The preamplifier remains the central control unit, the real heart of the hi-fi system. The preamplifier is irreplaceable for sonic reasons.
The Ideal Control Centre
With its elegant touch panel display, the CP1 is stylish and easy to use. The CP1 features a 4.3” colour TFT LCD full colour display, with capacitive touch. All features of the CP1 are controlled by this touch display which eliminates any front panel mechanical potentiometers and switches.
Unlike its mechanical counterpart, an electronic touch display also has the advantage of allowing the shortest possible signal path from inputs to outputs, thus ensuring the integrity of the audio signal. An additional remote control also performs the same functions of the touch display, including input switching, volume control, mute and standby modes.
Input and output signals are made through the highest quality silver-plated oxygen free copper (OFHC) RCA connectors. Input selection is made with high quality gold plated Swiss made relays, and only the selected input is connected - all other inputs are isolated. The selected input is followed by a buffer amplifier and presents a benign load to signal sources.
Ideal Volume Control
The volume control uses laser cut precision, low-noise and zero- induction resistors. It controls both volume and balance.
Dual Mono Layout
Audio purity is maximised by using minimal components in the signal path. Moreover, crosstalk is virtually eliminated by using a dual mono layout for left and right channels. Once again, only low-noise and zero-induction resistors are used.
Download CP1 User Manual: OAD CP1 Owners Manual
The CP1 is fitted with RCA connectors only. There is a great deal of discussion within the hi-fi community as to whether or not balanced or single-ended interconnections provide the best sound. Indeed, balanced interconnections are often portrayed by some manufacturers and the hi-fi press as being superior to the long-established single-ended connection. But, is this actually the case? Read more
There is a great deal of discussion within the hi-fi community as to whether or not balanced or single-ended
interconnections provide the best sound. Indeed, balanced interconnections are often portrayed by some
manufacturers and the hi-fi press as being superior to the long-established single-ended connection. But, is this actually
the case? In this paper, OAD Managing Director and electronics engineer, Jon De Sensi, points out the pros and cons of
balanced interconnections and argues that equally high fidelity can be achieved with either balanced or single-ended
interconnections. This paper is in no way intended to criticise the use of balanced interconnections, but rather to point
out some issues with their design.
As Douglas Self outlines in his text, Small Signal Audio Design , transformer balancing performs well in very hostile radio frequency (RF) and electromagnetic compatibility environments (EMC). This is because transformers are electrically bullet-proof and retain their high Common-Mode Rejection Ratio (CMRR) performance. On the down side however, transformers generate low frequency distortion. They are likely to have high frequency response problems due to leakage reactance and distributed capacitance. Inevitably they are also heavy and expensive. Transformer balancing is relatively rare in hi-end audio and consequently electronic balancing will be the focus here.
With electronic balancing, a following component extracts information by detecting the potential difference (by means of
subtraction) between the inverted and non-inverted signals. The two voltage signals are “balanced,” meaning that they
have equal amplitude and opposite polarity relative to a common-mode voltage. The return currents associated with
these voltages are also balanced and thus cancel each other out. For this reason, we can say that complementary voltage
signals have (ideally) zero current flowing through the ground connection. In real life however, the subtraction falls short
of perfection, as the gains via the inverted and non-inverted inputs will not be precisely the same, and the degree of
discrimination actually achieved is called the common-mode rejection ratio.
Compared to transformer balancing, electronic balancing has the advantages of low cost, smaller size and weight, superior
frequency and transient response.
We will now discuss the advantages and disadvantages of balanced interconnections, as outlined by Douglas Self in
Small Signal Audio Design .
There are both advantages and disadvantages to balanced interconnections, which much hinging on the quality of the design work involved. Both single-ended and balanced interconnections have the potential to create high fidelity, and it is not the case that balanced interconnections are always superior to their single-ended counterparts. To a large degree, the view that balanced interconnections are superior has been sustained due to a lack of understanding around the design issues involved. This lack of understanding has enabled some manufacturers and other key stake holders to embark on marketing campaigns which focus solely on the advantages of balanced interconnections, whilst unfortunately neglecting to point out their disadvantages. Hopefully this article has provided a more objective analysis of the issues involved, and has clearly established that it is inaccurate to maintain that balanced interconnections are always superior to their single-ended counterparts. It is worthwhile repeating again that this paper is in no way intended to criticise the use of balanced interconnections, but rather to point out some issues with their design.
 Self, D (2010), Small Signal Audio Design, Focal Press, Oxford UK, p. 493.
 Self, D (2010), Small Signal Audio Design, Focal Press, Oxford UK, p. 489.
 Wikipedia, https://en.wikipedia.org/wiki/Johnson%E2%80%93Nyquist_noise (accessed November 2017).
 Self, D (2010), Small Signal Audio Design, Focal Press, Oxford UK, p. 527.
 Self, D (2010), Small Signal Audio Design, Focal Press, Oxford UK, p. 527.
 Self, D (2010), Small Signal Audio Design, Focal Press, Oxford UK, p. 596.
Display: 4.3" colour TFT LCD full colour
Line Level Inputs (without phono RIAA card): 6
Line Level Inputs (with phono RIAA card): 5
Overall Gain (dB) -63 to 9.7
Frequency Response (Hz) 0-100k
Output impedance (Ohm): 50
CMRR (dB) 1kHz : -65
Signal to Noise Ratio (dB) 1kHz Ref 5V: -101
Weight: 7 kg (15.5 lbs)
Shipping Weight: 8.6kg (19 lbs)
Dimensions (WxHxD mm): 430x120x360
Shipping Dimensions (HxWxD mm): 235 x 570 x 500 (9.3” x 22.5” x 19.7”)
The specifications of a power amplifier are not the whole story of its sonic characterisitics. Only a holistic approach taking into account the real load of a loudspeaker can lead to the best sound reproduction. The ideal amplifier operates without level and phaseshift across any load.
The UF1 is the ideal power amplifier and complement to the CP1 pre-amplifier. Thanks to its unique technology, using the latest cutting edge bipolar transistors, the UF1 offers superb sound characteristics as well as incredible power and performance; a standard which is unsurpassed even by much more expensive amplifiers. Using a stable power supply, the UF1 is designed to accurately process relatively large signals to deliver current capacity and maintain performance, independent of the load presented by the loudspeakers.
The UF1 is extremely fast with ultra-wide bandwidth and has a high current capability. An amplifier must be able to cope gracefully with impedence dips to 4 Ohms and lower. As the load impedence of an amplifier is decreased to below 8 Ohms large signal non-linearities begin to appear. Unlike, crossover distortion, this large signal non-linearity is significantly dependent on the amplifier's output stage power transistors.
The Open Audio Designs UF1 utilizes the latest in transistor technology to deal with these significant distortions. The transistors used in the UF1 are in a different class from the more conventional transistors, in that, the current gain is completely maintained over its full power bandwidth. Correct utilization of these transistors minimizes not only the large signal non-linearities but significantly lowers crossover distortion.
Gain (dB) 26.4
Frequency Response (Hz) -3dB 0-100k
Power @ 8 Ohms 240VAC (W): 200
Power @ 4 Ohms 240VAC (W): 300
Dimensions (WxHxD mm): 430x160x360