The Darlings are a family of simple amplifiers based on a nice coke bottle triode - the 1626.
The idea of a supersimple lowpower (0,75W) SET seemed attractive but adding another trioded SE amp to my project plans was .... too much. Then I saw this idea on Matrix amplifiers which is a SE-amp using a PP-transformer. Er .. well two. The two triodes are connected to the first amp as normal for a PP-amp. On the secondary two outputs are made for left and right channel. As the OP signals are the difference signal of the input signals, the second transformer is used to form the sum of the input signals which is fed to the output cancelling the negative elements and thus regenerating the original two signals.
But then again, trying to stuff everything into the Swiss cheeze chassis seemed as a crazy task so I reverted to the first
idea - the Original Darling. For chassis I am using a wooden box, once containing a set of dosimeters (for detecting radiatiation).
Box painted greed indicating its military genes...
This projectet has come and gone, being built, debuilt, rebuilt, but, as it seems have evolved into two different projects. One based on the original 1626 and the PCB board from DIYTUBE and one based on 12B4A. The 12B4A is housed in the poor dosimeter box.
Then came the serious attempt. Scrapping all old builds and construction and going for
the 12B4A-Darling described on DIYtube-forum (see below). Again the dosimeter box.
Transformers are a custom made mains transformer and the Danbury budget SE-trannies. Driver tube - 12SL7; all heaters run on 12V.
Connectors attached to a piece of scrap metal screwed to the inside of the box.
The 1626-darling also got wings under the air ... or maybe the other way around. Using the PCB from DIY-tubes (now sadly dis-coninued) and fiddling a bit with different ideas for a chassis. Finally I settled for a wooden frame and an aluminum sheet that had been prepared in advance - maybe not the tidiest solution. The big hole in the alu-sheet will be used for a tube VU-meter. I guess that is needed to keep a watch on the power levels.