Brendan Power

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The New OVERBLOW-BOOSTER Mk2 – Special 20 Version!

Second Signed & Numbered Limited Edition Release

Overblow Booster Mk2 Special 20 Overblow Booster Mk2 Special 20 Overblow Booster Mk2 Special 20 Overblow Booster Mk2 Special 20 Overblow Booster Mk2 Special 20 Overblow Booster Mk2 Special 20 Overblow Booster Mk2 Special 20
Earlier this year I released my new Overblow-Booster Mk2 in an initial Signed & Numbered Limited Edition of 25 units, based on the classic Hohner Marine Band 1896. I've now tweaked the design so it fits another hugely popular Hohner harp: the Special 20 Classic. It will also be released in a Signed and Numbered Limited Edition of 25 units, with a small price reduction to reflect simpler assembly (see details below).

Overblow-Booster Mk2 - Special 20 Edition
All the same great features and stellar performance of the original OBB Mk2 release are retained , with a few updates:
  1. The formerly solid Teflon baseplates have been replaced by a composite baseplate with a Teflon top layer, where it seals to the stainless steel sliders. This retains the slippery interface between the two but is easier to make and attach to the harp.
  2. The rear push-bar has been thickened, so it doesn’t require an extra steel stiffening plate.
  3. The push-bar connection tabs of the steel sliders are now trimmed shorter, to avoid them being inadvertently lifted up by careless handling.
Shipping is included in all prices. For additional options, see your shopping cart.

Please include your phone number when ordering. Without a valid phone number we cannot guarantee delivery.

For full details see our Terms & Conditions

Overblow Booster Mk2 -
Special 20 version




(See Ordering Info at bottom of page about customisation)

Top session musician Ross Garren playing his Overblow-Booster

ORDERING INFO – Harps Made and Signed by Brendan

We only have 25 ready-made Special 20 harps with Overblow-Boosters fitted. Each one is hand-made, numbered and signed by me. The numbers will be from #26 - #50. This will be the last of the Signed and Numbered Hohner Editions of the Overblow-Booster Mk2. When they're gone, they're gone - so order now to avoid disappointment!


If you're skilled, you can customise your own Overblow-Booster Mk2 harmonica to the highest level of performance with reed-slot embossing etc. However, I suggest you get it done by a professional. The Overblow-Booster Mk2 is a sophisticated harp, with several carefully fitted components that must not be damaged during extra reedplate work. If you want customising done, I recommend my friends André Coelho and Kinya Pollard. André and Kinya have helped me test and tweak the initial two Limited Edition batches, so both have an intimate knowledge of the harp already. If you decide to choose André or Kinya to customise your Overblow-Booster, please email them first to discuss what you're after, prices, timelines etc. Once you have agreed the deal, choose either the Andre Coelho or Kinya Pollard custom option in the Drop-Down list. After you purchase we will post your Overblow-Booster Mk2 harp directly to them. They will post it to you after the extra work is done.


OverBlow Booster Logo

The New OVERBLOW-BOOSTER Mk2 – First Limited Edition Release!

Overblow Booster Mk2 Overblow Booster Mk2 Overblow Booster Mk2 Overblow Booster Mk2 Overblow Booster Mk2 Overblow Booster Mk2
In 2018 I released the first Overblow-Booster; it worked well, but had some issues so I discontinued it. However the demand was high, so I resolved to try and create a superior version. After a lot of trial and error it's finally here: the new improved Overblow-Booster Mk2!

It's based on a famous design by Professor Henry T. Bahnson, who patented it in 1993 . Like his original, my Overblow-Booster Mk2 uses two sliders and a push button to cover the lower 6 blow notes and upper 4 draw notes. However, that's where the similarities end… because, unfortunately, Henry Bahnson's design suffered from two main faults:

Overblow-Booster Mk2
Firstly, the sliders were mechanically attached to the reedplates with holding screws, and were not sealed in a fully airtight manner. Thus, the resulting overblows/overdraws were not as strong as optimally possible. Second, because the sliders were moving directly on the reedplate surfaces, if the reeds were in play and vibrating through the reed slots when the player moved the sliders, the slider slots would hit the vibrating reeds. This caused an unpleasant clicking sound, and damaged the reeds.

My patent-pending Overblow-Booster Mk2 overcomes these problems by introducing several novel features: First, it adds slotted baseplates between the sliders and reedplates. Just 1.5mm thick, they raise the sliders sufficiently above the reeds to avoid the clashing and clicking that bedevilled Bahnson's original design. Second, my enhanced design harnesses the magic of magnetism! Airtightness of all parts is guaranteed by sealing the baseplates to the reedplates and embedding small magnets in them. The magnets ensure that the ultra-thin steel sliders remain closely fitted to the baseplates, which are made of super slippery Teflon – so the sliders never stick! Tone and volume are not affected, and the super airtight seal makes the resulting overblows/overdraws on a standard Richter harmonica sound as pure and loud as your regular notes and bends! Watch the video to see/hear for yourself.

Shipping is included in all prices. For additional options, see your shopping cart.

