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.
Haven't made this one, but have made the K5881, now withdrawn, the headphone amp, etc. My experience was the instructions were ok but not great, and the quality of the supplied components average. The K5881 really came alive though, once I used paper in oil caps, and Black Gate electolytics. I would say give it a go!
I built the KiT88 amp about 8 months a go. Sounds pretty ok at first, but when I incorporated capacitor bypass on all caps, there is a huge improvement in terms of clarity and speed – especially on the mids and highs. There are downfalls though, i.e. the hum level is pretty loud, probably because the 6AU6 heaters are AC supplied - I could be wrong. So, if you're not particular about it, then go a head. Otherwise, search elsewhere.
My next problem is realibility. Right now, my amp couldn't even switch on w/o valves - the main fuse kept blowing and I still haven't got time to troubleshoot it properly. Did a sanity check on the primary trans coil (for 240 volts), and the resistance was 4.8 ohms.
Steve, could you do me favour and compare your readings ? I suspect my trans could have suffered from slight internal melting.
Those guys from Audio World seems to be of little help.