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Re: LTspice World Tour in Australia
John Woodgate
In message <kshfhj+al36@...>, dated Sun, 21 Jul 2013, Helmut <helmutsennewald@...> writes:
I want only remind that Mike is on tour in Australia this week.That will compensate them for losing the first two cricket Test Matches, but not 100%. (;-) -- OOO - Own Opinions Only. See www.jmwa.demon.co.uk Why is the stapler always empty just when you want it? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK |
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Re: MPS4250
Hello Jean,
My answers are below. --- In LTspice@..., "jean_claudeabeille" <jean_claudeabeille@...> wrote: R4 has to be ideally connected to the output as I did. Then the offset of the amplifier output will be only the offset of U1B. If we connect R4to the net "C5", the offset of U1B will be multiplied by the gain 25 of the amplifier. - D5 instead of Q5I don't have the model parameters for a Vbe breakdown. You also don't know what breakdown voltage you get. 7v, 8V, 9V? - D4 added1.5V of one LED is too less. - Q11 PNP instead of NPNYou had a NPN symbol but named it a PNP. That's a "foul play". :-) The simulation will simply not work as intended. I replaced it with a PNP to leave the PNP-type. Alternatively one could had rename the NPN with a NPN-type. - U1A output connected to I-I have shown the only correct usage of unused opamps. To make this even more save, connect a 10k resistor between GND and the +input of U1A. (I had forgot this resistor.) This is not the real schematic, the one I uploaded.You should look that the opamp output U1B is not at the rails. If this is the case and your circuit is correctly wired, you should try a slightly larger or lower value of R5 to bring the opamp output into its linear region. At very low frequency of a few Hz, this loop will cancel your AC audio signal. It will behave like having a highpass with a few Hz in the input. How do you worked to get this solution ? What is the trick ?I have 35 years experience with analog circuit design. At last, what is the job of D3/D107,It limits the input differential voltage during power-up and down or if somebody connects an AC-coupled pre-amplifier or the input voltage is faster than the amplifier can follow.. D102/D103.They avoid that you expensive amplifier will be destroyed due to reverse bias during power-up and down. I apologize wasting your time with so basic questions,You had made a mix of a few schematic drawing mistakes and a very few design errors. The combination makes it hard to get the first working simulation. Now it's working. PS: I like the idea with Q14. It limits the maximum current of Q8. Best regards, Helmut |
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Re: LTspice Genealogy - The Heritage of Simulation Ubiquity
Simulation Program with Integrated Circuit Emphasis -----Original Message-----
From: LTspice@... [mailto:LTspice@...] On Behalf Of Henry McCall Sent: Saturday, July 20, 2013 1:27 PM To: LTspice@... Subject: Re: [LTspice] Re: LTspice Genealogy - The Heritage of Simulation Ubiquity The grandfather of all spice programs was a phd thesis in one of the California universities. it was even called spice which indicated a ( S? Program for Integrated Circuit Engineering.) it's primary purpose was mos circuits as I recall. It was mid to late 60's I think. On 7/20/2013 1:16 PM, John Woodgate wrote: In message <kseg1d+mptm@...>, dated Sat, 20 Jul 2013, ------------------------------------ Yahoo! Groups Links |
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Re: MPS4250
jean_claudeabeille
OK. I agree, on your schematic, the amp works fine. Problem is : why did you changed, added components and changed some wires :
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- output on R4 in place of C5 - D5 instead of Q5 - D4 added - Q11 PNP instead of NPN - U1A output connected to I- - deleted R12. This is not the real schematic, the one I uploaded. What does mean : "Watch this voltage. Select R5!" ? I understand nothing about this :" This control loop has to be slower then the lower corner frequency of your amplifier". Can you develop this ? How do you worked to get this solution ? What is the trick ? At last, what is the job of D3/D107, D102/D103. I apologize wasting your time with so basic questions, but I try to understand. I read the first part of B. Cordell's book and learn a lot but not enough to understand this damn amp. I asked some help to B. Cordell but he answered to read chapaers 1-4. Am I stupid or something ? --- In LTspice@..., "Helmut" <helmutsennewald@...> wrote:
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Re: MPS4250
jean_claudeabeille
OK, thank you
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--- In LTspice@..., John Woodgate <jmw@...> wrote:
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Re: MPS4250
Hello Jean,
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I have uploaded a new version which tries to use most of your original values while still has all the necessary corrections. Please continue with this version in your project. Files > Temp > AmpJCA_1b.zip The LF353 regulates the DC-output voltage to the DC-input voltage. Therefore the opamp adjusts the current of the JFets which changes the voltage drop on R5. Basically it equalize the collector current of Q8 and Q12. This control loop has to be slower then the lower corner frequency of your amplifier. Best regards, Helmut --- In LTspice@..., "jean_claudeabeille" <jean_claudeabeille@...> wrote:
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Re: MPS4250
John Woodgate
In message <ksg876+8t42@...>, dated Sun, 21 Jul 2013, jean_claudeabeille <jean_claudeabeille@...> writes:
What I woud like to understand is HOW to equilibrate the voltages at the collectors of Q12 and Q13 to get quite the same current at R101 and R111.I suggest you follow Helmut's advice, because your question is about amplifier design, not LTspice simulation. -- OOO - Own Opinions Only. See www.jmwa.demon.co.uk Why is the stapler always empty just when you want it? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK |
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Re: MPS4250
jean_claudeabeille
OK, Helmut, if "we don't want discuss the design of audio amplifiers", I give up !
