A chain is no stronger than its weakest link.
Why I still do not see DIYers paying close attention to it? What I'm referring to, is the POWER TRANSFORMER! I've got lots of orders and queries about output transformers, inter-stage transformers, and input transformers. Only 10% or less are about power transformers or chokes!
Shame on you!
If output transformer is the heart of an amplifier, then the power transformer is the blood flowing in the veins that delivers energy to the whole body! How much influence the power transformer has over the overall sound? I cannot quantify but it definitely is very significant!
They've paid so much for the output transformer, capacitors, vacuum tubes, even expensive wires, and yet they ignored one of the most important component -> power transformer! I've customers using the absolute best output transformer and yet they asked for cheap power transformers that's like 10% or 20% of the output transformer price! What sort of logic that is?
All those that heard our Nightshade 1W amplifier told us that it does not sound like a 1W amplifier at all but something significantly more powerful. That's the strength of having a high quality power transformer.
Some use cheapo cores. Some undersized. Some buy from the shelf units that does not really fit the required applications. Some got the rong sizes. Some tolerate different input voltages (220V used as 240V, vice versa and etc) wrong VA ratings, wrong output voltages that require workaround or sacrifices to get to the desired specifications.
All these are just pure rubbish. Every little modifications or trade-offs you made take you further away from the audio truth!
Give yourself a chance of a life time, try a good custom power transformer that meets all your design requirements, and I guarantee you that it will be a ear enlightening experience that you swear you will never go back to other ordinary power transformers again. Period.
J&K Audio Design
5th June 2014