Theatrical power control – part 1

In my introduction to theatrical lighting systems I considered the many and varied lighting installations you might find in a performance venue and talked about independent power control which we will discuss further here. In days gone by, practically all of the performance luminaires in a theatrical installation would use filament lamps and be suitable… Read More »

Theatrical lighting – introduction

There are many different aspects of lighting in a public space – so many in fact that even seasoned technical crew can be confused. This article offers and introduction to the different lighting systems you might find in a performance environment. Consider a traditional small theatrical venue. The venue has public spaces and non-public spaces.… Read More »

Theatrical cue lights – part 4

Part 3 of this series introduced two professional cue light systems both using a three-wire system with an XLR grounded cable shield. One system is relay-based and the other microcontroller-based. Either system would be suitable for a professional installation. However, the two systems use different arrangements for the outstation. In fact there is no standard… Read More »

Theatrical cue lights – part 3

In part 1 we introduced cue light systems and discussed simple 2-wire a.c. systems. In part 2, we introduced d.c. switching and moved on to latching STANDBY. Later in part 2 we introduced a microcontroller-based design. In this part we will consider adding MASTER GO to relay systems and then expand on microcontroller-based designs. Note… Read More »

Theatrical cue lights – part 2

In the first part, we covered an introduction to cue lights are and how they are used. We also looked at a simple two-wire system. In this part we are going to look at three-wire systems with automatic flashing. Note that the circuits presented here are not complete designs and there are many and varied… Read More »

Theatrical cue lights – part 1

Some years ago I designed a theatrical cue-light system and I recently came across the drawings. The system was based on relays and I thought it would be interesting to see how cue-light designs have progressed over the years. I found that there are many different ways of doing cue lights and I thought I… Read More »

Balanced piezo transducers

I was asked to comment on whether the Phantom Piezo Preamp (available in the shop here) is suitable for connecting to a balanced piezo transducer as covered by Chrisitan Liljedahl here. The short answers is yes, absolutely – the Phantom Piezo Preamp has balanced input and output and effectively you connect a single or double… Read More »

Protecting piezo preamps

I had an enquiry (which which puzzled me slightly) about using LED’s to protect the input of the Phantom Piezo Preamp (available to buy in the shop here). However it was noted that if a piezo transducer is dropped onto a hard surface, the voltage spike generated could be high enough to damage downstream electronics.… Read More »

Wien Bridge Oscillator

You may have gathered from my last-but-one post on bit-banging the AD9833 DDS module that I have been playing with audio oscillator designs. As part of this process, I have tried a few Wien bridge oscillator designs that purport to not require a proper non-linear device (such as a miniature lamp or an RA53 thermistor).… Read More »

Substituting the 2N5457

Since Fairchild finally discontinued the 2N5457 JFET along with a number of other JFETS in the TO92 package, prices have been rising and tales of fakes have been increasing on audio and stomp-box forums. You can still buy the 2N5457 from Central Semiconductor, but they are very expensive – too expensive for Stompville to consider… Read More »