XLR Mics

[KC2UGV]

I've seen some pretty sweet deals on mics on Craigs List (Some starving artists are really starving). They're Shure mics (MC58 I think).

Looking at grabbing one or two. Problem is, I know studio mics are XLR mics (Balanced). What would I need to do to wire them for ham uses? Balun then to the mic jack is all, or is there more to do here?

[KG4CGC]

I've seen some pretty sweet deals on mics on Craigs List (Some starving artists are really starving). They're Shure mics (MC58 I think).

Looking at grabbing one or two. Problem is, I know studio mics are XLR mics (Balanced). What would I need to do to wire them for ham uses? Balun then to the mic jack is all, or is there more to do here?

I've been looking into that somewhat and I discovered that ham XLR mics come with 4 pins and studio XLR mics come with 3 pins. Consider the characteristics you seek in a mic, ie: strictly vocal etc... and if you choose a studio mic you will need to wire a PTT at the mic connector or use VOX. I prefer the switch. I'n some cases like Ten Tec, you may already have a place on the radio to plug in a PTT switch.

Aside from the common factors like impedance and frequency response, 3 pin XLR mounts and cords are available all day long at your local Rat Shack and pawn shop.

[N4VGB]

OK, I'll try this one more time. THERE IS NO SUCH THING AS AN XLR MIC. XLR references a type of connector only, it tells you nothing about the characteristics of the mic it's connected to. A mic with an XLR connector on the capable can be of any type and have any impedance.

The Shure SM58 is a dynamic cardioid pickup patern mic with brighted midrange specifically for vocals but it is low impedance and does not work well with most modern ham rigs. I've never heard of a MC58 but Shure has a website at http://www.shure.com/americas/products/microphones/ and any info on Shure mics is there or elsewhere on the web.

If your rig is built to use mid to high impedance mics, you're pissing in the wind with low impedance mics.

[KG4CGC]

OK, I'll try this one more time. THERE IS NO SUCH THING AS AN XLR MIC. XLR references a type of connector only, it tells you nothing about the characteristics of the mic it's connected to. A mic with an XLR connector on the capable can be of any type and have any impedance.

The Shure SM58 is a dynamic cardioid pickup patern mic with brighted midrange specifically for vocals but it is low impedance and does not work well with most modern ham rigs. I've never heard of a MC58 but Shure has a website at http://www.shure.com/americas/products/microphones/ and any info on Shure mics is there or elsewhere on the web.

If your rig is built to use mid to high impedance mics, you're pissing in the wind with low impedance mics.
Although this is lost on you, the XLR connector is something we're already aware of. Stick with program. The man also asked about impedance and the pissing in the wind comment was truly uncalled for unless of course you're pissing in an ocean of piss because you've grown weary of banging your cane on the ceiling.

[N4VGB]

Although this is lost on you, the XLR connector is something we're already aware of. Stick with program. The man also asked about impedance and the pissing in the wind comment was truly uncalled for unless of course you're pissing in an ocean of piss because you've grown weary of banging your cane on the ceiling.

Some hams most pressing problem these days is learning the proper nomenclature to describe what they are talking about. My post was very gentle compared to what a lot of OF hams would have laid on Corey.

If Corey was aware that XLR referred to only a type of connector and not mic characteristics, I don't believe he would have worded the post in such an irrational and completely incorrect manner.

I don't mind helping anyone who can at least formulate a question correctly. I was even about to sound the warning alarm about constructing antennas made with cheap dielectric Rat Shack speaker wire in one's attic but since none other thought anything about Corey possibly burning his home down, I kept my silence like a good boy. Being of an era when all hams knew the basics before being licensed, the new world is confusing me.

Carry on.

[WØTKX]

Anyway... you're on the right track.

XLR is balanced, as is tip-ring-barrel 1/4 inch plugs. Tip-barrel is your unbalanced 1/4 inch plugs. RCA phono is also unbalanced, though it tends to be used for line level, and not microphone level signals. And of course turntables. That is only a convention. But keep after the grounding and RF in the shack... unbalanced audio loves to pick up RF.

