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Topics - benzer

Amplifier Discussion / DSP = better filtering
October 08, 2007, 06:13:36 AM
hey folks , i just came by a tutorial about digital filtering using DSP implementation
its really a cure for killing the phase shifts with analog filters,but the circuit and programing would be much harder
its a case of not using a microcontroller but you have to go for a DSP processor for real-time application

thought i'd share it with anybody interested in the digital domain,
it also has a lot of examples and it explains how you can implement these filters using Matlab.
Preamps and Effects / DM K-2OX OUTPUT/FREQ PLOT
September 28, 2007, 12:30:23 PM
I Did draw the whole amp (with biggest gain and biggest boost for bass/treble/midrange) by spice (clean channel)
and i put input of 0.02 volts for (ac analysis)
(+15 -15)op amps feeding
and i got this curve,,, bUT ::::
it looks like there is not enough power in the bass and midrange  and too much distorion at high frequencies (over 6khz) (output more than 15v)...
this is a clean channel so there should be no distortion and if we preserve that the gain at midrange and bass would be very little wich leads to low power...... that looks weird,,any body can explain?
Preamps and Effects / tone frequencies
September 26, 2007, 05:10:56 AM
at what frequencies should we boost the bass/treble/midrange in the tone control circuit of a guitar preamp for best tone?
i read somewhere that the midrange should be between 300hz to 500hz
,,is it true?
Preamps and Effects / the K15
September 21, 2007, 07:03:20 PM
howdy folks, i decided to build this simple amp as a first step into building amps,,its a dean markley chip amp but the preamp is pretty cool,its capable of driving 10 watts into a 4ohms speaker.
i included the circuit here for anyone who's interested
anyways i have some points wich are not so clear to me in this circuit,
1/wuts the R1 for ?
2/about the caps its written for example c1= 473M,,, wut the hell is M?? microfarads?and some caps like c13 is 22/16 ,,whats that stands for? 22microF/16 volts?????
3/i didnt get what the rocker switch connet n disconnect,,can anyone discribe the way it works(what terminals it connects n dont)?
4/about the pots ,, wuts A250K B250K ?? wut ranges should they take?
5/can i get rid of c19? or its better to have it?
6/wuts the point of having R10 and C11 ???
7/any comments about what kind of speaker and op-amps are suitable for this circuit is pretty welcome
.....thanks already for any answers,,hope this amp sounds good
Schematics and Layouts / Rickenbacker RG7 AMP
September 18, 2007, 05:33:05 AM
Howdy folks, i was just surfin the rickenbacker site and i got this cool schematic ,,it looks neat and simple so i decided to included here for anybody interested.
if anybody knows how this amps sounds like let me know.
any explanation about the D1 D2 D5 D6 Q4 Q6 C4 is appreciated
,,have fun
Preamps and Effects / opamp or transistor preamps?
September 17, 2007, 06:08:08 PM
i have seen many schemtaics that build preamps with discrete BJT or mosfet transistor voltage divider bias circuit gain stages..some others use opamps
any idea how does this affect the sound? which one is better?
because using opamps means including many transistors in the circuit,,doesnt mean slower response to the input signal?
and same question about tone controls,,,active or passive? any one knows what diefference in the sound dose it make?
thnks already for any answers
Preamps and Effects / guitar output
September 16, 2007, 04:22:13 PM
i just have a little question,
whats the peak voltage an electric guitar can output?
isnt that something important to consider
when building a pre-amp ??

Schematics and Layouts / 18watts peak-power amp
September 15, 2007, 10:34:16 AM
hey folks ,,this is the amp that i told ya about ,,again i wanna say im new to this and i designed this one hoping it works
i would like to know if there is any mistakes and problems in this design.
the output transistors are
Q1 = BD139
Q2 = BD140
Q3 = BD540
Q4 = BD539
the op amp im using is the TL074 because it has a high slew rate about 13v/uS
in the offset circuit im using 2 opamps because one cannot sink the currnet coming from the diodes alone.
i put 5 diodes in series with the 0.8k resistor to provide quisent curent of 30 mA which i think is suitable and to provide enough voltage drop between the first two base emitter transistors junctions.
the offset circuit is nessasry bcz the output voltage is 0 when the input signal down the diodes is -0.5 volts,so i offset the signal by -0.5 volts before driving the power transistors
in the tone control citcuit im using a pot that should take the values between (10k and more) and a variable cap between (10nf and more)
to give the pot the minimum value which is 10k is to boost the bass.
to give the cap the minimum value which is 10nf is to boost the treble.
the bandpass fiter i chose is the first order one because the phase response is the best.
i hope that u guys tell me what do u think about this amp and any advice would be welcome.

The Newcomer's Forum / making my own first AMP
September 14, 2007, 01:03:27 PM
Howdy folks, im new to this forum so i gorra say howdy to everyone.
my name is Ben and im an electronics engineering student.
pretty much interested lately in audio .
i have very much information about electronics and pretty good in theory but i havnt built my first amp yet.
it is time to do so,,i have designed the amp (20 watts) using proteus and matlab to design my filter and tone control.
i would like to anybody to see the schematic and give me advice on wether its gonna work or not ,,or if there are some mistakes .
if anyone is willing let me know.
general info about the amp : >>
im using the compound configuration for my power transistors
they are the BD139-BD140  OUTPUTS TO BD539-BD540.
outputs +-12 volts into 8 ohms speaker
i used a first degree band pass filter 20-20000hz
and the general filter configuration for the bass-treble control with the variable cap and a pot.
let me know if anybody is interested so we can talk this amp up

thankya'll already