IC-735 es the D-104 W/pre-amp

During a QSO with HB9ASQ - Bob on Ten mtr AM the other day, I noticed his audio was very good and told him it sounded like Voice of America.  He came back es said he was using a solid state rig ( IC-735 ). That being very difficult to believe, I asked him what / how he was doing to make that rig sound so wonderful. Well, he was using a very high dollar Broadcast mike and audio processor, but the main detail was he he was not using the front panel mike connector.

He had used the Accesory DIN socket in the back of set to plug in his audio........to the afsk mod input.  In this rig it is pin 4.  Pin 2 is grnd.  There is also a T/R line there on socket.  Hmmmmmmm.....Well I could not wait to try this out. I took IC-735 over to my friend's house W4OP - Dale es he liked the idea.  He made up a patch cable so D-104 could be detached from IC-735 es put back on the 32V3 easily.  

Next came the TEST... Audio was very good, even without the $$$ audio processor.  Talked with Bob HB9ASQ on Ten this morning es he said audio was great es that I would not have to hang my head when using it on AM. It was good audio.  Tried it on Ten mtrs, 40 mtrs es 160 mtrs.  All reports are very good.  Some of the big audio guns even liked it... Its an almost no cost way of improving audio on the IC-735 es perhaps any solid state rig with a direct line to the balanced modulator.  Just remember to Test es be careful of audio input levels.  I used a D-104 that has a pre-amp in it. A scope es on the air tests helped me a lot.

Tnx Bob, I am enjoying my little 735 much more now !

P.S.  Folks still like the sound of the old V3 better though )

 

Fine Business. Thanks for posting this info.
I made some minor mods to a D104 and connected it to an Icom 260A 2m all mode (used for ssb only). It requires a preamp mike and the audio amp stage in the D104 is not hot enough on its own.
My mod let it acquire power from the radio itself, eliminating the battery, and brought the gain up to proper level. It is no longer adjustable as the volume pot has been bypassed. This is not a problem as all reports are of good audio, no splatter, and superior voice quality as compared to the stock hand mike.
My radio has the acc. socket in back but since it works fine now I won't fix it til it's broke.

 

I wonder if this would work on the Icom 730? Its got a similar accessory socket on the back. Where can I get details about the socket?

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (n7wsb @ Feb. 15 2002,13:23)</td></tr><tr><td id="QUOTE">I wonder if this would work on the Icom 730? Its got a similar accessory socket on the back. Where can I get details about the socket?[/QUOTE]<span id='postcolor'>
Go to www.icomamerica.com and either contact them by email or call them up (recommended) and get a info pack about your radio. It will be photocopies and they are not free but reasonably priced and gives operation and internal details that are hard to beat.

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (K0PJG @ Feb. 13 2002,15:26)</td></tr><tr><td id="QUOTE">During a QSO with HB9ASQ - Bob on Ten mtr AM the other day, I noticed his audio was very good and told him it sounded like Voice of America.  He came back es said he was using a solid state rig ( IC-735 ). That being very difficult to believe, I asked him what / how he was doing to make that rig sound so wonderful. Well, he was using a very high dollar Broadcast mike and audio processor, but the main detail was he he was not using the front panel mike connector.

He had used the Accesory DIN socket in the back of set to plug in his audio........to the afsk mod input.  In this rig it is pin 4.  Pin 2 is grnd.  There is also a T/R line there on socket.  Hmmmmmmm.....Well I could not wait to try this out. I took IC-735 over to my friend's house W4OP - Dale es he liked the idea.  He made up a patch cable so D-104 could be detached from IC-735 es put back on the 32V3 easily.  

Next came the TEST... Audio was very good, even without the $$$ audio processor.  Talked with Bob HB9ASQ on Ten this morning es he said audio was great es that I would not have to hang my head when using it on AM. It was good audio.  Tried it on Ten mtrs, 40 mtrs es 160 mtrs.  All reports are very good.  Some of the big audio guns even liked it... Its an almost no cost way of improving audio on the IC-735 es perhaps any solid state rig with a direct line to the balanced modulator.  Just remember to Test es be careful of audio input levels.  I used a D-104 that has a pre-amp in it. A scope es on the air tests helped me a lot.

Tnx Bob, I am enjoying my little 735 much more now !

P.S.  Folks still like the sound of the old V3 better though )[/QUOTE]<span id='postcolor'>
Msg from KS7W, who I met on the air during initial testing;

Hi Tom
Thanks for sending the info from B0B (HB9ASQ).I have been
having lots of fun with this (IC-735) mod.
Next,i plan to try different mikes.Will try a ceramic element.
Also enjoy cw,maybe we can get together sometime.
73 KS7W (BOB)

Mebbe we could designate the users of HB9ASQ's technique by saying
  " Rig hr is an IC-735 Pro "  

 

Saw the same kind of note about the IC-746 in Yahoo Groups. Same comments on the good audio...

