Matt, not trying to top your wire wrap story, when I was doing my electronics/microprocessing course I wire wrapped a whole 8085 micropressor trainer, ran it on batteries so I could use it in class. I added to the trainer a stack more RAM and an A2D and a D2A so I could interface it to control externals. This was possibly the first truely portable computer!!
I still have it.
I have finsihed the Universal preamp. Apart from a short on the HT after the 300ohm filtering resistor in the PS it works and sounds great. A friend built a Shuguang 300B amp but it has a slight hum in one channel he cannot find. I said I would have a look at it. He happen to have a box of 12AT7s and has leant me four or five different ones.
I put in one of the GE tubes and fired up the Universal. I did not have a 250K pot so I used a 100K dual gang. This preamp/tube combo has a huge amount of gain and goes from nothing to loud on less than a 1/4 of a turn. Still controlable but it comes up fast. The GE tubes glows like a Xmas tree dowsed in kerosene and set alight. Not only is the tube bright but so is the overall sound. I would say it is tilted up. Mids are bright where The Black with the 12AU7 GD tube is rich through the mid range and a solid bass. This sounds thinner through the mid. I always wanted a tube preamp that sounded like a solid state preamp (bull!).
The sound stage is wide bit not deep. The preamp with the 12AT7 would suit a system that leans to the dark side, one Luke Skywalker might have, or his dad with emphysema. I have only had a brief listen with one tube so a way to go yet. Based on this empty evaluation The Black is still the one to beat. But I'm open to change.
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MKIV in caseSS.jpg
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