The Cayin HA-6A Headphone Amplifier delivers the lush character of tubes with the power to handle any headphone in your collection.
Support for both EL34 and KT88 tubes allow you to shape your sound from smooth warmth to bold dynamics, while Triode and Ultra-Linear modes let you switch between romantic mids or a more energetic punch.
Add in transformer-coupled balanced outputs, selectable impedance for perfect matching, and hand-wired internals for optimal signal purity, and you get a one-of-a-kind tube amplifier that brings a unique blend of musicality and precision to your listening sessions.
The Cayin HA-6A features a transformer-coupled balanced circuit with vacuum tube amplification, giving you the flexibility to tailor your sound while enjoying the richness of a true tube amp.
EL34 tubes deliver lush, natural mids and a more musical presentation, perfect for vocals and acoustic instruments. KT88 tubes bring greater headroom, tighter bass, and more authoritative impact, ideal for complex or high-energy music.
Cayin gives you the freedom to roll tubes and fine-tune your listening experience to match your preferences or mood, so you can hear music exactly as you want.
With a simple switch, the HA-6A lets you choose between Triode mode and Ultra-Linear mode, so you can find the perfect sound every time.
Flick into Triode mode, you’ll get smoother mids, a more relaxed top-end, and an overall richer, warmer sound - great for intimate recordings and late-night listening.
Switch to Ultra-Linear mode and enjoy increased power output and extension at both ends of the frequency spectrum, producing greater bass slam, speed, and control for demanding tracks and headphones.
The HA-6A lets you enjoy the best of both worlds - all in a single device.
The HA-6A features Low, Mid, and High impedance settings so you can get the best sound from any headphone or IEM.
From ultra-sensitive IEMs in the 8–64Ω range to classic high-impedance dynamic headphones, or even 600Ω studio reference headphones, the Cayin HA-6A's variable impedance feature ensures every headphone in your collection sounds its best.
Experience cleaner, more precise sound with the Cayin HA-6A's true transformer-coupled balanced outputs.
At the heart of the HA-6A are custom in-house wound transformers - a hallmark of Cayin’s high-end designs. Unlike amps that rely on re-wired single-ended circuits, the HA-6A provides true transformer-coupled balanced outputs, resulting in superior channel separation, lower distortion, and a cleaner, more impactful signal - perfect for driving demanding planar headphones or other models with high current requirements.
The Cayin HA-6A boasts hand-wired internals for maximum purity, minimal signal interference, and enhanced long-term reliability.
Point-to-point hand wiring ensures shorter signal paths, reduced interference, and maximum clarity in the audio chain. Paired with Cayin's bespoke transformer and meticulous build standards, the HA-6A is built to deliver consistent performance for years to come.
Connect any headphone without the hassle of adapters with the Cayin HA-6A's multiple output options.
Whether you prefer balanced or single-ended connections, the HA-6A has you covered. With a 6.35mm single-ended output, a 4.4mm balanced output, and a 4-pin XLR balanced output built-in, the HA-6A lets you connect virtually any headphone or IEM seamlessly, so you can plug in and jump into your favorite tunes instantly.
The Cayin HA-6A has the finesse and power your need to drive everything from sensitive IEMs to demanding planar headphones in your collection.
With up to 4.5W of power per channel, the HA-6A has enough clean power to drive even notoriously difficult headphones like low-sensitivity planars or 600Ω studio dynamics, allowing you to enjoy studio-like clarity through your favorite headphones and IEMs.
The HA-6A is built around a premium chassis, for striking aesthetics and rock-solid durability.
Featuring multi-layer automotive-grade paint for enhanced scratch and fingerprint resistance, precision-machined and polished tube cage and top panels for a blend of durability and aesthetics, and a thoughtful layout that emphasizes user accessibility for tubes and connections, the HA-6A is made to last.
Every detail, from the premium ALPS volume knob to the stunning VU Meters, is designed to combine robustness, ergonomics, and visual presence, making the HA-6A both an exquisite listening device and a stunning centerpiece for your home listening setup.
The premium 24-step potentiometer features matched-pair resistors for low-noise performance and enhanced reliability. Adjust your listening level with tactile precision and virtually zero channel imbalance with the Cayin HA-6A.
The HA-6A’s chassis and tube cage are designed for optimal airflow, keeping tubes at stable operating temperatures for enhanced reliability and longevity. The user-friendly layout also allows easy access to all tubes, making maintenance and tube rolling a breeze for enthusiasts and professionals alike.
