Arkless Electronics
Trade: Amp design and repairs.
'its nothing to do with my phono stages' ?? Not once but twice!!! Over the past 25 years I've build many, I mean many Avondale amps (amp8, 200's, 220's, 300's and others) in various configurations and never have I had one blow up, let alone like that in gavreid's photo.
Just saying.
This is now getting off track ..back to the NCC300 builds.
Right... The Avondale amps are not particularly reliable and have issues with SOAR and a complete lack of protection circuitry. I know of several cases of them self immolating in exactly this way and without my phono stages, which are without fault in this, being involved. In this instance it has been a combination of the user leaving the volume up very high whilst changing records and the excessive rail voltages of the power amp. There was a good reason why Quad used current limiting when employing a single pair of OPT's from + & - 50V rails in the 405.... in many cases people are using 55 - 60V rails with the Avondale amps and this sort of thing is not unexpected. Some are even using 60V rails and 4R speakers!