ULTRA NEW TO VOODOO WITH LEGIT QUESTIONS.

Hookin up those Audio Boxes without gettin yourself Perplexed.
kf6phx
Voodoo Audio Head
Posts: 14
Joined: Sun May 01, 2011 5:42 pm

ULTRA NEW TO VOODOO WITH LEGIT QUESTIONS.

Post by kf6phx »

brand new to voodoo...loving it so far. ill get to it...i have a icom 756 pro 3(i know,not the best for voodoo), a behringer c-1 mic,xenyx 1002fx mixer, fbq1502 eq...all leftover equipment from dj'ing.

questions:
1-want to get the behringer mdx1600. but i notice guys run the dsp2024 a lot in conjunction...aernt they very similar in function except the 2024 adds effects? could i get by with just the mdx1600?

2-do i have to run an ibox? or can i use the audio input on acc1 in the back of the radio?and if i use the acc1 in the back do i have to go unbalanced or balanced into the radio from the mixer?

3-i have the fbq1502 eq...but i see again everyone likes the dsp1124p. does this have a real deal eq built in or is it mostly for the feedback section used? would my eq suffice?

4-balanced or unbalanced cables between the interconnections for everything?

5-currently run the audio out from acc1 in back of the radio to my soundcard input on my pc fro recording. i notice when i run the soundcard out back to the mixer for playback i get a great hum in the playback audio...any thoughts?

trying to lay out a decent above average ham station without breaking the budget...any help would be immensely appreciated.

thx guys!

User avatar
Voodoo Guru
VooDoo Site Admin
Posts: 719
Joined: Wed Feb 23, 2005 8:47 am
Location: Down there on the right...

Post by Voodoo Guru »

Howdy kf6phx,
Welcome to the Forum!
Were glad you decided to turn to the Dark Side of Voodoo Audio!

1-want to get the behringer mdx1600. but i notice guys run the dsp2024 a lot in conjunction...aernt they very similar in function except the 2024 adds effects? could i get by with just the mdx1600?
These are actually 2 different units completely. The MDX1600 is a compressor which regulates the dynamics of the mix as to where the DSP2024p adds effects to the mix such as plating/reverb. The both have very different applications as to what you want to do to the final mix.

For example -- The MDX1600 would be used for sibilant suppression such as severe ss'ing as to wear the DSP2024p would add the effect of Plating to the mix for some more dimension and 'Air'.

2-do i have to run an ibox? or can i use the audio input on acc1 in the back of the radio?and if i use the acc1 in the back do i have to go unbalanced or balanced into the radio from the mixer?
Were not to sure on the Icom, but generally the ACC input is a Line level input. The big plus is that the I-Box (or something similar) has an attenuation control to adjust the gain going into the radio. This is important for correct gain structure as most of the Behringer equipment do not have input and output gain controls. Something like the Ibox will also transition from a balanced output from the rack equipment to the unbalanced input of the ACC Connector.

3-i have the fbq1502 eq...but i see again everyone likes the dsp1124p. does this have a real deal eq built in or is it mostly for the feedback section used? would my eq suffice?
These are 2 totally different types of EQ's. The FBQ is a Graphic compared to the 1124 which is a parametric. The Parametric allows you to adjust each filter individually with Frequency, Gain and Bandwidth as to wear the Graphic can only adjust gain. So the Parametric is ultimately more adjustable then the graphic.

The Feedback section is not even used in this application.

Yes yours will suffice, but you will probably want to change/upgrade later down the road.

4-balanced or unbalanced cables between the interconnections for everything?
Balanced is the way to go. Far superior Hum rejection and RF Interference rejection.

5-currently run the audio out from acc1 in back of the radio to my soundcard input on my pc fro recording. i notice when i run the soundcard out back to the mixer for playback i get a great hum in the playback audio...any thoughts?
Sounds like you have a Ground Loop somewhere. Those are always fun to find and fix.

