(Warning:Keith is not a real expert, he's just the guy with the website and too much time on his hands, so don't take anything he says as gospel.)

> Steve wrote:

>I have been playing blues harp for about 28 years now.
>One item of interest, recently I decided to experiment
>with tube preamps and different mics.
>A Shure 520 D has been my mic of choice, but a friend gave
>me a JT30. I install volume pots on all my harp mics, and
>use a '63 Fender Tremolulx amp.
>In addition, I have a "Fisher" tube preamp. This is a
>dual tube, 6SG7 and 12AU7 preamp. I modified it
>to use only the 6SG7 and accept HI Z input. Currently,
>1 Meg Ohm.
>What it interesting is the output of the SHure 520D is
>higher than the JT30. The Shure can over drive
>the preamp giving a wonderful Chicago sound.
>The JT30 doesn't overdrive, is a bit less bass present,
>and offers a nice alternative....
>Have you any experience comparing these mics?????
>PS, the pot I use is a 1 meg ohm inside the mics....
>On the JT30, I added the .001 uF cap, with the 520D, no
>cap added.....


I am finding that the JT-30 elements vary a lot. I have a real hot one, but I have a few others which are not as hot. What I find is that the elements mellow out with age.

My objection with the 520d (Green Bullet) is that the response is too good. I wind up amplifying all the the little breathy reedy sounds when I want to only get the rich horn like overtones. I don't play loud at the harp and rely on the amp to make me loud. As a result I get good rich tone, but have to turn the treble down to avoid the reedyness. If I want a Chicago sound, the jt30 is better for me, because it has that limited response. It also seems to cover up my lack of skill in playing a little. The 520 seems to emphasize my mistakes.

The 1M pot is what I use because it's hard to find 5M audio taper pots. The only difference between 5M and 1M is the 5M seems to feed back a little less, but that may be because there is a difference in the element. It's hard to tell. I am told that If they made 10M pots, that they would be even better.

I can't see any difference from adding the cap. I've added a cap to a couple of mics and I can't hear the difference. The cap is like chicken soup for a cold. It won't hurt and I might help.



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The JT30 Page Popular links

I began collecting data about the microphones used by blue harp players before there was an internet. I began organizing it into JT30.com in the late 1990s. I accumulated more stuff than I remember. This is some of it.

Street Theory

A Harp Player’s Guide to Music Theory

Learning Harp

Picking Up Blues Harp

A guide to learning to play Blues Harp

Microphone Information

Usenet Articles

Harp Amps

I've been collecting Harp Amps for a while. This is the old Harpamps.com website. There is lots of information here. Here a coupld of links.

Harp Tab

A collection of songs and riffs that I’ve worked out over the years, plus some libraries of stuff I’ve converted to tablature. I’ve included most of the notes and instructions that helped me when I was learning to play blues harmonica.

Basic Riffs Simple harp tabs for songs Blues riffs and phrases.

Harp-L Archives 1992 to 2002


Harp Frequently Asked Questions