C3g Aikido Phono
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#271 Re: C3g Aikido Phono
Well that's quite amusing. No wonder it wasn't simming well. Sometimes you can't see for looking.
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#272 Re: C3g Aikido Phono
I don't think I should be allowed to play with spice really. As far as I can see nothing's changed after fettling Q2, so there must be something fundamentally wrong in the model somewhere.
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#273 Re: C3g Aikido Phono
Are you using AC on the input? if so, whats the 1.4V
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#274 Re: C3g Aikido Phono
These are the settings. The 1.4V was a relic of another sim I modded. I didn't give it much thought as I figured I was interested in relative gain. I've tried 10mA and it didn't seem to make any difference.
I'm not sure though what the small signal AC analysis is though?
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I'm not sure though what the small signal AC analysis is though?
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#275 Re: C3g Aikido Phono
The small signal section is for AC analysis of fr and phase. It may be you need to set that depending on the analysis you are showing. The left hand side is for voltage/current against time.
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#276 Re: C3g Aikido Phono
Just a thought, take the 'V' out, after both the numbers.
I never use 'V' here, by default the field is a Voltage value.
On the graph, green should be 0 dB, if 'AC 1'.
I never use 'V' here, by default the field is a Voltage value.
On the graph, green should be 0 dB, if 'AC 1'.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
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#277 Re: C3g Aikido Phono
Whoah I've just noticed something, R2 is 1 milliohms!
That's a virtual short circuit.
I presume you meant 1 Megohms, so you have to write '1meg' or '1Meg' (can't be an 'M' on its own, and no spaces).
That's a virtual short circuit.
I presume you meant 1 Megohms, so you have to write '1meg' or '1Meg' (can't be an 'M' on its own, and no spaces).
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
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#278 Re: C3g Aikido Phono
Second problem, you've got '-12V' for V3 (and you don't need the 'V'), but you're already using its negative terminal for the supply rail, so you've inverted it and made it +12V. As it is, just needs '12'.
V2: again don't need '+12V', just '12'. The text box value is a Voltage by default, so don't need the 'V', and the object has positive and negative terminals, so don't need the '+'.
HTH.
V2: again don't need '+12V', just '12'. The text box value is a Voltage by default, so don't need the 'V', and the object has positive and negative terminals, so don't need the '+'.
HTH.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
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#279 Re: C3g Aikido Phono
Great spots Mike, thanks! I'll see what difference they make.
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#280 Re: C3g Aikido Phono
I took the liberty of having a play with it - didn't take long - so this is my tidied up version - yes it has a Voltage of X4 (12 dB).
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"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
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#281 Re: C3g Aikido Phono
You're a genius Mike .
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Yes, 4x gain, f-3 under 2Hz. Probably a bit low. I think what happened with the 1M resistor is that 1M is interpreted as 1m, which I missed.
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Yes, 4x gain, f-3 under 2Hz. Probably a bit low. I think what happened with the 1M resistor is that 1M is interpreted as 1m, which I missed.
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#283 Re: C3g Aikido Phono
Now the sim's working (thanks Mike!) it's been interesting to have a play. Reducing the coupling cap to 20nF gives a f-3 of 9Hz. I suppose one might want to go even higher to filter warp/rumble maybe.
But playing with the two resistors, R1 and R6 was interesting. The sim suggests there is a practical maximum difference between the two. 9x was the most I could squeeze out until the gain went screwy. Whether that would be achievable in reality I don't know. I guess this is what Nick was referring to?
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But playing with the two resistors, R1 and R6 was interesting. The sim suggests there is a practical maximum difference between the two. 9x was the most I could squeeze out until the gain went screwy. Whether that would be achievable in reality I don't know. I guess this is what Nick was referring to?
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#284 Re: C3g Aikido Phono
As I'm on a roll here's a sim of Boozehound Labs MC preamp
https://cdn.shopify.com/s/files/1/0289/ ... PrePre.pdf
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Uses 2SK170 or LSK170s. Similar 9x gain. Who knows which one sounds best.
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https://cdn.shopify.com/s/files/1/0289/ ... PrePre.pdf
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Uses 2SK170 or LSK170s. Similar 9x gain. Who knows which one sounds best.
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#285 Re: C3g Aikido Phono
You can play with the source resistor in the case of the jfet to alter the gain, and also try paralleling up 2 or more.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.