what am i powering with the 18V? Is it just the preamp circuitry or is it 9V preamp 9V PU? Also, if passive PUs give a strong enough signal at full volume knob, what does the passive PU-active preamp system do?

another thing is, i was actually referring to the volume knob and not tone or EQ. For example; back to guitars...i play a classic standard strat on an all tube amp and i overdrive the tubes. When i turn the volume knob down, i reduce the signal level and thus reducing the OD. So i end up with an almost clean sound....

Now the problem is... if the PUs are not "hot" enough, as some people say, then the PUs sounds flat with a lot of bass and low mids but the hi freqs are cut off (even with full tone knobs)....resulting in a changed signal (for bass it's usually from 10kHz that get cut off)...Apparently something to do with resistance of wires something something bla-.... How do active PUs solve this?

ok case settled. There is no such thing as an "active" PU. It's just the preamp that makes it "active"

ok a little explanation.. but this may be wrong.. plz correct me if i am wrong

some technical background.. putting it simple :
coils means inductance .. means phase shitfs - bad to signal.. thats y normally we have a tone control to compensate for the phase shifts.. basicly a simple cicuit with variable capacitor

whether its active PU or passive PU, its still coils and magnet. Electromagnet is oso coils so there is no escape. Since coils is passive component so i guess this made up the statement above?

i believe active PU is introduced to reduce coils; reduce phase shifts and compensation. Coil also contributes some resistance which acts like a load. To put it simple.. it may take part of the signal.. thus reduce output. With active PU introduced, we may only need a scaled down magnet + coils.. then amplify them with active preamp circuits..it should be opamp filter circuits(lowpass filter, bandpass filter, high pass filter ect) this way the circuit can choose which freq range to amplify n which to amplify less.

passive PU on the other hand works like a simple electric generator.. how much u turn the rotor equals how much power generated.. for this case the output is ur signal of course.

another long boring post

isit true tat passive sound more warm than activs?
wit the tone rolled off all the way it sounds more gentle

I deleted 13 posts talking about amps.

Let me remind you guys that this is a Guitar/Bass Pickups Thread.

i don't think so. But correct me if i'm wrong. An active PU can behave like a passive PU as well because of its ability to both cut and boost frequencies.

I have compared a fender precision 1968 to a G&L L-2000 1995 and the g&l can be set to get almost the same sound as the fender by turning the bass boost on and messing around with the 2-band EQ (bear in mind that the preci is using split PUs and the G&L uses double humbuckers). Of course you can't get the same sound since the PUs are different (not to mention the age of the fender). But in terms of warmth of tone, both basses are great.

So for warmth, i think other factors affect it more like the type of wood, amp, speakers blablabla. So in my comparison, i managed to get very smooth warm tones out of both basses (using the same amp of course).

shouta, your long and not-so-boring post seems to be very logical... thanks for the clear explanation
1) could you develop about the phase shifts ? i know that inductance will induce phase shifts, but why is it bad ? IMO, the whole signal is being shifted, so it doesn't produce phase-cancellation. (???)

2) how does the tone control work ? if it's just an inductance, then what's its effect ?

3) << bassix >> about the treble being diminished when the volume knob is turned down : on my guitar (the ibanez), there is a push-pull on the volume knob that, when pulled, will allows the higher frequencies to remain high and clear even when the volume is lowered... i think it uses a different kind of resistance (10k ?).

Dude...my ibanez needs a new colour...
can u tell me the best shop that can do that...
with the good price also la...
anything just pm me guys...
thanks...

was wonderin bout those large-pole pickups n close close-up 1s
wats so different bout the sound? stronger?? meatier???

looking for gibson burstbucker type 1 and type 2. know anywhere to get them and their prices? if cant get those probably a burstbucker pro

its not urgent since i might be getting a midi controller first...
or hopefully if i manage to save enough(and get another part time job during my hols) and get a nice amp

I believe I saw some in Wohfatt. Around the 300 to 500 range.

ive never been to woh fatt.

blacktrix, maybe u can help me find out when u go there this tuesday

echo...u in UTM rite?
woh fatt in KL kota raya...wen u comin??
keke

burstbuckers rm500?
i know the tony iommi pickup is already rm400 in woh fatt, so use that as a guide to how much the burstbuckers will be.

hmm..how about SD SH-4 JB Model?

i'm looking forward to this humbucking pickup.....great jazz and great distortion.....

Will find out when I go to Woh Fatt...... Just remembered....... might schedule quite packed, so might go on Thursday instead.

ok i am still learning.. plz correct me if i am wrong and i hope u understand this.

This may require some maths (complex notations). resistance, reactance, impedance.
resistance is a real component (R )
reactance is an imaginary component (jX or jwL or j2πf)
impedance is the complex component (Z or R+jX)

phase degree is the angle between the real component, resistance to the complex notations/line, impedance.

π = pi = 3.142
f = frequency
w = 2πf = 2 x 3.142 x frequency; thus the imaginary component, reactance vary accordingly to frequency change.
phase degree vary accordingly to the imaginary component, reactance.

Putting it simple, inductance/coils induce phase shifts based on frequency.

phase shifts will affect signal amplitude, either reduce more or reduce less.. commonly termed as attenuation. Generally it will have sort of a negative line gradient attenuation in the frequency spectrum (juz take a look at an equalizer).. from lowest frequency to highest frequency..
So for a guitar it may sound blunt since the higher freqs are cut off.

The nyquist plot in the following site show it all...
http://www.consultrsr.com/resources/eis/induct1.htm

-Z" is the imaginary component, reactance
Z' is the real component, resistance
the complex notations, impedance,Z are summed all together to form the circular line.

capacitor does the opposite of inductance, induce reactance to the opposite direction of the imaginary axis... +Z" positive. (inductance induce to -Z" negative direction). Therefore capacitace can reduce phase shifts, reduce attenuation and solve this problem. Now the question is what capacitance value should be applied tocompensate for the attenuated signal? that hence the tone control.

The RLC circuit shown may be an example of how a tone control may work. It could be done by varying the resistance value of the resistor parallel to the capacitor.

This post has been edited by shouta: Jul 18 2006, 03:32 PM

The Phase-Shifter has spoken

This post has been edited by Bassix: Jul 18 2006, 03:39 PM

Ever since high school I've lost touch with everything science...

I was in Woh Fatt for a while today. Sorry Echo, no burstbucker. They do have 57 classics and some 4xxT or something like that. The Iommi humbucker is RM570 before discount.