PCS Electronics PCS Electronics - home page PCS Electronics  
RegisterSearchFAQAM & FM Radio transmitters shop UsergroupsLog in
Received my new AM Max II

 
Reply to topic    PCS-Electronics Forum Index » AM transmitters View previous topic
View next topic
Received my new AM Max II
Author Message
AM-Enthusiast
New registered user
New registered user


Joined: 26 Aug 2004
Posts: 12

Post Received my new AM Max II Reply with quote
I just received my AM MAX II modified for the 6000-7000 range. I ordered the 19 volt power supply from PCS as well.

I've done very little testing so far but first impressions include: Very clean layout and well designed appearance, Very clean modulation and appears to easily modulate 100% (no measurements taken yet), Runs surprisingly cool with a small fan blowing across it, Uses the popular IRF 510 final for about 7 to 9 watts with peaks that appear to hit around 40 watts at 19 volts. I think it is a broadband design so it might be a good idea to put a filter after it but I didn't notice any major problems just listening on a radio and tuning around. The treble control works great and you can make the high end really sing if you want with up to +15db in just the right frequency range. The compressor has lots of options. The LPF seems to do it's job. I noticed no noise hum or anything noisy at all. It was very clean sounding. The board has a carrier and a modulation adjustment for tweaking the unit.

Packing was great and the unit arrived safely. The instruction manual is lacking but is in the process of being re-written I am told.

Overall I would say that it has given me a great first impression. I'll post more information as I get to know the transmitter better. AM-Enthusiast
Thu Aug 26, 2004 3:27 pm View user's profile Send private message
AM-Enthusiast
New registered user
New registered user


Joined: 26 Aug 2004
Posts: 12

Post Reply with quote
I've been out of town for a couple weeks but I'm back and will be posting more information soon including a voltage verus output chart and some basic modulation testing results.
I have found that the transmitter will easily modulate 100% + on a typical modulation meter. Carrier and modulation levels are adjustable on the board and I found that I cranked the modulation way up from the default settings.
Make sure you have plenty of current available for this transmitter or you will experience serious distortion. I'm currently using a 24 volt 6.5 amp power supply for testing which provides more than enough current. A fan keep the board cool. I also have tested with an adjustable 12v to 24v 4.5 volt power supply as well as the 19 v supply that Marko sent.

I apparently blew the IRF-510 yesterday by cranking the carrier level up to about 18 watts with 100% modulation. It seemed to run fine at 18 watts but when i came back later it was not working. Luckily a quick trip to Radio Shack turned on up for a couple bucks and the transmitter was back on the air in no time. The board layout is very clean and it was fairly easy to replace.

More results later.
Sun Sep 12, 2004 2:02 pm View user's profile Send private message
pcs
Site master
Site master


Joined: 18 Jan 2002
Posts: 3063
Location: Radio Land

Post Reply with quote
Cool!

How do you like audio?

A warning to others: please don't try to crank the
power up unless you know what you're doing and
know how to replace that output fet, if needed.

And if you're going to crank it up make sure you
always replace the fuse with specified type.
Any failure will just kill the output fet and nothing
else since the fuse will blow and protect the rest of
the circuit.

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Sun Sep 12, 2004 4:40 pm View user's profile Send private message Visit poster's website
pcs
Site master
Site master


Joined: 18 Jan 2002
Posts: 3063
Location: Radio Land

Post Manual Reply with quote
I've just completed and uploaded the manual for AM MAX II DSP,
you can check it out here:

http://www.pcs-electronics.com/software/Manuals/AM%20MAX%20II%20instructions.pdf

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Tue Sep 14, 2004 2:23 am View user's profile Send private message Visit poster's website
AM-Enthusiast
New registered user
New registered user


Joined: 26 Aug 2004
Posts: 12

Post AM MAX II Reply with quote
After playing around with the unit and tweaking the settings to my preferences I can only say the audio is wonderful! The sound is ultra clean. At first I thought the sound might not have enough beef to it. That is, until I heard an off-air recording of the transmitter. The sound was very beefy and was very very clean. I was able to push the modulation peaks well above 100% and I was surprised how good it sounded. Keep in mind I'm not an expert so I can't give you a whole lot of technical details. Mainly just practical experience.

I'm still tweaking the compression settings to figure out what I like best, but so far I prefer a ratio of around 2 and threshold of around -15 db. I like keeping the EQ nice and crisp at around +12 with an LPF cutoff of 7500 to keep the signal from going too wide.

So far a very happy customer - AM-Enthusiast
Mon Sep 20, 2004 1:52 pm View user's profile Send private message
pcs
Site master
Site master


Joined: 18 Jan 2002
Posts: 3063
Location: Radio Land

Post Reply with quote
I bet you like the new manual, too

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Mon Sep 20, 2004 1:58 pm View user's profile Send private message Visit poster's website
erobertg
Compulsive poster:)
Compulsive poster:)


Joined: 29 Oct 2004
Posts: 113

Post Recieved My Unit... Reply with quote
I received my transmitter all assembled in the rack enclosure and a 19V power supply. I noticed the small fan already installed. Did have to take a trip to Radio Shack to get a power cord because of the international power supply. Connected a temporary 6 ft. wire antenna. I was ready to go after connecting to the low level audio to my PC and turning to streaming audio from Air America Radio.

The unit went bonkers when tried to set the treble, compressor and lpf settings. It kept rapidly toggling thru all the settings and wouldn't stop until turned the transmitter off. I took the screws off the front panel and 2 screws of the top. I notice the three buttons had a small a mechanical clearance issue that was easily fixed. All is well.

Range was good enough to hear around the neighborhood with a short wire antenna in my basement. Next thing to address is a good antenna for 1640 kHz and will try a few experimental designs.

A few questions, what are you recommended settings?

Attack?
Decay?
Integration interval?

Is there supposed to be a XLR input on the boxed unit?

Bear in mind that I'm using low level headphone output from my computer. Modulation appears good and I'm sure the unit will sound even better when connected to a good antenna. All in all, I'm very pleased with the transmitter and pleased with the short delivery time from Europe.

Highly Recommended!
Sat Nov 06, 2004 2:41 am View user's profile Send private message
Antler
Compulsive poster:)
Compulsive poster:)


Joined: 29 May 2004
Posts: 90
Location: Somewhere between the RJAA and EHAM airports

Post Reply with quote
AM enthusiast, anyone....

Just curious if you got around to comparing power out with supply voltage. I have a great power supply that puts out 15 VDC and wonder what kind of power out I would get using 15 VDC as my supply voltage? (I guess I could do the math, but I am lazy and would like a real world number anyway)

Did you ever figure out how to run balanced input (XLR) into your transmitter?

A-man
Wed Dec 22, 2004 1:30 pm View user's profile Send private message
pcs
Site master
Site master


Joined: 18 Jan 2002
Posts: 3063
Location: Radio Land

Post Reply with quote
Hello!

First, AM MAX II DSP does work at 15V, but your power is usually
limited to 3-4W.

It really takes 19V (original supplied power supply) to make this
unit show its muscle. 19V is just about perfect for 24/7 broadcasting
as it limits heat disipation to sensible level.

XLR input: IF your audio source does not feature balanced output,
connect audio ground to Audio - and ground, and connect center
conductor to Audio +

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Wed Dec 22, 2004 2:11 pm View user's profile Send private message Visit poster's website
Display posts from previous:    
Reply to topic    PCS-Electronics Forum Index » AM transmitters All times are GMT + 1 Hour
Page 1 of 1

 
Jump to: 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group