Single-Ended / Balanced Output (EL34)
TR: 750mW + 750mW (L); 1400mW + 1400mW (M); 2200mW + 2200mW (H)
UL: 1000mW + 1000mW (L); 2000mW + 2000mW (M); 3300mW + 3300mW (H)
TR: 1000mW + 1000mW (L); 1800mW + 1800mW (M); 2900mW + 2900mW (H)
UL: 1600mW + 1600mW (L); 2800mW + 2800mW (M); 4200mW + 4200mW (H)
Frequency Response
10Hz – 65kHz ±3dB
THD+N
≤1% (@1kHz)
Sensitivity
220mV ~ 450mV
Signal-to-Noise Ratio
98dB (A-Weighted)
Input Connectors
XLR x2,
RCA x2
Phone Output Connectors
6.35mm Standard
4.4mm Balanced
XLR4 Balanced
Phone Impedance Selection
L: 8~64Ω
M: 65~250Ω
H: 251~600Ω
Vacuum Tubes Supplied
Electro-Harmonix EL34 EH x2
Electro-Harmonix 12AU7EH x2
RCA ECA 22DE4 x2 (NOS)
Dimensions
360mm (L) x 322mm (D) x 197mm (H)
Net Weight
19.5kg
Overall Power Consumption
140W
Fuse
~220V~240V: T1AL250V
~100V~120V: T2AL250V
Working Condition
Temperature: 0°C~40°C
Humidity: 20%~80%
Storage Condition
Temperature: -20°C~70°C
Humidity: 20%~90%
Tubes Supported
Electro-Harmonix 12AU7EH: 12AU7, ECC82, ECC802S, CV4003, 5814A, 6189
Electro-Harmonix EL34 EH: EL34, EL37, 6CA7, 6L6GC, 5881, KT66, KT77
RCA 22DE4: 22DE4
When TUBE SEL. is switched to KT88: KT88, KT90, KT100, 6550, 6550A, 6550EH
Shipping is FREE on all orders to customers within the USA.
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We get it. Audio gear can be subjective. That's why we offer our industry-leading 365 day return policy. Here's a quick rundown;
We get it. You've got a lot of choice when it comes to online retailers. Here's why we think you should shop with us at HiFiSoundGear.
I found HiFi Sound Gear on Google and was cautious at first, but working directly with Adam (owner) changed that quickly. I ordered the Thieaudio Monarch MKIV on Sept 9, 2025, and he had them in the very next day. Since I’m local, he set up a smooth in-person pickup in Broomfield, CO after I completed the purchase. Communication was fast and clear, and he even recorded a personalized thank-you video showing order status and my pickup window. Adam also walked me through their policies, the 5-year warranty really is five years, and the 365-day return is real as long as the product isn’t end-user damaged. This was hands-down the best customer experience I’ve had in audio retail. I’m 100% a new repeat customer and highly recommend HiFi Sound Gear.
The Noble Audio Knight is a really cool product. It's solidly built with a really nice cable, and it sounds great. The separation of the highs, lows and mids is terrific. I was never really able to heart the texture of bass guitars until I tried these IEMs. The soundstage and everything else is really source dependent, but the detail retrieval could be a little better. Overall, an awesome entry level IEM that sounds as good, if not better, than it's price tag.
Adam and Alexa at HifiSoundGear are awesome at personalized customer service (the video thank you was a really sweet touch). They are easy to reach and quick to respond to inquiries. We had an issue come up with UPS and they worked hard to get it straightened out. This company also honors their veteran customers with a nice discount-thank you!
The Noble Fokus line is the best TWS I've heard. Excellent service from HifiSoundGear -- I'm a satisfied repeat customer (quick shipping, had to make a return and they were fantastic, great follow up, etc). Highly recommend the TWS and HifiSoundGear.
Adam and Alexa were total professionals. Adam went above and beyond as to send me a personalized video explaining the process and what I would expect after placing my 64Audio custom IEM order. He did this the day before his wife was due to give birth!!! He only told me this to warn me that he may be a bit late to answer emails or calls due to his child being born. However, he did make sure I had a point of contact in Alexa. She was very prompt in her call backs and email responses. I typically heard back within the same day or by the next day at the latest. This was my first time doing this and of course I had lots of questions as this was a big investment and they were more than helpful and very kind and understanding at the same time. Truly a class act and I wish you all the very best with your business and your newly expanded family. God bless!
Great experience from my first purchase here. Even received a personalized video from the owner for my purchase. Customer service above and beyond in all facets! Thanks so much for a fabulous customer experience!
Amazing customer service. Adam went into great detail with his experience on these IEMs. Would definitely go to him again!
Good communication throughout the process with fast shipping.
It's such a pleasure doing business with Adam and Lauren that I am honestly looking for an excuse to buy more equipment there. I don't really have a good personal audio store anywhere around; and while I am not exactly morally opposed to Amazon or whatever, it's so much nicer dealing with real people and a small business. I cannot even imagine what else I could ask for.
Great work, to communicate every step along the way. Very personal touch. I will visit the office one day to personally thank them. I love the website. I love the product. I love the state where they are located. Awesome awesome awesome!
Everything went really smoothly and I'm enjoying the headset I purchased. It shipped quickly and arrived well packaged. I had a question about my purchase and received a quick response from the seller. I would buy from HiFiSoundGear again.
