how create a tone selector passive filter

[bent]

Hi everyone,

i have search without success....

I'm looking info on how to create some tone selector passive filter like the avalon u5 have:

http://www.avalondesign.com/pdfs/hr_avalonLit_U5.pdf
bottom page 2

I know hot to make high pass (#5) , low and high pass (#6) ... but how to create curve like # 1 - 2 - 3 - 4

Anyone can help me out on this....
Thank's
Bent

[Electron Tornado]

Download the Duncan Tone Stack Calculator. It's very easy to work with and you can come up with something you'll like.

http://www.duncanamps.com/tsc/

[FiveseveN]

Sorry for the OT but something caught my eye: for such a highly respected manufacturer, it seems odd that they don't give a reference for their specs (plus, noise is unweighted). I assume it's 0Dbu. One should not leave his/her specs open to assumptions.
PS: we have a 737sp and it's brilliant but I don't have the manual at hand so I can't say if the reference is mentioned there either.
End of rant.

[PRR]

> they don't give a reference for their specs

Page 2 in the linked sheet sure seems to say dBu....?

Noise 20kHz unweighted  -100dBu minimum gain position

Unless something is very odd, the A-weighted spec can be derived by integrating the A curve over a 20KHz bandwidth. IIRC that's about 6dB.

True, it is also customary and useful to know the noise at MAXimum gain. However $5 chips come within 2dB of noise perfection. It is unlikely that this box does worse; or that if it is 1dB better that you could tell in blind tests. In fact hi-gain noise is easy; many preamps don't get a lot quieter when gain is reduced. This 7uV spec at min gain is excellent.

Avalon's come-on isn't their specs. 0.5% THD ?? Only 30dB gain?

As you say, Avalon IS a "highly respected manufacturer.... it's brilliant". I think they are expensive, but that goes with people who try to get EVERYthing musically right, from the screws to the biasing. I'm not even sure why they have specs, except size and max gain (this 30dB would not be go-to for ribbons on harpsichord).

The EQ looks like something to balance the front panel layout. Maybe useful in a minimalist system. Perhaps a lot smarter than giving some people 5-band parametrics: those 5 shapes ARE generally musically useful (and 1-3 can be found in a Fender tonestack, 4 if you shift the caps).

[Mark Hammer]

The Roland Double Beat provides a nice example of how to accomplish the objective.  It only has 3 such settings, but there is no reason why other types of filter functions cannot be employed with a 6 position switch.  In this schematic, you can see that the switch selects between full spectrum (330k), high pass (150k / 250pf), and bandpass.  The various Superfuzz workalikes also include a two-position tone switch with a fixed mid-scoop filter and a full-spectrum setting.

[bent]

thank's for the reply !!!! 

Download the Duncan Tone Stack Calculator. It's very easy to work with and you can come up with something you'll like.
http://www.duncanamps.com/tsc/

thank's electron tornado, i forgot about this tool....really usefull...
2 question:
- do i need to put somesort of a opamp (gain boost) in front of the schematic a choose, cause most of them bring down the frequency in the minus (-5db to -10db) (avalon stay at 0 to 2dB except the frequency need to be bring down)....
- can i put the passive tone filters in front of a passive DI...

thank's

bent