The SR555, which is manufactured by SRS, is a high-bandwidth, fixed-gain current amplifier that is suitable to use together with locking amplifiers that are also from SRS. The unit generates a gain of 107 V/A near the experimental detector which enables the user in reducing input cable length and the corresponding input capacity. It also reduces sound pressure levels to prevent degrading the signal-to-noise ratio which minimizes measurement time.sr555的是由SRS是一个带宽固定增益放大器用于使用与定放大器也从SRS。单位产生增益107 V /实探测器使用户减少入电缆度和相应的入容。它也减少了声压水平止低信噪比最大度地减少测时。