BOSE® QC-25 Head-Set
Why Bose® QC25?
Essential, Functional, and Comfortable! The only things that matter when it comes to Ham Radio Accessories.
The Bose® QC-25 Ham-Set is essential because, in addition to the Noise Cancelling System, it does not have circuits that could cause annoying audio feedback, such as Bluetooth. Moreover, the Bose® brand guarantees unparalleled clarity and precision of sound, especially in CW mode.
The Bose® QC-25 Ham-Set is functional thanks to its lightweight boom microphone, which is high-quality and highly compatible with our radio models, enabling operations in all bands and modes. Additionally, it comes with a new RF-proof connection cable that prevents interference even at higher transmission powers.
The Bose® QC-25 Ham-Set is comfortable because you can wear them for the entire 48 hours of a contest without experiencing the slightest ear discomfort!
Make Your Choice!
Our headsets can be customized to suit your specific needs. You can choose the type of microphone and cable you prefer, as well as the level of refurbishment, color, and the option to add your own callsign.
Your Perfect Match: Grade A, B, or C!
After Bose discontinued the QC 25 in 2020, these headphones are now available only second-hand, and we offer them refurbished in three grades and two color options (black/gray and white/beige)
Grade A: As good as new, with the best quality you can expect from a refurbished product. These headphones have passed all functional tests and are in excellent aesthetic condition with almost no signs of prior use. They come complete with the original box, carrying case, all accessories, and new ear pads.
Grade B: Also in excellent cosmetic condition, these headphones have passed all functional tests and are “like new,” with only slight signs of prior use. They include a carrying case and new ear pads, but do not come with the original cardboard box.
Grade C: In good cosmetic condition, these headphones have passed all functional tests but may show some signs of prior use. They are complete with a carrying case and new ear pads but lack the two rubber blue/gray bands on the speakers.
All headphones, regardless of grade, have been thoroughly tested, cleaned, and disinfected. Any worn or broken parts have been replaced or properly repaired before installing a new boom microphone and a 5-meter coiled RF-proof connection cable.
A true commitment to Refurbishing
We use only the highest-quality spare parts, ensuring that they look great and last for years to come. We avoid non-original and low-quality components, as they compromise the integrity and durability of the headset. Our commitment ensures that every headset maintains the quality and reliability of the original Bose® design.
We want only original parts!
At Ham-Set, we source genuine parts exclusively from other headsets, carefully selecting them for refurbishment. Damaged aluminum components are re-anodized and recolored to restore their original appearance. Ear pads are always replaced with a new pair, and both the cable and microphone are brand new. This rigorous process guarantees a product that feels and performs just like new.
The Microphone That’s Right For You
Dynamic Capsule 600 Ohm
The Professional DYNAMIC MICROPHONE CAPSULE (not electret) does not need power to work and is the most compatible solution for any radio or accessory on the market today, including brand like Yaesu, Icom, Kenwood, Elecraft, Flexradio, Micro Keyer, etc. It’s the best solution for Multi Op contest Stations where many operators need to be plugged in a few seconds without changing any radio set up.
Just like the famous headphones with HC 4 – 5 – 6 capsules, they can be connected using only a simple adapter to the microphone plug without needing connection to the +5V.
Each dynamic microphone headset includes a small decoupling capacitor for safe connection to Icom radios or Microkeyer with voltage on the positive pin. Therefore, you will not need the connection cable with the capacitor inside, but just a simple adapter between radio’s microphone plug and 3.5mm jack.
Just like the famous headphones with HC 4 – 5 – 6 capsules, they can be connected using only a simple adapter to the microphone plug without needing connection to the +5V.
Each dynamic microphone headset includes a small decoupling capacitor for safe connection to Icom radios or Microkeyer with voltage on the positive pin. Therefore, you will not need the connection cable with the capacitor inside, but just a simple adapter between radio’s microphone plug and 3.5mm jack.
Electret Capsule 600 Ohm
The Professional ELECTRET MICROPHONE needs to be powered.
It is professional capsule ensures excellent vocal amplification, is noise-canceling and omnidirectional. The quality is undoubtedly better than the dynamic capsule, the voice is much richer in bass, the dynamic range is wider and the power greater, but compatibility is certainly reduced.