Jim N8AVX

 

Folks, this is not uncommon.  You have heard of Audio shaping.  That is how the manufacturer takes the audio from the front panel and makes it fall off on the high and low end of the audio specterum for better communications punch in an appllication such as ssb.  Now we enter the audio from the rear panel and this is not the case.  Hence systems such as AFSK for some of the digital modes as when we use a TNC or in my case I have an Icom 706 hooked up as a 6 meter to 80 meter remote base that is controlled from 440 MHZ.  This system is located away from my house where there is not any antenna restrictions.

Dick,
WA6MDI
Salem, OR.

 

I wonder if all the Icom radios are capable of this? Can an unamplified D-104 work with the ICOM 706 Mk II G ? Or would it be a amplified type be needed ? The radio seems to work well with the hand mike but an improvement on the AM mode without an outboard proecessor would be nice...

 

ABOUT BANDWIDTH:
For the record, feeding audio directly into the balanced modulator does NOT increase bandwidth. I would be against that myself for reasons of band economy and courtesy. What it DOES do is permit you to process the audio the way *you* want it, and not way the TX manufacturer has decided it should sound. The TX's bandpass filter is still operative! This is the way it's done in broadasting.

I'm modulating my 735 with an Orban Optimod-HF 9105A. It's especially designed for HF broadcasting, and achieves incredibly high quality audio WITH NARROW BANDWIDTH! In fact, it's designed to sound good on a typical SW radio with a bandpass of only 2.5 kHz! The secret of the sound is in the Optimod's unique equalizing, limiting and clipping system.

Improving the sound of a ham station *within the confines of established good operating practice* is a real challenge and a worthy addition to technical specialties within the hobby.

73

Bob HB9ASQ/WA2UPQ

 

Increasing the voice range does not increase bandwidth, just as voice compression does not decrease bandwidth.
The idea of voice compression was to increase "talk power", that is only the voice range needed for intelligibility would be transmitted thus increasing the average voice level without the wide swings in output power on sideband. The problem is there can always be too much of a good thing. Listen to many of the South American stations that compress and amplify to the point of un-intelligibility. These stations are using up bandwidth broadcasting signals few can understand, and the number of times repeat information is asked for is a waste of space and time on the bands.
Over deviation is what causes splatter, which causes the signal to occupy areas outside the bandwidth of the transmitted signal.
Kicking on that amplifier to talk to a neighbor is also bad operating practice. It overloads receivers and kills contacts anyware close to that frequency.
Good audio is prudent and pleasing to the ear, you would be supprised at the number of DX stations that will pick you out of a pile-up to acknowledge good audio is appreciated without actually saying it.

 

This is the first I've heard of using a D104 on ICOM rigs. Great!

I use one on a TS-830 as it's a high Z audio input to match. The 830 processor is great and well matched to the D104 Hi-Z output. I get great audio reports also. One was I had "VOA Audio." I asked what that meant and he said "I had Voice of America Audio-loud and clear."

My best report went like this on 10M. This JA starts out and says you have really big signal, you have really big signal, you rattle my windows, you rattle my windows, you right in shack, you right in shack, I could shake your hand, I could shake your hand , he went on and on and was all shook up. Then there was an interruption. His wife was talking to him. My audio was rattling something in the other room that affected her TV and she told him he had TVI. It was when I was transmitting-not him. He said to her "that's k7gco with the TV--not me." I'd given anything to have had that recorded.

When you hear a signal that gives you RF burns off the RF gain control and audio burns off the audio gain control, that's a D104 into a TS-830. Long live the D-104. They have made an aniversory model now. I'd like to get one.

I'd like to also get a JT-30. That'a a great mike also. Anybody know where to get one? Also a EV 650 mike. I want one of those also.

I used to give talks a Dayton on Better Audio. My Audio hand out is 65 pages long now.

I just noticed something on the TS 830. Norrmally the compression level kicks up to about 20 db and the ALC about 10 dB. I noticed the day before the ALC meter wasn't moving yet still seemed to be working OK. I heard someone say that the tuning had something to do with it. I checked it carefully, the drive was peaked and the loading was set for max output as I always do driving the linear. Has anyone had this problem before? There is a tech at Kenwood that is intimate with the TS-830 and I will have to check with him. The TS-830 was recently modified for more power cut. Perhaps that had something to do with it.

The ICOM 761 with Heil mike and the line amplifier give great audio. The Heil doesn't have enough output for the ICOMs. k7gco