bass tightener

[mhartington]

Question everyone, i saw this video today from the Hughes and Kettners website about a frequency control on their Triamp. They added a pot to either boost or cut at 95 hertz. Its supposed to tighten up the bass on the high gain channel so it doesn't get "woof" at high volumes and lower tuning. I think Rivera has something similar too on the KR7 head. How would i go about doing this in a stand alone pedal or incorporate it into a pedals circuit? Any help is greatly appreciated.

[PRR]

[mhartington]

I understand just about most of this except for what come before the input. It seems the signal goes through the circuit in on direction, then go through a 50k resistor and something thing else. I don't recognize the symbol. Anyone know what it is?

[blooze_man]

The signal hits a capacitor next. I would do some googling and learn schematic symbols

[Quackzed]

boh, bsorry, bI bmisunderstood bthe bpost.

[ashcat_lt]

V2 is an AC voltage source, and 50K is a (rather large) source resistance.  These two bits are meant to represent whatever is coming before the circuit itself, and is used to generate the graphs seen below the circuit.  If it was supposed to be a pickup, it would want a bit lower R9, with an series inductance and a smallish cap in parallel with both.

[Gurner]

And should anyone happen upon a bigass tightener...I'd like to show my wife the details.

[runmikeyrun]

nothing wrong with a bigass... i've got one at home    don't you know the words to Big Bottom by Spinal Tap?

The bigger the cushion, the sweeter the pushin'
That's what I said
The looser the waistband, the deeper the quicksand
Or so I have read

My baby fits me like a flesh tuxedo
I'd like to sink her with my pink torpedo

Big bottom, big bottom
Talk about bum cakes, my girl's got 'em
Big bottom drive me out of my mind
How could I leave this behind?

I met her on Monday, 'twas my lucky bun day
You know what I mean
I love her each weekday, each velvety cheek day
You know what I mean

My love gun's loaded and she's in my sights
Big game is waiting there inside her tights, yeah

Big bottom, big bottom
Talk about mud flaps, my girl's got 'em
Big bottom drive me out of my mind
How could I leave this behind?

[MetalUpYerEye]

The bigger the cushion, the sweeter the pushin'
That's what I said
The looser the waistband, the deeper the quicksand
Or so I have read

My baby fits me like a flesh tuxedo
I'd like to sink her with my pink torpedo

Big bottom, big bottom
Talk about bum cakes, my girl's got 'em
Big bottom drive me out of my mind
How could I leave this behind?

I met her on Monday, 'twas my lucky bun day
You know what I mean
I love her each weekday, each velvety cheek day
You know what I mean

My love gun's loaded and she's in my sights
Big game is waiting there inside her tights, yeah

Big bottom, big bottom
Talk about mud flaps, my girl's got 'em
Big bottom drive me out of my mind
How could I leave this behind?

This is not the song you want to sing to your girlfriend for her birthday.

I speak from experience. 

[amptramp]

The bigger the cushion, the sweeter the pushin'
That's what I said
The looser the waistband, the deeper the quicksand
Or so I have read

My baby fits me like a flesh tuxedo
I'd like to sink her with my pink torpedo

Big bottom, big bottom
Talk about bum cakes, my girl's got 'em
Big bottom drive me out of my mind
How could I leave this behind?

I met her on Monday, 'twas my lucky bun day
You know what I mean
I love her each weekday, each velvety cheek day
You know what I mean

My love gun's loaded and she's in my sights
Big game is waiting there inside her tights, yeah

Big bottom, big bottom
Talk about mud flaps, my girl's got 'em
Big bottom drive me out of my mind
How could I leave this behind?

This is not the song you want to sing to your girlfriend for her birthday.

I speak from experience. 

Does this explain your screen name?

[PRR]

> except for what come before the input.

Signals come from somewhere.

The circled-Sine is a Perfect AC source. Will make its designed AC Volts into ANY load.

Real-world sources can be loaded-down. They have some impedance.

The box is a generic medium-high impedance AC source.

That's why it has "IN" to the left of the box. That's where your work starts.

> ....50K is a (rather large) source resistance. ...If it was supposed to be a pickup, it would want a bit lower R9, with an series inductance and a smallish cap in parallel with both.

Valid point. Guitar can be under 5K in bass and over 50K in treble; not sure about bass pickups but they are in a similar zone. Guitar with 250K pot can easily be as high as 50K, or much less.

Not shown: I did try several source values and determined that over a wide range up to 50K it made little difference. Values above 50K reduce the bass lift/droop effect but do not affect the treble response (well-above the ~~90Hz resonance the input impedance is very high). Knowing this, I did not model a "full" pickup. If I have to suppose any specific values, then it may not work right in other situations. Showing that it works OK with small to medium-high impedance means it will usually work on stage.

Many effects have fairly high output impedances. 1Meg pots are sometimes seen, potentially 250K at the wiper. This will skew/smear the bass bump/drop..... if you want universal application you will want any simple buffer in front.

Not going to touch the subsequent thread from Reply #6.