However; the issue of transformer quality boils down to one of simple economics. They are labor intensive to build; they require large amounts of material and extensive attention to quality control. Not to mention they are heavy and expensive to ship. They are design dependant; ie. they are usually specific to each design so as a result they are small batch items. They have an inordinate effect on the sound of tube circuits, poorly regulated and constructed examples result in poor sound period. Well constructed units are expensive. Quality units are big and heavy and rely on the quality of the raw materials used to construct them for their sound.
There are no exceptions to this rule. With transformers; Quality=money. And you can't design around poor transformers. Cheap trans are not good; good trans are not cheap.
My point was the cost of good iron prohibits designers from making money on inexpensive amp kits. So by definition they must compromise on the transformers and no amount of tweaking passive parts can overcome that limitation.