Maybe un-mount the headphone jack and let it lie outside. Then run 3 strands of hook-up wire out through the hole for the jack, Ground, Left, and Right. Then let the capacitors live outside the box for a time.
There are folks on this site (and others) that positively insist there will be a noticeable difference. Your *mileage* may vary.
The input bias idea seemed so straight-forward when I first imagined it .. I'm just not yet ready to accept defeat. Maybe another week or two wouldn't crash your plan?
There are folks on this site (and others) that positively insist there will be a noticeable difference. Your *mileage* may vary.
The input bias idea seemed so straight-forward when I first imagined it .. I'm just not yet ready to accept defeat. Maybe another week or two wouldn't crash your plan?
Im not sure if somebody else has suggested this blogpost but please go through it NwAvGuy: Cmoy With Gain
He has mentioned in detail about layout, gain, coupling caps and opamp choices for CMOY. I have built many CMOYs and never faced any problems of noise as I use low gain (2X-4x) and low value resistors in feedback 470R-1.5KR,input resistor in 10K-33K range, wallwart tranny to protect noise sensitive, JRC4556 opamp to deliver current in range of 70mA, input GND soldered to metal case.
He has mentioned in detail about layout, gain, coupling caps and opamp choices for CMOY. I have built many CMOYs and never faced any problems of noise as I use low gain (2X-4x) and low value resistors in feedback 470R-1.5KR,input resistor in 10K-33K range, wallwart tranny to protect noise sensitive, JRC4556 opamp to deliver current in range of 70mA, input GND soldered to metal case.
What measurements were you thinking of?
I've forgotten what impedance your headphones are. 220uF is OK if they're 80 ohms or so and up. It might be a little light for driving those of lower impedance. Bigger caps probably won't fit at all ..
But the best, and most important test, is surely "Sounds good to my ears".
I'm awful sorry I haven't been able to design the bias/offset circuit for you in a timely manner.
I've forgotten what impedance your headphones are. 220uF is OK if they're 80 ohms or so and up. It might be a little light for driving those of lower impedance. Bigger caps probably won't fit at all ..
But the best, and most important test, is surely "Sounds good to my ears".
I'm awful sorry I haven't been able to design the bias/offset circuit for you in a timely manner.
Unless your 220uF bi-polars have a leakage problem, or have failed outright, there can be no offset -- at the 'phones at least.
So, does the bass drum sound right? And the open 'E' string of the bass guitar, or double bass? If they do, maybe it's time to put a wooden stake in the bias circuit and start enjoying the darned thing.
You'll still need the 68k to ground. If you want you could lower it to 27k or 33k -- would slightly reduce the input offset, and proportionally that of the output. But no appreciable performance change would result.
Just for the record, I am not one of the folks that abhor any capacitor in the signal path. Different strokes for different folks ..
So, does the bass drum sound right? And the open 'E' string of the bass guitar, or double bass? If they do, maybe it's time to put a wooden stake in the bias circuit and start enjoying the darned thing.
You'll still need the 68k to ground. If you want you could lower it to 27k or 33k -- would slightly reduce the input offset, and proportionally that of the output. But no appreciable performance change would result.
Just for the record, I am not one of the folks that abhor any capacitor in the signal path. Different strokes for different folks ..
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I'll definitely look into Anita Baker. I'm not familiar with her.
What are your thoughts on the 10k resistor to ground after the output cap?
I took a look at my resistors. I have 24k and 39k. The 24k is metal film. The 39k
Is metal oxide. Does that mater? I'm also going to try and tidy up the wiring.
Looks like a rats nest.
What are your thoughts on the 10k resistor to ground after the output cap?
I took a look at my resistors. I have 24k and 39k. The 24k is metal film. The 39k
Is metal oxide. Does that mater? I'm also going to try and tidy up the wiring.
Looks like a rats nest.
