Join the JK 4C Exclusive Mouthp. Trumpet Fans Community
Use the tabs below to see what music people who love this gear like, explore its tech specs and read reviews by other members. Stay tuned, more community features are coming up!
2 reviews from our community
Please note that the following reviews have not yet been verified for authenticity

"The enjoyment I received deserves 10..."
The enjoyment I received deserves 10 stars!

"Shipping was fast and has lead to much..."
Shipping was fast and has lead to much more festive evenings at home.
3 reasons why people want to buy it
Actual feedback of people who want to buy JK 4C Exclusive Mouthp. Trumpet
- "It's very nice"A 17 y.o. or younger male fan of Gary Moore from Romania
- "I love it"A Musicngear user
- "It is realy good gear for music which i like"A 25-34 y.o. male fan of Def Leppard from Bosnia and Herzegovina
People that took the "IS IT GOOD FOR ME?" test said they wanted to buy JK 4C Exclusive Mouthp. Trumpet for the above 3 reasons. Their opinion is based on their own independent research and should help in your own purchase decision.
Still undecided? Take the "IS IT GOOD FOR ME?" test
Related reviews
We recommend the following related gear as JK 4C Exclusive Mouthp. Trumpet is not so popular with our community

"Compact, hard-driving lead mouthpiece that trades low-end fullness for razor projection and endurance."
Review of Bach L551 10.5MV trumpet mouthpiece
I spent a couple of weeks taking the Bach L551 10.5MV through rehearsals, sectionals and a few loud chart gigs to see how it behaved as a lead mouthpiece. I came in looking for projection, center and stamina at loud volumes - and that is exactly the territory this piece lives in, with a noticeably small cup diameter, a shallow modified V cup and a narrow backbore.
First Impressions
My first moments on the L551 10.5MV were a mix of surprise and immediate understanding - surprise at how compact it feels against the face and understanding that the design is laser-focused on lead playing. The rim is medium-wide and comfortable, but the cup is definitely on the shallow-V side, so my initial expectation was that I would have to adapt my embouchure and air approach. Sonically it jumped forward right away - a bright, focused top end and a penetrating center that cuts through a loud band in a way most general-purpose mouthpieces do not.
Design & Features
The L551 10.5MV is part of Bach's Commercial series and blends outer shape cues from the long-standing 351 profile and the MegaTone K351, giving it a feel that sits familiar but distinct. The specs are consistent - a modified V cup, roughly 15.34 mm cup diameter and a #27 backbore around 3.66 mm, delivered in a silver-plated finish. Physically it feels solid and well-finished - the plating and machining are what you expect from Bach, and the throat/backbore sizing emphasize a smaller, more focused airstream rather than openness.
Playability & Usability
Once I settled into the rim and adapted my support, the mouthpiece became easy to navigate in the upper register - I could get a commanding high range with less fatigue than I'd expected for such a shallow cup. The flip-side is that the smallish cup diameter and modified V shape require tighter lips and more precise aperture control, so players coming from a medium or deep cup will need time to adjust. For lead lines, pit work and charts that need projection and cut it does exactly what it promises - comfortable rim, razor focus and efficient high-range response.
