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Originally Posted by amphead  Dsavitsk, how about 119DA and the Bijou?
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One answer is that I think the Amveco toroids actually sound better for less money. Or, the Lundahl LL1930's also sound better for about $40 extra (these use mu metal rather than amorphous cores and lack the shielding of the other Lundahls which is why they are less expensive. They are still quite good, and probably the best deal in the Lundahl line.) If you have the Hammonds, use them, but otherwise they probably aren't the best deal in the price range.
By the way, here's a post on how to pick your power toroid for output use:
HeadWize: View Post [DIY Workshop > Less-pressivo: High performance, low cost, all tube, headphone amp]
The other answer is that the Bijou is not really the ideal platform for transformer coupling. It will work, but the amp uses various features to obtain a low Z out, and my sense is that using those features is an either or with transformers. That is, transformers allow you to build much simpler circuits that use many less components -- less tubes, less capacitors, etc. The trade off, of course, is that you have to spend the extra money on the transformer. But, doing both in the same amp is probably not the best idea from a design perspective as I think it probably compromises both designs. That is to say, I don't think adding a pair of OPTs is going to bring much to the table.
I like to joke about the original L'espressivo being so cheap to build, but honestly, the only reason it ever becomes expensive is if you start adding expensive parts -- the parts list remains pretty constant.
