OK thanks. That makes sense.
Also upon closer inspection, the rolloff is only 1db.
Best not trouble myself trying to fix things not broken.
Also upon closer inspection, the rolloff is only 1db.
Best not trouble myself trying to fix things not broken.
Ya I wouldn't sweat a teeny tiny bit of rolloff like that graph in the article. That's like tenths of a db there in your area of concern..
Another quick thing.. C1 is really optional if you can be certain that anything feeding this circuit does not have DC on it. A greenhorn might be better off leaving it in place as a safety blanket. If a source has DC offset, the individual that designed it should be drawn and quartered because that's not acceptable in my world.
Another quick thing.. C1 is really optional if you can be certain that anything feeding this circuit does not have DC on it. A greenhorn might be better off leaving it in place as a safety blanket. If a source has DC offset, the individual that designed it should be drawn and quartered because that's not acceptable in my world.
I intend to make a new pcb with the psu integrated to fit a particular chassis.
If regulators were placed right beside the fe2022, could the rc network on the supply rails be skipped or are they an important part of the circuit?
If regulators were placed right beside the fe2022, could the rc network on the supply rails be skipped or are they an important part of the circuit?
You can skip the RC on the rails. But I think capacitance on the output of the regs is still recommended.
Somehow the store FE '22 boards get by without compensation caps. Be sure you check for stability on your new pcb, it may oscillate with a different, less optimized layout.
Somehow the store FE '22 boards get by without compensation caps. Be sure you check for stability on your new pcb, it may oscillate with a different, less optimized layout.
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I ordered the kit from the store so I will be very carefully studying the layout.
Does anybody know what the current consumption is per board with a standard implementation?
Does anybody know what the current consumption is per board with a standard implementation?
See Papa's post #20: https://www.diyaudio.com/community/threads/diy-front-end-2022.394339/#post-7231380
Thanks.
So 3mA + 9mA = circa 12mA
Do r11 and r12 have an important function?
They look to me like bleeder resistors for c4/c5?
Assuming say 20vdc power supply rails then they would add another 2 mA.
So conservative 15mA seems realistic?
So 3mA + 9mA = circa 12mA
Do r11 and r12 have an important function?
They look to me like bleeder resistors for c4/c5?
Assuming say 20vdc power supply rails then they would add another 2 mA.
So conservative 15mA seems realistic?
15mA is a good ball park number. The actual number may be a bit higher or a bit lower.
R11 and R12 form a voltage divider for the unipolar power supply option, to equally divide the voltage between the two capacitors. It is not needed if the power supply is bipolar, although it can be left in place.
R11 and R12 form a voltage divider for the unipolar power supply option, to equally divide the voltage between the two capacitors. It is not needed if the power supply is bipolar, although it can be left in place.
OK thanks.
With a regulated bipolar supply.
Could the value of c4/c5 be reduced to something like 100uf like one might typically see with supply rail decoupling?
With a regulated bipolar supply.
Could the value of c4/c5 be reduced to something like 100uf like one might typically see with supply rail decoupling?
I have wired the pre as balanced input,single output and with a 36v single supply.I am getting a slightly variable static sound at all times that increases with volume control. It is on both channels. Is this transistors failing? Appreciate any suggestions to cure this problem.
Does it work - does it play music? Or does it only output static?
Have you double checked component placements, wiring, and solder joints? Bad solder joints can result in noise.
Post some clear, focused pictures. Include shots of the overall construction and closeups.
Have you double checked component placements, wiring, and solder joints? Bad solder joints can result in noise.
Post some clear, focused pictures. Include shots of the overall construction and closeups.
Just an academic question as I have a parts kit from the store.
Would the circuit work properly if one were to buy a bunch of J113 from mouser and throw them into the circuit with no matching?
Higher distortion?
Would the circuit work properly if one were to buy a bunch of J113 from mouser and throw them into the circuit with no matching?
Higher distortion?
I'm stuffing resistors into a bunch of boards, (V0 and V1) and came across an ambiguity (at least in my eyes). Guidance on setting the gain is clear here:
TIA, Skip
But I'm not sure what to do with R4. I've selected 30k for R3 and will be using a 48VDC positive supply with single-ended input. Should R4=R3 as directed above with balanced input, or use 100k as shown on the schematic since I will be using single-ended input?
TIA, Skip
For unity gain and SE input, I would go R1=R2=R3=R4=10k
Connect -IN to GND
For something other than unity gain, keep things real simple and just do R1=R2, R3=R4 as specified, balanced or not. As a more advanced move with just an SE input, you can use R3 to set the input impedance, and R1 forms an RF input filter along with the combined capacitance of the input jfets (2x Q1). For further confusion, I still keep the ratio the same from R1,R3 and R2,R4 in my current setup.
Connect -IN to GND
For something other than unity gain, keep things real simple and just do R1=R2, R3=R4 as specified, balanced or not. As a more advanced move with just an SE input, you can use R3 to set the input impedance, and R1 forms an RF input filter along with the combined capacitance of the input jfets (2x Q1). For further confusion, I still keep the ratio the same from R1,R3 and R2,R4 in my current setup.
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Understood. As I mentioned, I've settled in 30k ohms for R3, looking to get 10X gain. Once I decided that, up jumped my quandary about R4.
Thanks, Skip
Thanks, Skip