Sound & Tone
In a big-band or loud charts context the L551 10.5MV produces an immediate, forward sound with a bright edge and narrow beam - it projects in a way that makes lines pop and sit on top of the section. I noticed less warmth and fundamental presence in the low register compared to a medium/deeper cup, which is expected given the very shallow-V profile; the tone is more brilliant than round. Backing off the volume softens the top-end edge and you can coax a less aggressive timbre, but it never becomes a lush, orchestral cup - this is a lead tool first and foremost.
Real-World Experience
I played charts that demanded long lead lines and also used the piece during section rehearsals where I needed to peek over a loud rhythm section - the L551 delivered every time without sounding thin in a mix. Endurance-wise I found it efficient for extended high passages; my chops were more fatigued in the low tessitura than with my usual cup, but the stamina for repeated high-projective playing was noticeably better. In studio checks and mic’d runs it cut through without having to strain or over-blow, which is exactly what I want from a lead mouthpiece.
The Trade-Offs
The biggest compromises here are the reduced low-register warmth and the steep learning curve for players used to deeper cups - the 10.5MV is not a one-size-fits-all swap. It also sits at a price point higher than entry-level replacement mouthpieces, which makes it an investment primarily for players who really need projection and lead capabilities. Finally, if you play mostly orchestral or solo repertoire that relies on a broad, warm middle, this isn't the ideal everyday piece unless you're prepared to change your approach.
Final Verdict
Overall I came away impressed - the Bach L551 10.5MV is a specialist's mouthpiece that shines for lead, commercial and loud ensemble work. I recommend it to experienced players who need uncompromising projection and top-end response and who are willing to accept a trade-off in low-register fullness and a short break-in period to adapt. For generalists or orchestral players who prize a broad, warm middle the compromises may be too great, but for a dedicated lead role it is one of the stronger options I've used in this size class.
by Musicngear Verified Community ReviewsHelpful Tips & Answers
- Will this mouthpiece fit my standard Bach trumpet?
- Yes - the L551 10.5MV uses a standard Bach-sized shank so it fit my Bach trumpet with no adapters and performed as expected.
- Is it a good switch for a player coming from a 1C or 3C?
- It will feel noticeably shallower and smaller than 1C/3C; I would recommend trying it first because it demands a tighter, more focused embouchure and different air approach.
- Does it help with high-note endurance?
- Yes - in my experience the design improves endurance for high, loud playing compared with deeper cups, provided you adapt your support and aperture.
- How does it sound in quieter, small-ensemble settings?
- It sounds bright and focused even when played quietly, but it won't deliver a warm, rounded low-middle the way a deeper cup would.
- Will beginners be comfortable on this piece?
- I wouldn't recommend it as a first mouthpiece - the small diameter and shallow V cup require experience and control to avoid strain and to access a full range.
- Is silver plating durable and does it affect tone?
- Yes, the silver plating is durable and gives a familiar bright response; I didn't notice any negatives in feel or finish during my time with it.

