aion Cirrus Podręcznik - Strona 5

Przeglądaj online lub pobierz pdf Podręcznik dla Sprzęt muzyczny aion Cirrus. aion Cirrus 10 stron. Based on ibanez st-9 super tube screamer

BUILD NOTES

Mid-boost resistor & capacitor values

The original ST-9 and STL used a 20kC dual pot for the midrange control. This value is hard to find, at

this time only available from Tayda Electronics in straight-pin knurled shaft format. It can be made to

work for this PCB, but it's not easy.

Fortunately, this type of parametric filter can easily be adjusted for different potentiometer values. In

fact, most other circuits that use this type of parametric EQ use 100kC—for example, the Lab Series L5

Preamp and the Pearl OD-05 Overdrive.

Accordingly, for this project, the surrounding values in the parametric filter have been modified so

you can instead use a 100kC dual pot, which is much easier to find. By increasing the resistor values

and reducing the capacitor values in the mid-boost section by a factor of 5, it will preserve the same

frequency characteristics.

If you do find a 20kC potentiometer and want to use it, here are the original values:

• C3: 27n

• C4: 68n

• R4: 1k5

• R5: 1k5

Boost level

The Ibanez ST-9 Super Tube Screamer product manual says that the midrange supplies a +25 dB boost.

However, some who have played it have noted that it doesn't sound like it's anywhere near +25 dB, and

in fact others have calculated it at +8 dB, which seems more accurate.

If you don't feel like +8 dB is enough, the gain boost can be adjusted by increasing the difference

between C3 and C4. The only side effect is that in this type of parametric circuit, by increasing the

frequency gain, you also increase the Q (width). If the Q is too wide it won't sound very good at all.

To get the full 25 dB with the same available frequency range, use the following values:

• C3: 5n6

• C4: 270n

If you want more than stock but not that much more, use the values from the Pearl OD-05, which at +15

dB is right in the middle:

• C3: 4n7

• C4: 68n

Note that these are changes from the 100kC adjusted values, not the stock 20kC values. Scale

accordingly if using a 20kC boost pot.

CIRRUS DYNAMIC OVERDRIVE