Little Bear Vacumn Tube Mini Phono Stage RIAA MM Phonograph Preamp & HiFi Tube Pre-Amplifier (Silver) Description Brand New. Little Bear Vacumn Tube Mini Phono Stage RIAA MM Phonograph Preamp & HiFi Tube Pre-Amplifier (Silver) This product can be used as a MM Turntable Preamp or a HiFi Tube Pre-Amplifier This product can provide high fidelity and warm sound beyond your expectation Its tube(6J1) can be directly replaced with tubes like 5654, 6AK5, EF95 .etc Its mini size makes it more portable and be suited for a variety of scenarios and Its alluminum body makes it strong and elegant. Now according to our customers needs, a Gain control switch has been added on the PCB. Notice: As a phono preamp, it is suited for MM turntables only. Do not support MC turntables. As an AUX preamp, it is suited for devices like CD, DAC, PC, cellphone. Parameters: RIAA phono part: RIAA freq response 20hz-20kHz +- 0.5dB, S N ratio> 85dB THD Nominal max output 300mV 1.8V Output impedance 200 ohms, input 47k ohm 220 pF AUX part: Input voltage: AC12 ~ 18V Frequency response: 20 HZ - 20 KHZ Input sensitivity 300 mv SNR: 96 db Total harmonic distortion Power range output: 0.2 W Output impedance: 100K Input impedance: 50K Chassis size: 80×116×28mm Net weight: 0.24Kg (0.55Kg with package) Package includes: 1 x preamplifier 1 x power supply 2 x 6J1 tubes Whats more: Please do not use the BACKUP tube(with a letter B) when you start the device for the first time. It will be better if its GND jack can be really connected to the ground, which can decrease the background noise to a very low level. For MM turntables, please check whether your MM cartridge is the old version. If so. we suggest you to upgrade it as a new version one will bring much better sound. Please make sure that your turntable has a PHONO output. A LINE OUT turntable has a built-in preamp and it wont work well with T7. Please keep T7 away from devices that can transfer signal like cellphones and routers. Do not connect T7 to any inferior Bluetooth digital amplifiers except Class T digital amplifiers, since all Class D amplifiers have very loud background noise. Payment Payment accepted through Paypal. Shipping FREE SHIPPING to the continental United States.Please make sure shipping address is correct when checking out as the address cannot be changed after order is placed. Return We want you to be happy with your purchase. You may return items in its original condition within 30 days. Please contact us to process a return.