Thursday, August 27, 2015

VPI 16.5 - New Housing

I got this machine in the early 90s from Steve at Angela Instruments when he upgraded to a more deluxe unit. It was originally a VPI 16 (note the traces of the lid mounted vacuum nozzle), surplus from Towson University Library. Eventually the turntable motor burned out and when I placed an order for a replacement motor, I also opted for the ".5 upgrade kit". 

After 8 years in the tropics, the particle board housing started to rot due to extreme humidity.  So I took it apart, labelled the wiring and took pictures for easier reassembly.

I enlisted the help of Joey's woodworking shop foreman, Badjo, to duplicate the original using higher quality phenolic plywood.

This is the new box in its final reassembly phase - vacuum motor installed, turntable motor, platter and switch plate next.

Good for another lifetime?

With over 2000 LPs to care for, I need a back up in the form of my trusty Nitty-Gritty 1 from the 80s ;)

Tuesday, August 25, 2015

Dai-Ichi PT-6 Horn Tweeter

Over a year ago, I blogged about the cheap 'n cheerful locally manufactured Konzert/Micro PT6A horn tweeter which visually looks like a lineal descendant of the highly regarded Pioneer PT-6.  I have no experience with the Pioneer PT-6, but have owned and enjoyed the similar Pioneer PT-3K.

My buddy Rex chanced upon another PT-6 local clone made by Dai-Ichi which used to supply OEM drivers for the late lamented Radio Shack. He also supplied an original Pioneer PT-6 but unfortunately, it has a blown mylar diaphragm. So I pictured it in the middle of this trio as a visual reference.

The Dai-Ichi PT-6 is finished in a nice black powder coated cast aluminum instead of cheap molded plastic in the Konzert/Micro. However, the mostly useless specs are similar: 
100 watts max, 60W nominal (Good marketing, but...)
8 ohm voice coil impedance +/- 15% (...hmmm)
2.5khz-20khz frequency response (parameters??)
94dB sensitivity +/-2dB (ditto???)

Off the bat, I will caution anyone not to even consider using either the Konzert/Micro PT-6A or Dai-Ichi PT-6 as a super tweeter for speaker systems with 96dB/1M/1W (or greater) efficiency. In spite of the horn loading, they are just not efficient enough to match the 99dB/1M/1W efficiency of my Altec 414 or 416 woofers.  My ears tell me that these tweeters should be rated 95dB/1M/1W, tops!

However, if you are looking to augment the falling high frequency response of a typical low to mid 90s efficient 8" full range driver or woofer on a budget, the Dai-Ichi PT-6 and Konzert/Micro PT-6A are worthy of consideration.

Saturday, August 1, 2015

SJ4000 + Kingone K5

Don't worry folks, JE Labs has not ditched retro tech.

I just needed a cheap video cam to capture my treks in the Mini + a cheap bluetooth speaker which disappears in the dashboard and prevents road rage in Manila traffic, even on weekends ;)

 SJ4000 factory default settings at 1080p 30fps

At less than half the price of an entry level Go Pro Hero, the video quality is good enough for my purpose. As I get to know the menu and settings, I might tweak it a bit later. 

Original 720p 30 fps color video converted to B&W

I've paired CD quality tracks from my iPhone with Bose, Braven, JBL and other touted/branded bluetooth speakers in showrooms but could never justify their cost to sound value. Just like the others, the Kingone K5 has a built-in EQ network which aids the tweeter-sized drivers in fooling the ears to hear a bigger than actual sound by boosting the frequency extremes. Kudos to Kingone engineers for designing an EQ curve which does not muddy the midrange, renders clean bass overtone clues and is rid of tinnitus inducing highs. 

Default settings @ 720p 30fps

The savings from buying cheap clones can be appropriated for retro tech projects ;)