# Do you use the bright switch on your Fender amp?



## Prosonic

Do you use the bright switch on your Fender amp?


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## hollowbody

No, it's plenty sparkley on the top end without it. I find with the bright switch on, it gets way too harsh in the treble.


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## theelectic

Yes... but only with a somewhat dark sounding LP.


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## gtrguy

Occasionally... with a dark humbucker guitar, and usually in combination with the low input.

gtrguy


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## mhammer

Maybe it's hearing loss from those years spent in factories, but I *gotta* have my treble. And that means single coils, 1meg volume pots, tone-cap bypass, low capacitance cables, buffering, and a bright switch. Two of my models for sublime tone are Nile Rodgers and Johnny Guitar Watson, so I suppose that says something.


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## greco

Treble and I don't get along together very well...never have.

The bright switch on my BF BandMaster head also seems to add extra noise.

Cheers

Dave


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## mhammer

Note that the bright switch does very little if the volume is cranked. The way the circuit works requires the volume pot to be turned down in order for the bright/bypass cap to do anything useful.

Incidentally, changing the value of the bright cap is one of the easiest mods in the world to do.


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## Prosonic

Ah, ok. I didn't know that the bright switch was affected by the volume. In my Deluxe Reverb (no bright switch) I was told that the brightness was tied into the volume so that as you increased the volume the brightness was decreased, but with my Super Reverb I thought the bright switch was either on or off (not affected by the volume setting). I'll have to do some experimenting with that!


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## mhammer

If you are familiar with the compensating cap that Fender puts on guitar volume pots to prevent loss of treble and clarity as you turn down, the bright cap works *exactly* the same way.

The thing is that, on guitars, usually our starting point is max volume, and we turn down from there. With amps, we start from min volume and turn up from there.

So, if you're the sort of person with a channel/master volume and you keep the channel volume dimed, or near dimed, you'll never notice the bright-switch doing anything useful. If you enable the bright switch on non-master amp similar to a Deluxe or Super, but have a post-transformer "presence" control and turn that all the way off, you will also likely not notice much effect of the bright switch.

As a sidenote, the 59 Bassman, and similar has two channels, a bright and normal channel. The "bright" channel basically has the brightness cap hardwired to the volume pot.

Seems to me that a smart thing to do on amps that have the traditional fender tonestack and bright switch would be to use a DPDT slide switch and simultaneously change the corner frequency of the treble control when you engage the bright switch. Or, if you can find a 3-position slide switch that fits in the same space, have a centre off position, one side position where you have bright on, and a second side position where you have either a bright cap and treble-range cap-change, or simply a treble-range cap change on its own. Juggling what the bright cap enhances, and what the treble control affects can get you improved control over "glassy" tones (think Robert Cray), or more "biting" tones with more upper midrange to them.
of course, all of this depends on where you normally set your amp's volume pot. If you're a fan of using a medium-to-low wattage amp dimed (and there are plenty of great reasons to be that way), then very little of this will matter to you.


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## lbrown1

mhammer said:


> If you are familiar with the compensating cap that Fender puts on guitar volume pots to prevent loss of treble and clarity as you turn down, the bright cap works *exactly* the same way.
> 
> The thing is that, on guitars, usually our starting point is max volume, and we turn down from there. With amps, we start from min volume and turn up from there.
> 
> So, if you're the sort of person with a channel/master volume and you keep the channel volume dimed, or near dimed, you'll never notice the bright-switch doing anything useful. If you enable the bright switch on non-master amp similar to a Deluxe or Super, but have a post-transformer "presence" control and turn that all the way off, you will also likely not notice much effect of the bright switch.
> 
> As a sidenote, the 59 Bassman, and similar has two channels, a bright and normal channel. The "bright" channel basically has the brightness cap hardwired to the volume pot.
> 
> Seems to me that a smart thing to do on amps that have the traditional fender tonestack and bright switch would be to use a DPDT slide switch and simultaneously change the corner frequency of the treble control when you engage the bright switch. Or, if you can find a 3-position slide switch that fits in the same space, have a centre off position, one side position where you have bright on, and a second side position where you have either a bright cap and treble-range cap-change, or simply a treble-range cap change on its own. Juggling what the bright cap enhances, and what the treble control affects can get you improved control over "glassy" tones (think Robert Cray), or more "biting" tones with more upper midrange to them.
> of course, all of this depends on where you normally set your amp's volume pot. If you're a fan of using a medium-to-low wattage amp dimed (and there are plenty of great reasons to be that way), then very little of this will matter to you.


must be the same on my Traynor.....I usually have my channel volume cranked.....with the master volume at whatever is suitable at the time.....the bright switch makes almost no difference


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## Jimi D

There is no bright switch on my SF Deluxe Reverb, but I keep the Treble turned down to 2-3 anyway...


