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I’m back
And I’ve just translated essential parts of TONE TwEQ document (not the complete combo exemples part).
It’s in the same folder as the others docs.
I’ve read this in the archive forum:
Wilki1 said: Each tone section consists of resistors and capacitors to determine the frequency. The associated pots determine the boost or cut of each band. There is no adjustment for Q on each band. In Archived forum
And I would like to know the determined frequencies for bass, mid and treble to have a better understanding of what I’m doing 🙂
Is it possible to know it? without to build it and use a spectrum analyser? Or calculate it with resistors an capacitors?Sorry if I’m boring with my questions 😛
See you.
Since you are native French speaking I would suggest Google using the words Baxandall EQ as there is a ton of information out there (perhaps in French) and this would allow you to learn everything you would wish to learn and more if you like.
A Baxandall tone stack is a high/low shelf EQ. Versions can be found in Ampeg, Orange, Tweed Fenders, Sunn amps and more. With the controls set to 12:00, the frequency response is essentially flat, as opposed to a std TMB tonestack, which has a mid-scoop and bass roll-off with the controls set the same. A Bax stack is capable of essentially a mid-hump, which a std stack is unable to accomplish at any setting.
This circuit has been used in every stereo system since the 70’s for good reason and as a result there is plenty of information readily available. Also here is a link to a great Tone Stack Calculator.
Thanks for the Doc.
The toneTwEQ circuit consists of 3 filters. The Treble and Bass filters are shelving type filters that boost or cut frequencies using a 1Khz midpoint. The Mid filter uses a center frequency of 1KhZ to boost or cut. The amount of boost and cut is about 15dB. Here is a diagram of the frequency response:
Hi,
Thank you Barry and Wilkie1!
I am curious to know what capacitor values for the Midrange control could be used to vary the midrange frequency. Specifically for Bass Preamp to have midrange center frequencies at 200,400, 800 and 1K. I assume that the two capacitor values for C6 and C5 would vary to support the midrange frequencies.
The MID filter in the Tone TwEQ is an active bandpass filter that has a center frequency about 1K. You can use the following equations to calculate different values:
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