Trasmac Tech Technology

This completely new amplifier circuit incorporates most of the features of our Ultra-LO Mk4 200W amplifier module but uses easy-to-solder through-hole components. There are no tiny surface mount components.   Very keen audiophiles have built it in large numbers but being Class-A, it does have the normal drawback of being quite inefficient and therefore it dissipates a lot of heat for its modest power output of 20 watts. Finally, the next most notable amplifier module was the Ultra-LD Mk4 design which not only has high output power but its very low harmonic distortion levels challenge even those achieved by the 20W Class-A design. Indeed, the 110W version of the Ultra-LD effectively renders the modestly-powered 20W Class-A design irrelevant. Why would you build that Class-A design when you can build a much more powerful Class-AB design for the same money and with virtually indistinguishable performance? So why are we producing this new SC200 module? Firstly, we have f

If you're into electronics, you probably know - and use - breadboards. But if you're new to the game, these handy devices will make it a lot simpler! Here's a brief introduction. Using  Breadboards T hese imentation, onto PCBs, days, 99% or circuit Printed of electronics development Circuit Boards. projects and "proof But arefor soldered of exper- concept" (ie, does it work!), nothing beats a solder-less breadboard (sometimes called a prototyping board). Every hobbyist and even professionals should have one or more of these in their arsenal! They're available in various sizes, depending on your particular applications. However, it may be that you have never used one of these before so a few words of explanation now might save a few tears later! What are they? They're simply a way of mounting and connecting components, thus making it easier to work out what you're doing and at the same time, minimise the chances of components or connect

For previous parts of the article, must see page 1 here. Chassis restoration Superficially at least, the radio looked reasonably serviceable as it came to me. The speaker had obviously been replaced at some time in the past, because the Plessey brand did not appear until the 1960s, well after the set had been manufactured. The replacement speaker was also a twin siliconchip.com.au  cone type which made it all the better for quality though not authenticity. A couple of problems were also immediately evident. First, the wiring to the grid cap of the 6U7 was in rather a poor state and would have to be replaced. In addition, the external insulation on the mains transformer had broken away, exposing the low voltage filament winding. Removing the chassis exposed further problems. The first thing I noticed was that it was covered in a uniform brown staining that was particularly evident on the plates of the tuning gang. This radio had obviously spent quite some time absorbi

Here is the video on the subject: T HE of Pye's MODEL Manufactured in 1951, it reflects the shortages imposed by World War 2 on Australian society at the time. The first thing you notice is that the simple timber case is made of 5-ply timber. In this respect, contemporary timber cabinet Astors and STC radios both had similar minimalist construction techniques during the early 1950s. The veneered cabinets have character but they don't really compare to the high-quality timber cabinets seen on pre-war radios. Pye's model APJ is some 520mm wide, so it is quite a large mantel ra dio. It uses a fairly standard superhet circuit with a proven valve line-up and the only two real advances incorporated into the radio for the time are a thermo-mouldable plastic surround (i.e, not Bakelite) and a 6AV6 miniature valve. As well as tuning the standard broadcast band, this radio also covers three shortwave bands and the dial shows the wavelengths on which major Euro