Unexpected as in very pleasantly surprised at the sound quality coming out of these :)
I took my Mega5-EST and hooked em up wirelessly and don't miss the wire sound AT ALL!! IMO the wireless sound was 98% of the wired sound without the PIA of the wire. Unless you have some amazing source gear, which thanks to Adam at hifisoundgear I do, you would be hard pressed to hear a massive difference. Especially with a phone as your source.
I did A/B noble Fokus Prestige vs Go pod w Mega 5 and gotta say l, there is more balanced sound with the Go pod chain then the Prestige on its own. To be fair the Mega 5 punches WAY above its price... so the 2 are a match made in heaven.
I find the connection very stable as well. I've used my iPhone AAC/SBC as well as with FiiO BT11 to get other than Apple codecs and was pleasantly surprised as well.
The ear hooks are very comfortable. Actually prefer them to the wire hanging over my ear with a tie behind my neck. For some reason that's hard to get used to and pulls as I wear loose shirts. The hooks stay in as I like to move around a bit. Also the weight is better distributed than other wireless IEMs as the components are in the hooks. The prestige, unless I have foam tips, which I'm not a fan of, will pop out of my ears when I move around. These stay stable and I do not have to re-seat the IEMs to get that great bass nearly as often with other wireless IEMs.
Battery level has been all day 10 hrs so far with intermittent breaks and still have 28% left.
The case also is deep enough to fit the Mega w hooks as it charges which is very convenient. Some IEMs may be too big but they fit with a tad bit of room to spare.
Of course having the flexibility to swap out your favorite IEMs as needed is awesome!!
5 stars for the Go pod and more importantly 5 stars to Adam and his team for such amazingly awesome customer service!! You guys ROCK!! Thanks :)
The iFi Audio iDSD Diablo 2 is an absolute masterpiece in the world of portable amps. It delivers an audio experience that redefines what’s possible in a compact, travel-friendly device.
To all the "haters" out there who mention that the 5180mw output is an overstatement and the "balanced" is not a true balanced output... I say whatever... it drives anything I throw at it with aplomb! FostexTH900mk2, ZMF Caldera Open and Closed, ANY IEM my friends and I have tried ...too many to list. If you need more power than this portable titan.... well you may have hearing loss. And it drives all I mentioned without using "beast mode" (they refer to it as Nitro (1 of 3 settings)). If anything, it could use a lower gain option / IEM match for some sensitive IEMs.
The implementation of BT 5.4 (supports all codecs) is a welcomed addition for quality, but in general, the distance it can be from the source is very small for consistency. That is not a Diablo issue, but a BT5.4 issue IMO.
As for the sound quality...simply unparalleled. I have compared this to desktop headphone amps in the same price range and I would put it toe to toe with them. It even ran close to my buddy's Burson Soloist 3x!!! and the Diablo 2 is portable :)
I run it using A&K SP3000T and it oozes warmth and richness in the lows and highs WITHOUT covering/smoothing anything up in the mids, which is my jam.
It is on the heavier side and will still fit in a pocket... barely. built like a brick. At the limit of what I would like to carry but totally worth it! I get about 6 hours of the 8 rated battery with constant listening, no Bluetooth on, hard wired, IEMs / Caldera tested on the battery life.
In conclusion, the iFi Audio iDSD Diablo 2 is nothing short of extraordinary. It’s the ultimate portable amp for those who refuse to compromise on sound quality, power, or versatility. If you’re serious about your audio and want the best experience on the go, the Diablo 2 is the perfect choice.
Shout out to Adam, a massive THANK YOU!!! for your absolutely OVER THE TOP customer service and shopping experience :) :) Seriously, your dedication and attention to detail have been nothing short of exceptional.
With all the online ordering over the years, HifiSoundGear provides the best service I have encountered. It was as though they were good friends. They responded so nicely to all my questions about the product and shipment. As it works out, while I liked the IEM's, I concluded they were not sufficiently different from the ones i had been using. Again, for the process of returning and getting a refund, they could not have been nicer. Buying from them was a first rate experience.
Recently had a great experience with Adam and Laura. I requested a price match for the FiR KR5 and it was such a painless process. Adam and Laura’s communication is top notch! Adam even sent me a personal thank you video. In my experience, this level of service is hard to come by these days. I highly recommend going through HifiSoundgear for your audio needs….I know I will be going forward! Thanks Adam and Laura!
The quality of service, level of help provided, and overall customer satisfaction is beyond anything I have experienced. I cannot say enough good things about the people who belong to this company!
As for the U4S, these are my first foray into 64 Audio but I am SO thankful that I got to experience them! My goodness the soundstage, bass response from the m15 module, and overall quality is just great!
Please, buy from these wonderful people! And if you can swing it, get a set of U4S! You will not regret it!
Only complaint is the cable. For the price, I expected better, but it works well and is just fine.
Thank you HiFi Sound Gear! I look forward to purchasing more from you in the future!
HifiSoundGear offers exceptional quality products and unparalleled customer service. Their wide selection of high-end audio gear, including in-ear monitors and amplifiers, are praised for delivering outstanding sound clarity, detail, and an immersive listening...
