Thin to Fat in 10
Hello Harp Techs
“Thin to Fat in 10” minutes does not refer to a new diet, but how you can fatten your amplified sound in ten minutes.
For numerous years, readers and students know that I have been drawing attention to swapping diatonic harmonica cover plates from vented to non-vented as the best method to fatten up the tone of a thin amplified sounding harmonica.
“How is that possible”?
The reason for this is that the player must direct 100% of their air through their instrument and into the microphone. Without a terrific mic “gripping” technique, those harmonicas with vented cover plates (Hohner Marine Band, Crossover, Rocket, etc.) allow copious amounts of air pressure to escape through the side vents--making it more stressful for the player to create the FAT amplified sound.
Recently, I hooked up with a Rock Band that requires a big fat “Rockin’ harmonica sound”. So yesterday I ordered a set of non-vented Hohner Rocket AMP harmonicas from Rockin’ Ron’s. The AMP model is exactly the same as it’s cousin, the Hohner Rocket, with the exception of the non-vented cover plates and (weird) green comb. Unfortunately for me, my new Rocket AMP harmonicas did not arrive, and I had a last minute show to perform. This is what I successfully pulled off in ten minutes:
Remove cover plates
List of supplies and tools: single edge razor, shears, tweezers, cotton swab, 3m Painters Blue Tape
Apply strip of Blue Tape to the interior side of the cover plate and use a cotton swab to form the tape tightly into the irregular corners and crevices
Top view
Trim excess tape with razor (or shears)
Outside looking in
Apply a strip of Blue Tape to the outside vent as well. This will seal the deal and prevent debris from sticking to the tape. In the photo it appears my fingers are doing some clever Yoga moves, because my other hand was holding the camera ;o)
The 10 minute modification to seal off all four vents worked perfectly. Although my cut lines were a little choppy, my monster performance brought the audience to tears :o)
Your Harpsmith, Kinya
Welcome aboard Sanshinboi. Where in Japan are you living? As you get deeper into your Harp Tech studies, don't hesitate to direct your queries and progress reports here. We are interested!
Your Harpsmith, Kinya-san
I live in Takatsuki city it between Osaka and Kyoto it's convenient as I can go to both cities. I will definitely be asking question as I progress, thanks
Kohai Sanshinboi
Dōitashimashite Kohai-san,
I have been a "Tinkerer" all my life, my largest project building a sports car--but nothing is as satisfying as working with harmonicas. I'm challenged by the simple, yet complex design elements of the harmonica. The reward, of course, is to play the "thing" we just worked on, then enjoy the music we had created.
p.s. have you ever been to TANIGUCHI GAKKI, 1-8, Kanda Surugadai, Chiyoda-ku, Tokyo
Your Harpsmith, Kinya-san
Kinya, if you were going to close off that vent for good, how would you do it? Would you do it at all? Or is it a really bad idea?
Hi AC, I'll check back with you shortly with how-to-do photos!
Your Harpsmith, Kinya
Hi AC, My first choice would be to swap the Hohner Rocket vented cover plates with the AMP non-vented cover plates. Sort of like not breaking up the family ties between the Rocket and Rocket AMP. Unfortunately, I do not have any spare AMP cover plates, and my go-to source, Rockin’ Ron’s do not stock them, so I decided to simply use the Rocket’s cousin, the Hohner non-vented Special 20 cover plates (maybe having a couple hundred Special 20 cover plates in my shop had something to do with my decision ;o)
Hohner Special 20 (left) requires a straight blade screwdriver, while the Rocket (right) requires a Pozi Drive screwdriver
Straight blade screwdriver
Although, I have an open ended wrench for this stamped square nut, I use finger pressure to hold the nut in place, while I loosen/tighten the cover plate machine screw
Most Hohner harmonicas now use “binding posts” to secure the cover plates
Wiha is the Mercedes of jewelers screwdrivers. A perfect fit will be the Wiha #262/PZ0 x 50
Original Special 20 reed plates have a single hole on each side of the reed plates, but the comb underneath (no photo of comb) will have three holes on each side--matching the new architecture of the Rocket/Amp reed plate shown on the right. Smartly, Hohner engineers made it easy for users to swap Crossover cover plates (2 binding bolts on each side), single sided and centered Special 20 and Rocket/Amp (2 binding bolts front/corners)
Original Hohner Rocket side view
Original Hohner Rocket at side/back view
Using the original Special 20 cover plate machine screws, align and insert into center holes of the reed plate. New style binding posts will not fit without drilling the SP20 cover plate holes to a larger diameter.
Hold the Hohner Special 20 vintage square nut with finger pressure, while you torque down on the cover plate machine screw.
Now you see it, now you don’t--the vents have disappeared!
Here you can see the super cool modification I created for the Special 20 cover plates. This application will mellow out some of the treble frequencies from shorter reeds 6 through 10, while allowing reeds 1 through 5 to be voiced with a big, fat tone!
Your Harpsmith, Kinya
Ah, thanks for the time you put into that tutorial. What if there wasn't a readily available cover plate that would fit like that? Like if you wanted to close the vents on something like an Easttop or Kongsheng.
Ah so, now I'm following you. In that case a semi-permanent solution would be to use the 3M HVAC Tape (1.4 mil general purpose aluminum foil backing with acrylic adhesive). Available at most hardware, do-it-yourself stores and all over the internet.
p.s. this should please Kohai-san
Your Harpsmith, Kinya
Thanks :)
Hello Mr. Kinya as a 30 year retired 3m worker I applaude your use of 3M tape. I live in Japan and just purchased a harmonica tool kit. Thanks to you and this great site I plan to dabble into tuning my harmonica's. I was a machinist at 3M so I love to tinker with tools! Again thanks for all your videos and tips.