ok...here is original schematic....
http://bas.elitesecurity.org/technosema.pdf
try to modify earth symbol from ltspice schematic and tell me slew rate? On web site it says 62V/us... When you have around 62V/uS then earth symbol is working...
http://bas.elitesecurity.org/technosema.pdf
try to modify earth symbol from ltspice schematic and tell me slew rate? On web site it says 62V/us... When you have around 62V/uS then earth symbol is working...
This one should work better 
I've added transistors.txt for those that don't have the models (add to standard.bjt under ltspiceIV\lib\cmp)
Also the LED used in the original model wasn't working properly I think that the one in the diode.txt file should work better. add to standard.dio under ltspiceIV\lib\cmp
I don't know how to set the quiescent current so have just set the pot to .5
Oh and you need to put potentiometer.sub under lib/sub and potentiometer.asy under lib/sym (you can probably get away without installing them and just leave them in the same directory as the techno.asy if you want).
I don't think I missed anything, but it appears to be working correctly now based on a rudimentary look at the fact that a 1V input produces a 30V output with a 1Khz sinewave (and the gain of the amp is indeed 30).
Tony.
I've added transistors.txt for those that don't have the models (add to standard.bjt under ltspiceIV\lib\cmp)
Also the LED used in the original model wasn't working properly I think that the one in the diode.txt file should work better. add to standard.dio under ltspiceIV\lib\cmp
I don't know how to set the quiescent current so have just set the pot to .5
Oh and you need to put potentiometer.sub under lib/sub and potentiometer.asy under lib/sym (you can probably get away without installing them and just leave them in the same directory as the techno.asy if you want).
I don't think I missed anything, but it appears to be working correctly now based on a rudimentary look at the fact that a 1V input produces a 30V output with a 1Khz sinewave (and the gain of the amp is indeed 30).
Tony.
Yes, now is working.. it has 30V output...which correspond to 60V/us (In reality is 62V/us)...so EARTH symbol i need to ground it...and LED was that that causing simulation problems...many thanks...i im now getting to put Lambda Amplifier from Dr.Bora in simulation in a want to know how is Slew Rate...It is same as Sigma(115V/us) or greater or less...when i complete drawing schematic i will attach it here to modify if somthing goes wrong in simulation.
Thanks, guys for solving this out..problem in Techno simulation. Techno is very good amplifier...
it has 30V output...which correspond to 60V/us (In reality is 62V/us)...so EARTH symbol i need to ground it...and LED was that that causing simulation problems...many thanks...i im now getting to put Lambda Amplifier from Dr.Bora in simulation in a want to know how is Slew Rate...It is same as Sigma(115V/us) or greater or less...when i complete drawing schematic i will attach it here to modify if somthing goes wrong in simulation.Thanks, guys for solving this out..problem in Techno simulation. Techno is very good amplifier...
Ok..i have forgoten that i have a few days ago completed drawing Lamda schematic into LTSpice IV.
Here is schematic in LTSpice IV
http://rapidshare.com/files/456355731/Lambda.asc
And here is a original schematic:
http://bas.elitesecurity.org/Lambda-sema.gif
I run simulation (i need models for input tranzistors) and i im getting only 20V/us output at 1V input...could some one change earth symbol and put tranzistors models like original schematic and put here as zip file? I would like to know how many Slew Rate has, and THD at 20kHz...
I really having interest in building this amplifier but before i would like to know simulations results.
Here is schematic in LTSpice IV
http://rapidshare.com/files/456355731/Lambda.asc
And here is a original schematic:
http://bas.elitesecurity.org/Lambda-sema.gif
I run simulation (i need models for input tranzistors) and i im getting only 20V/us output at 1V input...could some one change earth symbol and put tranzistors models like original schematic and put here as zip file? I would like to know how many Slew Rate has, and THD at 20kHz...
I really having interest in building this amplifier but before i would like to know simulations results.
Yes, now is working..
To measure/sim a slew rate of an amplifier you have to assignee a pulse voltage source as input... For an example:
PULSE(-.1 .1 0 10u 10u 5m 10m) 100Hz
PULSE(-.1 .1 0 1u 1u 500u 1m) 1kHz
PULSE(-.1 .1 0 100n 100n 50u 100u) 10kHz
PULSE(-.1 .1 0 10n 10n 5u 10u) 100kHz
I just spent a few minutes looking carefully through this schematic (both the .gif and LTSpice .asc files in post #26) to determine the reasoning behind these two grounds, and the way they are used in this circuit. I don't mean just in general as in "It prevents a ground loop" - I KNOW that's what it's supposed to do, but I wanted to know exactly how that works.
From my initial partial analysis, it appears the input section (along with the input cable's ground connection) is referenced to the standard GND of LTspice, and the output section is to the "Earth" ground, and they of course are connected through the 47 ohm resistor.
I think I have it figured out. A (small 50/60Hz mains) ground current would appear as a small voltage across the 47 ohm resistor, and would appear at other places, but specifically between the emitter and collector of the second pair of transistors. As the collector circuits of these operate essentially as constant current sources, the difference in voltage between each collector and the other side of its load resistor would not appear on the load resistor.
Thinking more along the lines of which ground does what, the original .gif schematic is incomplete, in that doesn't tell which ground the voltage sources should be connected to, nor the ground the speaker load connected to the output should use. It looks to me that the LTspice similation as drawn gets both of these wrong - the power and output grounds should be referenced to the "Earth" connection rather than the GND connection. With all the output bypass connections referenced to "Earth," especially the 10 ohm and 100nF snubber right at the output, I'd think having the speaker/load also referenced to "Earth" would make good sense.