It’s ideal for direct connection is with ICOM radios or to Micro Keyers that have power on pin 1.
For all other brands, a special connection cable that ensures correct power to the capsule is necessary, which we can provide upon request
It is professional capsule ensures excellent vocal amplification, is noise-canceling and omnidirectional. The quality is undoubtedly better than the dynamic capsule, the voice is much richer in bass, the dynamic range is wider and the power greater, but compatibility is certainly reduced.
It’s ideal for direct connection is with ICOM radios or to Micro Keyers that have power on pin 1.
For all other brands, a special connection cable that ensures correct power to the capsule is necessary, which we can provide upon request
True Condenser Capsule 300 Ohm
The microphone with the classic CONDENSER CAPSULE must be powered with +5/8V, but unlike the electret, the capsule’s power supply is separate from the signal. The audio quality is high and the amplification is excellent. For connection to amateur radios, an adapter that correctly connects its three poles is necessary: power supply, signal, and ground. For connection to Icom, it will be necessary to install a decoupling capacitor in the adapter cable to prevent a second power supply from reaching the capsule through the signal cable.
Dynamic vs. Dynamic:
Ham-Set vs. Heil Sound®
Magic Capsules Do Not Exist
In the world of amateur radio, there is often talk of “legendary” microphone capsules that seem to magically transform our transmissions and facilitate DXing. However, with all the modern technologies available—compression, DSP, equalizers—it is clear that the quality of transmission does not depend solely on the microphone.
In the past, when radios did not have compressors, processors, or equalizers, the microphone capsule was the only tool available to characterize modulation. Fortunately, modern microphones no longer have exaggerated curves like the +10 dB at 2 kHz of the Heil HC-4 or the +12 dB at 2.9 kHz of the Shure 444. They have flatter frequency responses, although each still retains its own characteristic curve, which we can adapt with proper equalization.
In the past, when radios did not have compressors, processors, or equalizers, the microphone capsule was the only tool available to characterize modulation. Fortunately, modern microphones no longer have exaggerated curves like the +10 dB at 2 kHz of the Heil HC-4 or the +12 dB at 2.9 kHz of the Shure 444. They have flatter frequency responses, although each still retains its own characteristic curve, which we can adapt with proper equalization.
Be Careful of the Differences: Ceramic or Dynamic Capsule?
The HC4 and HC5 capsules have become famous for their distinctive modulation. The HC4, known for its strongly accentuated response curve around 2100 Hz, was particularly appreciated by amateur radio operators for its ability to penetrate noise well, providing clear and incisive communication. Later, the HC5 replaced the HC4, offering slightly softer and less aggressive modulation but still effective for amateur radio use. Despite these capsules being considered “dynamic” by most of us radio operators, the truth is quite different. Just like the previous HC3, which Heil Sound itself had declared to be a ceramic capsule, the HC4 and HC5 are actually piezoelectric ceramic microphones. It has never been correct to compare them to real dynamic capsules, such as the HC6, which is indeed a dynamic capsule.
The Right Comparison
Unlike the HC4 and HC5, dynamic capsules like the HC6, HC7, and the Ham-set capsule have completely different construction and operation. While ceramic capsules are based on the piezoelectric principle, dynamic ones utilize a moving diaphragm associated with a coil immersed in a magnetic field. This generates a very different (generally lower) electrical signal with a wider and more natural frequency response compared to piezoelectric capsules.
The Ham-set capsule sounds very similar to the HC6 and should be evaluated in this light, rather than in relation to ceramic capsules. Achieving that type of sound curve, characteristic of ceramics and much loved by DXers for being very penetrating and low in bass, is absolutely possible with the correct bandwidth settings of the RTX, equalization, compression/processor, and mic gain.
The Ham-set capsule sounds very similar to the HC6 and should be evaluated in this light, rather than in relation to ceramic capsules. Achieving that type of sound curve, characteristic of ceramics and much loved by DXers for being very penetrating and low in bass, is absolutely possible with the correct bandwidth settings of the RTX, equalization, compression/processor, and mic gain.