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## mhammer

Looking over the schematics of a bunch of AB-series Deluxes at schematicheaven, it appears that the "bright" function is built in to your Deluxe, like it is on my Bassman, rather than switchable.

For example, look at this particular issue: http://www.schematicheaven.com/fenderamps/fender_deluxereverb_a1270_schem.pdf

You can see that there is a 47pf cap straddling the input and wiper lugs of the volume pot for the Vibrato channel, but NOT for the Normal channel. Although this will not provide as much treble bypass as the 120pf cap does on the Twin Reverb shown here: http://www.schematicheaven.com/fenderamps/twin_reverb_ab763_schem.pdf it still provides a tonal difference between Normal and Vibrato, even when the tone controls are set identically.

That's probably why you turn the treble down to 2-3.


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## Spellcaster

I have a blackfaced 70 Twin Reverb head and 68 Dual Showman cabinet, and always use the bright switch. Whether it's real or just perceived, the treble control seems to operate at a higher frequency when the bright switch is on (which I find quite pleasing). When the bright switch is off, turning the treble control up seems to "fatten" the top end but doesn't add any sparkle. 

My usual settings are : Bright - On, Treble- 5, Mid- 4, Bass- 5


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## allthumbs56

Not a switch per se but my DRRI has the dreaded bright cap on the "effects" channel. Where many have clipped this cap, I chose to do a mod that adds the reverb/vibrato to the "normal" channel. This in effect (no pun intended) makes the difference between channels as bright or normal. I almost always use the normal channel now - the exception being with my Tokai LC Loverock, which is all mahogany.


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## Zman

IF it has a bright switch I use it. I am always looking for the "Talent" switch but I can't find it.


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## mhammer

Spellcaster said:


> I have a blackfaced 70 Twin Reverb head and 68 Dual Showman cabinet, and always use the bright switch. Whether it's real or just perceived, the treble control seems to operate at a higher frequency when the bright switch is on (which I find quite pleasing). When the bright switch is off, turning the treble control up seems to "fatten" the top end but doesn't add any sparkle.
> 
> My usual settings are : Bright - On, Treble- 5, Mid- 4, Bass- 5


Normally, a bright switch/function simply bypasses the volume pot for the upper high end such that upper treble passes unaffected by the volume pot setting until you hit around 6 or so. However, the only stuff that can bypass the volume pot is stuff that reaches the volume pot, so your treble control still has a role to play.

It is not all that difficult to wire up the bright switch so that it changes the functioning of the treble control when the bright function is off. The schematic for a blackface Twin shows a 250pf capacitor used for each of the treble controls, and a 120pf cap straddling the volume pot for the bright function.. I gather that Fender uses a DPDT slide switch for all switch functions, whether needed or not, just to keep inventory simpler. That means the switch only uses 2 of the 6 solder lugs available.

It is a simple matter (once you get in there) to wire up the bright switch to provide two different bright functions, or to shift where the treble control acts when the bright function is on vs when it is off. For example, the switch could select between 120pf in one bright setting, and 220pf in the other. Or, you could use the switch to make the 120pf cap straddle the volume in one setting (for the bright function) OR be placed in parallel with the existing 250pf treble cap (for an effective capacitance of 370pf and a lower corner frequency for more upper mids) in the other setting. You don't have to buy another switch or even another cap for that one.


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## keithb7

Might a well glue my bright switch in the off position on my 1964 Bandmaster. It's shrill and hurts my ear if it's on.


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## gtone

Of my two Fenders, the SF Super Twin is the only one that has the bright switch (the '51 Deluxe is too ancient) and no - it doesn't get used unless I wanna crack ice or eardrums.


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## TimH

you mean the thin switch...no I don't like thin and crappy sounds.


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## georgemg

It depends on the room. I usually don't use the bright switch but I have played a few gigs where it did sound better with it on. If the place has a carpeted stage, the bright switch can help make the amp sound better - mirrors all over the place, not so much.


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## LowWatt

Yep. I like some jangle with my dangle.


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## Cary

super reverb bright switch + single coils = twang city


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## GuitarsCanada

Cary said:


> super reverb bright switch + single coils = twang city


I will have to try that


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## Steadfastly

I voted no and I have a good reason. I don't own a Fender amp. However, I do use the "bright" switch on my Traynor amp.


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## closetmonster.

I like to use the 'bright' switch on my Concert II.

I find the 'verb reacts to it very well. 