You may want to get your hands on a cheap mixer, it's more fun to play with different microphones, especially one with an EQ. Guitar Center does have ham equipment. :mrgreen:

I use a cheap Behringer and soon will have a Tascam PortaStudio 564 inline... 4 track Minidisc recorder, so I can record QRM from multiple receivers. :snicker:

What radio? For some reason I think you have an FT-897?

[N4VGB]

What radio? For some reason I think you have an FT-897?

Amazingly 600 ohm impedance input is listed as nominal for the FT-897. Which would mean a Shure SM58 would be a good choice for that radio.

[WØTKX]

Yes, which was gonna be my next point. Though I really like my Yaesu MD-100... I had the FT-897D and traded for an 857D.

There's a cheap Rat Shack copy of the SM58 with a better 3k voice peak... poor man's Heil.

[KG4CGC]

Some hams most pressing problem these days is learning the proper nomenclature to describe what they are talking about. My post was very gentle compared to what a lot of OF hams would have laid on Corey.

If Corey was aware that XLR referred to only a type of connector and not mic characteristics, I don't believe he would have worded the post in such an irrational and completely incorrect manner.

I don't mind helping anyone who can at least formulate a question correctly. I was even about to sound the warning alarm about constructing antennas made with cheap dielectric Rat Shack speaker wire in one's attic but since none other thought anything about Corey possibly burning his home down, I kept my silence like a good boy. Being of an era when all hams knew the basics before being licensed, the new world is confusing me.

Carry on.
How can anyone ever tell if you're being helpful when you're constantly berating everything?

[N4VGB]

when you're constantly berating everything?

Correcting error is not "berating".

[KG4CGC]

Correcting error is not "berating".
It's your bedside manner OM.

[N4VGB]

There's a cheap Rat Shack copy of the SM58 with a better 3k voice peak... poor man's Heil.



Shhhhhh. Those Rat Shack cheap mics are one of my best kept secrets. Even the electrets are great for mil surplus gear. Oops, I blew away another secret myself.:wtf:

[WØTKX]

:roll:

http://derek4messiah.files.wordpress.com/2010/03/angry_preacher1.jpg

[KG4CGC]

I always look a mic specs etc. In the CB daze, I would buy RS mics when they went on sale and wired them together tracking the impedance as I went along. I once used a small guitar preamp and ran it into a 10 band equalizer before connecting it to a multi tap audio transformer and then into the rig. The problem I kept running into was that I would border on distortion while trying to adjust the settings.

Not a real hi-tech set up but I was experimenting. I later changed to a "proper" mic preamp that was built into a late 70's early 80's Panasonic stereo. Ran that into the EQ and changed to a 1:1 isolation transformer. That was the ticket.

[KC2UGV]

Some hams most pressing problem these days is learning the proper nomenclature to describe what they are talking about. My post was very gentle compared to what a lot of OF hams would have laid on Corey.

If Corey was aware that XLR referred to only a type of connector and not mic characteristics, I don't believe he would have worded the post in such an irrational and completely incorrect manner.

I don't mind helping anyone who can at least formulate a question correctly. I was even about to sound the warning alarm about constructing antennas made with cheap dielectric Rat Shack speaker wire in one's attic but since none other thought anything about Corey possibly burning his home down, I kept my silence like a good boy. Being of an era when all hams knew the basics before being licensed, the new world is confusing me.

Carry on.

Thanks for the tip. I do know XLR is a type of connector (ie XL3 XL4 XL5 etc). Typically, a mic with an XLR plug is a balanced audio system, contrasted with mics that have a tip-ring connector.

That's primarily why I asked if I would need some sort of balun, to change from balanced to unbalanced; or if the mic input for average ham rigs is already a balanced system.

My FT-840 has an input impedance of around 600 Ohms. I was pretty sure the impedances matched from my little bit of knowledge of most studio mics.

I have to ask, how would I burn down a house with an attic dipole that has 6" of standoff from any combustible? Unless you would consider every ham who has ever employed an attic dipole to be fool hardy?

[WØTKX]

The premise of high voltages and potential arcing... off the ends.

[KC2UGV]

The premise of high voltages and potential arcing... off the ends.

And, the breakdown of voltage of air is...

