Cayin C9II Portable Headphone Amplifier
SKU: 94438313512

Cayin C9II Portable Headphone Amplifier

Sale price$1079.55 Regular price$1199.50
Save 10%

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Jul 4 - Jul 9

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

Description

Cayin C9II Portable Headphone AmplifierProduct Highlights 1. Gen5 Nutube 6P1 Vacuum Tube Audio Circuit Cayin has applied this vacuum tube to multiple products, including the N8, C9, N8ii, and N30LE, and now the C9ii. After years of continuous circuit experimentation and technical refinement, Cayin has equipped the C9ii with an adjustable anode (plate) voltage feature and the highly praised Classic and Modern dual tube timbre. This adjustable plate voltage feature offers two levels: high

Product Highlights

1. Gen5 Nutube 6P1 Vacuum Tube Audio Circuit 

Cayin has applied this vacuum tube to multiple products, including the N8, C9, N8ii, and N30LE, and now the C9ii. After years of continuous circuit experimentation and technical refinement, Cayin has equipped the C9ii with an adjustable anode (plate) voltage feature and the highly praised Classic and Modern dual tube timbre. This adjustable plate voltage feature offers two levels: high and low.

1.1 Dual Tube Timbre Circuit

Modern Sound: Introduces a large-loop negative feedback system, with total gain determined by the large-loop negative feedback circuit. By incorporating negative feedback over multiple amplification stages, the total harmonic distortion (THD) will be reduced significantly. The harmonic distortion characteristics and sound signature lean more toward a modern style, with greatly reduced thermal noise and a slightly cleaner tube sound. The original C9 was designed with a similar NFB circuit.

Classic Sound: No large-loop negative feedback; each stage operates independently through local feedback, with the overall gain determined by the cumulative gain of each stage. The distortion characteristics of the tube amplification circuit dominate the sound signature, resulting in a higher THD value. The distribution of harmonic distortion and the sensor signature exhibit a classic vacuum tube amplification circuit, with relatively more thermal noise and a richer vacuum tube presentation. The N8 DAP was designed with a similar NFB circuit. 

1.2 Anode (High/Low) 

Cayin introduces a new feature, “Anode” to C9ii. The High/Low adjustable anode (plate) voltage further enriches and refines the range of vacuum tube timbre. The working principle is that applying different operating voltages to the plate of the vacuum tube alters its operating state, ultimately affecting the sound signature of the timbre circuit. This mainly manifests in changes in audio linearity, and it will adjust the overlay, spectrum, amplitude, and ratio of second-order harmonic, resulting in perceptible audible differences.

∙ Classic + Anode (H): The richest tube sound, with intense emotional depth, suitable for vocal music with a lot of details. 

∙ Classic + Anode (L): Slightly lighter tube sound, suitable for vocals with thicker tones.

∙ Modern + Anode (H): Less tube character, with moderate smoothing in the midrange and a slight sweetness added. 

∙ Modern + Anode (L): Minimal tube coloration, without affecting resolution and definition.

∙ Solid State sound: Balanced across the entire frequency range, musical without tube coloration.

2. Fully Discrete, Fully Symmetric Differential Headphone Amplifier 

The C9ii's headphone amplification circuit is significantly different from that of the first-generation C9. While both amplifiers employ a fully discrete, fully differential four-channel headphone amplification circuit, the C9ii adopts a fully symmetrical circuit architecture. 

2.1 Fully-symmetric Headphone Amplifier

Cayin has designed a three-stage amplification circuit to embrace the fully symmetric design into C9ii: a differential input stage, a voltage amplification stage, and a power driver stage. 

Stage One: Symmetric JFET Common-source Differential input amplifier.

Stage Two: Symmetric BJT Common-emitter Push-Pull Differential Voltage Amplifier. 

Stage Three: Symmetric BJT Common-collector Push-Pull Parallel Current Amplifier(emitter follower).

2.2 Negative FeedBack (NFB) 

The C9ii has an integrated precision control circuit that allows the headphone amplifier to operate in various modes such as NFB/LFB, Class A/Class AB, Hyper, single-ended, and balanced input/output modes.

On the C9ii, when NFB is on (indicator light on), the audio output presents more spatiality with stellar dynamic range, excellent transient response, and relatively fewer harmonics, delivering more neutral sound with impressive detail and speed. Audiophiles frequently associate these changes with “higher resolution.” On the other hand, when NFB is off (indicator light off), the audio output displays richer harmonics. You can hear a more cohesive and full-bodied presentation, with stronger imaging and more textured and elastic mid-bass frequencies. 

Total Sound Shaping Options:

  • Timbre: 3 options (Classic Tube, Modern Tube, Solid-state) 
  • Amplification Mode: 3 options (Class A, Class AB, Hyper) 
  • Anode: 2 options (High, Low) 
  • NFB: 2 options (On/Off) 
  • Input mode: 2 (Line, Pre)

 

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 94438313512

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.4 ★★★★★
Based on 1581 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
D
Verified Purchase
Denise Z
Lowell, US
★★★★★ 5
Good protection for my ipad
Color: Sky Blue
Flap to close is magnetic, so it stays closed. Has a spot for the open for the ipad. Keyboard is a handy feature to have, and love that it lights up.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 11, 2026
O
Verified Purchase
Omar Zapata
Pawtucket, US
★★★★★ 3
Case quality is great, but keyboard is disappointing
Color: Mulberry
The quality of the case is really great. Plum color is beautiful. However, the keyboard is not the best quality. The keys are not sensitive enough and you can easily misspell words if you don’t click a key hard enough. The trackpad shortcuts are cool but inconvenient since you can turn off the shortcuts. You can turn off the trackpad but that just doesn’t work for me.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 16, 2026
T
Verified Purchase
Timothy N.
Phoenix, US
★★★★★ 5
Economically priced ipad case
Color: Mulberry
There's absolutely no way you could find a better ipad case with a wireless keyboard for this price. My daughter loves it. I was expecting it to feel a little cheap because of the price. I was wrong, this is a great find... thanks
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 7, 2026
B
Verified Purchase
Breana Lopez
Port Orchard, US
★★★★★ 2
Cute but beware of buttons with a mind of its own.
Color: Pink, Color: Pink
Super cute. Only has 3 keyboard multicolor options and one white light setting. Dimmable. But its functionality needs work. But the keys keep doing weird things like skipping lines, changing excel sheet formatting and just moving where I am typing on it own. Like it will be typing and then move to the beginning of the sentence and keep moving. The feel is super light and the quality of the case is great though. It’s easy to use and install to device with Bluetooth. Value is you get what you paid for. This keyboard is cute but not working quite well. I accidentally ordered a different model for a later iPad and had to return it, but based off of a leader model in comparison to this one, the keyboard just isn’t that great
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on December 29, 2025
J
Verified Purchase
Jennifer Kuhse
Pawtucket, US
★★★★★ 5
Cute pink keyboard
Color: Pink
Good product. Serves it purpose and a nice shade of pink. So far no issues with compatibility or usage.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 23, 2026

recommand products