I generally run my amp treble-6 bass-3, clean.

Mostly because the stock gain channel in this amp is barely usable at bar volume, it gets very bitey.


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## keto

Fenders are all about bright, for me. My old Pro Reverbs, it was an 'always on' feature. Just love the little extra glassy shimmer, never ever found it ice-picky, and that was with Strats.


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## GuitarsCanada

I tried it on the Super Reverb. Did not like it much


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## GTmaker

just voted NO....my Super Reverb RI is bright enough for me without the bright switch.


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## mhammer

As I noted in an earlier post, the impact of a bright switch depends on the volume pot setting. A bright switch works *exactly* the same way the volume compensating cap does on a Strat or Telecaster. That is, it provides a low-impedance path for the treble when the volume is at less than full. 

I have a 59 tweed Princeton; a 2-knob amp that has a bright switch built into the tone pot. You can see the schematic here: Schematics: Fender: Princeton 5F2-A Schematic : Updated Friday, November 04, 2011

The 1M volume pot is the one with the arrow pointing down, and the tone control is the 1M pot with the arrow pointing up. Yu can see that the tone control has a .005uf cap on one end, and a .0005uf cap on the other. When the control is set to max treble, that .0005 (i.e., 500pf) straddles the input lug and wiper of the volume pot, the same way a "bright" cap would. Rotate the tone control the other way, and it introduces resistance in series with that 500pf cap, and simultaneously _reduces_ the resistance in series with the .005uf cap going to ground.

At low volume settings, the tone control provides a very wide range of action, from biting bright to very dull. As you turn up the volume, though (i.e., move the wiper from where the M is towards where the G is), the 500pf cap straddling it provides very little advantage for the treble since there is little resistance between input and wiper on the pot. The net result is that, on the amp, the tone control provides audible treble boost and cut when the volume is down, but when you max out the volume, it provides *only* treble cut.

Now, on a *guitar*, one's volume generally IS at full, and is turned down only occasionally, such that most people will not notice the influence of the compensating cap unless they turn down often. On an *amp*, unless it is a low-power unit, one generally keeps the volume pot at much less than full, so the influence of the "bright" bypass cap tends to be very pronounced. Indeed, if your volume pot is at 1 or 2, turning on the bright switch is like cranking the treble up full tilt. Of course, if there is any hiss on your input signal, the bright switch will accentuate it.

Which leads me to these generalizations: 
- If you run your amp near full-out a lot of the time, the bright switch will seem superfluous to you;
- If you play clean and like to enhance the single-coilness of your single-coil guitar, the bright switch will seem useful to you;
- If you tend to feed your amp a distorted signal, the bright switch will be annoying to you.

In thinking over the differences between amp and guitar, it seems reasonable to suggest that the ideal is a 3-position bright switch (and there are 3 position slide switches that will fit in the same space) where one position is just the cap itself, and the other position is a resistor in series with the cap. The cap-only is for those who either like a lot of treble or generally play with the amp volume higher (where the cap will have less impact). The resistor+cap is for those who like a gentler boost and tend to play with the amp volume set lower. The specific cap values do not need to be the same. So, for instance, I see on an AB763 Super, the bright cap is 120pf. A suitable alternate position might be 180pf in series with a 100k-150k resistor, yielding a bit less boost when your volume is down, but starting at a little lower frequency range.


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## Cary

GTmaker said:


> just voted NO....my Super Reverb RI is bright enough for me without the bright switch.


I will say that i'm playing a rented Super reissue while i wait for my Silgo to get out of the shop, and I find that the bright switch is a little too much for me on this one. Could be the fact that it's a different circuit, or it could be the alnico speakers. Either way, I find the sound is a bit harsher on the high end than my sligo (bfsr clone built from a mojotone kit)


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## keefsdad

Never. Fenders are bright enough for me.


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## gtone

Just re-visited this thread and have to update my response. I fitted hempcone Tone Tubby alnicos shortly after my previous post and I can honestly say that I occasionally use the bright switch on the Super Twin now. These do help to remove the ice-pick and make the upper mids and higher freqs that cause it to be much smoother and more musical. Go figure...


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## SaviArt

I have one with my beginner Mustang amp but I used it once. Somehow I managed to play without it. Mustang also has very bright sounding options


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## BEACHBUM

Occasionally, but with my Twin it's almost always overkill.


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## gtone

Another update. The Super Twin's been replaced by a '66 Bassman head and yeah, I use the bright switch very often with that amp.


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## jdguitarbuilder

I have a 64 Fender 4x10 Concert and the bright switch is on all the time. The amp does need a cap job so this may change after I get it back.


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