Tone Stack Challenge

[cservonyec]

Originally posted by Funker
Hi Laszlo,
Id burn some brain cells with this kind of tone control and made my modifications as I thought it could be arranged like this (see attachment) It is, of course a peculiar circuit far away from others.
My rearrangement using all of the existing parts and noone is left over.

regards from Hamburg
Wolfgang

Thanks Wolfgang.
I really appreciate all solutions. However I would like to stick to the original as possible. Looking at your drawing, it looks more like a bandaxall circuit, that countless amps use, perhaps with not exactly these values or extra component. Like I said before, this circuit has to work based on the picture. There are not many variation as how to actually connect the part together. Some connections are obvious from the image. Some are either this or that.
Last night I've rebuilt it like the above drawing and finally it started to behave as it should and as I remember when I had the opportunity to listen to the original amp. When you turn on full the treble it rolls off the bass and the sound high, and when you turn on the bass it does the job too. All I have to do now is to work out the best values of the three unknown capacitor values by playing with different ones and listen to the sound. I'm afraid my electronics knowledge is not up to calculating the frequencies, unless you know how to do it and let me know the formulas.
By the way what program did you use to draw your schematic?

[Funker]

Hi Laszlo,
as you wrote there are not much possible variations , but the pictures are not the same like to have the amp on the bench.
The circuit is only a little bit like baxandall, the latter has no low pass filter in it. (ref. obove picture R6, C7,R7)

The behavior of all these passive tone controls are deeply depends on the in/ output impedances of the associated circuts.

You wrote you build the circuit of the obove picture. Did you build your or mine version?

yes I can calculate the tone control component values by given roll off frequencies and impedances, but not from memory, I have to use my old radio education books for this. Due to them they are written in german I found and english link to the formulas.
Look at this:

http://www.schmarder.com/radios/tech/tone.htm

I use splan for my drawings , look here:

http://splan.softonic.de/

I is a german software and I don´t know if an english version are available.

regards from Hamburg
Wolfgang

[Funker]

Hi, me again,
I found an english link for splan,
look at this:
http://www.abacom-online.de/uk/html/produkte.html

regards from hamburg

Wolfgang

[cservonyec]

Originally posted by Funker
Hi, me again,
I found an english link for splan,
look at this:
http://www.abacom-online.de/uk/html/produkte.html

regards from hamburg

Wolfgang

Thanks again Wolfgang.
I get stack in right away.

Cheers
Laszlo