I wanted to see how compact I could make a high-voltage, point-to-point wired Tweed Champ. Here’s the result. Leo Fender’s 5F1 circuit, but with a solid-state rectifier, built into a tiny vintage NOS Bud hammertone chassis. Front panel is gain (standby switch at zero), pilot lamp, input; rear panel is fuse, power switch, IEC and speaker jack. See my Instagram page for sound sample.
Hey yall… this month’s Preservation Sound Radio show has already aired, but you can catch in the WPKN archive thru April 26 2020 at this link. This episode is a deep deep trip into v obscure 1968-1976 moody light rock and psych. As usual, the entire show is assembled directly from the original LPs. An alternate pop past that never was. Here’s what you’ll hear:
Click this link to stream a special two-hour Preservation Sound Radio show focusing on: Psychedelic Soul. (show starts approx 12 minutes into the file). This show was assembled in my studio and relayed for broadcast on WPKN. Audio-nerd notes: the entire program was assembled from my vinyl LP collection, freshly transferred via a vintage Denon DL207 MC cartridge through a 1:20 ADC step-up transformer unit I assembled this week. My voice via a 1950s EV 666.
Tracklist:
Above: prototype of a novel design for an economical all-tube headphone amplifier. I have been hunting for a way to build an all-tube cue amp into the @berlinettabrewing DJ console. I was forced to design this because no decent schematics exist anywhere online for something like this: something compact, simple, and inexpensive to make that can run either 600 ohm cans or modern low-impedance cans.
This design uses a basic voltage amp (1/2 a 12AX7, although a 12AT7 would work fine too) driving one paralleled cathode-follower 6CG7 per channel. In theory, with a big enough output cap and 300 plate volts, this SHOULD be able to drive 600 ohm headphones to a very high level. And it does. But here’s the twist: the “600 ohms” jack is a switching jack that, when blank, sends the signal to a pair of 600 ohm:8 ohm “70v” 5-watt line-to-voicecoil transformers: I used inexpensive old Stancors. These are the sort of transformers that you often find inside old schoolhouse baffle speakers.
At full rated level, the low end of these transformers is weak. But at the 1/2w that they see in this circuit, they sound absolutely fine. The amp sounds great with either variety of cans- i tried @akgaudio 600 ohm k240s and @audiotechnicausa ATHM50, which I suspect are 30 ohms-ish. Way way more then enough level, great fidelity and just great sound all around. A little experiment that paid off, coming soon to the world’s most esoteric DJ console.
I recently needed a pair of working Weston 862s. I only had one busted one, and a pair of 861s with different gfx that Weston OEM’d for some other firms. So i’ve scanned the 862 panel at 600DPI and I am going to attempt to print and re-cover the panels in the 861s. Wish me luck! Here’s the art at 600DPI if anyone else needs it:
This month’s P/S Radio show has already aired, but you can listen to the program via this archive link thru Jan 10 2020. As usual this show is broadcast 100% from vinyl. Check it out while you can, some incredible rarities here.
PS dot com reader Frank B sent in these pics of his SpectraSonics console. This 6×2 board was custom built for NBC Television in the late 60s or 70s. Here’s Frank’s description of it:
“..its one of a kind…6 preamps and two 610 limiters plus some high pass filters. It was built for nbc-tv. Im guessing this is the only one in existence….The wiring for the patchbay is unique and crazy. “
Interestingly the comp controls are located on the rear of the unit and the compressors have their own points on the bay. Frank, I am curious what that other board you have to the right of it is!
Any of yall got a custom mini-console by a big maker like this? Let us know!
G. Frudd worked at ADM technology from 1976 – 1989. He sent us the photos above and below. These document some of his work at ADM during that period. Frudd started at ADM as the “console fitter,” previously having worked as a tool & die maker.
Frudd went on to run all of the mechanical shops- machine, cabinet, engraving, and fitting, eventually becoming the Mechanical Engineering Manager. Frudd was directly involved in the design of all consoles and rack products during that period.
G. Frudd: “In my time at ADM we transitioned the product from wood cabinet based to metal and extrusion based structures. It was a great and exciting place to work. After ADM’s demise I went on to be a mechanical designer and product line manager at several companies in the lighting and automation industries.”
The two images above are burn-in racks for console modules.
Thanks for sending in these great images GF!
For previous ADM coverage on P/S dot com, check out these links:
Catalog images and a TON of comments – click here
When State House New Haven asked me last month if i’d be interested in opening the first-ever New Haven appearance of Anika, i think I said YES halfway thru the “…ka.” Her 2010 Stones Throw LP, produced by the legendary Geoff Barrow, he one of my all-time greatest musical influences, is one of my 5 or 10 favorite albums of the past decade.
Nyasha Chiundiza is a tremendous singer+songwriter whom I have been working with the past coupla years and we’ve put together a set of all-new material especially for this show: a six-song suite based on ancient Russian folktales titled ‘Russian Folklore Variation #127.’ It is something else. We are super-excited to premiere it for you. Get tix here.
Several years ago I received a telephone call from a man named Johan VanLeer. VanLeer designed reverb systems for Hammond many many decades ago, and later developed a very rare spring system for Quad Eight. He sent me some interesting information regard the Quad Eight system; click here to read that earlier post. VanLeer is still developing new spring reverb approaches to-this-day. Here is a bit of of info on his latest project.
“Still tinkering with spring (4) reverberation systems, I thought updating you. Due to the 17″ rack width dimensions, the DELAY TIME is limited to the spring length, which has to be less than about 13”.
To double the DELAY TIME I constructed a few systems by using and updating the 1964 US Patent No: 3,159,713 by W.C. (Bill) Laube, Jr., like me, a Hammond Organ Co. Engineer.
In the so called “single ended system” both the receive- and send transducer are on the same side and the other side has the spring-ends firmly anchored.
So, the send-signal bounces back doubling the delay time before it reaches the receiving transducer.
To avoid cross-talk from the sender (1 coil), the 2 coils of the receiving transducer are connected out-off-phase.