TUCSON ANALOG WORKSHOP: GALLERY

November 4, 2024

Below are some of my most prized pieces of audio equipment...I have always been a big music listener and have been interested in electronics since my youth (special thanks to my grandfather--he was an electrician who patiently taught me some of the basics).

Around 2010 I decided it was time to go deeper. Not even knowing how to read a schematic, I bought a few kits and learned how to build simple circuits, like an op-amp based phono pre-amp. I soon graduated to tubes and made a number of barely passable devices that hummed and occasionally released magic smoke.

By 2015 I was feeling confident enough to attempt something that was visually appealing, reliable, and of course, wonderful sounding. A "statement" so to speak...

The result was a stereo, single-ended, two-stage amplifier using zero electrolytic capacitors and generating roughly 6 watts per channel. The output transformers are by Transcendar. The enclosure is a powder-coated aluminum unit from Landfall Systems and the power transformer is a multi-voltage unit made by ClassicTone (RIP).

The output tubes are 6CB5As and the preamp/drivers are 6N7s (though at the time the above photo was taken, I was experimenting with a 2 stage driver, using 6GL7s).

The footprint is relatively compact at 13x11x3.25 inches (335x275x8cm) and it weighs in at 26 lbs/12 kg.

The circuit is inspired by Thomas Mayer's beautiful amp here

By using smaller chokes and modern automotive/solar film capacitors, I was able to fit a lot of otherwise unwieldy parts inside the chassis while still avoiding electrolytic caps.

The DC rectifier tube is the venerable Zenith/Sylvania 5AR4 'fat boy'.

Total DC current for both channels is about 150mA with 375V on the plates of the output tubes.

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This is my modded LENCO L75 Turntable with Birch Plywood Plinth and Audio-Technica AT-1503 III Tonearm. Lenco was a Swiss turntable manufacturer with factories in Switzerland and Italy. This particular L75 was made in Italy circa 1974. The tonearm was made in Japan in the mid 1980s.

Building the plinth proved challenging as I don't have many woodworking tools. After 3 attempts, I think this final version came out pretty well. Total weight is about 45 lbs.

The turntable's metal base plate is original, but has been carefully cut down to a 'half-circle' and re-painted in black hammertone. The on/off switch has been relocated closer to the platter (and away from the stylus).

I know there are thicker top plates available ("PTP" aka Peter's Top Plate) and they do offer better isolation and stability, but I did not want to lose the easy-to-use speed control lever--a defining feature of Lencos with their unique idler drive system. I don't know of any other turntable capable of stepless speed control from 16rpm to well above 78rpm.

Armboard is Solid Walnut

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No vintage audio system would be complete without a cassette deck!

Here is one of my favorites, the incredible Nakamichi RX-505.

This is a truly unique auto-reverse 3-head deck that is technically not an "auto-reverse"deck. It actually flips the tape over to play the other side, instead of reversing the tape direction. That way the heads remain stationary, which results in more reliable alignment.

Nakamichi calls the system UDAR "Unidirectional Auto-Reverse".

It is a 1986 model and I am the second owner. I obtained it in partially working condition. After completely refurbishing the transport and aligning the heads, I got to work doing some mods.

Mod #1: Upgrading the Peak Meter from 10 LEDs to 20 per channel.

Mod #2: Adding infrared remote control

The meter mod was a lot of work!

My other favorite deck is an Aiwa XK-007. And there are others...many others!

Below are the bespoke circuit boards I designed for the RX-505s new peak meters.