SSB: Proper Equalization
The main goal of equalization is to maintain a constant output level during both vowels and consonants. The dynamics of the human voice change: vowels tend to be stronger and more consistent, while consonants, which occupy the sibilant part of the spectrum (frequencies between 2000 and 4000 Hz), can sound weaker. This is why we need to focus on the mid-high frequencies to emphasize the consonants and reduce low frequencies that do not contribute to intelligibility.
Equalization and microphone settings are not only about making us “sound louder” but also about making our voice clear, understandable, and pleasant to listen to. Broadcasting is a medium where intelligibility is crucial: having a powerful signal is of no use if you cannot be understood by the listener. This is why it is important to take the time to optimally configure our Ham-Set dynamic capsule without excessively pushing the Mic Gain or compression controls. With the right adjustments, you can ensure that your capsule delivers high-quality modulation, comparable to—or even superior to—that of the “legendary” capsules of the past.
Equalization and microphone settings are not only about making us “sound louder” but also about making our voice clear, understandable, and pleasant to listen to. Broadcasting is a medium where intelligibility is crucial: having a powerful signal is of no use if you cannot be understood by the listener. This is why it is important to take the time to optimally configure our Ham-Set dynamic capsule without excessively pushing the Mic Gain or compression controls. With the right adjustments, you can ensure that your capsule delivers high-quality modulation, comparable to—or even superior to—that of the “legendary” capsules of the past.
Reducing Low Frequencies (below 200 Hz):
Low frequencies can create a “boomy” or “muddy” sound that does not help voice clarity in SSB. Attenuating these frequencies improves overall definition.
Action: Cut frequencies below 200 Hz by about -6 dB or more, depending on your voice. This will help prevent low frequencies from overloading the modulation.
Action: Cut frequencies below 200 Hz by about -6 dB or more, depending on your voice. This will help prevent low frequencies from overloading the modulation.
Emphasizing Mid-High Frequencies (between 2000 and 3000 Hz):
These frequencies are crucial for improving consonant understanding, which would otherwise risk being less audible. Slightly boosting these frequencies enhances intelligibility without making the sound too sharp or metallic.
Action: Increase mid-high frequencies between 2000 and 3000 Hz by +3 dB or +5 dB, as needed. This will help make consonants clearer and more present.
Action: Increase mid-high frequencies between 2000 and 3000 Hz by +3 dB or +5 dB, as needed. This will help make consonants clearer and more present.
Maintaining Balance in Mid Frequencies (500-1500 Hz):
Mid frequencies give body to the voice and are essential for keeping it natural and balanced. If we attenuate them too much, we risk having a modulation that sounds empty or too flat.
Action: Try to keep the mid frequencies balanced, making only slight adjustments to avoid a “nasal” effect.
Action: Try to keep the mid frequencies balanced, making only slight adjustments to avoid a “nasal” effect.
Limiting High Frequencies (above 3000 Hz):
Frequencies that are too high can create annoying sibilance and reduce listening comfort. A slight cut in this area can help make the sound softer.
Action: If you notice your voice is too shrill, slightly reduce frequencies above 3000 Hz.
Action: If you notice your voice is too shrill, slightly reduce frequencies above 3000 Hz.
Compressor and Mic Gain: Crucial Settings:
Once the microphone is equalized, it’s time to adjust Mic Gain and compression. The Mic Gain should be set so that the signal level is optimal without causing distortion. Start with a moderate value and gradually increase it until you reach a good modulation level. Do not overdo it with the Mic Gain: too high values can lead to a distorted or excessive signal.
Compression is equally important: it helps make the level of your modulation more consistent, limiting volume variations between the louder and softer parts of your speech. Start with light compression and increase it until you reach the desired ALC level, avoiding constant flickering of the ALC indicator.
Compression is equally important: it helps make the level of your modulation more consistent, limiting volume variations between the louder and softer parts of your speech. Start with light compression and increase it until you reach the desired ALC level, avoiding constant flickering of the ALC indicator.
Connect it to your Radio
Adapter cables are available for connection to your radios: Yaesu, Icom, Kenwood, Elecraft, FlexRadio, SunSDR… and more.
The Contest Station Choice
The Bose QC25 Hamset is becoming a must-have for major global contest stations. Their reliability and durability ensure intensive use, such as in a high-traffic contest station, without any issues.
