Leak TL50 Plus
A mono valve amplifier delivering 50 watts using KT88 tubes, produced from the late 1950s onward.
Overview
The Leak TL50 Plus is a mono power amplifier built by H.J. Leak & Co. Ltd. It belongs to the brand's "TL" series, named for its Triple Loop feedback design. High Fidelity magazine referenced it as early as October 1957, and it stayed in use into the late 1960s. The design is built around the high-output KT88 beam tetrode. It can also run on 6550 tubes. Output transformers came in standard 4, 8, and 16 ohm versions, plus a 100-volt line version for commercial installations.
Specifications
| Power output | 50 watts into 8Ω (mono) |
| Power tubes | Dual KT88 per channel (push-pull) |
| Compatible tubes | KT88 or 6550 |
| Output impedance options | 4, 8, 16 ohms or 100v line transformer |
Market
The Leak TL50 Plus is considered a rare vintage amplifier. A pair was listed for $2,650 in November 2019 (USAudioMart). AUD $8,250 was the asking price in July 2022 (AussieAudioMart, including preamps), and €1,600 in April 2026 (HiFiShark). Units are sometimes offered "for spares or repairs," which points to a possible need for restoration. Reproduction decals are available.
eBay Listings
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