New Guy

[Bow]

Hello Voodoo Audio Guys,

My name is Bow and I am in the Northwest Houston area.

I have been a side-band operator for a while on the 11 meter band. I know, mentioning 11 meters on a ham band may be the wrong way to start, but sideband ops tend to know how to operate a radio and act on the air. I am also a Tech since 2000, and now that the FCC is finally dropping the Code requirement, I am upgrading my ham license…

Here is my Gear that I am getting started with…. (I am now Donning Flame retardant gear):

Transceiver: Icom IC-718 with the FL-257

Antennas (I am in an antenna restricted home-owners association):
40 Meter inverted –V
20 meter inverted-V
10/11 Meter vertical (Shakespeare NBS-2010)

Audio Gear:
MXL V57 Condenser
Behringer VX-2000 Microphone Preamplifier/Voice Processor
Behringer PEQ-2200 Parametric EQ
Alesis Nano-Compressor
Rolls DB25 Match Box
Behringer MX-602A Mixer

I have the Equipment setup in this order:

MXL V57 -> VX-2000 -> MX-602A
MX-602A Effects Loop Send -> PEQ-2200 -> Nano-Compressor -> MX-602A Effects Loop Return
MX-602A Mains Out -> DB25 -> IC-718 Modulator Input (On the back ACC Jack)

I just picked up the VX2000 on Ebay for $30 and got it in the rack.
The PEQ-2200: Can anyone suggest a good starting point for the settings across the board?


Any other suggestion sto get some Voodoo from my setup, or am I hoplessly doomed to be a tinny wanker on SSB?

[Voodoo Guru]

Howdy Bow!!
Welcome to the Voodoo Forum.

No worries on the 11 meter mention, Hell...we think most of us have come from there...We know we have!!

Sounds like you got a real good start on the Voodoo there Bow!
As far as getting Mega Voodoo out of your setup?
Well, you will be able to get some Extremely good audio from that line up,
but to be honest, you will be limited in the ESSB Voodoo Department.
More from the IC-718 then anything.
It just does not have the bandwidth nor the TX Frequency response to do it.
Don't get us wrong....
You have the capability of sounding better then any one else at that bandwidth....IF you take the time to get it right.

As far as the Settings for the PEQ-2200, the best advice there is to read and study the terrific website of John, NU9N.
He gives so much info there, it is better to go there and study and learn, then for us to right it all out here.

http://www.nu9n.com/tx.html#EQ_Setup

Good Luck Bow!!!!
Take Care,

[Bow]

Thanks Mike,

Yup, I've trolled NU9N's site quite bit, great info on there, but no much in the vain of the parametric EQ...


You are correct, I figured teh IC-718 would be my bottle neck in the quest for better audio, but thankfully, I have electrinics knowledge, a good soldering iron, and very few morals.

The TX audio on the IC-718 is run through a Murata CFJ455K5, which is 2.4khz (at 6db) filter.

I am currently looking for a replacement filter to drop in there.

I am trying to decide on either a 3 khz, 3.5 khz, or possibly a 4.0 khz. Any suggestions?

The MuRata filter line information shows that the CFR455 filters are drop in replacements, size-wise.
The CFR455H is a 3khz (+ or -) at 6 db or a CFR455G is a 4khz (+ or -) at 6db.


Am I on the right track to the Voodoo Audio?

[Voodoo Guru]

Ok Bow,
Great on trolling John's site.
There is lots of good info on there. also on the internet to supplement that knowledge.
Then the most important thing is to spend the hours in the dummy load testing, testing, and testing.
Then when you think you got it.....test some more.
Its the best way to learn, hands on....or We should say ears on!!

Great on your carnal knowledge of electronics raping and disfigurement!
We like that!!! Mooo hooo ha ha ha ha ha!!!!

The first thing you need to do is to see what kind of circuits you have for setting the carrier point (carrier offset) of the filters.
Is it adjusted with pots or caps, or is it menu controlled via the microprocessor?
Also, how much adjustment will you have for each sideband?
Are the individually adjustable, or are they linked like a IF shift control?