Take Care,
Voodoo Guru
From Deep in the IDD of the Sub-Harmonix Realm

kf6phx
Voodoo Audio Head
Posts: 14
Joined: Sun May 01, 2011 5:42 pm

Post by kf6phx »

first and foremost...thankyou so much for the time to really answer my questions.

for clarification...i will want to run balanced cables throughout the audio section all the way up i get to the radio where the ibox converts it to unbalanced plus gives me a gain adjustment. i think ill go with the mdx1600 and an ibox addition for now still running the graphic eq for now per my current budget. are there any audio mods known for the icom 756 pro 3 to get a wider bandwidth or am i pretty much stuck with what ive got?

thx again

KC7OV
Voodoo Audiophile
Posts: 61
Joined: Wed Feb 25, 2009 11:37 am
Location: Yelm,Wa.

Post by KC7OV »

Icom`s DSP brickwalls the tx bandwidth at 2.9 khz.but it will rx out to 3.6 khz

User avatar
Voodoo Guru
VooDoo Site Admin
Posts: 719
Joined: Wed Feb 23, 2005 8:47 am
Location: Down there on the right...

Post by Voodoo Guru »

Howdy kf6phx,
Glad to be of help!

for clarification...i will want to run balanced cables throughout the audio section all the way up i get to the radio where the ibox converts it to unbalanced plus gives me a gain adjustment.
You got it Exactly.

i think ill go with the mdx1600 and an ibox addition for now still running the graphic eq for now per my current budget.
Very wise choice. I think you will be happy with that for now. Once you get everything tuned in the way you like, and climb the learning curve, you may want 'more' latter down the road. This is a natural progression and the best way to do it actually.

are there any audio mods known for the icom 756 pro 3 to get a wider bandwidth or am i pretty much stuck with what ive got?
Unfortunately, you are pretty much stuck. Icom has a brick wall filter at 2.9kc on their TX that no one has been able to circumvent. It doesn't look like it will ever be.


You should be able to get your bandwidth sounding like a million bucks with what you have. Just remember to have fun!

Take Care,
Voodoo Guru
From Deep in the IDD of the Sub-Harmonix Realm

kf6phx
Voodoo Audio Head
Posts: 14
Joined: Sun May 01, 2011 5:42 pm

Post by kf6phx »

so the deeper i delve into this the crazier it gtets and i see why u guys just spend the dollars to do it right.here are my issues im realizing:

1-you suggest to run balanced throughout the audio section...
problem:being that for now im using the mixer as my mic preamp,the outputs on my 1002fx mixer are all unbalanced(main outs,control room,efx)..which means i will not have balanced lines going into the mdx1600 and eq. can i still get by on this?

2-the impedance output on my mixer is 120 ohms. the impedance input in the back of the icom 756 pro 3 is 10k ohms. im assuming this is why the need for the ibox?

and then of course i may as well ask for a diagram using:
behringer c-1 mic
behringer 1002fx mixer
behringer mdx1600
behringer fbq1502 eq
ibox?
icom 756 pro 3

thx again. jon

User avatar
Voodoo Guru
VooDoo Site Admin
Posts: 719
Joined: Wed Feb 23, 2005 8:47 am
Location: Down there on the right...

Post by Voodoo Guru »

Howdy Jon,
Ohhhhhhh yea.....
it can get reeeeeeeal deep!

problem:being that for now im using the mixer as my mic preamp,the outputs on my 1002fx mixer are all unbalanced(main outs,control room,efx)..which means i will not have balanced lines going into the mdx1600 and eq. can i still get by on this?
Sure, You can only use what you have. We would say try it and see what happens. If it works, Great! If not then you have to determine why. That's part of the fun actually!

