Certain methods of handling components and installing them can make the already “easy” task of PCB assembly even simpler. With any kit or project, it is best to organize the components. If it is a kit, empty the parts out of the bag, identify them, group them, and make sure everything is present. Look at[…]
Category: Tech Articles
Learn more about tube amp and hi-fi audio design in these articles by Kevin O’Connor.
Hammond Transformers for Tube Audio Amplifiers
The specs for each Hammond output transformer are listed along with our own supplemental data. We have standardized the listings to make transformer selection and amp design application simpler. This transformer information appears in print form in our book, The Ultimate Tone Vol. 5 (TUT5), along with details of output and power transformer matching procedures.[…]
Cathode-Bias/Fixed-Bias Switching in Tube Power Amps
~The following is an excerpt from our book, The Ultimate Tone – Vol. 2 (TUT2) by Kevin O’Connor Vintage guitar amps often produce a tone that is described as “round” or “mellow,” and they can produce a desirable overdrive sound. Some of these amps are low powered, and others have lower supply voltages than later[…]
PCBs – Colour Considerations
PCB SOLDER MASK AND SILK-SCREEN COLOURS Printed circuit boards are now available in an array of colours, allowing hobbyists and manufacturers the opportunity to achieve a “signature” look. London Power has traditionally used green PCBs, but lately we wanted to see what yellow boards would look like. The obvious choice for the silk-screened printing on[…]
PCBs vs. Hand Wiring
PCB Facts Myth: electronic equipment built on printed circuit boards (PCBs) is somehow “inferior” to hand-wired equipment. This belief is perpetuated by some amp builders, hobbyists and amp reviewers who do not have enough of the facts – let alone “all of the facts” – about this subject, rendering their statements too sweeping and frequently[…]
Standby Switches
Misunderstood and Hazardous The design of the earliest guitar amps was not so much “beginning with a clean slate” as it was an application of hifi circuits for use with pickup-equipped guitars and basses. Portable hifi gear was not new -just the intended use. Clean sound reinforcement was still the mandate. Tube manufacturers “of old”[…]
Power Scaling vs. Variable Power
Electronics often allows for the accomplishment of a particular goal in many different ways. For guitar amp users, controlling how loud or quiet their amp is while achieving a “cranked” sound has always been difficult. Attenuators can be placed between the speaker and amplifier to provide some means of control, but they tend to alter[…]
Raw Bias Supply Issues & Mods
Need a More Capable Bias Supply? Often, when implementing mods or improvements, you’ll need a raw bias supply that is higher in magnitude or capable of more current delivery than your existing bias supply. Low Impedance and High Impedance “Low-impedance” supplies are either a tap or dedicated winding, with a rectifier and filter cap. Minimal[…]
Super Scaling Q&A
What is Super Scaling? The ultimate source of accurate information regarding Super Scaling is found in our book, The Ultimate Tone Vol. 4 (TUT4) (and the two Super Scaler projects in TUT5). • Super Scaling is a technique that allows the power output of a small amplifier to be boosted to a higher level to[…]
Power Scaling for Tube Amplifiers – Q&A
What is Power Scaling? Power Scaling’s goal is to achieve the same tone as one’s preferred “loud sound,” but at a much lower volume. The method can involve one of over sixty distinct approaches, each with many variations. Power Scaling™ is a methodology developed by Kevin O’Connor of London Power. Is Power Scaling simply power reduction? • No.[…]
