Mic for Kenwood TS-520

[RickC.]

My old TS-520SE is as good as ever, but is the backup rig now. I have a late 70s MC-50 which is convenient to use, but has always sounded a bit muddy to me in on-air tests and the switch in the PTT base has started creaking unless you are very careful with the switch-- and it comes across pretty loud! I've tried all the usual fixes and have been able to reduce that some, but it's still there. It's also not a very tall mic and I don't like bending down into a mic anymore.

I do have a Behringer mixer and several mics at my disposal but don't want to go that route with this rig, so what I'm thinking is a hand mic. I do have a D104-M6 which would probably work, but that mic has way too much handling noise for my liking.

I can't see paying what Astatic 575's go for these days, and just sent back an 878 DM because of RF feedback issues- though I did like the sound of that mic on the Kenwood.

As an interesting note to all you hear about impedance matching, the 520 is designed for a high impedance mic but with the MC-50 set for low impedance the rig's sound wasn't any different-- just a slight difference in the mic gain setting for the same output as on high.

So-- I haven't been in the market for a handheld mic for some time- has anyone here used the current crop that's out there with these old Kenwoods, and what did you think?

Rick

 

[Captain Kilowatt]

I'm surprised switching impedance on the MC-50 didn't make any differance in tonal quality. I have the MC-50 paired up with a TS-820S and it makes a notable differance when switching impedance.If you can find an old unamplified D-104 it will sound great on that radio. The newer D-104's with the builtin amplifiers sound pretty good as well.Sometimes I use my D-104 with it but mostey use the MC-50 because it works well and is part of the matched TS-820 station that I have.

 

[RickC.]

QRN-- thanks, and yeah, it surprises me also that there's not any difference anyone can tell with the MC-50 high/low.

Have you had the creaky switch problem? Do you know of a good solution for it aside from the usual cleaning/lubrication/contact burnishing?

 

[WX2MIG]

I run a TS-130S, I bought it use off of eBay, and it came with a Cobra CB hand mic that had marginal audio quality. Wired up an amplified D-104 and it got a lot of good audio reports, and a few average reports, mostly some think they lack the low frequencies needed to produce a quality broad based rag chew voice.

Now I'm running a Heil GM-5, this mic has two elements, the wide band broadcast element that sounds great in good conditions for every day rag chewing, and the HC-5 element that pinches off some of the low frequencies, and helps punch your voice through the noise level.
I'm using the Heil CC-1-K4 cable made to connect these mics right to the older 4 pin Kenwood's, and a foot switch, although the mic does have it's own PTT switch on it, the foot switch makes for hands free operation with no handling noise.
You can get a cheap desk top stand at Rat Shack for 12 bucks, or do like I did and mount it on a goose neck so you can set it exactly where it's comfortable.....

 

[RickC.]

Hey thanks, MIG- I have a Heil ICM on my IC-718 on a boom and it works pretty well. No doubt any of the Heils would work well for this and if I used it much that's not a bad idea at all, but I'm looking for a simpler solution. I think before I'd buy another mic like that I'd probably just dig out one of my SM-57s and the smaller mixer and run in into the Phone Patch In jack and use a foot switch.

 

[bioman]

another vote for a NON-amplified D-104 ..........thats what i run on BOTH of mine after going thru about 20 mics for them

i run a 10DA sideband head on mine for "ragchew" tone or the original crystal head if i'm working DX or have alot of QRM to deal with

one of mine is box stock but someone modified the other for 11M

both original 520 (plural) no "S" or "SE" models here


love my old 520s

scott

 

[RickC.]

Thanks!

Whoever modified that 520 for 11 meters went to a LOT of trouble, unless he sacrificed 15 for it. One good thing about the 520's is they were a lot harder to modify like that than say, the FT-101s, and as a result if you find one it's much less likely to have been hacked. Kenwood put those 10m xtals at the bottom of the board (underneath the bandswitch, etc.) on purpose!


Rick

 

[bioman]

nope they're on the 10M positions of the switch.......

looks to be a serious pain to go back...that's why i havent done it yet....

way it looks to me is that you have to pull apart the bandswitch and unsolder the board that the xtals are on

too much work for me

scott

 

[RickC.]

Ha, yeah Scott, somebody was determined!

 

[RickC.]

Found a solution, at least for now.