"It's awesome !!!!!"
Review of Marcinkiewicz E5 Bobby Shew 2 Mouthpiece It's awesome !!!!!

"Slotting is better. Range is better...."
Review of Warburton Backbore Qm for Trumpet Slotting is better. Range is better. Core is better.

"Bright, focused projection with a compact feel - a go-to shallow JK for lead and jazz players who need edge and clarity."
Review of JK 1-1/2E Mouthpie. Trumpet USA
I came to the JK 1-1/2E expecting a thin, edgy lead mouthpiece and that is exactly what it delivers - a very shallow USA-line cup that biases the sound toward brightness and forward projection. My testing was across short classical excerpts, some big-band charts and a few jazz sessions, so I could hear how its shallow E-cup shapes upper-register ease, attack and tonal color compared with the medium cups I usually play.
First Impressions
The first time I put this mouthpiece to my trumpet I noticed how the rim and throat feel familiar in size yet the cup is unmistakably shallow - it invites a bright, immediate tone and an aggressive attack that sits well on top of a horn section. It felt light in my hand, nicely finished in silver plating, and the rim felt firm without being sharp, which helped with endurance during longer takes when I pushed the upper register.
Design & Features
The JK USA-line design philosophy is clear in this 1-1/2E - the dimensions are aimed at players who want a narrow, projecting sound with a 27.3 mm rim and about a 16.8 mm cup diameter riding over a 3.6 mm bore. The throat and backbore choice (the USA-line often ships with a more conservative A2-style backbore) gives the piece a focused core while still allowing enough airflow for ear-catching projection. The silver plating is even and polished, and the machining tolerances feel tight - there are no rough edges or imbalance in weight that would affect feel.
Playability & Usability
Playability is where the 1-1/2E really defines itself - it is fast to articulate and responds instantly on attacks, which I liked for lead lines and for cutting through loud ensembles. The trade-off is a smaller, more concentrated core and a thinner lower register compared with deeper cups; I found I needed to moderate my air and support to coax a rounded low C and to avoid sounding pinched. Intonation in the upper register is stable once you learn the piece's tendencies, and flexibility across small intervals stays surprisingly good for such a shallow cup.
Sound Quality & Tone
Tonally this mouthpiece emphasizes brilliance and edge - it gives a crisp, forward sound that makes lead lines and cuts sit in a mix very well. On mellow jazz ballads it can sound thin if you try to force warm, rounded low register tone, but when I matched my embouchure and air to the piece it produced a singing, brassy top with excellent projection. Harmonic content is strong in the high partials, which helps with projection and clarity in ensemble situations.
Real-World Experience
I used the 1-1/2E in a rehearsal, a small club gig and a section rehearsal to see how it behaves in different contexts. In the club I appreciated how easily my high Gs and A flats spoke, and in the rehearsal it helped me lock in a clearer lead line without having to force extra volume. On the flip side, during a short classical excerpt that required a broad, rounded low-middle range I missed the depth and warmth of my usual medium cup - it wasn't the best choice for orchestral or purely lyrical repertoire in that context.
The Trade-Offs
This mouthpiece is an example of the usual shallow-cup compromise - you gain speed, edge and projection but sacrifice some core thickness and low-register robustness. It demands attention to support and embouchure to get a musical low range, and players who rely heavily on warmth and roundness in the middle will likely find it limiting. That said, for lead, high-register work and certain jazz styles the trade-offs are exactly what you want.
Final Verdict
Overall, the JK 1-1/2E is a very capable, well-made shallow mouthpiece that excels at projection, clarity and upper-register play - ideal for lead trumpet, jazz solos and situations where presence matters more than a broad, dark core. I recommend it for players who already have a reliable medium or deeper cup in their rotation and are looking for a sharper, more projecting option for lead work; players seeking a universally warm, orchestral tonal palette should be cautious.
by Musicngear Verified Community ReviewsHelpful Tips & Answers
- Will this mouthpiece help me play higher notes more easily?
- Yes - I found the very shallow cup makes upper-register notes speak faster and with less physical strain, though you still need clean support to keep the tone musical.
- Is the rim comfortable for long practice sessions?
- The rim is firm but not harsh; after long sessions I noticed less numbness than on some sharper rims, though it does require consistent technique to avoid fatigue.
- Does it fit all trumpets or do I need a special shank size?
- It uses the standard USA-Line sizing I tested and sat solid in my horn, but if you have an unusual receiver you should check shank compatibility before buying.
- Is this a good mouthpiece for jazz and big-band work?
- Absolutely - I preferred it in big-band and small jazz ensemble settings for its projection and cutting presence.
- How does the low register respond compared with a 3C or deeper cup?
- The low register is leaner and requires more air and careful embouchure adjustments to keep it full, so it won't replace a deeper cup for low-end warmth.