2-the impedance output on my mixer is 120 ohms. the impedance input in the back of the icom 756 pro 3 is 10k ohms. im assuming this is why the need for the ibox?
Not really, that is usually how the impedance will work with audio equipment. The output impedance will be low into a High Impedance input. The I-Box is used to match the Balanced Output to the Unbalanced Input and also to give you some type of gain control.

and then of course i may as well ask for a diagram using:
behringer c-1 mic
behringer 1002fx mixer
behringer mdx1600
behringer fbq1502 eq
ibox?
icom 756 pro 3
Sorry, No diagrams, but we can suggest a better order of equipment.
We would swap the EQ and Compressor positions as so...

behringer c-1 mic
behringer 1002fx mixer
behringer fbq1502 eq
behringer mdx1600
ibox?
icom 756 pro 3

Take Care,
Voodoo Guru
From Deep in the IDD of the Sub-Harmonix Realm

kf6phx
Voodoo Audio Head
Posts: 14
Joined: Sun May 01, 2011 5:42 pm

Post by kf6phx »

got my mdx1600 finally and saw your diagram and will go with that. question though...i see a lot of guys use one side of the 1600 for say the compressor/limiter and then jump it into the other side for the noise gate or vise versa...any suggestions on how to run that 1600 or can i just use 1 channel for everything(noise gate,limiter,compressor)?

SawzAll
Voodoo Audiophile
Posts: 66
Joined: Fri Jun 25, 2010 4:22 pm

Post by SawzAll »

You could use the noise gate too.
Yes; I would run a noise gate.
But I would take each step carefully (preamp, EQ, compressor, etc) and fully understand what each one does first before the next step/piece of gear. Measure success this way; I do.

Remember, that each time you add another piece of gear in the chain before it gets to the radio; the more operational amplifier-induced noise the system will have.

Getting the compressor to work optimally is something that even seasoned audio engineers sweat over. The Guru can give you some starting pointers that can get you out of the gate and running. Not that you need to worry about it after you get it finally set right; unless you change other system components out or change their settings. Compressors are a little bit tricky to use and understand; but not all that difficult either.

If you are going to use an external compressor in the chain; then be sure to turn off the radio's onboard 'processor'. Having and using two compressors together can be done; but certain rules need to be followed for best results. One can be used as a compressor, and the last one can be used as a limiter if set up right.
. . .

kf6phx
Voodoo Audio Head
Posts: 14
Joined: Sun May 01, 2011 5:42 pm

Post by kf6phx »

ok...wow....opened up the instructions and holy smokes. being a dj and into audio somewhat for years i can understand many of the terminology......but, some setting suggestions would help to start and then we can tweak it from there. any suggestions on settings for the mdx1600?

User avatar
Voodoo Guru
VooDoo Site Admin
Posts: 719
Joined: Wed Feb 23, 2005 8:47 am
Location: Down there on the right...

Post by Voodoo Guru »

Howdy,
You can glean the start out settings from this thread....

http://www.wz5q.net/talkvoodoo/viewtopi ... ht=mdx2600

Have Fun!
Voodoo Guru
From Deep in the IDD of the Sub-Harmonix Realm

kf6phx
Voodoo Audio Head
Posts: 14
Joined: Sun May 01, 2011 5:42 pm

Post by kf6phx »

SO...SOME MORE QUESTIONS AFTER MUCH TWEAKING WITH THE NEW MDX2600. BUT FIRST ILL LAY DOWN THE SYSTEM ONE MORE TIME IN ORDER:
BEHRINGER B-1 CONDENSER MIC
BEHRINGER XENYX 1002FX MIXER
BEHRINGER FBQ1502 GRAPHIC EQ
BEHRINGER MDX2600 COMPRESSOR/GATE
ICOM 756 PRO 3

RUNNING ALL NON BALANCED LINES DUE TO MIXER OUTPUTS ARE UNBALANCED AND RADIO INPUT (IN THE BACK ,ACC1 PLUG) IS UNBALANCED AS WELL.


1-CAN I RUN JUST ONE CHANNEL ON THE MDX2600 FOR EVERYTHING(COMPRESSOR,GATE,ETC)? OR SHOULD I RUN ONE CHANNEL FOR COMPRESSION AND LINK IT INTO CHANNEL 2 FOR GATING?

