The dream that wasn't a dream

In 1990, I bought a record that continues to influence my life to this day – Amarok by Mike Oldfield. This album represents the "Holy Grail" for me in terms of creativity, complexity, dynamics, and sound quality.
Many years ago, I read that Mike Oldfield used Harrison's Series Ten mixing console for this album (and others, such as Islands and Tubular Bells II). But owning a studio console of that class was simply unimaginable at the time.

Over the past 20 years, through working with my brother Steffen and developing our modular synthesizer, I've gained extensive experience in analog and digital circuit design, as well as programming in assembly language and high-level languages such as C and C++.

One day, I remembered the Series Ten and started looking for information about it. I was completely surprised to discover that CML in Putzbrunn was offering a used Series Ten at a price that was actually within my reach. I thought about it for a few days – and then I bought it.
At that price, I had no illusions that I’d get a fully functional console that I could just plug in and start using. Its power consumption must be enormous. Besides, there’s hardly any information available online, and Harrison wasn't able to help me either.
In any case, I’m sure I’ll have a lot of fun and stress over the next few years researching, reverse-engineering and repairing the Series Ten.

Now the battleship is standing in my living room – and in the small town of Hoym, Saxony-Anhalt, I’m now officially regarded as a lunatic.

Holger Marienberg, August 2025

74HC Series

• 74HC74Dual flip-flop
• 74HC109Dual flip-flop
• 74HC126Quad buffer 3state
• 74HC1373-to-8 line decoder with address latch
• 74HC221Dual monostable multivibrator
• 74HC2373-to-8 line decoder with address latch
• 74HC373Octal latch 3state
• 74HC374Octal flip-flop 3state
• 74HC3934bit counter

Analog-to-Digital Converters

• ADC08098bit with 8-channel multiplexer

Digital-to-Analog Converters

• ADC75288bit buffered
• DAC08328bit double-buffered
• DAC123212bit double-buffered

Diodes

• 1N1183A/1N2128A

Voltage Regulators

• LM723

Memory

• DS1220Y16k nonvolatile SRAM

Microcontrollers

• 80C318bit microcontroller
• 80C51family programmer’s guide
• MCS51instruction set

Multiplexers

• MC14051
• CD4052/CD4053

Operational Amplifiers

• LT1057Dual OP-Amp
• MC33078Dual OP-Amp

Others

• LM393Dual comparator
• UDN25858-channel source driver

Transistors

• 2N6057NPN Power
• MJ15016PNP High-Power

Anacapa Industries
"Model AI 213" Power Supply

This power supply was most likely commissioned by Harrison, as it was also used in at least the 1983 MR‑4 console.

The first time I opened the power supply, there were no surprises. Many years of use had left the interior dirty and dusty. All electrolytic capacitors in the rectifier circuits have failed, some even leaking. The mechanical construction is of very high quality and extremely safe, with all components still in place. In this unit, the insulation of the power cord is dangerously damaged. All other internal wiring remains in good shape.

Each 16-channel frame of the Series Ten console requires its own dedicated power supply unit. This PSU operates from a 240VAC mains input (7A, 1600W) and delivers regulated DC outputs of ±15V (25A), +5V (15A), and +48V (0.5A). All output voltages are adjustable.

Transformer

The transformer is marked “WTI 8750C”. The primary side consists of two separate windings, switchable for 120V (parallel connection) or 240V (series connection). For series connection, terminals 2 and 3 are linked; for parallel connection, terminals 1 and 3 as well as terminals 2 and 4 are bridged. The secondary side has four windings, three of which have a center tap. It weighs 15.5 kilograms.

The secondary side (no load):

Secondary Windings Rectification

21VAC Secondaries

Each end of the winding is connected to the anode of a 1N2128A diode. The cathodes of the diode pairs form the positive output, which is connected to two 43,000µF/40V electrolytic capacitors in parallel. The negative terminals of the capacitors are connected to the center tap of the corresponding winding.

12VAC Secondary

Each end is connected to the anode of a 1N1138A diode. The cathodes form the positive output, which is connected to a single 82,000µF/25V electrolytic capacitor. Its negative terminal is connected to the center tap of the winding.

51VAC Secondary

This winding is connected directly to the mainboard of the power supply.

Mainboard

Description to follow.