Working on a super-preamp design. 12 dB gain. 50k input, 2 Ohm output, 3 Hz-90 KHz bandwidth, 2 sockets for headphones, can drive a pair of 32 Ohm headphones at once, up to 30 mA output current. Up to 70V output swing.
8AL9 tubes, a triode with 56 mu, and a frame grid pentode, 10W, 30 mA/V
8AL9 tubes, a triode with 56 mu, and a frame grid pentode, 10W, 30 mA/V
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Yes.1) is that a ruler used as a heatsink
Yes, VR tube, but instead of a VR tube.
There: Wavebourn - Home | Facebook It is a commercial project, so I can't reveal all details, but everything that I used in the preamp, I suggested here on the forum many times to different DIYers when they asked for advices. It is an affordable high end line. The preamp has 12 dB gain, uses 8AL9 Compactron tube, with a triode with mu=56 and a frame grid pentode with gm=30, 10W dissipation. The preamp is a single stage, with directly coupled catghode follower. The triode is Gyrator loaded, the cathode follower is loaded on CCS. The preamp can swing at least 60V, up to 20 mA, output resistance is 2 Ohm. 230V regulated B+, 8.6V rectified and filtered filament voltage. 4 pairs of RCA inputs with input selector. 50 kOhm input resistance. 2 TRS sockets for hearphones.
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