Please include your phone number when ordering. Without a valid phone number we cannot guarantee delivery.

For full details see our Terms & Conditions

Overblow Booster Mk2


(See Ordering Info at bottom of page about customisation)

After a lot of hard work perfecting the new design, it's so nice to hear the Overblow-Booster MK2 being recorded for the first time ever in a music track by Andre Coelho ! The overbends sound pure, strong and sweet 🙂 Part of that is down to Andre's custom reed work, which is highly recommended for top performance (see Customisation option in the Ordering box).


This is an initial Signed and Numbered Limited Release of 25 harps. They are being released to gauge interest in the Overblow-Booster Mk2. If the demand is there I'll explore a way to make it available in the future – but that could take a while! So, if you are interested now, this is your chance to own one of these unique revolutionary diatonic harps: handmade, numbered and signed. When they're gone, they're gone!


André Coelho

If you're skilled, you can customise your own Overblow-Booster. However, I suggest you get it done by a professional. The Overblow-Booster Mk2 is a sophisticated harp, with several carefully fitted components. If you want customising done, I recommend my friend André Coelho. André helped me assemble the initial batch of 25, so he has an intimate knowledge of the harp already. He's already customised several of them for top players, and he can take your Overblow-Booster Mk2 to the highest level of performance.

If you decide to choose André to customise your Overblow-Booster, please email him first to discuss what you're after. Once you have agreed, choose the Andre Coelho custom option in the Drop-Down list. After you purchase we will post your Overblow-Booster Mk2 directly to him.


Overblowing is the common term for an increasingly popular technique used by players of the 10-hole Richter diatonic harmonica to obtain missing chromatic notes on the instrument. A more accurate term is "overbending", because it can be done on both breath directions: blow notes are raised with overblows, and draw notes with overdraws. Even though they are different, the widely-used term that applies to both is Overblowing. Combined with traditional interactive-reed bending (which lowers reed pitch), overblowing raises the pitch; using both techniques players can achieve a full chromatic scale on an ostensibly diatonic instrument.

But it's not quite that simple. For overblowing to work well, the harmonica needs to be finely adjusted, with close reed gaps and slot-embossing. Out-of-the-box harps will overblow, but any serious player who uses the technique will either buy expensive hand-customised harps, or spend considerable time working on their own harps to optimise them for overblows and overdraws. Even with such customisation, overbending is a high-level playing technique that takes years to master throughout the whole range of the harp. As a result, the number of really good overblow players in the world is still small, even 40 years since the technique became widely known. Harmonica chat groups are littered with posts describing the struggles of beginners trying to incorporate overblows and overdraws in their playing.

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My Overblow Booster makes overbends much more user-friendly, enabling total beginners to overbend with ease straight away - all the way from hole 1 to hole 10! For advanced players, it enhances their sound, volume and expressiveness. It gives greater control of both overblows and overdraws, allowing easier bending of them, adding soulful expression such as vibrato on overbends, plus new effects never before possible. The Overblow Booster works great on standard harps without any special gapping or embossing. Even the difficult-to-get overblow in hole 1 is now a breeze to get on a stock harp out-of-the-box! On a fully customised harp the overblows will sound and play like butter, sounding as strong and expressive as standard bends, and give expert overbend players a whole heap of extra fun. Watch the video to see/hear for yourself.

For a long time it's been known that if you stop the lower-pitched note in a chamber from sounding, the overblow/overdraw plays much more strongly. Various harps have been created in the past to make this happen, but none succeeded - because they were either too complicated, too expensive (often both), and forced players to buy new harmonicas. My Overblow Booster is far simpler, cheaper, and doesn't require you to buy a new harmonica: it can be added to your favourite harps in under a minute, and removed just as quickly!

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The Overblow Booster only works with harps that have open-back covers. These include the Hohner Crossover & Marine Band Deluxe, Seydel 1847, Suzuki Manji, and some of the models from the excellent new Chinese brands Easttop and Kongsheng. Make sure the harp you are ordering for has open-back covers; select the brand and model in the drop-down list. It comes in two versions: Basic and "Full Monty". The Basic version comprises two light ABS plastic parts that sit almost invisibly beneath the coverplates, fitting snugly to the harp with small tabs that correspond to the reedplate screw positions for each model. The open outer ends of the individual reed channels can be closed with your fingers as you play, thus stopping the inactive reed and making the overblow/overdraw much stronger, and play with greater control.

The Full Monty version adds the Booster Bar: a rear hinged lever attached at the bass end of the harp that closes all the coverplate channels with one quick movement - thus avoiding the need to select the individual channels with your fingers. The Booster Bar's neoprene pad seals to the channel openings when closed, but the harp plays normally when it's held away from the back. It doesn't affect the tone of the harp, hand wah-wah effects can be used on all notes (including overblows/overdraws), and it works well with a handheld microphone too. Watch the first video from 9:15 to see the Booster Bar in action!


The Overblow Booster requires harps with open-back coverplates, such as the ones listed below. However it can be added to other harps (eg. Hohner Marine Band 1896) if the rears of the covers are opened up. Here are the prices for the Basic and Full Monty options; choose the harp model that you want to fit your OBB to.