2-ON THE MDX2600...WHAT AM I TRYING TO ACHIEVE WITH THE 3 LED'S THAT TELL YOU WHETHER YOUR ABOVE OR BELOW THE ADJUSTED COMPRESSOR THRESHOLD?AM I SHOOTING FOR IT TO HIT THE MIDDLE YELLOW ONE(IKA SOFT KNEE) WHEN I MODULATE?

3-GETTING A GREAT AC HUM ONLY WHEN I RUN MY HENRY TEMPO 2000 AMPLIFIER AND ONLY WITH THE MDX2600 IN LINE. IF I TAKE THE 2600 OUT OF LINE AND RUN ONLY THE MIXER AND EQ...EVERYTHING SOUNDS GOOD EVEN WITH THE AMP RUNNING(EXCEPT OF COURSE PICKING UP ALL THE ROOM NOISE NOW). WOULD A GROUND ISOLATOR BETWEEN THE EQ AND 2600 BE A POSSIBLITY? I WAS EVEN GOING TO RUN A DIFFERENT AMP JUST TO SEE IF MAYBE THE AMP IS RUNNING DIRTY AS WELL.

4-WHAT FREQS CAN I CATCH YOU GUYS ON TO GET SOME AUDIO REPORTS AND HEAR HOW U GUYS SOUND?
AS ALWAYS..YOU GUYS ARE AWESOME AND THX FOR GETTING ME GOING.

BillPaul
Digital Voodoo Guru
Posts: 66
Joined: Wed Jan 19, 2011 11:52 am

Post by BillPaul »

I wanted to give you a quick run down of my modest audio chain, and comment on the problem you had with hum.

In my case, I have a Behringer B1 condenser mic, and three active components:

- Behringer Xenyx 502 mixer/pre-amp
- Nady single channel 31-band analog equalizer
- Behringer MDX1600 Autocom Pro processor

The audio path is basically:

mic -> 502 mixer -> MDX1600 channel 1 -> equalizer -> MDX1600 channel 2 -> radio

All of the connections prior to the radio are made using balanced XLR cables, except for the connection from the mixer to the MDX1600, because sadly the mixer only has an unbalanced output. (The only balanced line is the mic input.)

Note: most newer Xenyx 502s supply 48v phantom power, but older ones didn't. Check the box: if there's a big yellow sticker that says "Now with phantom power!" then you're ok.

The connection from the MDX1600 to the radio is a little convoluted. At one time, I bought an MFJ 655B equalizer/compressor/noise gate, but it turned out to be a generally bad investment. The only good thing about it is that it has several auxiliary audio input jacks on the back. I have my Kenwood hand mic plugged into the front which I can use as a hand switch. The jumper for the hand mic's audio input is unplugged inside the MFJ 655B. The output from the MDX1600 goes to a Radial Engineering Pro ISO isolation transformer:

http://www.guitarcenter.com/Radial-Engi ... 1527435.gc

Note that this is a cheaper one: there's a more expensive one with ever-popular Jensen transformers in it.

I decided to try this to combat RFI and ground loops. The unbalanced output of the Pro ISO goes into the unbalanced aux input on the MFJ 655B.

I think most of the time, people just get an iBox from W2IHY. I could probably replace the Pro ISO/MFJ-655B combo with that, but I wanted to see if I could salvage some use out of the MFJ unit since I blew all that money on it.

As for the hum, when I first got the EQ and MDX1600, I also ran into a nasty hum. I was very disappointed and frankly stumped. After a while though, I noticed something peculiar. The EQ and the MDX1600 both had the standard 3-pin AC cable sockets in the back, but the EQ came with a cable that terminated with a 2-pin AC plug. I'd never seen this before: usually there's a 3-pin AC plug on the end of those (i.e. hot, neutral and ground).

I realized then that the MDX1600 was the only device in my station that had a 3-pin AC plug. The Kenwood PS-52 power supply for the radio (I was using the TS-850 at the time), the DSP-100, the mixer and the EQ all had 2-pin plugs. (the mixer had a 'wall wart' power supply.) All were connected to the same power strip. Note that I have a ground wire connecting the radio to the steam radiator pipe in my room. It's the best ground I can get in a 2nd floor apartment.