Usually if it is pot or cap controlled, you will not have enough swing to swing the carrier point high enough to get the most bandwidth out of the filter.
Worst thing of all is that you will not have good opposite sideband suppression. More often then not if you go to wide up to a certain point you will be Double Sideband.
If this is the case, usually 3Kc is the largest filter you can go with.

If it is microprocessor controlled, then you might have a chance to use the 4kc filter. Depends on how far you can swing the carrier point on each sideband. You might still have a opposite sideband leak thru if you are not very careful on the adjustments.
Depending on the Carrier offset swing adjustments will determine the width of the filter you can use.

Second, and most important thing....
How flat is the receiver AF section?
You might be able to pass 4kc bandwidth, but can your reciever
Audio Frequency strip pass it?
Probably not.
Most Receiver's Audio bandwidth is fairly flat from 90 to 3.2KC at the most.
And that is being optimistic.

On the TX side of things, the most limiting circuit is the mic amplifier.
Most will go around this and feed it behind that circuit.
We are not familiar with the rig you are using.
We hear most people say they are going into the rear of their rig in the ACC jack into the "Balanced Modulator".
This is 90% of the time WRONG!
It might be feeding the TX audio into the TX mic chain BEHIND the mic amps but it is usually not a direct input into the balanced modulator.
A Balanced Modulator directly fed requires line level audio and has sooooo much more fidelity it is unreal.
Look at your schematic and see.
There will usually be some Audio frequency shaping capacitors and resistors before the Balanced Modulator.

Another thing is that allot of these newer rigs are using DSP on TX also.
So without looking at the Schematics, We really couldn't tell you what it is doing in your case.

OK Bow....hope we didn't disappoint you too much.
Take Care,

[Bow]

Thanks Mike,

I need to know what I'm up against to get good tone on the air, so information is good, even if it is not what I really wanted to hear!

I did scope my Audio, you can check it out here:



The SSB is with the FL-257 3.3khz filter.

I'll be looking for a schematic next....

[Voodoo Guru]

Howdy Bow,

Looks like at 4kc there is a 15db drop from the baseline.
This is Typical as I was saying.
The Low Freq. Response looks surprisingly good.

So it really looks like that just the High Frequencies are being limited.
The Trick here is to look at the schematics and identify any RC low pass filter combinations in the AF strip that would limit the audio bandwidth.
Also look for Sallen Key Low Pass Filter combinations with op amps, and for caps shunted to ground that would limit the high frequencies.
Key places to look are directly after the Demodulator IC, or if DSP demodulated, look directly after the DSP where it is injected into the AF Strip.

You must choose the correct capacitance to raise the Cut off frequency for the low pass filters, but don't change the resistance or you run the risk of changing the gain structure of the circuit.

OK Good Luck!!!!
This is our favorite part of the hobby!!! hahahaha
Take Care,

[Bow]

Thanks Again Mike.

I found a schematic of the section:
http://riley-music.com/BowsStuff/IC718RF.gif

What go ya think?

Am I barking up the wrong tree?

[Voodoo Guru]

Great on finding one!
We will look at it, but really the Service Manual is the way to go for the complete Monty.
It has way more information in it instead of just a schematic.
We'll look and see if there is one available on the internet and let you know.
In the mean time when we have a chance, We'll look at the schematic.
Take Care,

[Bow]

Thanks Mike.

I have the Factory Service manual, You can see it here:

www.riley-music.com/BowsStuff/718+Service+Manual.pdf

I have never gotten into the theory behind RF equipment, so this is a big learning curve for me...

Thanks a lot for your help!

[Voodoo Guru]

Well Bow,
After looking at the Service Manual.
Good and bad things were found.

First of all there is a Balanced Modulator that you could inject Line Audio directly too and bypass the Mic Preamplifier circuitry.

The bad thing is that it looks like the carrier set points for the IF Filters are automatically set by the CPU when adjusted.
There does not seem to be an option to manually set the Carrier points.
So we would think the maximum you can install is the FL-257 3.3kc filter.
But there is a twist here also....
It looks like the ic718 is like the ic706 were it defaults back to the fl-65 2.4kc filter on Transmit.
So even if you put the 3.3kc filter in the optional slot, it will only use it for receive.
To get around this, you must install the FL-257 in the FL-65 place.
This usually requires soldering.
Once this is done, you will then be able to TX at 3.3Kc.

