Wish A "Bright Pot" in series with the "Bright Cap."

Postretro

Postretro

Inspired
The Mod:

Add a "Bright Pot" by placing a "~1M Pot" in series with the "Bright Cap."

Pros:

1) No new extreme settings are introduced.
All new tones added are subtle variations between "Bright On" or "Bright off."

2) This mod would not affect any current amp settings.
As long as the Bright Pot is set to 0 ohms, everything remains the same.

3) Being able to adjust the Brightness with a "Bright Pot"
avoids compromising other tone settings by trying to compensate
for a "too bright/Bright-On" or "too dull/Bright-Off" sound.

4) A Bright Cap/Pot is similar to the Treble Tone half of the 5E3 Tone circuit.

5) This is a real-world mod with real-world advantages.
I have swapped out Dual Showman Bright Switches for small Russian 1M pots.
This mod makes it much faster and easier to dial in a sound that can't be achieved otherwise.

6) A FAS "Bright Cap/Pot" would be superior to the 5E3 tone circuit
-- because the Bright Cap is also variable.

7) Adjusting the Bright Cap size sets the frequency at which the "Bright Slope"
begins to rise.

8) Adjusting the Bright Pot controls the angle of that slope.
This has a very noticeable effect on the overall tone.

9) A FAS "Bright Cap/Pot" would introduce a whole new realm of "Ideal" tone choices
and possibilities to any Fractal amp model.

10) It would add another unique advantage to owning and using a FAS modeler.

11) Likewise, the "Bright Pot" could just as easily be ignored without problem.

12) This might be very easy mod to implement. I have no way to know this.
But, if it is, it would provide a lot of additional tonal value
for a small effort.

Cons:

1) Not enough available space on the UI page.

2) It may not be as easy to implement as it appears.

3) Another control may already be functioning
as a "Bright Cap Volume Control."
 
Dave Merrill said:
Practically soaking, how different would this be from decreasing the value of the bright cap, which we can already do?
Click to expand...

Decreasing the value of the bright cap only raises the frequency point at which an upward slope begins. The angle of the slope of increasing brightness will always be just as steep. Adding a resistance in series allows that slope to become more shallow. You can add brightness in a more subtle fashion. Start at a lower frequency (larger cap) without being overly bright in the high frequencies (resistance in series.)
 
Could replace the Bright switch with a Bright level knob (0=off, 10=on) - maybe slid over to right of treble.

That UI change could break some user's presets or switching setups tho.

[As an aside I would love to see Input trim, Drive, MV, and Level on same row for ease of leveling from the front panel. BMT & PD on other row.]
 
The size of the capacitor determines the frequency where the Bright Boost will appear. The resistance of a Bright Pot determines how much brightness it will add. As a rough example these are the results from a 22n coupling cap into 1Meg volume pot (set at 500K) with various bright caps (50p, 100p, 200p, 500p) and 1Meg Bright Volume (sweeping at 50k intervals from 0 to 1 Meg.) Even with a full 1Meg resistance there is still a 1-2db bright boost. The Bright Pot allows you to adjust how bright the bright switch is going to be. The capacitor allows you to choose which frequencies to brighten.
 

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Dave Merrill said:
I get the electrical principles, I was wondering how much difference it would make in practice.
Click to expand...
I've done this to my own Dual Showman. I simple removed the switch and swapped in a small 1Meg Russian pot (sold on ebay.) It fits right into the bright switch slot. The adjustable difference in brightness is very noticeable. For me it made getting the sound I wanted possible. It allowed me to shape the upper highs with one control and reserve the BMT controls for the ranges they work best in. If the Bright switch is too bright for you. But, you still wish you could add some brightness. Then, this mod makes a big difference -- in practice. It clearly isn't a dramatic new sound. It just lets you get the exact sound you wanted -- without fighting your tone controls. You can get the precise amount of brightness that you want. And, you don't have to adjust the main treble control away from what sounds good in the 800 Hz to 5K range to do it. The audience isn't going to be floored by my more subtle bright adjustment, lol. It won't give me a new hot sound. But, sometimes cutting the bright, by even just a touch, is all the difference between an annoying, strident tone and an attractive, sparkling, tone.
 
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Yeah this is a mod that seems right in line with FAS's philosophy: take a relatively standard amp control (e.g. Bright switch) and expand it's capability/flexibility (Bright switch -> Bright level).
 
Seems like a good idea. I already like ability to set bright cap, but even more control of those freqs would be great. I often find with Fenders (both real and FAS) I want something between bright switch on and off.
 
guitarnerdswe said:
What will this achieve that can't be done with the input EQ? Just curious.
Click to expand...
it would be a much simpler and user friendly full control over the bright cap. I could imagine that the average guitarist is easily intimidated by using EQs to do something that could also be done with one simple control...
 
guitarnerdswe said:
What will this achieve that can't be done with the input EQ? Just curious.
Click to expand...
This is a good question. To some extent, the input EQ could shape the overall frequency contour in a similar way. The main difference is location of the EQ. The input EQ is before the first stage. For most amps after the 50's the bright switch will be on the volume control -- after the first stage -- or a later stage. Being able to shape the bright frequencies after the first stage allows the first stage to be driven more dynamically -- in contrast to relying entirely on the Input EQ before the first stage. It is as much about signal dynamics and the harmonics that a more dynamic signal will generate. It is also about a tighter control of the frequency contour that hits the following second stage or overdrive stages. In short, tone circuits at different stages of the preamp can't really do each other's job -- in terms of harmonics, dynamics and shaping the input of the next stage.

A less important, secondary factor is that a bright cut control (bright volume) is precisely targeted to the frequencies boosted by the bright switch. If the bright switch were on -- and a separate tone circuit were used, at another preamp stage, it would not be as precise. It would end up cutting frequency bands that had not been boosted -- or not cutting all the boosted frequencies. Also, any significant change of the volume control changes the relative brightness. The EQ would add the same brightness at low and high volume settings.
 
I was about to post a wish for bright cap variations, resistors in parallel or series, this idea seems even better.

dual rec red modern has a 1nF cap on the gain pot, but in the models anything that high sounds like a cocked wah in the lower half of the gain range, it's really really harsh and abrupt. +1 for adjustable potency
 
I get around this by balancing the gain and bright cap to where I think the "brightness" is about right, then either increasing or decreasing the input level.
 
onebaldbloke said:
I get around this by balancing the gain and bright cap to where I think the "brightness" is about right, then either increasing or decreasing the input level.
Click to expand...

there's an EQ slope element to it, where it will be in the right spot but way too peakey if pushed with input trim, same with the master cap
 
+1

Was going to post this but you got it @Postretro. This mod makes the bright cap a lot more useful as you can make it work at lower gain settings. On Marshalls I always turn it off since I’m not a high gain player, and without a control on the cap it’s over the top. I have this installed on my homebrew 1987 jumped. Thanks for posting this. I hope this wish gets fulfilled.
 
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