วีดีโอ

I tested the lateral mosfets on a cheap tester & on a test rig. Fitted the PCB's into the heatsinks & after a few minor mods, tested them for OP power, frequency response, THD & stability. Tested on a 8 ohm dummy load, a 100n capacitor & an audio test. Bit of a long one, but needed to put this to bed. Apologies for the repetition re the Hitachi fets, I was in a dilemma.

Changed some OP valves on an amp which wasn't straight forward, it never is. Identify & fix some issues.

Trying to repair the BJT transistor stage. Testing the good channel. Lateral mosfets.

An attempted repair of a vintage mosfet amp. Originally it used lateral mosfets, one channel is working - ish. For all the solid state amp buffs, I'm more used to working with valves, if I'm a bit slow, I'm learning on the job, bear that in mind.

Bit of a detour into getting an emitter follower based on a circuit found online to work. Also a few other little jobs.

Chap asked me to look at his fet amp, a first look.

Continuing on from part one, subjects covered, what is NFB, how it works & further testing & recording of data. Some annotations lost, have had PC issues, edits lost. Re the helicopter, had an argument with Jose Guevara a while back over goose tampering in the 1996 Goose & Chipmunk Jockey Race, keeps haunting me in his ghost helicopter, nuff said : )

Why, & how to, apply negative feedback on a valve/tube audio power amplifier.

More fun footage from the annals of The Artificer in which our hero battles with vintage technology. There's also a dead rat.

Building a power supply, testing of. Starting to replace valve bases.

Attempting to find out why part of the preamp isn't working, a look at the circuit, a lot of waffle & mucking about. Capacitor testing @ 07:05 to 16:00 - skip if not interested.

Identification, appraisal & evaluation of a vintage Stern's Preamplifier.

Bit of a filler video, busy doing other stuff, chewing gum for the eyes.

Valve Amp Delayed Start- Fault Finding & Wotnot.

Fault finding & fixing a valve amp.

Valve/Tube Matching - Is It Important? Matching 807's

Testing 807 Beam Tetrode Valves/Tubes - Part 1.

Sanyo G-2615 N Briefcase Music Center.

50w Class A 807 PPP Valve Amplifier Refurb - Part 2

50w Class A 807 PPP Valve Amplifier Refurb - Part 1

DIY Valve Tester - Penultimate Episode.

DIY Valve Tester Build - Part 4.

DIY Valve Tester Build - Part Three.

DIY Valve Tester Build - Part Two.

DIY Valve Tester Build, Re-Build - Part 1.

How to stick loose valve bases.

Rewinding A Mains Transformer - Tek 585A - Part 7 - Final.

Fitting a Transformer Into a Tek Scope - An Hour in the Workshop.