bancho

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #20 on: January 21, 2017, 06:37:53 PM »
Frontpannel looks very nice  :D
Any chance for Output Level/GR switch for the meters?
Is this 2U high?


bernbrue

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #21 on: January 22, 2017, 03:32:23 AM »
Hi,
You can build it in a 2U enclosure.  The gain reduction/output level switch can be implied as well, but only with real VU meters. My meters are  200 uA DC meters with a custom VU meter scale and wouldn't work as output level meters. The way it's done in the original Federal causes a lot of distortion. So we left out the rectifier part.
Bernd

zayance

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #22 on: January 22, 2017, 01:46:23 PM »
Hi There,

PCB's are in Stock.
https://groupdiy.com/index.php?topic=53011.msg676707#msg676707


Thanks a lot.


T.

Unit-8

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #23 on: January 22, 2017, 08:08:26 PM »
Hi Zayance, PM sent. Thank you.

bernbrue

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #24 on: January 24, 2017, 03:24:36 AM »
updated first post

bancho

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #25 on: January 24, 2017, 05:59:48 AM »
So I think I don't get it right: when using real VU meters there will be distortion? or were you talking about uA DC meter?

bernbrue

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #26 on: January 24, 2017, 06:12:31 AM »
You can strap a vu meter across any output of any audio device and distortion (thd) will slightly increase. In order to avoid this vu buffers are used.  Google JLM VU buffer. If you really need to have a meter showing  output level, then take a VU meter and connect it as shown in the original federal schematic, but leave out the rectifier diodes.
Bernd

djfatum

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #27 on: January 26, 2017, 11:59:48 AM »
 8) 8) 8) Dual & Mono







bernbrue

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #28 on: January 26, 2017, 12:15:27 PM »
Very nice! And it's your own frontpanel design! That's what I like!
Bernd

Winetree

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #29 on: January 26, 2017, 02:20:10 PM »
Are these cases available for sale?


gaetan

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #30 on: January 27, 2017, 06:45:11 AM »
Looks like a great project, Any numbers on attack and release time?

bernbrue

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #31 on: January 27, 2017, 07:00:21 AM »
I think dj fatum bought these cases including frontpanel from Frank
https://www.frontpanels.de

I haven't measured the attack/release times, but they are way faster and more usable then the original.
Bernd

bernbrue

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #32 on: January 27, 2017, 09:23:49 AM »
Did some measurements today. Updated 2nd post.

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #33 on: January 27, 2017, 01:34:54 PM »
Thanks for the measurements!

solderboy

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #34 on: January 28, 2017, 03:21:45 PM »
got the pcb´s today, thanks! will start soon after some other projects.
question... whats about the sidechainfilter?  is there one and if yes at aproximitly with frequency? if not would it be possible to do one?


bernbrue

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #35 on: January 28, 2017, 03:44:30 PM »
Hi,
The sidechain is according to the original. I wouldn't change anything here. Build it and try to get accustomed to what it does. You'll like it.
Bernd

solderboy

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #36 on: January 29, 2017, 09:18:09 AM »
thank you for the fast reply. i am ordering parts right now and like to go stepped. found everything exept 25k log. would it be possible to use 50k log for attack?

bernbrue

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #37 on: January 29, 2017, 10:46:50 AM »
Hi,
Either take something like 22K log or you could indeed try a 47/50k log pot.  But then you should reduce R13 to 4K7. If it works without any side effects (not guaranteed) you've got a faster attack.
Bernd

Unit-8

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #38 on: February 05, 2017, 01:57:45 PM »
Hi Bernd,

I have a couple of questions to do about the limiter and his nature.
I would use it for mastering, but looking around on the internet I have not found useful informations or someone who has built a stereo version for this job so far.
Do you think this compressor can find a place in my mastering rig?
Then, I read about the sensitivity and behaviour of the threshold and ratio controls in this design and I saw other mono compressors derived from Fed AM864, like the Audio Dizengoff D864 or the Schmidlin Fed + have both full control of the ratio and threshold and they seem not to have this kind of problem, so I believe that it is possible by adapting a few components on the circuit to get a normal use of the controls and compressor itself without having a motor boat on board. Everything to try, I know it. Any input or help is appreciated. Thanks. Andrea

bernbrue

Re: [BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
« Reply #39 on: February 05, 2017, 02:28:34 PM »
Hi,
The Federal Limiter is/was a single channel (mono) broadcasting limiter.  As far as I know there has never been a stereo version of this limiter and I've never seen this compressor in a mastering chain. A few recording engineers modified this limiter and used it mainly on vocals and bass. It became a kind of secret weapon.
The other compressors you mentioned are, same as the NU Federal, free adaptions of the Federal Limiter circuit and have shurely  been modified. They are not 1:1 copies. Our adaptation of the circuit has full control over threshold, ratio, input/output gain, attack and release. Read other threads about the Federal Limiter and you will find further information.
I don't see this unit in a mastering rig. It's indeed a very quiet compressor in terms of noise/hum, but I can't imagine that mastering guys appreciate the relatively high thd figures.
I strongly recommend to build it and then decide on your own for what purpose it might be predestined.
Bernd
« Last Edit: February 05, 2017, 03:36:45 PM by bernbrue »


 

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