[BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD

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Yep, you've got to love that!!

so new tubes in mine! I was able to find a couple real close to each other, now the voltages are cool!
Next up is metering, I've got a 1mA meter. But the dial wil not go upto the max value, and with extreme settings the dial is halfway the scale... not usable I would say...

What do you guys sugest?
 
iampoor1 said:
This might be better in another thread, but what CNC are you using? Are you just engraving anodized aluminum? Love the look of your panel. :)

I’ve got a BZT PFE1000PX, and Yes anodised aluminium. And thank you!
 
djfatum said:
The VU must have 200 micro amperes (1 milli amper too much)

Could you tell me what meters you bought and where you got them? I'm having trouble finding them.
 
Eliani said:
Not to brag but i'm kind of proud of this build!

At least of how it looks because wiring could have been a bit cleaner, but I'm sure I'll get it next time. I'm waiting for new 6BA6/EF93 tubes to arrive, I've bought like 10 and hope to good pair out of them. I'm not totally aware of how one would match tubes, or if I even need to, but I'm guessing it wouldn't hurt as I can't seem to get C and B to the same voltage! This might explain that the input get's distorted when cranking the input?

I've yet to do the threshold/ratio range reduction mods

IMG_7604.jpg


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IMG_7609.JPG

Really great job - you should be proud!

I've been a bit out the DIY loop for a while but seeing your project had inspired me to get back to a couple of half-finished projects of my own...
 
Yeah, I tend to lose interest in certain projects after a while too, but most of the time it's lack of time or funding!

By the way, about the 200uA DC meters, Aaron from Don-Audio let me know he's doing a run for them, now available in his store, although they will not be available for another 3 to 4 weeks. So I bought another Weston 2521 meter, but instead of the 1mA I found a 200uA version. And I bought a bunch of strange 200uA meters just for future projects.

I ordered 4 more PCB's from Zayance for a single control stereo version and one with a mono switch and dual controls... looking forward to that, because I just spent over €1000 for all the parts!
 
Hi everybody,
Here, finally I finished the unit.
not without trouble with my beginner errors when buying audio transformers without CT eg: thank you bernbrue for your information that allowed me to finish this jewelry without too much trouble.
indeed I say: "without much" because during my measurements I fall on these values, and this as well on the left unit as on the right unit:

B + = 230 V

A = 14.46V
B = 224 V
C = 227 V
D = 173 V
E = 1.09V
F = 1.09V
G = 230 V
H = Over Load on the multimeter.

When I turn on the beast, the two hands go up to +2 dB then go down slightly, tremble lightly then come to fix on -3db is in the center of the VU meter. knowing that I was mistaken for sensibility of Vu meter as seen before with Eliani.

If you have a small idea of what might possibly be there. I take.

 
bernbrue said:
Either you've got a bad output tube (12AX7) or your output transformer is not wired correctly. You should have the same voltage as on G.
Bernd

I bought a pair of 5751 RCA Jan NOS. I hope these are not the tubes: D
I will test that.
 
ok, so I just changed by 12AX7B China to test something else and the values are:
A = 14.30 V
B = 223 V
C = 224 V
D = 173 V
E = 315V
F = 357V
G = 230 V
H = 230 V

either, no more coherence with the previous results.
I also have the hands that are at the bottom right of the Vu meter and bouncing in rhythm ...
 
bernbrue said:
E and F are not measured correctly.
Bernd

ok, sorry E = 315 mV 
                    F = 330 mV
you think that the bouncing needle is due to bad wiring trim pots?
When I turn the threshold to the max the needle does not bounce but is fixed a little lower.
 
Watch my video.  The meter needs to be retrimmed quite often. Did you tame the pots as suggested in the first post?

https://www.youtube.com/watch?v=0eJVCCYApOw
Very nice unit. Be proud of yourself !
Cheers
Bernd
 

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