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--- In LTspice@..., "Helmut" <helmutsennewald@...> wrote:
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Re: MPS4250
jean_claudeabeille
Hello John
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You are right, there are some errors in the schematic. I uploaded the new corrected one along with the missing components files : AmpJCA.zip. I hope that this time the schematic is correct. Meanwhile I received 2 models of mps4250. Simulations with one of them and with BC557 give very different results. Which one is true ? LTSpice's one - BC557B or BC557C - I guess. In fact results are very dependent of model's parameters. Besides, I don't know if it's important but on my amp, U2 is CNY17-4 which is not present in LTSpice's OPTOS. What I woud like to understand is HOW to equilibrate the voltages at the collectors of Q12 and Q13 to get quite the same current at R101 and R111. --- In LTspice@..., "Helmut" <helmutsennewald@...> wrote:
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Re: MPS4250
found this old thing ...similar, somebody may want it.
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.model PN4250 PNP(Is=6.734f Xti=3 Eg=1.11 Vaf=45.7 Bf=388.2 Ne=1.806 + Ise=6.734f Ikf=.205 Xtb=1.5 Br=2.635 Nc=2 Isc=0 Ikr=0 Rc=1.67 + Cjc=6.2p Mjc=.301 Vjc=.75 Fc=.5 Cje=7.5p Mje=.2861 Vje=.75 + Tr=9.861n Tf=467.9p Itf=.17 Vtf=5 Xtf=8 Rb=10) * National pid=62 case=TO92 * 88-09-08 bam creation hmmm...don't need the parentheses anymore eh? --- jean_claudeabeille@... wrote: From: "jean_claudeabeille" <jean_claudeabeille@...> To: LTspice@... Subject: [LTspice] Re: MPS4250 Date: Sun, 21 Jul 2013 00:01:32 -0000 Thank you for your answer, it's very kind --- In LTspice@..., ¨¢???????? ?????????¡Á <BordodunovAlex@...> wrote:
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Re: MPS4250
jean_claudeabeille
Thank you for your answer, it's very kind
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--- In LTspice@..., ¨¢???????? ?????????¡Á <BordodunovAlex@...> wrote:
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Re: LTspice Genealogy - The Heritage of Simulation Ubiquity
The grandfather of all spice programs was a phd thesis in one of the California universities.
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it was even called spice which indicated a ( S? Program for Integrated Circuit Engineering.) it's primary purpose was mos circuits as I recall. It was mid to late 60's I think. On 7/20/2013 1:16 PM, John Woodgate wrote:
In message <kseg1d+mptm@...>, dated Sat, 20 Jul 2013, |
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Re: MPS4250
--- In LTspice@..., abeill?? jean-claude <jean_claudeabeille@...> wrote:
Hello Jean, The circuit had a lot of mistakes. I tried to correct them. Please watch all the circles and my other comments in the schematic. My files: Files > Temp > AmpJCA_1.zip I have used most of the missing transistor models from bordodynov's file standard.zip. Over all we don't want discuss the design of audio amplifiers in the LTspice Yahoo group. You should do that in DiY-Audio groups. There are also books about audio amplifiers, e.g. this one from Cordell, . Best regards, Helmut |
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Re: LTspice Genealogy - The Heritage of Simulation Ubiquity
John Woodgate
In message <kseg1d+mptm@...>, dated Sat, 20 Jul 2013, legg@... writes:
Mind you, there are spice era files from (likely) elsewhere that predate these - mostly libraries. The same file type from a Basso Pspice CD install is marked Nov98.It's normally completely impossible to know when anything really started. I know that an ex-colleague was doing simulations at Kings College, London of audio circuits using FORTRAN with matrices no later than early 1964 (because that's when the lab caught fire). -- OOO - Own Opinions Only. See www.jmwa.demon.co.uk Why is the stapler always empty just when you want it? John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK |
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Re: LTspice Genealogy - The Heritage of Simulation Ubiquity
--- In LTspice@..., "Helmut" <helmutsennewald@...> wrote:
The old W98 installation on this machine has files in the SWCAD directory, probably copied from an installation CD, that have 'modified' time stamps of Oct'99. This is likely when the CD contents originated. That would have been probably the only time a CD install was performed - updates being from the web. The V1.001 web installer is in a folder dated Oct 2002. Mind you, there are spice era files from (likely) elsewhere that predate these - mostly libraries. The same file type from a Basso Pspice CD install is marked Nov98. RL |
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Re: MPS4250
It is missing the symbol for "LF353". That is the error message I get when trying to load your file into LTspice. If your schematic uses any new symbols or models or subcircuits that didn't come with LTspice itself (such as the LF353), then you will need to upload those along with your schematic file, also to the group's "Temp" folder. The recommendation is that you ZIP all the files, with your schematic file (except for .log and .raw files), into one .zip file, and then upload just the .zip file to the Temp folder. I also just noticed: You have a 2N5401C shown as both a PNP and an NPN. I see you also have many unique transistor part numbers, which are not in LTspice's transistor library. Will you also have SPICE models for them? Currently they will not simulate as the part numbers you've given. Regards, Andy |
Dick Benson
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