[BUILD] NU FEDERAL AM-864 PCB OFFICIAL BUILD & HELP THREAD
- Thread starter bernbrue
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bernbrue
Well-known member
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
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
Hi There,
PCB's are in Stock.
https://groupdiy.com/index.php?topic=53011.msg676707#msg676707
Thanks a lot.
T.
PCB's are in Stock.
https://groupdiy.com/index.php?topic=53011.msg676707#msg676707
Thanks a lot.
T.
bernbrue
Well-known member
updated first post
bernbrue
Well-known member
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
Bernd
bernbrue
Well-known member
Very nice! And it's your own frontpanel design! That's what I like!
Bernd
Bernd
Winetree
Well-known member
Are these cases available for sale?
bernbrue
Well-known member
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
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
Well-known member
Did some measurements today. Updated 2nd post.
rock soderstrom
Tour de France
Thanks for the measurements!
bernbrue
Well-known member
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
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
bernbrue
Well-known member
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
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
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
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
Well-known member
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
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
