggle, volume and bass contour?
Can't do diagrams on here, but basically you want to set it up like this:

Image

Play around with the cap till you find something you like, I've used 0047 and 0015 before.

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Re: Reverend Style Bass Contour wiring?

Post by arri93 » Sun Apr 17, 2016 7:42 am

borntohang wrote: So what would a diagram look like for 2 JM pickups, 3 way toggle, volume and bass contour?
The same but without the tone pot
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Re: Reverend Style Bass Contour wiring?

Post by mahak » Mon Aug 12, 2019 7:47 pm

member has been banned for spam.

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Re: Reverend Style Bass Contour wiring?

Post by sciuri » Wed Dec 07, 2022 10:03 am

Hi, old thread but I was hoping for help troubleshooting…. Has anyone successfully done a bass contour for a 4 knob setup?

I’m trying to do a tele deluxe with volume, volume, master tone, master bass cut. My tech used the Reverend Kyle Shutt wiring diagram I found on TGP, but with 1meg pots.

Image

For reasons he can’t figure out, the bass cut is sudden and acts more like a switch than a steady taper. Other comments online seem to run into this problem as well, but I didn’t come across any solutions. Also tried a similar wiring from AaronLumGuitars, but my tech said it was the same issue and even more sudden.

Is the answer to use a linear taper pot rather than an audio taper, or is the wiring diagram not correct?

Thanks for any help!

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Re: Reverend Style Bass Contour wiring?

Post by Embenny » Wed Dec 07, 2022 10:39 am

I think the issue might be the 500k pot. 500k pots are notorious for crappy tapers.

I started to use 1M pots just about anywhere I'd be considering a 500k pot, and the tapers are so much smoother, even for the same brand/spec (e.g. CTS audio taper 500k vs 1M).

Thanks for reminding me of this, I'm currently rewiring two 3-knob Flying Vs and volume/tone/bass contour is far more useful than volume/volume/tone for my purposes.
The artist formerly known as mbene085.

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Re: Reverend Style Bass Contour wiring?

Post by sciuri » Wed Dec 07, 2022 10:46 am

Hi Mike, love your insights! This is for a tele deluxe with CuNiFe WRHBs, so I asked to substitute the 500k pots in the diagram with 1meg pots (I know they’re new pots but don’t know the brand or tolerance, but this repair shop seems legit). I think he used the same cap values as the diagrams.

Any ideas why the taper isn’t behaving as expected?

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Re: Reverend Style Bass Contour wiring?

Post by JackFawkes » Wed Dec 07, 2022 3:13 pm

One thing to consider is that G&L uses C1M (reverse audio taper) pots for their bass cut.

If I'm not mistaken, the main reasons for using a "C-type" reverse audio taper pot is so that the knob of the bass cut responds intuitively in the same direction that a guitar tone pot does, and that it gives a little finer control throughout its range with the majority of the bass cut happening at the end of the rotation. I think if you use a regular "A-type" audio taper pot, or a "B-type" linear pot, most of the bass cut effect will occur rapidly at the beginning of the rotation.

You might want to check out the Bass-cut and the G&L PTB system thread at GuitarNuts; it's a big read, but chocked full of good information on the PTB/Bass Contour circuit.

Jack

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Re: Reverend Style Bass Contour wiring?

Post by sciuri » Wed Dec 07, 2022 9:13 pm

Thanks for the input!

I had read about the C1M reverse log pots but that they were also hard to find in standard 24mm sizes. A quick search seems to only come up with 17mm ones. Is there a good source for 24mm pots? Would the schematic be the same? (I know next to nothing!)

That guitarnuts thread is a great deep dive and way over my head! But I see on page 3, there is skepticism about Premier Guitar’s diagram 1c, which I think is identical to the Kyle Shutt diagram.

All of this leaves me confused. I would assume Reverend figured out a viable schematic for a production line guitar, so perhaps the Kyle Shutt diagram I have is inaccurate? I’ll have to ask around for actual KS guitar owners for how the bass contour behaves (I didn’t find good examples on YouTube), and maybe write Reverend directly.

Thanks!

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Re: Reverend Style Bass Contour wiring?

Post by JackFawkes » Thu Dec 08, 2022 11:01 am

In a month or two, I'll be implementing my first attempt at passive treble & bass controls in a parts Jag that I'm building... and my biggest fear is that I'm misinterpreting the direction/pot orientation and might be wringing the wrong legs of my bass and/or treble control.

I've read so many different (and sometimes conflicting) posts on various forums, and I have heard that at least one of the common diagrams out there on the internet is incorrect, so I've been pretty unsure how my diagram will turn out... but worst case scenario, I guess I just try to logic out what's happening if something isn't working right, pull it out and, and just try again. Though the people at GuitarNuts seem more experienced and technical than most when it comes to circuits and wiring details, so I've felt fairly confident reading the various posts there.

As for sourcing a C1M, since I'll be working in a fairly small cavity anyways, I just decided to go with a 17mm Bourns; but you can also get C1Ms from G&L's online store:
Pot - USA models - Split Shaft
Pot - Tribute Series - short shaft
They specify that the USA models use sealed Mighty Mites for the C1Ms, which I think are 24mm?