The quality of Bose’s noise-cancelling system ensures perfect listening even in noisy and crowded environments, such as a room full of radio amateurs in the midst of a pile-up.
About the mic choice, contest stations prefer the use of the dynamic capsule just because it can be connected directly to all radios (including Icom) without the need for specific cables. It is preferred for its plug-and-play speed.
The tests for functionality, RF returns, and ergonomics were conducted at CN3A and II2S radio stations. Their teams use these headphones with the dynamic microphone capsule in all their contests.
The quality of Bose’s noise-cancelling system ensures perfect listening even in noisy and crowded environments, such as a room full of radio amateurs in the midst of a pile-up.
About the mic choice, contest stations prefer the use of the dynamic capsule just because it can be connected directly to all radios (including Icom) without the need for specific cables. It is preferred for its plug-and-play speed.
The tests for functionality, RF returns, and ergonomics were conducted at CN3A and II2S radio stations. Their teams use these headphones with the dynamic microphone capsule in all their contests.
Specifications:
Headphones
Speaker: 40mm
Impedance: 32 Ohm
Frequency response: 20 – 20,000 Hz
Battery life with Noise canceller on: 35 hours
The headphone also works without battery with Noise canceller turned off.
Dynamic range: -54dBFS
Connection: 3.5mm stereo male jack+ 6.3mm adapter
Microphone
Capsule: Dynamic
Impedance: 250 Ohm
Polar Pattern: Cardioid
Sensitivity: -60 dBV/Pa (1mW)
Frequency Response: 150 – 10,000Hz
Max SPL: 136dB SPL
Connection: 3.5mm male jack
Frequently asked question
Why should I choose the Bose QC25 over the QC35 or QC45, which are also Bluetooth?
The QC25 does not have any Bluetooth system, only a wired connection and good noise cancelling, which is very useful in cases of noisy multi-op SSB contests.Simplicity is all that’s needed to avoid battery drain during a run or annoying feedback that interferes with listening. The QC35, 45, and SE models have very limited space inside, making it impossible or at least too complicated to install a durable boom microphone. The only professional solution if you want to use these latest models is to buy the Ham-set kit for QC35-45-SE, available soon.
I found a cheap boom microphone online that can be attached to the QC35/45/SE and seems compatible. Will it work?
Yes, it is possible to use the new QC35/45/SE with the accessory available for sale (including on Amazon) similar to our proposed solution, but be aware:
1. The microphone included in that kit is a very poor-quality electret and it’s not of the right impedance for ham’s radios. So, you will have to replace it.
2. The connection cable is not shielded at all and uses a common negative pole for both mic and speakers. This leads to inevitable re-entry of your own voice into the headphones.
3. You will need to buy another cable to adapt the 3.5 mm 4-pin jack to the 2 jack 3.5 mm 3-pin required for the correct connection to our equipment and radios.
By replacing the electret capsule with a good quality one, you can yield decent results, but the connection cable remains a big problem. Moreover, with the electret microphone, you lose the great compatibility and versatility of the dynamic capsule. In contest stations, the immediacy of unplugging and re-plugging the next operator’s headset without touching any mic gain or processor settings on the radio is critical.
1. The microphone included in that kit is a very poor-quality electret and it’s not of the right impedance for ham’s radios. So, you will have to replace it.
2. The connection cable is not shielded at all and uses a common negative pole for both mic and speakers. This leads to inevitable re-entry of your own voice into the headphones.
3. You will need to buy another cable to adapt the 3.5 mm 4-pin jack to the 2 jack 3.5 mm 3-pin required for the correct connection to our equipment and radios.
By replacing the electret capsule with a good quality one, you can yield decent results, but the connection cable remains a big problem. Moreover, with the electret microphone, you lose the great compatibility and versatility of the dynamic capsule. In contest stations, the immediacy of unplugging and re-plugging the next operator’s headset without touching any mic gain or processor settings on the radio is critical.
Dynamic or Electret Microphone? What’s the difference and which should you choose?
