Charlotte 猫 Awoo Fide @confusedcharlot@awoo.space

DC test. the tubes are working the voltages seem ok. The upper power supply is supplying 280 V to the plates, and the lower power supply is powering the heaters at 11 V.

i miss incandescent light sometimes

how come no one told me pogo pins are a thing?

Heater test on the phono board

Anyway I'm trying to make things instead of drowning a sea of despair. On some days it even works.

Anyway, that's what I've been up to

for what it's worth, the source followers (topology of the fet stages) should be almost sonically indistinguishable from the same stages made with a triode.

there's a bit of silicone caulk here and there to keep things together, and insulate son if the exposed junctions.

riaa! not road

the added elements are wired from the existing traces using 18 age wire (which is all I had at the time).

I was able to use about 90% of the original solder traces.

The fets are mounted on little pieces of perf board, and then wired into the rest of the circuit. It wasn't to hard to add them, because since the last stage is directly coupled to the road equalization filter, i was able to basically swap a cap for a transistor (connecting the third lead to the power supply)

At this point I have modified the phono stage (using a new circuit board). Mind you, this is the first board I have wired up for myself ever, so it looks a little rough.

however, vacuum tubes require little electric heaters to work, and that draws a lot of current. so much current, in fact, that you have to upgrade the power supply. that's a lot for a beginner's project, so I redesigned the circuit slightly to use mosfet transistors in the two added stages.

The layout of that page is appropriately old timey. Anyway the two main circuits go from a 4 tube layout to a 6 tube layout

Since it is working perfectly well, I've decided to mod it. My mods are based on this article from the mid 90's http://www.normankoren.com/Audio/Spice_preamp_2.html

It is in good, original working condition. However, there are lots of mods you can do to "improve" it's function. Some of them even help.

Anyway this is a Dynaco Dyna PAS 3 preamplifier. That is to say it is my Dynaco Dyna PAS 3 preamplifier. Also, my cat.

However, I've never really done any circuit assembly(a little bit for school), so this has been a bit of a challenge.

This is not so strange as my dad was into Hi-Fi back in the day, and that involved a lot of tubed gear.