Stupid and easy question

Frequent asked about building blocks: gain stages, buffers, clipping configurations, ...
Post Reply
User avatar
POTL
Resistor Ronker
Information
Posts: 335
Joined: 26 Sep 2016, 03:11
Has thanked: 58 times
Been thanked: 67 times

Post by POTL »

Greetings
The question is really simple, I played many times with the equalizers of various amplifiers, but only recently drew attention to the fact that the mid-frequency and high-frequency controls of different amplifiers have different characteristics.
Mesa boogie (mark)
VOX
Fender black / silverface
and many other names for logarithmic features characteristic of high and medium pots.
On the other hand, Orange, Marshall, Soldano and many others are on the rise, with no linear features of medium and high pots.
I do not have potentiometers of different characteristics in the right values ​​to compare.
Perhaps someone will be able to clarify the situation, why are different characteristics used?
On the one hand, linear potentiometers should work more evenly and smoothly, on the other hand, the design of the fender is later and possibly more thoughtful.

Or is it all about the level of distortion?
Do linear characteristics work better with dirt, and logarithmic with a clean signal?

User avatar
ppluis0
Diode Debunker
Information
Posts: 915
Joined: 14 Jul 2010, 18:33
Location: Argentina
Has thanked: 127 times
Been thanked: 299 times

Post by ppluis0 »

Hi POTL,

Just download a free software to run simulations on tone stacks: http://www.duncanamps.com/tsc/download.html

You can edit values and types of potentiometers and also the remaining passive components for several tone control arrangements and see the resulting response curves.

Cheers,
Jose

User avatar
FiveseveN
Cap Cooler
Information
Posts: 591
Joined: 25 Oct 2009, 21:20
Location: Romania
Has thanked: 215 times
Been thanked: 116 times
Contact:

Post by FiveseveN »

I don't think he's asking how different tone stacks have different responses but why.
Do linear characteristics work better with dirt, and logarithmic with a clean signal?
No. There's not even a direct correlation and I don't think your assessment is even correct. Most FMV stacks have linear mids control, and some have linear treble.
Orange, Marshall, Soldano and many others are on the rise, with no linear features of medium and high pots.
Are you saying that these (Marshall-derived) designs do have lin pots or that they don't? Because they do. And what do you mean by "on the rise"? These are 50- and 35-year-old companies.
I do not have potentiometers of different characteristics in the right values ​​to compare.
You're going to have to get some and hear them out for yourself.
Ignorance more frequently begets confidence than does knowledge. (Charles Darwin)

User avatar
bmxguitarsbmx
Cap Cooler
Information
Posts: 510
Joined: 25 Mar 2010, 21:15
Has thanked: 704 times
Been thanked: 216 times

Post by bmxguitarsbmx »

A log Treble pot will make the amp seem dark. Or, you can use a log treble pot on a very bright amp to make it seem even in the top end. I have accidentally installed a 250k Log pot in a Marshall based build and the customer came back complaining about how dark it was. Only changing the pot to linear changed his mind. I thought that was pretty interesting. If you look up the graph, it makes sense though. It was just disconcerting for the player to put the treble on 9 to have it sound good, which is halfway on a linear pot roughly. I like linear Mid, Log Bass, Linear Treble. That to me makes sense. If you put everything at noon, it is an even response.

Post Reply