I did the following experiments:

- Removed the EQ from the audio chain, leaving just the mixer and MDX1600-- hum still there
- Removed the MDX1600 from the audio chain, leaving just the mixer and EQ -- hum is gone
- Put the MDX1600 back into the chain and took the EQ out -- hum returns
- Kept just the MDX1600 again, but this time swapped its 3-pin AC cable for the 2-pin one that came with the EQ -- hum is gone again

So I dug up a small adapter designed to plug 3-pin AC cables into older 2-pin outlets, in order to break the MDX1600's electrical ground connection, then hooked the mixer, EQ and MDX1600 all back up again, and presto! The hum was gone!

Basically, I think there was a ground loop being formed between the building AC electrical ground on the MDX1600 and the RF ground on the radio. I suspect the manufacturers of the Nady gear anticipated this problem and supplied a 2-pin AC cable with their unit on purpose.

Anyway, my suggestion is to check for such ground loops in your setup. Your configuration is not that different from mine, though you have the MDX2600 instead of the MDX1600. It probably also has a 3-pin AC cable and as such you may be running into the same kind of problem.

Your mileage may vary of course, but this is probably a good place to start.

-Bill

kf6phx
Voodoo Audio Head
Posts: 14
Joined: Sun May 01, 2011 5:42 pm

Post by kf6phx »

thx bill for your input. i did wind up running a ground loop isolator in between the mdx2600 and the radio and it took 85 percent of the hum away. i also changed out the amp to a newer ameritron and it all went away.at this point im thinking of adding an art tube mp mic preamp and all balanced cables and run everything into the mixer then from the mixer to the radio. im seeing a lot of guys doing this rather than using the mixer preamp...plus it seems like it gives you a chance to run everything balanced all the way from the mic to the mixer.

any other thoughts from anyone is appreciated.

SawzAll
Voodoo Audiophile
Posts: 66
Joined: Fri Jun 25, 2010 4:22 pm

Post by SawzAll »

Which ART preamp? Not one of those little boxes/non rack type - I hope. Do yourself a favor, and just spend the extra $50 and get the Behringer 2200/rack type for ~$100 from Guitar Center. I think you will be glad that you did. The 2200 has balanced in's and out's. Not the best piece of gear out there; but it is the best that will perform the way you want it to. And expect it to. I went through two of those little non-rack type preamps - an ART and a Behringer - before I got the Behringer 2200 rack mic preamp.

All you need to do is find the cheapest price for the 2200 online and then call up Guitar center and ask them to match that price. They claim that they will match any advertised price, so that works. Got my MXL V69 mic for $240 from Guitar Center, because they matched Musicians Friend's advertised price. Saved about $100 that way, and it is legit!

JMHO . . .

kf6phx
Voodoo Audio Head
Posts: 14
Joined: Sun May 01, 2011 5:42 pm

Post by kf6phx »

i will always take good advice. i would like to know what the benefits of the behringer 2200 preamp is as opposed to the art tube mp preamp are. i was going for cost effeciency as they sell for 30.00 on ebay. and according to the specs it is also balanced in and output. so...pretend your a salesman and give me the ultimate reasons as to why to buy the bigger one.(humor me). because all im trying to do is keep the mic balanced to the gear and have a ground lift switch to keep ground loops from occuring. thx

SawzAll
Voodoo Audiophile
Posts: 66
Joined: Fri Jun 25, 2010 4:22 pm

Post by SawzAll »

To begin with, none of these preamps are true tube preamps. They have a tube in there; but the tube is merely 'emulating' tube harmonics. A true tube preamp uses ~200dcv to power the tube. With those little wall-wart power supplies that come with the cheap preamps - there is literally 'no way' that the tube is getting the real harmonics that would be derived from them if they were getting hot 200vdc voltage to warm the tube. Not talking about the 12v heater elements here either. What they do is use the tube as a kind of 'coloring device' to get some of the tube sound without getting the best of what true tube warmth - aka 'voodoo' - can accomplish.

