Hi Necks,

I've just picked up an NRG Pro 6 Transmitter & Pro 3 stereo coder.

All sounds well just temporarily being fed audio from a CD source, and output power into a Dummy load is to spec'.

I have some questions, though; without any audio in, the Pro 6 display shows 3% deviation and 2.8Khz as per the attached image. Why is this?

With regards deviation, am I correct in thinking 75Khz should be the maximum level (100%)?

Finally, can anyone shed any light on how to set up the "MPX" level on the rear of the Pro 6, please?

I've attached an image of the Pro 6 LCD display with no audio in to illustrate what I mean.

Many thanks.

the stereo encoder pilot causes deviation. should be set to 7-10%. to adjust the mpx level you will probably have to open the cover of the device.

mikroman wrote: ↑Wed May 03, 2023 8:12 pm the stereo encoder pilot causes deviation. should be set to 7-10%. to adjust the mpx level you will probably have to open the cover of the device.

Cheers for the reply bud.

I'm only really used to the old NRG/Veronica gear and don't recall doing any of this, so your info' is gratefully received.

The MPX level control is accessible through an hole on the rear of this, so it's easy enough to adjust.

Is there a particular "spot frequency" of deviation I should be looking for while setting the MPX level, or is it literally anywhere between 7-10% that will be fine?

while the stereo encoder is connected to the transmitter, without audio modulation, any pilot deviation value between 7 and 10% will be satisfactory. I personally adjust it to 8%. Then you connect the sound source via the L/R input st. encoder whose level must not cause more than 75KHz deviation (100% modulation). Of course, 50us preemphasis must be active on the encoder. Note that without an additional limiter/clipper you will not always be able to stay within the deviation limit.

Thanks a lot for the guidance, Mikroman. I'll set it up as you suggest.

Now I just need to find out how to turn the power down, as I intend running this into an Amplifier at some stage.

Thanks again bud.

I know very little about the newer versions of the NRG series?

But they look Shit Hot!!!

Thanks for sharing Mixin! Feel free to post any more pics you may have!

He has a stock of them if you want one - $750 New Zealand - £375 Sterling or €425 Euro And there'll be import tax on that. Read the specs here - delicious.
https://nrgkits.co.nz/index.php/product ... ansmitter/

sinus trouble wrote: ↑Thu May 04, 2023 12:23 am I know very little about the newer versions of the NRG series?

But they look Shit Hot!!!

Thanks for sharing Mixin! Feel free to post any more pics you may have!

From the limited use I've had with it, it works really well.

I recall horrible distortion on lows & particularly highs with the old NRG PLL Pro 3, but this Pro 6 reproduces them nicely with no discernible distortion - and that's just with direct connection to a CD player for test purposes.

probably caused by overdeviation, but unlike the 6 series that shows it on the display, on the 3 series you couldn't read it without an additional device.

mikroman wrote: ↑Thu May 04, 2023 1:44 pm probably caused by overdeviation, but unlike the 6 series that shows it on the display, on the 3 series you couldn't read it without an additional device.

I'd set the audio really quiet with the NRG PLL Pro 3, and it was still noticeable mainly on Cymbals & high frequencies at all volume levels - but not so on this Pro 6.

I recall some people saying a 15Khz brickwall filter was needed with the Pro 3 to eliminate the distortion with Cymbal & high treble frequencies, but my memory is vague from all those years ago.

I've only done a quick test & not monitored the audio through earphones yet, though.

Having the features on the display are great, though, & a good step up from the older NRG gear.

yellowbeard wrote: ↑Thu May 04, 2023 2:19 am He has a stock of them if you want one - $750 New Zealand - £375 Sterling or €425 Euro And there'll be import tax on that. Read the specs here - delicious.
https://nrgkits.co.nz/index.php/product ... ansmitter/

Oh yes i am tempted! A few too many beers and a credit card could be the ultimate decider!!

Dat guy is a member here so there may be help and advice available if you need it, though he has not commented in this thread, I find that strange. Publishing his designs or software would not be a good idea - just saying.

between 7 and 10% is how much to read on a deviation meter like pira in khz ?

Any photo of what is inside?

5,25-7,5K

Krakatoa wrote: ↑Sat May 06, 2023 8:21 am Any photo of what is inside?

Itll be one of these pro 6 boards

https://nrgkits.co.nz/index.php/product ... mbled-pcb/

A tidy looking board. About what you'd expect for a modern design. Don't forget your screening cans / biscuit tin. Just needs an equally small 100W amp using an MRF101, you'd end up with a heatsink, fan and power supply as the biggest parts.

mikroman thanks

jvok wrote: ↑Sat May 06, 2023 12:40 pm

Krakatoa wrote: ↑Sat May 06, 2023 8:21 am Any photo of what is inside?

Itll be one of these pro 6 boards

https://nrgkits.co.nz/index.php/product ... mbled-pcb/

A747A590-5F66-4527-8668-F5C7F0264AFE.jpg

The board in mine looks different to this.

Here are the internals of mine.

one with1971 and other with rd06 mos so why looks diff