Need imput on harp mic. element

[Pastor Harmonica]

Hi Guys, Its been awhile since I've been on. What do you suggest for a Harp mic. element. I am going to build my owm harp mic.

[jeffl]

I've never had a harp mic built, but I have one mic with a dynamic element and another with a crystal element, and they are totally different animals. We have a coupla pro mic builders on this board, and I'd sure tap them for some info. and consider just having them build ya' one. It isn't as much fun to do it that way, but I've seen what these guys do and they're worth more than they charge.

[MakaInOz]

Pastor H,

I'd suggest practicing on something that is not too valuable first. Those old CM elements are worth a lot these days!

I've got a few dynamic mics that I've made from the element from an old telephone handset (the 'hearing end' element usually works better than the 'talking end' element, but either will do, so long as they're passive), a 1/4" female jack and a small 10K log pot for a volume control. The latter two can be purchased for less than a couple of bucks each at any electronics supplies store (Tandy etc). All you need then is a shell about the right size. All sorts of bottles etc have been used, but I've found a roll-on deodorant bottle works great - once its empty, just punch the ball out and the element fits in there just right. A couple of holes in the bottom for the jack and pot, a bunch of small holes in the cap to let the noise in, and you're in business. Based on the i-mic described here:
http://www.planetharmonica.com/ph2/VE/TMI-micUK.htm

Good luck

[jbone1]

one of my favorite mics was built into a motorcycle turn signal bezel. it features a crystal element like those used in the jt30 mics of yesteryear. light, chrome, sweet sounding. not a lot of low end breakup but more a clean clear warm tone on this element. high inmpedance.

i have also an old shure bros 707a shell which houses a 99b86 controlled magnetic element. this is one of the fairly hot elements a lot of guys play through. lots of breakup and can be made to distort very easily. high impedance (this means use with a tube amp)

the latest mic i have and my current favorite is an electrovoice m43u military issue mic, built for comm in tanks. talk about rugged! this was a low inpedance mic when i got it and i had greg heumann modify it for me to high impedance and add a volume pot. very ballsy.

john popper has shure sm57 or 58 elements installed in bullet shells. these elements are built like tanks and provide a fairly clean tone. low impedance- solid state amp or p.a. friendly.

[bottleneck]

as some of you might know,i'm harp mic crazy.i have several hudred pounds of them.

i suggest a shure CM/CR even though they are expensive.they're also bullet proof!astatic elements have gone through the roof lately.

www.myspace.com/shakeylyman

[bottleneck]

oh,i also suggest a good gasket from www.harpmicgaskets.com they make a BIG difference.they can turn a lousy mic into a honker.

www.myspace.com/shakeylyman

[gheumann]

Good: Shure 99S556 dual impedance controlled magnetic element (was in a 520D among others)
Better: 99A86 or 99B86 Shure controlled magnetic - was in the original 520
Best: 99H86 controlled reluctance - only a tiny bit better than a good 99A or 99B, but better. Cost a lot more too.
Other: MC-151 crystal - getting very expensive - has all the problems crystals are known for but there are still "like new" elements out there.

I have all of these available for sale if you need.

[Pastor Harmonica]

Thanks for the replies guys. I found an old RCA mic. at a flee market ( it looked like somebody ran over the back end of it) The guy just gave it to me. It had a CM element in it, that still works great. Now the problem is my volume switch is to big for the casing I have. Need to find a super small one to fit. Don't want to post any pictures untill its done. I think I'm on to something good.

[MakaInOz]

PH,
For a real small volume control I use a 10K 9mm Square Potentiometer Log Single Gang (A) These pots are rapidly becoming the industry standard for miniaturised audio, digital and telecommunications equipment. This series (I get them from Jaycar) features good solder bath immersion resistance, 300° rotation and standard 18 tooth metric pre- cut actuator shafts. Electrical Linear Taper (B) Other Taper- Rated Wattage: 0.05W 0.02W- Rated Voltage: 50VAC 50VAC- Slider Noise: <100mV- Insulation resistance: >100Mat 250VDC- Dielectric: 300VAC/Minute- Tracking Error: Within 3dB at 40~0dB- Mechanical Rotation Angle: 300° +/- 5°- Rotation Torque: 20~250gf.cm- Shaft Stop Strength: 5kgf.cm/min.Value10K

I don't bother with a knob - the 18 tooth metric pre- cut actuator shaft is easy enough to grip. Costs about $3 at your local electronics store and it is SMALL.

[gheumann]

Maka

If you can get 9mm pots at your local electronics store you're lucky. they're not that common.

10K is the wrong value for any high impedance mic.

The rest of the specs don't matter much.

[MakaInOz]

Greg,

Thanks - you're an expert/professional/do this for a living, I'm just a potterer.

The 10k pot was recommended in the i-Mic design (the link is somewhere above) and as I am just 'fiddling', I use elements from old phones - because they work and they're free. They behave like the LoZ mics I have (SM58) so I assume they're LoZ.

Jaycar (not sure if they're just Aussie or are in the US as well) sell all sorts of hobbyist electrical components and I'm always buying 1/4" jacks or switches and pots for mics or speaker cabs or whatever I'm fiddling with at the time. They've got 9mm pots in 1K, 10K, 50K and 100K - log or linear, single or double gang. Cost $3.25 (inc tax) so they don't break the bank! And they're only 10 mins from work.

Thanks for the input. That's the joy of this sort of site - the real experts help us 'mug amateurs' with advice

[Pastor Harmonica]

I can't seem to find any electronic stores in my area (delaware USA) that carry what I need,
and dont want to go on line to order so I guess I'll keep looking.

[jbone1]

a volume pot is not a necessity. it's nice to have sometimes but just for example, i was using a mic with vol pot this weekend and spent just too much time trying to find the balance between loud enough and feedback. we had a very loud drummer one night, he set the stage volume at about double what it needed to be. i finally switched to a mic with no vol pot. left the amp volume set at just below feedback and the only time i had any squeal or hum was if i cupped the harp and mic just too tight. it's not a huge leap to learn volume control with your mouth, cup, breath, etc.

[kingley]

Yes I agree.
I don't ever use volume controls on my mics these days. I have on/off switches to avoid noise when I'm not playing or am singing.
Learning to change volume with your technique makes you are far better player and can also create some wonderfully subtle dynamics within your solos.

[Pastor Harmonica]

Thaks guys, With that said I think I'll make it with just an on-off switch. I do have good volume control on my own so there should be no problem. I will get back to you later with the finished product. More like after Christmas or New year. So to everyone out there have a safe and blessed Christmas and a happy new year. Things just got to get better in 2010.