Having said all that, even the 2200 doesn't have 'true tube warmth'. It - too - is using emulation. Real tube preamps can and do cost $400 or more. Usually a lot more for the high quality ones. But what the 2200 does provide is far less noise and distortion than the little ART or even the cheaper Behringer units produce. The 2200 uses op amps that are passable for relatively low noise output; but even voodoo guys have replaced these same op amps with the high quality/ultra low noise parts. But as the 2200 is - right out of the box - is a unit that is fairly dependable, low cost, low noise, and is the best bang for buck. Remember; I already went the route with the ART MP preamp, and the small Behringer unit too. Took them both back after using them for a day or so each. Paid the small difference and bought the 2200 and haven't needed to look back since. Noise in the audio chain is as welcome as sharks at a shipwreck, if you get my drift. Adding more rack gear in the chain is going to amplify the noise floor even greater still; so keeping it to a minimum is highly recommended.

Having true tube warmth was accomplished in my setup by using a tube condenser mic. Now these mics have a tube in them and a dedicated power supply that gets REAL ~200vdc to power the tube inside. I get the 'voodoo harmonics' in this way. Nothing sounds like a warm tube that is getting the right voltage to make it sing. The simplest way to describe what is happening with a tube vs solid state, is that a tube tends to amplify the 'even harmonics' while solid state devices tend to amplify 'odd harmonics'. With so many transistors in the chain - from the mic all of the way down to the radio's final transistors - the tube harmonics added into the chain makes a noticeable audio improvement for the better. That is what 'voodoo' is all about; and is the definable difference between eSSB vs voodoo eSSB.

TO run ALL tube gear will cost thousands of dollars; while having at least one hot tube in the audio chain makes a marked improvement without breaking the bank.

Tube emulation is better than NO tube emulation. But along with a real warm tube in the chain along with tube emulation from a clean preamp is certainly a great place to start. As said before; it is the difference between eSSB and VOODOO eSSB.
Last edited by SawzAll on Sat Jun 11, 2011 11:02 am, edited 3 times in total.

kf6phx
Voodoo Audio Head
Posts: 14
Joined: Sun May 01, 2011 5:42 pm

Post by kf6phx »

i loved your explanation and description and will go your route...2200 it is. very good salesmanship! lol thx again.

just for the record.the main reason im going this route is to get everything balanced audio in the chain and give the mic a solid preamp besides the xenyx preamp in that tiny mixer.

SawzAll
Voodoo Audiophile
Posts: 66
Joined: Fri Jun 25, 2010 4:22 pm

Post by SawzAll »

Since you will be getting/using the 2200; you may consider taking the mixer out of the chain. Not saying you have to do as I suggest; but having another device in the chain that is unnecessary will amplify that noise floor a bit higher still.

Mic>2200>EQ>compressor>radio
Or.....
Mic>2200>compressor>EQ>comp/limiter>radio
Ideally - IMO.....
Mic>2200>EQ>comp/limiter>noise gate>radio

If you are planning to add reverb; then having the EFX send/return loop in the mixer would be the way to go. Just remember: that another piece of gear in the chain begins to make the noise floor a more formidable foe to deal with in the final product. . .

kf6phx
Voodoo Audio Head
Posts: 14
Joined: Sun May 01, 2011 5:42 pm

Post by kf6phx »

i appreciate the input..very good advice which is what i need right now.almost wanted to throw in the towel on this gig after only a month of playing with this. a question though...ive read that its best to go:
mic>mic2200>mdx2600(light noise gate,light compression)>eq>mdx2600(final compression,limiter)>mixer(which im using for audio from computer and for recording into computer).

so whats the question? what are some good starting settings for light compression in channnel 1 then settings for final compression in channel 2?

thx again.

Post Reply