Key Features
The Stereo 25 MkII uses a Class A, all-triode front end with an ultralinear output circuit, and is built using hand-wired point-to-point construction rather than a printed circuit board, an approach Icon Audio favour for sonic purity. New to the MkII revision are 6SN7 and 6SL7 driver valves for improved sound, along with a headphone output offering genuinely high performance thanks to a dedicated winding on the output transformers. The amplifier is designed with the valve enthusiast in mind: its simple bias circuit means replacement valves of the same type require no rebiasing, while still allowing “tube rolling” between several valve types for those who wish to experiment, with the ST25 MkII supporting 6L6, EL34, 6CA7, KT66, KT77, KT88 and 6550 output valves. This example is fitted with the punchy, high-headroom KT88.
Build quality reflects Icon Audio’s usual approach at this level: hand-wound transformers, Hi-Fi grade Solen capacitors, silver PTFE audio cable internally, and gold-plated input and speaker sockets. Three line-level inputs are provided for sources such as CD, tuner or phono stage, with a 250mV input sensitivity for full output. Icon Audio pitch this amplifier as an accessible way into valve ownership without a step down in build quality from their higher models, and despite its affordable positioning it is designed to comfortably drive a wide range of loudspeakers, including many that a typical valve amp of this power might struggle with.
Technical Specifications
(Source: Icon Audio official product leaflet, corroborated via Audio Affair and AudioGold London)
- Type: Integrated valve amplifier, Class A triode front end, ultralinear output
- Output Valves: 4x KT88 (as fitted); also compatible with 6L6, EL34, 6CA7, KT66, KT77, 6550
- Driver Valves: 6SN7/6SL7 double triode
- Power Output: 2x 30W RMS (Ultralinear)
- Frequency Response: 20Hz–20kHz +0/-0.5dB
- THD: Typically less than 0.2% at 1kHz
- Inputs: 3x line level (CD, Tuner, Phono, etc.), 250mV sensitivity for full output
- Speaker Outputs: 4Ω and 8Ω
- Construction: Hand-wired point-to-point, no PCB
- Power Consumption: 100W nominal, 180W maximum, 220/240V
- Dimensions: 340mm (W) x 340mm (D) x 210mm (H) approx.
- Weight: 17kg
- Country of Origin: United Kingdom
Important Owner’s Notes
As a valve amplifier, this unit runs hot in normal use, with the output valves reaching high temperatures during operation. This example is supplied without its original acrylic valve cover, so care should be taken to keep it well clear of curtains, furnishings, pets, and small children, and to allow adequate ventilation around the chassis. Please allow the valves to cool fully before moving the amplifier. As with all valve equipment, output valves are a wearing item and will need periodic replacement over the amplifier’s life; Callum has checked this unit and confirmed correct operation on test, and the simple bias circuit fitted to this model means straightforward replacement valves of the same type will not require rebiasing.
Why Buy From Us
With over 40 years of experience in the Hi-Fi industry, we are well placed to assess and test equipment of this type. Every item we list is fully inspected and tested before sale — this unit was checked by Callum in our workshop.
When you buy from us you can expect:
- Full inspection and testing prior to listing — not simply a visual check
- A 3-month guarantee on every item we sell
- Transparent descriptions with no omissions
- Professional packaging to ensure safe delivery
- After-sales support available by phone or email should you have any questions
Summary
This Icon Audio Stereo 25 MkII is a well-regarded, hand-built British valve amplifier fitted with punchy KT88 output valves, presented in excellent condition. It offers a genuine step into serious valve ownership without the higher cost of Icon Audio’s flagship models. Please note it is supplied without its acrylic valve cover, so appropriate care around heat and ventilation should be taken. This is a single-unit listing. Please feel free to get in touch with any questions prior to purchase.
