Especially if you count in the additional power just to run the heater filaments on a tubes version, which is about 5.5 W for 1x EL84 and 1x 12AX7. Anyways switching DC supply bricks are pretty cheap and readily available to run a Class A at 5 to 10 W. The preamp will draw maybe an added 100 mA, negligible. I think Nelson Brock is offering the ACA MinMax PCB (bare) at around $10 (USD) for a set of two boards. I don't have any experience with the ACA Mini, and not personally involved in any way with that project. I imagine the JLH would be similar in performance though?One day I will get back to it. I figure the power wasted in a 5W SS Class A amp will not be any worse than a 5W tube amp.
Incredibly they used a single 2N3055 driving a very common EI transformer.Was that design not with two 3055's, in antiphase driving a symmetrical transformer?
And from there, the next progress was an OTL.
And now we're stuck with this DIYaudio.com website.
Obviously on purpose, they must be after some quirk or non linearity they like.
They are still using it today, so it' s by choice, not by "need".
Some early design stage work I was doing on Class A Jfet push pull preamp stage driving an audio transformer. I have since gone to a less expensive open frame style audio transfo, which performs very well especially considering it's about 1/10 the price. The final version has a high impedance (1M) buffer input, variable gain 0 to about +23 dB (local NFB) and balanced transformer isolated output. To do a full on guitar preamp, I am planning on putting an additional gain stage at the input, either a passive or active tone section after that..haven't decided which. Cheers!