Overblow Booster


The OverBlow booster products are currently unavailable while we work on a new and improved design

All prices include international shipping. Orders over £60 will add Tracking
Update 14 July
I've now updated the Hohner version of the Booster Bar to a quick-release attachment system: it can be snapped on and off in seconds, and you can switch it over to another harp. This means for Hohner harps, if you wish, you only need one Booster Bar for multiple harps. This saves you money! Check out the Quick-release Booster Bar in this video 0:10-1:45 I'm developing the quick-release system for the other brands/models - but for now, they all have the screw-fit Booster Bar.

FITTING - it's a Breeze!

If you want to get playing straight away, simply remove your coverplates, position the two parts of the Overblow Booster in place, replace the covers and start overblowing! The longer part goes on the blow reedplate, the smaller one on the draw reedplate. It’s pretty obvious how they fit around the reedplate screws; watch the video on the main page from 7:20. However, I recommend you take a bit more time to get the seal on the lower surface of the Overblow Boosters really airtight. For a demonstration of some simple steps you can take to that end, as well as advice on fitting the Booster Bar, please watch the video below.


Listen to the multi-talented Ross Garren in this video of his impressions.

Also check out Ross's website.

" I heard about the Overblow Booster from my teacher, Clint Hoover, and having 'hit a wall' in developing overblows, we thought it could be a good way for me to experience the proper embouchure to get them going across my diatonic harmonicas. After mounting mine on a C Crossover, both Clint and I were startled by the strong, clear and expressive overblows I immediately got. You should hear what Clint did with it! It's designed and constructed very well and durably - I understand you have used 3D printing to develop the prototypes, and the lever basically gives me a chromatic harmonica. I only have one problem with it - it's too easy! We are trying to use it as if it was a set of training wheels on a bicycle, getting an overblow and then carefully opening the lever, but obviously I'm still relying too much on pressure and the overblow disappears when the lever opens. Working with it is improving my overall tone, anyway, and even if I never learn to overblow without it I'm happy to have an Overblow Booster. If you have any suggestions for Clint and me about generalizing overblow skill to unequipped harmonicas, we'd love to hear them. Thank you for your musical genius! "

Ralph F Wilps Jr, Ph.D. , USA (Sep 2018)
An impromptu late-night SPAH clip from Swedish harmonica maestro Filip Jers. Filip finds the Overblow Booster very useful for getting overbends on low-key harps (like this Low Eb Manji), which is normally very difficult. Apologies for the poor sound from my phone! Check out Filip's website for more of his music.
Listen to the super-talented Chinese player Long Deng Jie trying out the Overblow Booster at the Asia Pacific Harmonica Festival in Beijing 2018. The harp is a standard Easttop 10 hole, with no reed gapping or embossing:
Check out the in-depth review and demo of the Overblow Booster by Christelle Berthon in this video.

Subscribe to Christelle's popular YouTube channel .

" I recommend you try these Overblow Boosters Brendan's come up with.

I tried them out on a standard out of the box Marine Band Crossover - I wonder how they would work on a custom harp?

Once fitted they are invisible and make it easy to get overblows on holes 1, 4, 5, 6, and overdraws on holes 7, 8, 9, 10.

Not only will you get the 'overbends', you will also get further bends on each one - the pitch shift on my A harp was a major 5th pitch raise on the overblows and a little less on the overdraws.

Now you are pitch bending the overbends - who knew that was possible?

You will also notice drawbends are now possible on hole 5, blowbends on hole 7.

All this enables you play a blues scale in 2nd position from hole 6 going upwards and in 1st position from hole 4-7. New territory for expression for most of us.

This is a similar effect that you can get with the expensive and now ex-production Suzuki Overdrive (with 20 cover plate holes) and the Bahnson Overblow Golden Melody with a button.

The optional extra 'Booster Bar' - which now has a quick release cullet attachment so so would only need one bar for all your boostered harps - serves to close all the holes at the same time in a simple hand movement.

One of my friends - let's call him Pete - had never achieved an overblow until I forced him to try the overblow booster. It taught him a lot about the technique, so I guess it also has merit as a learning tool - like stabilisers on a bicycle.

So with the increased range of notes available, your capacity for playing different tunes, scales, and keys, your improvising takes a sudden leap forward.

With the boosters in you can choose to ignore them completely and the harp is as 'normal'. You can use hand vibrato, microphones - all as usual.

With a custom harp many of these things are also possible so compare the cost of a good custom job with the overblow boosters.

Must be worth a try for everyone I think - and I believe they are cheaper if you buy a set of 12 or so. You probably need to ask Brendan that question unless he puts that as an option in the cart which I would encourage him to do. "

Ben Hewlett (July 2018) - Online harmonica courses - one new course made every month.
Gold Level Membership one month free trial.

" Finding that the one and four overblow adds many new options to first position blues !! Having fun with that. Still tweaking the harps but the overblows and overdraws are coming easier now. Thanks again for your innovation. "

Joe Galicic (July 2018)

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