"A compact, sharply focused lead mouthpiece with clear projection and quick response."
Review of Marcinkiewicz E13.8 Mike Vax for Trumpet
I approached the Marcinkiewicz E13.8 Mike Vax expecting a small, signature-style cup aimed at lead playing, and that is exactly what I found - a tight, responsive mouthpiece that favors edge and projection over breadth and warmth. I tested it across rehearsal, sectionals, and a handful of shorter gigs to judge endurance, centering, and how it sits in my chops compared to my usual mouthpieces.
First Impressions
The first time I put the E13.8 to my lips I noticed how compact it felt - smaller rim diameter and a perceptibly shallow cup make it feel like a precision tool rather than a general-purpose mouthpiece. The silver plating is smooth and the rim reads fairly flat to my embouchure, which helped me find a consistent placement quickly; immediately the cup gave me a focused core and fast articulation but required more concentrated air than I normally use.
Design & Features
The E13.8 is a Mike Vax signature Endorsee model built by Marcinkiewicz with exacting, small-ish dimensions - outer diameter around 27.10 mm, inner cup diameter about 16.36 mm, cup depth roughly 9.40 mm, a bore near 3.56 mm and a total length around 87.63 mm. It ships silver-plated and uses a flat rim contour, which contributes to the tactile feel and the direct sound projection I experienced. In short, the piece is engineered for a bright, focused center and quick response rather than a dark, roomy sound.
Build Quality & Protection
Physically the mouthpiece is well made - the plating is even with no obvious seams or machining burrs, and the shank finish mates cleanly with my trumpets. I felt comfortable using it without worrying about rough edges; the silver finish polished up well after a quick wipe and the rim ergonomics felt stable even during louder passages. As with most silver-plated mouthpieces, I still wipe it between sets to keep the plating looking and feeling its best.
Playability & Usability
Playability for me meant quick articulation and a direct sound - the E13.8 delivered both, particularly in the staff and just above it where I do most lead work. The small cup and relatively narrow throat give you immediate response and a sharp attack, which I loved for cut-through section work and piccolo-register lines, but it also demands very precise support and embouchure control to keep pitch and tone centered over long runs. I found short to medium playing sessions comfortable, but extended marathon rehearsals required deliberate rotation back to a slightly deeper mouthpiece to avoid lip fatigue.
Real-World Experience
I used the E13.8 in a big band rehearsal and a couple of studio-style run-throughs. In the big band setting it cut cleanly through horns and drums, giving me the kind of focused projection I want on lead lines; in the studio it translated to a tight, present recorded sound with minimal extra processing needed. Where it really shone was in classical/concerto-style high passages and lead jazz trumpet spots - the fast response and bright edge made accents and dynamic jumps very reliable when my air and embouchure were locked in.
The Trade-Offs
The trade-offs are straightforward - you get projection and immediacy at the expense of breadth and creamy midrange, and you trade some endurance for precision. If you need a warm, round orchestral lead or long endurance for continuous marching-band style sets, this mouthpiece will feel thin and demanding after a while. Intonation in the extreme low register sits a bit behind the sound unless you compensate with more oral cavity and support, so it’s a mouthpiece that rewards players who already have solid control and are looking to sharpen their upper-register command.
Final Verdict
Overall, the Marcinkiewicz E13.8 Mike Vax is a specialist’s tool - it excels for lead trumpet work where focus, articulation, and projection are the priorities, and I would recommend it to experienced players who need a compact, responsive cup for cut-through playing. It is not a one-size-fits-all choice, but for the right player it’s a very effective mouthpiece that offers a bright, immediate voice and reliable high-register performance.
by Musicngear Verified Community ReviewsHelpful Tips & Answers
- Is this mouthpiece good for high-register lead work?
- Yes - I found its small cup and narrow throat ideal for focused, confident high-register playing when my airflow and embouchure were steady.
- Will it work for orchestral repertoire?
- Not my first choice for orchestral work - it’s brighter and thinner than most orchestral lead needs, so I wouldn’t use it for long symphonic passages without swapping to a fuller cup.
- How comfortable is the rim for long rehearsals?
- Comfortable for short to medium sessions, but it fatigued my chops more quickly than a deeper, wider-rim piece during marathon rehearsals.
- Does it play well on different trumpets?
- I used it on a standard Bb lead horn and a piccolo trumpet and it responded consistently - the character stayed focused across instruments, though tonal color varied with the horn.
- How does articulation feel with this mouthpiece?
- Articulation is very immediate and clean; single-note attacks snap nicely when I used concise tongue placement and focused airflow.
- Is the finish durable?
- The silver plating held up well during my sessions and cleaned up easily after use.
- Who should consider buying this?
- Experienced lead and commercial players after projection and agility should try it, especially those who play a lot of big-band, studio or lead jazz parts.


