In theory, isolation transformers (IST) sound like “the” essential safety device for an ECE workbench. The question is, are you trying to protect your equipment, yourself or both? The two other essential safety devices for your ECE workbench are a decent variac and Differential Probes. A Note from HL: I wanted to go ahead and […]
Video #2 in the HL Complete Build Series, found on YouTube. This time I am showing my EDS 88A Capacitor Tester build. This one runs a bit under an hour in length. Soldering well over a hundred pad locations in this one!
HL tears the ES9038 DAC down to the bones for a full hardware upgrade! In stage 1 of upgrades, I worked on the analog side of the board, replacing nearly all the stock parts, including: resistors, DIP-8 sockets, and capacitors. The results have been impressive, giving a much more reference leaning tone. (ELNA SILMIC Super Gold included)
A look at the design process for the upcoming HL THD Tester for capacitors. I will be using SPDT or SPST switches to allow a variety of capacitances. Resolution depends on quality of reference arm, but measuring down -160dB, is easily achieved.
Update 8/6/20: Grades for the 5V Charger were posted today. I got a 190/200 (95%) on the final project, giving me an A (overall) in Jr Design. If I hadn’t forgotten to show the PCB partially inserted in the enclosure, I would have made a 100! Update 7/30/20: Revision 2.2 arrived in the nick of […]
Tore down the AU-517 once again, to get at the Power & Protection circuit. I made a mistake in replacing the 10D7C silicon diodes and hoping this fixes the relay issue.
Edit: 7/26/19 I got these molded last night (myself, at home) and must say, I was shocked at the difference (a word I rarely use on this site, except in the literal sense). I was expecting bass to improve, but it improved way more elements than that! Expect a full review in about a week, […]
The first part of my Sansui AU-517/717 restore guide, from recapping to finding those pesky shorted diodes. Not to mention how daunting it is just to remove and then rewire all the PCB’s! Here I hope to help shed some light on the subject.
As you may already know, I started the Hallman Labs Vintage Store a few months back. I am currently using EBay to sell these items and I came across a handful of rules that aren’t exactly easy to find. So, I have created a list of the most commonly encountered EBay rules. 1: You can […]
A look at the Potomac AA-51 Audio Analyzer: schematic, calibration procedures, service manual and more inside. Produced in the 1980’s, the AA-51 is still of great use.