I started with +12dB (which is R3 & R4 = 40kohm) on my MoFo. I like to socket things until I settle on a permanent value,
When I'm happy with the value, I remove the socket then solder in permanently.
BTW, these are my own PCBs with Texas Instruments JFE2140 as the long tailed pair. Can also use LSK389 SOIC or TO-71.
I got a little impatient waiting for boards to be stocked in The Store.
View attachment 1186813
For singel ended input make jumper between G and -
Edit:
And shouldn’t you take signal out from (out) and ground?
Edit:
And shouldn’t you take signal out from (out) and ground?
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Andrian, Your diagram looks correct.
sov, With an unipolar V+ power supply, R10 is jumpered and V- becomes ground. VG is not ground. One half of the power supply voltage would be present at VG.
sov, With an unipolar V+ power supply, R10 is jumpered and V- becomes ground. VG is not ground. One half of the power supply voltage would be present at VG.
I do not have a board to measure but Nelson wrote that the board is 1.7" x 3" with mounting holes spaced at 1.575".
With those dimensions you can scale the spacings from the picture.
And Happy Thanksgiving to you too.
With those dimensions you can scale the spacings from the picture.
And Happy Thanksgiving to you too.
Proof of concept works! I built and added R0 boards to my TDV. Stock FE2022 with kit transistors. 10x gain. Power supply is a mere +28VDC. Sounds quite nice.
Now I gotta figure out how to securely attach them to the chassis.
After this success, I’m going to get fancy with the R1 kit I have. That one will get either a bunch of K170s, a double bunch of K209s on adapter PCBs, or some K369s I have stashed away.
Those boards will go in my BOO OS build.
Thanks again, Nelson!
Now I gotta figure out how to securely attach them to the chassis.

After this success, I’m going to get fancy with the R1 kit I have. That one will get either a bunch of K170s, a double bunch of K209s on adapter PCBs, or some K369s I have stashed away.

Thanks again, Nelson!
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Boo is for Halloween 🎃. I have it in the main rig for the season.
For this TDV, I affixed the FE boards and now have hum. Is it likely that the noisiness is due to routing the DC power lines around the inductors, or due to proximity with mains input?
I’m owning up to my greenhorn status.
For this TDV, I affixed the FE boards and now have hum. Is it likely that the noisiness is due to routing the DC power lines around the inductors, or due to proximity with mains input?
I’m owning up to my greenhorn status.

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My use here is single supply, single ended input. Is it advised to make a CL60 connection from V- to chassis earth?
Heck yeah! CL60 earth worked a charm!
No more buzz. Turn-on transient also gone.
Thank you, ZM! All back to a silent background.

Thank you, ZM! All back to a silent background.
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Nelson did you ever get around and publish the balanced out version of this? Thanks!It's not done yet.....
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