The main difference is that the dynamic microphone capsule does not need to be powered up, but is simply connected to the positive and negative poles of our radios’ microphones. The electret capsule, however, requires +5V directly on the positive pole, a specific feature on Icom radios and Micro Keyers.The choice between the two types should be based on two main factors:compatibility (dynamic capsule) and voice sound quality (electret capsule).The two modulations are quite different and certainly depend on the voice timbre as well. The dynamic capsule has a cardioid pickup pattern, performs very well when pointed towards the sound source and at a distance of a few centimeters, is extremely compatible, easy to connect, and offers good performance in terms of quality. It’s possible to adjust the rather flat frequency response with the radio’s EQ.The electret capsule is omnidirectional, can be used even 10 cm from the sound source, is noise-cancelling, and has the great advantage of excellent audio quality, great amplification, and color. On the other hand, it is not very compatible with various radio models. It can be connected to Yaesu, Kenwood, Elecraft, and others with a special cable upon request.
I own a pair of QC25, can I modify mine? What does the modification entail and how much does it cost?
Yes, it is possible! Just send an email with your request and send your headphones to Ham-Set. The modification includes complete cleaning and regeneration, changing the ear pads, and adding the microphone and new connection cable. The modification is irreversible. The cost is €120.00, excluding shipping costs.
I noticed that the Bose capsule seems not to perform like my old Heil HC dynamic, why?
The microphone capsule applied to the Bose Ham-Set headset is of the dynamic type with a cardioid pickup pattern. Optimal gain will therefore only be achieved if the capsule is kept close to and directly in front of the mouth, oriented in the correct direction.
Given the small size of the capsule, covered by a foam pop filter, it is possible that the microphone may not be pointed directly at you. Dynamic capsules lose a significant amount of gain if the sound source is at a relatively far distance. In our headsets, lightness and compactness were prioritized; the dynamic capsule sounds good and has a natural frequency response. The sound is very similar to that of the Heil HC-6 capsule, although due to its smaller size (the Ham-set capsule measures less than half the size of the Heil), it may seem to “push” less. The difference is truly minimal when comparing the graphs and can be compensated for with the help of equalization.
The comparison with the HC 4 and 5 is almost impossible and incorrect! These capsules are, in fact, NOT dynamic but CERAMIC; they are completely unbalanced towards the mid-high frequencies and completely lack low dynamic range. For fans of radio conversations, it will be possible to compensate for and emphasize the desired frequencies with the radio’s EQ. While you certainly won’t win the bass battle in 80-meter QSOs in the evening, you will still achieve surprising results.
For a more enveloping and rich sound, it is possible to switch to the condenser capsule, which is directly compatible with Icom and Micro Keyer or for all other brands with an adapter cable available upon request.
Given the small size of the capsule, covered by a foam pop filter, it is possible that the microphone may not be pointed directly at you. Dynamic capsules lose a significant amount of gain if the sound source is at a relatively far distance. In our headsets, lightness and compactness were prioritized; the dynamic capsule sounds good and has a natural frequency response. The sound is very similar to that of the Heil HC-6 capsule, although due to its smaller size (the Ham-set capsule measures less than half the size of the Heil), it may seem to “push” less. The difference is truly minimal when comparing the graphs and can be compensated for with the help of equalization.
The comparison with the HC 4 and 5 is almost impossible and incorrect! These capsules are, in fact, NOT dynamic but CERAMIC; they are completely unbalanced towards the mid-high frequencies and completely lack low dynamic range. For fans of radio conversations, it will be possible to compensate for and emphasize the desired frequencies with the radio’s EQ. While you certainly won’t win the bass battle in 80-meter QSOs in the evening, you will still achieve surprising results.
For a more enveloping and rich sound, it is possible to switch to the condenser capsule, which is directly compatible with Icom and Micro Keyer or for all other brands with an adapter cable available upon request.
I like the idea of having a headset with a professional microphone, but I would really like the condenser mic for a broader and more powerful dynamic range. Is that possible?
Sure, our BOSE QC25 are also available with the ICOM IC electret microphone capsule. Be careful about compatibility with various radios.
YOU OWN A PAIR OF BOSE QC-25?
Modify your
Bose QC-25
With Dynamic Microphone, REFURBISHED AND MODIFIED by HAM-SET ®