I have a D-104 with a T-UG8 base in which the ceramic head died a while back that I put a Radio Shack electret condenser in, along with a simple single transistor preamp. I've had it wired for the Icom the past couple of years but have not used it much because the local AM group tells me the Heil ICM sounds better on AM with the IC-718.

So.... Just for grins I bought a 4 pin plug from Radio Shack (thought sure I had one in the junkbox somewhere) an wired the reworked D-104 for the Kenwood, having no idea how it would sound with the old 520.

Well, it sounds great! I haven't made any contacts with it yet, but off the air recordings from the Icom show this mic has more clarity than the MC-50 without sounding tinny, and a much more open sound but still with good bass response. I don't remember what value capacitors I used in the circuit, 10 uf, I think.

I also added a couple of 2.5 mH chokes in the audio chain since I had the soldering iron out.

This is still my backup rig but I'll fire it up on the state traffic net tonight on 3965 and see how it does with the amp.


Thanks for the suggestions, if this doesn't work out (or if I change my mind), I'll explore some of those. P.S.- the Kenwood doesn't need the preamp (the mic's output as well as the mic gain on the 520 are both turned down quite a bit), but it does apparently avoid the impedance issue. I could find my notes on the circuit here in a file somewhere and calculate the output impedance, but that's too much like work. Sounds good, I'll leave it alone.


Rick

 

[bioman]

if it aint broke don't fix it lol

i used both powered and non on mine and they both seem to work fine although as you noticed that 520 has PLENTY of gain all by itself,,,,

long as your not overdriving it should work fine for you

i was going to build a condenser desk mic along with a 5 band EQ for my 940 but saw that HRO still had a couple heil classics left at the discontinued price of 79.95 so i snatched one of those up

let us know how that condenser works for you

which IC did you use for the pre-amp?

if you feel ambitious about building i'll send over the schematic for the 5 band EQ

uses a single BA3812L chip

scott

 

[RickC.]

Scott,

I didn't even get that fancy. It's just a single NPN plastic transistor I dug out of the junkbox. The circuit is very similar to this one:

Single Transistor Microphone Pre-Amplifier for Both Dynamic and Condenser Type Mics | Free Circuit Diagram

I didn't use the 100 uF cap. I suppose that's there to prevent motorboating, but it's not needed and I think that would cause the Vcc to come up slowly anyway. I did put a pot on the output and it's just about a minimum with the Kenwood. It wasn't up all that high with the Icom, really. You probably could get away with just a supply voltage and a transformer with the 520, might even be able to get away with feeding it with the 1K impedance. I may try that sometime just to see what it'll do.

One thing about these little electret elements is that they are very sensitive to wind/air. I at first just used a foam cover that came off an earbud with it when I first cobbled it together, but it wasn't enough. I ended up sacrificing a regular black foam screen from one of my SM-58s I used in the bands and cut it to fit the mic head. It didn't change the tonal response that I can tell, and if I close-talk it I need to talk across it at an angle. It does sound good with this Kenwood, though!

Send that eq circuit to me anyway, I may just build it sometime!

Thanks,

Rick

 

[bioman]

here ya go with the EQ circuit

cap values as given should give you
* 100Hz
* 300Hz
* 1kHz
* 3kHz
* 10kHz

as the 5 frequency bands......

probably 30 bucks in parts depending on where you find the chip

i was going to use a rat shack project box (one of the bigger ones) to build the EQ in mount a small gooseneck on it for the mic....then i would have the mic gain and the EQ and PTT button right there at my fingertips

i'll still build it someday but right now the bench is full of the dynaco tube amp i am restoring

have fun
scott

 

[RickC.]

Hey thanks-- I like that circuit. I built a 6 band EQ several years back using bipolar transistors, this looks a LOT easier and probably is quieter to boot.

I like the shack photo. I've been trying to figure out the best way to keep an antenna switch right in front of me so I don't have to keep either bending over or getting out of the chair switch antennas over, and without buying more expensive switches or building a remote switch. Your arrangement is just what I was thinking about.

What are you feeding with the open line?

 

[bioman]

the open line is running a "cobra" antenna as seen here http://www.nonstopsystems.com/radio/frank_radio_cobra.pdf

the other one you see when you look at the other pics of my shack is just a shortwave antenna for the little grundig......

i also have a G5RVjr, a maco5/8 11M vertical,a 11M double bazooka and a giant 2M vertical that supposed to be for a repeater .was given to me for free tho

some more pics of my stuff here http://www.worldwidedx.com/station-mobile-pics/33915-my-shack.html

scott