In any case, you and I are in similar boats, so I'm hoping for the best for both of us!

Jack

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Re: Reverend Style Bass Contour wiring?

Post by sciuri » Thu Dec 08, 2022 2:48 pm

Hi Jack,

Thanks so much for the source! I'm going to send that to my tech right now.

If using a C1M pot for bass, would the schematic be the same or would the hookups be different since it's a reverse pot?

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Re: Reverend Style Bass Contour wiring?

Post by JackFawkes » Thu Dec 08, 2022 4:27 pm

sciuri wrote:
Thu Dec 08, 2022 2:48 pm
If using a C1M pot for bass, would the schematic be the same or would the hookups be different since it's a reverse pot?
Oof... see, that's the thing I'm least sure about on my own diagram too...
Since I've seen different diagrams out there showing PTB with the bass cut pots as A (audio taper), reverse-wired B (linear taper), and C (reverse audio taper), and in so many threads people had subbed out different ones because they couldn't find a C1M, I honestly feel like I just don't even know which is "correct" anymore, haha...

After feeling overwhelmed with so many different diagrams and so much contradictory information on forums, I decided to try and stick as closely as possible to most "common" PTB diagrams for my first attempt; and that if I wasn't happy with those results I'd make modifications from there... (and I believe Reverend's "Bass Contour" is just a slightly modified "common" PTB)
Even though I'm not super-confident about it, I think the PTB in the diagram I made for myself is "correct" for using a C-type potentiometer.

However! It seems PTB commonly has the pickup signal go through Treble-cut and Bass-cut first (in either order), and to Volume-cut last before the output.
If I'm correctly understanding the many (many) things that I've read, having the Volume pot last helps stabilize the output impedance. If the Bass or Treble cut is the last thing before the output, then I think your output impedance will vary depending on how you have your controls set, which may or may not cause odd results depending on what equipment your instrument connects to first.

But in any case, it looks like all of the diagrams that I happen to have saved on my laptop show the pickup signal going IN to the Bass pot on post #2, and OUT on post #3 (with a 0.0022 uF capacitor between them), just like on your Kyle Shutt and my own; regardless of what pot type the various diagrams indicate.

Hopefully that helps!
(or that you're at least now as confused as I am, haha)

Jack

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Re: Reverend Style Bass Contour wiring?

Post by sciuri » Fri Dec 09, 2022 11:54 pm

Thanks so much for sharing what you've learned! I also read about PTB having the signal go through bass and treble before volume. Premier Guitar's diagram 1b (3-knob setup, G&L-based) has it that way, but for some reason their diagram 1c (4-knob setup) does not.

For what it's worth, Reverend support responded pretty quickly that they don't have (or aren't allowed to distribute?) specific wiring diagrams available for all their models, but they did send me these two general diagrams for their 3-knob guitars... Looks almost identical to Premier Guitar's diagram 1b with volume last in the signal chain.

Any idea how two volume knobs could be incorporated into this? (and then how 1meg pots and caps would need to be adjusted...)

Image
Image

My tech was going to try the Kyle Shutt diagram with different caps (to adjust for the 1meg pots), then try a linear taper pot, then try a C1M pot, but now I'm not sure if I should just abandon the Kyle Shutt / 1c schematic altogether if it's ultimately not sound.

Maybe I should just turn the tele deluxe into a 3-knob setup (volume, treble, bass) with a 4th dummy knob (any creative easy ideas to add for that 4th knob?). I think for me having a bass cut would be more useful than being able to blend neck and bridge volumes.

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Re: Reverend Style Bass Contour wiring?

Post by JackFawkes » Sat Dec 10, 2022 11:52 am

Hmm... those are good questions that I wish I had more first-hand experience to be able to help you answer; but unfortunately, I don't yet.
I did a little Googling and came across this thread at the Gear Page where they are discussing the exact issue you're facing, and come up with a couple theoretical alternatives you could try.

As for the effect of different pot and cap values on the bass-cut control, the on-paper results are fairly straightforward...

Ignoring the various pot tapers, a pot with a smaller value like 250K will only scoop away a small amount of low-end at its maximum setting (say 3-5 dB worth); while a pot with a larger value like 1000K (aka 1M) will carve out a much bigger chunk of low-end at its maximum setting (more like 9-12 dB worth*).
So the pot value affects the magnitude of the bass-cut.

Changing the capacitor value will change where the potentiometer starts its cut. A small cap like a 0.001 uF will start the cut up near the lower-mids; a bigger cap like a 0.0068 uF would make the control only affect the really deep low-end.
So the cap value affects what frequency the bass-cut begins at.

Jack

*the numbers given here are just relative examples, not the actual amounts of cut you will experience; furthermore, the magnitude of the bass-cut isn't based solely on the value of the bass pot alone... it's also affected by the difference in value between the Volume and Bass pots (for example, using a 500K Vol with a 500K Bass will give less total cut than using a 250K Vol and 1M Bass will)
Last edited by JackFawkes on Sat Dec 10, 2022 5:25 pm, edited 1 time in total.

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