Another problem with my F5 build.

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#21
Please don't change the color of the wiring. Green should only be used for the safety ground.
And the red/black pairs helps to avoid a wrong connection, because red is always the more positive
of the two nodes. This is exactly how it should be done to avoid mistakes when using two isolated,
identical supplies.
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#22
Rayma has a good point about the green wire being safety ground but I was trying to point you in the direction that in future projects Red should be positive and Black should be negative. This is assuming that you're in the U.S.

NEC (National Electrical Code)

3-Wire Grounded DC:

Positive (labeled as “L+”): Red*
Mid-Wire/Center Tap (labeled as “N”): White*
Negative (labeled as “L-“): Black*

* These colors are not required by the NEC, but have been adopted as local practice.

Regards,
Dan 🙂
 
#23
In hindsight, I'd like to avoid any debate or conflict here because I see you followed the same practice as 6L6. Exiting his universal power supply I see he has red as positive and green as negative. As long as the colors are consistent and you understand them. That is good advice.

Regards,
Dan

P.S. Where are you located?
 
#24
This is DIY. Use the colors that makes sense to YOU. Just be consistent about it.
There is no point following NEC or any other standard if you don't now it well.
I for one use red as positive, blue as negativ, black as 0V(everywhere there is a 0V), yellow/green as safety earth (and ONLY for that).
 
#26
Back to the task at hand which is getting you up and running. I support your choice of installing terminal blocks because depending on the circumstances they can be very handy. One thing they will allow you to do is to disconnect everything and verify that you have a properly functioning power supply. The other advantage they offer is if you’re troubleshooting you can hookup one channel at a time. Look at replacing the parts 6L6 suggested and we’ll go from there.

Regards,
Dan 🙂
 
#27
Hi again. I received my matched LS-k170B matched quad. As I’m looking at my build guide, that is a little different that the devices recommended for q1 and q2. Do I need to source more matched devices as in 2SJ74? I feel more and more like a novice as this project goes on.

Thanks.
 
#28
I have figured it out. I am quite annoyed by the way things are described and pictured in the diy audio store page where I ordered the damn jfets. I read the description and looked at the picture and hit order. It’s my 3rd error trying to get these things. It’s another $40 and another week waiting to finish my build. Grumpy I am.
 
#30
Just in case you're unsure of what you need. This is where to look for the JFETs for the F5.

Linear Systems Matched JFETs – diyAudio Store

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#31
Hi all, I received my correct jfets and installed them in the correct spots. I wired it all up, hooked up my multimeters, said a prayer to the magic smoke gods, and turned it on. There were no sparks, snaps, crackles, flashes, or breakers blown. My multi meters on R11 and R12 read 0 volts. My multimeter on the output posts read 10 volts. So I let it set and turned the trim pot at R11. It started switching between 0.1 and 0.2 mv. And that’s all it will do on either side. Any ideas?
 
#35
Since, you installed the terminal blocks on your PS board we can now easily disconnect all the wires and verify that it's producing the correct voltages?

With pictures? If you need help I'll post an illustrated version of my PS.

Regards,
Dan 🙂
 
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