From my initial partial analysis, it appears the input section (along with the input cable's ground connection) is referenced to the standard GND of LTspice, and the output section is to the "Earth" ground, and they of course are connected through the 47 ohm resistor.
I think I have it figured out. A (small 50/60Hz mains) ground current would appear as a small voltage across the 47 ohm resistor, and would appear at other places, but specifically between the emitter and collector of the second pair of transistors. As the collector circuits of these operate essentially as constant current sources, the difference in voltage between each collector and the other side of its load resistor would not appear on the load resistor.
Thinking more along the lines of which ground does what, the original .gif schematic is incomplete, in that doesn't tell which ground the voltage sources should be connected to, nor the ground the speaker load connected to the output should use. It looks to me that the LTspice similation as drawn gets both of these wrong - the power and output grounds should be referenced to the "Earth" connection rather than the GND connection. With all the output bypass connections referenced to "Earth," especially the 10 ohm and 100nF snubber right at the output, I'd think having the speaker/load also referenced to "Earth" would make good sense.
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Looking at the PDF file in post #21 (a significantly different design, with the usual single longtail pair instead of the more complicated but symmetrical input circuit in the other schematic), it's a lot easier to see how the use of the two separate grounds increases immunity to ground currents (usually called "ground loops"). Any variation in the voltage at the input ground resistor along with the input signal is a common-mode signal and will be cancelled by the longtail pair, whereas a signal at the input REFERENCED to the input ground will be amplified. The feedback resistors will keep this cancellation from being theoretically perfect, though the ground signal will be reduced by the resistor ratios, 10k to 330, or about 30 to 1.
Yes, now is working..
Thanks, guys for solving this out..problem in Techno simulation. Techno is very good amplifier...
I think you missed my post 22
the biggest problems were in that one ie the missing connections Oh and I think I hard coded the timestep in the sim command to 10uS because I didn't want to wait for the solve time in case you didn't notice.... Tony.
Hi robydream the best way to learn is to fix it yourself I probably should have only pointed out where the problems were last time and let you work out from there... Apart from the misunderstanding with the earth terminals the main problem with the first circuit was that you had missed two connections, and had not used a pot for one of the resistors (You could use two resistors in place of a pot if you don't have a pot and take the tap off the centre of the two) ie you were missing the connection from the base of Q6 to the wiper of the pot, and you were also missing a connection from the base of Q5 to the collector of Q1.
Both of these problems were pretty obvious when doing a comparison of the two schematics. So my advice would be to print out the two schematics (or just put them side by side on screen if your screen is big enough) and double check that you have connected everything correctly.
I helped the first time in the hope it would show you how to troubleshoot so you can help yourself in future.
Another thing that will help you to track down problems is checking the waveform at different stages throughout the circuit not just at the output. thus you can work out where it is still ok and where it goes wrong.
Tony.
I probably should have only pointed out where the problems were last time and let you work out from there... Apart from the misunderstanding with the earth terminals the main problem with the first circuit was that you had missed two connections, and had not used a pot for one of the resistors (You could use two resistors in place of a pot if you don't have a pot and take the tap off the centre of the two) ie you were missing the connection from the base of Q6 to the wiper of the pot, and you were also missing a connection from the base of Q5 to the collector of Q1. Both of these problems were pretty obvious when doing a comparison of the two schematics. So my advice would be to print out the two schematics (or just put them side by side on screen if your screen is big enough) and double check that you have connected everything correctly.
I helped the first time in the hope it would show you how to troubleshoot so you can help yourself in future.
Another thing that will help you to track down problems is checking the waveform at different stages throughout the circuit not just at the output. thus you can work out where it is still ok and where it goes wrong.
Tony.
oh and one other thing robydream, I think you are confusing slew rate with gain... here is a link from wikipedia on slew rate Slew rate - Wikipedia, the free encyclopedia
The ratio of the resistors in the feedback network (R10 and R11 in your original schematic) will determine the gain of the amplifier, in the first amp you posted this ratio was ~30:1 , hence when feeding the amp a 1V signal the output signal was ~30V.
Tony.
The ratio of the resistors in the feedback network (R10 and R11 in your original schematic) will determine the gain of the amplifier, in the first amp you posted this ratio was ~30:1 , hence when feeding the amp a 1V signal the output signal was ~30V.
Tony.
Yes...you are right wintermute...thank you for your all help...
I im just begginer playing with simulation and audio amplifiers...and would like to know how amplifiers in simulation works...
About Slew Rate...i have wrong way before understand...
Now i will go to study schematic and try to making in working in simulator.
I im just begginer playing with simulation and audio amplifiers...and would like to know how amplifiers in simulation works...
About Slew Rate...i have wrong way before understand...
Now i will go to study schematic and try to making in working in simulator.
Oh...if i understand good in Lamda the two resistors in feedback network (R23(3.9k) and R21(200R)). Ratio between this two resistors is --> 3900R / 200R = 19,5 so the ratio will be
~20:1 feeding the amp with 1V input it will result output signal at ~20V.
That my simulation confirmas...and i im getting in ltspice output 20,156V
~20:1 feeding the amp with 1V input it will result output signal at ~20V.
That my simulation confirmas...and i im getting in ltspice output 20,156V
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