We see allot of Frequency shaping using RC Low Pass filter circuits and also Shunt Capacitors to cut High Frequencies in the Audio Amplifier circuitry.
We wouldn't even mess with this since your SSB Frequency response through the filter will be about 3.5kc anyway.
We do see were there is an "Expansion Filter" option in the Set Menu to give you a wide setting on SSB receive of 6KC.
What this does is bypass the IF filters on receive, We'll bet it is 6Kc Double Sideband reception in this mode.

OK, Good Luck with it Bow.
Take Care,

[!KANT]

Hiya Bow. nice to see you have that burning desire to play Audio


A couple years ago John [WO2D] modded his FT-840, by swapping fils and feeding the BM he had incredible audio that easily put him in the upper ranks of the Audio Game.

Keep us updated on the progress of this project....

Also which receiver did you use for the SpectraPLUS reading....

[Bow]

Hey Man...

That was the RX of my IC-718 with the 3.3khz filter on.

[!KANT]

Kewl. Maybe one of these nights when the band is playing right [and I have the 870 inline] we'll get a snippet of you and give an "official" on air reading...

[SMC Productions]

Kewl. Maybe one of these nights when the band is playing right [and I have the 870 inline] we'll get a snippet of you and give an "official" on air reading...

Where do you guys 'hang out' now?

[!KANT]

I roam 75M looking for the VooDoo Audio and [true] ESSB guys, but most of the time I'm at 3933MHz. Like most groups on 75M, can be a tough crowd, but great bunch of guys--no they're not into TRUE ESSB....but like "nice" audio nonetheless.

[Bow]

I roam 75M looking for the VooDoo Audio and [true] ESSB guys, but most of the time I'm at 3933MHz. Like most groups on 75M, can be a tough crowd, but great bunch of guys--no they're not into TRUE ESSB....but like "nice" audio nonetheless.

Good info, thanks...

You on late in the evenings?

(BTW.... Holy Sheep $hit, you got a rack....)

[Voodoo Guru]

Most of us in the South are usually on after about 10:00Pm Central Time.
The bands have been so bad the last few months that most of us have not been on the air at all at night.
The band has been going real long and we cant hear each other.
Where beginning to get on during the afternoons again on 7235Mc.
When we start up again in the evenings, It is usually on 3870Mc after about 10:00pm.
John, NU9N and the Northern ESSB Dudes are usually on 3635 in the evenings.

[SMC Productions]

Most of us in the South are usually on after about 10:00Pm Central Time.
The bands have been so bad the last few months that most of us have not been on the air at all at night.
The band has been going real long and we cant hear each other.
Where beginning to get on during the afternoons again on 7235Mc.
When we start up again in the evenings, It is usually on 3870Mc after about 10:00pm.
John, NU9N and the Northern ESSB Dudes are usually on 3635 in the evenings.

Well, I figured something was up...as I couldn't find you guys anywhere. Last few nights/week, etc. though noisy, us in TN, KY, AL, GA, etc. have had pretty good conditions. I also talked to my buds in Wichita, KS area on 75/80, and on 7 meg until the band died there at around 2200 or so...

Let us know here, on or the ESSB mailing list when you guys get 'fired' back up in the evenings...

LTR

[Voodoo Guru]

Were on Now!!!
Its 10:44pm.
3869 at this moment.
Got a bunch of us in here.
W5UDX, W5CUL, WD0CT, K0NT, W5KO.
Havin Fun!!!

[SMC Productions]

Were on Now!!!
Its 10:44pm.
3869 at this moment.
Got a bunch of us in here.
W5UDX, W5CUL, WD0CT, K0NT, W5KO.
Havin Fun!!!

TNX for the note, but I was 'out of it' last night. Spend the whole bloody weekend at the Hospital, as my 1st and 3rd wife had gall bladder surgery.
I will try and 'drop by' tonight!

LTR