• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Photo Gallery

That’s just freakin gorgeous!!

Thank you so much. I wish I had a better picture of the face. the lighting is not good in the rack.

Here is one from during the restoration process.
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It wasn't too shabby. But it had clearly been sitting for a long time. I just took the time to replace all the caps, many of the resistors, built a rectifier, re-flowed almost all the solder joints, and polished the chassis.

I am still in the process of tuning the phono stage. I am adjusting the resistor values on the input to match my MC Cartridge.

I am also going to be replacing the volume pot with a 23-step attenuatior.

Sorry for over sharing. lol
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Oh yeah, and matched up with my restored Thorens TD160.
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50W Williamson

Here are a couple of 50W Williamson monoblocks I built 18 months ago. Based on My KT88 Williamson Amp Build but with modifications to accommodate 6GU7s and 6550s and an LC power supply. I believe this was originally a GEC design.

There's 12.5dB of feedback.

For stabilisation I tried 47pF across the feedback resistor and various RC combinations across the V1A anode resistor but settled on 4k7 in series with 470pF across the V1A anode resistor.

In addition to the pictures of the units and circuit diagrams there are 5kHz scope shots of no added stabilisation and with the stabilisation (resistive load and 2uF load).

They sound great!

Thoroughly enjoyed the whole process of simulation using LTSpice, ordering parts, designing the physical layout, having the chassis' laser cut, bent, welded and painted, assembly and testing.

I learned a lot. Like if I ever build more, don't put the bias test points so close to the hot output valves!

The only major problem I had was electromechanical hum induced into the chassis' by the mains transformers (another thread) reduced to an acceptable level by putting sliced rubber grommets under the feet of the mains transformers.
 

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