20-30KV.

A 100 W (My max output) source driving a 20 KOhm load (Tip impedance estimated)= 1400V RMS? (I think I did my math right)

[N4VGB]

I have to ask, how would I burn down a house with an attic dipole that has 6" of standoff from any combustible? Unless you would consider every ham who has ever employed an attic dipole to be fool hardy?



If you used the Rat Shack speaker wire that you claimed, there is a distinct chance of dielectric heating of the wire insulation taking place and meting down to the point of igniting. Many insulating materials are not suitable for exposure to RF. Taint ya never seen any coils wound on phenolic, bakelite, PVC, etc. with big burned blisters on the coil form?

I seem to remember warning you about the extreme RF voltages that could exist in your attic? Causing RF arcs and sparks to happen on any metallic substance up there.

[KC2UGV]

If you used the Rat Shack speaker wire that you claimed, there is a distinct chance of dielectric heating of the wire insulation taking place and meting down to the point of igniting. Many insulating materials are not suitable for exposure to RF. Taint ya never seen any coils wound on phenolic, bakelite, PVC, etc. with big burned blisters on the coil form?


Wal Mart speaker wire. Wal-mart lol But yes, I suppose if I were running more than 100 W it would be a problem.



I seem to remember warning you about the extreme RF voltages that could exist in your attic? Causing RF arcs and sparks to happen on any metallic substance up there.

Right, sparks would be a concern, if there was any metal in the attic... The only metal are the occasional nail. Of which the antenna is a minimum of 6" away from...

So, again, we get to the breakdown voltages of air, which would need to be surpassed in order to arc. I figure one who states so often how long you've been into ham radio would understand how insulation works... Including air, which has a pretty consistent breakdown voltage.

I'm not running an amp. I'm running at most 100 W (Hardly ever, except for tuning tests).

[N4VGB]

I'm not running an amp. I'm running at most 100 W (Hardly ever, except for tuning tests).



I wouldn't bet the deed to the farm on any calculated voltages with a multi band fan dipole being correct, could be lots of weird stuff going on.

I had an old friend that thought he'd come up with the best mobile antenna idea ever, mounted an insulated metal bar on top of his van and attached every Hustler antenna on it. Like the fan dipole idea, the RF will find the correct antenna.:wtf:

It wasn't long before he calls and wants to know if I have high voltage ceramic disc caps and compression trimmers that he can "borrow". So I load him up with parts and about a month later I run into him and the antenna bar is gone, back to the standard Hustler setup. I even got a few unexploded ceramic discs and compression trimmers back.:lol:

His 100w mobile sure did fry a lot of high voltage parts.

[KC2UGV]

Anyway... you're on the right track.

XLR is balanced, as is tip-ring-barrel 1/4 inch plugs. Tip-barrel is your unbalanced 1/4 inch plugs. RCA phono is also unbalanced, though it tends to be used for line level, and not microphone level signals. And of course turntables. That is only a convention. But keep after the grounding and RF in the shack... unbalanced audio loves to pick up RF.

You may want to get your hands on a cheap mixer, it's more fun to play with different microphones, especially one with an EQ. Guitar Center does have ham equipment. :mrgreen:

I use a cheap Behringer and soon will have a Tascam PortaStudio 564 inline... 4 track Minidisc recorder, so I can record QRM from multiple receivers. :snicker:

What radio? For some reason I think you have an FT-897?

Sweet. In fact, I knabbed a mixer on CL for that very reason :) For the right price too, $0 :)

Tascam... ::DROOL::

[W1GUH]

Go ahead and use a "low impedance" mic with a Hi-Z input. All you need is an adapter with a transformer in it and will convert balanced to single-ended. There's two types available. First is a stright mic cord with all that built in...plugs directly into the mic and into a 1/4" jack. Of, of course, the "usual" type of adapter that the "output" end of the cable plugs into is also available.

That's what I used with ol' scratchy, with the addition of an HB adaper that went from 1/4" phone jack to that wierd coax-type mic connectors in the 'pache. Also used that mic configuration when I drove the modulators in a Valient with a guitar amp. Works just fine.

Mic was a Shure SM58