I am building a clone of the EAR834 phono amp and was wondering if it would affect the circuit negatively if I resized C3 from 0.15uf to 0.22uf?
0.15uf film caps are not as readily available is why I am asking this. If it will negatively affect the circuit then I will make up the value with two caps (0.1uf and a 0.047uf)
0.15uf film caps are not as readily available is why I am asking this. If it will negatively affect the circuit then I will make up the value with two caps (0.1uf and a 0.047uf)
I am building a clone of the EAR834 phono amp and was wondering if it would affect the circuit negatively if I resized C₃ from 0.15 μf to 0.22 μf?
You could use larger. But I don't see that they're particularly rare, 0.15 μF: ECW-FD2W154KQ Panasonic | Mouser
45¢ ea, quantity 1
GoatGuy
In any case , I very very very much doubt you can hear an y difference .
make that even *measure* any difference , in the audible band.
.15 + 2M means 0.53 Hz crossover frequency.
.22 + 2M means 0.36 Hz.
Maybe a whale can sense some difference, and even so I doubt it.
That said, you have been kindly suggested a supplier in the post above
make that even *measure* any difference , in the audible band.
.15 + 2M means 0.53 Hz crossover frequency.
.22 + 2M means 0.36 Hz.
Maybe a whale can sense some difference, and even so I doubt it.
That said, you have been kindly suggested a supplier in the post above
if you have the 220nf cap on hand use it, you may also want to try 100nf as well,
heck even a 47nf will work just fine in that position...
look at the resistors used, i wonder why the use of highish coupling caps to begin with...
rp//R1//R8 will not be so low to use such a big cap...
heck even a 47nf will work just fine in that position...
look at the resistors used, i wonder why the use of highish coupling caps to begin with...
rp//R1//R8 will not be so low to use such a big cap...
The saving grace is that the negative feedback network has a 330pF in series driving the rest of the RIAA parts. 330pf does not load a 0.15uf which is driving the 2 Meg Ohm and grid.
If C6 had been much much larger, then the 750k Ohm would have raised the low frequency pole versus the 2 Meg Ohm.
If C6 had been much much larger, then the 750k Ohm would have raised the low frequency pole versus the 2 Meg Ohm.
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Well if Vp=100V then there won't be 280V to work in the formula but I get it. Somewhere between 50 and 100 volts at less than 1mA. I was mostly interested in how low a voltage rating the OP could use for his coupling cap. Low voltage rated film caps can be a lot cheaper.
Looks like the OP has more than a few possibilities to choose from.
Looks like the OP has more than a few possibilities to choose from.
Well if Vp=100V then there won't be 280V to work in the formula but I get it. Somewhere between 50 and 100 volts at less than 1mA. I was mostly interested in how low a voltage rating the OP could use for his coupling cap. Low voltage rated film caps can be a lot cheaper.
Why such a low operating point in the first place would my question. Seems like different tube choices could yield quite different results, being in a less linear range if I understand correctly.
Surely tdp was thinking when he designed this. He chose these values intentionally. He is not an amateur designer and has a noted background. It is also quite a well-liked design.
What is the logic to unpack from this?
How would you approach bringing this design into more conservatively operating territory?
Why such a low operating point in the first place would my question. Seems like different tube choices could yield quite different results, being in a less linear range if I understand correctly.
Surely tdp was thinking when he designed this. He chose these values intentionally. He is not an amateur designer and has a noted background. It is also quite a well-liked design.
What is the logic to unpack from this?
How would you approach bringing this design into more conservatively operating territory?
even at a 100 volts plate, you have potential of 50 volts peak to peak, a 25 volt peak or 18 volt rms, the second stage may not even eat 1 or 2 volts of input swing....
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