UNCLE DOUG: Valve Amplifier Explainers

I could just bookmark these in my browser, but hey…   here they are.   If you struggle with complex explanations of how valve amplifiers work, here’s a collection of easy to understand valve amplifier basics from Uncle Doug.  Don’t let the pets and other distractions put you off – there’s really good information in these videos.   … Read more

BELL & HOWELL: Model 601 Amplifier Conversion Project

Screenshot 2024 11 24 at 3.23.52 pm 19bbff518f98

When I started this project, I knew some people prefer to keep these amps stock. However, running something with electrolytic capacitors from 1948 seemed like a disaster waiting to happen. If one failed, it would be a nightmare to fix. In fact, if anything failed, the cramped design would make repairs extremely difficult. On top … Read more

BELL & HOWELL: Gaumont, Model 601 Projector Amplifier, 1949

Bell Howell Model 601 stack f3b4c5075f7e

I know, I know—this is starting to drift even further from pedal circuits with each post, but stick with me for a moment. These old Bell and Howell projector amps have quite the following, so I’ve been keeping an eye out for one for a while. The catch is, they don’t pop up on the … Read more

PHILIPS: 976B Valve PA Amplifier, 8 watts

Philips 976B front b86800e68b09

eBay purchase – it listed a bit on the high side, but after a quick chat the seller revised the price down to something very reasonable, so I couldn’t pass it by. External references:  Tim Robbins blog.  Radio Museum  PHILIPS MODEL 976B, VALVE PA AMPLIFIER Made in Australia in the mid to late 1950s, this … Read more

STEANE’S SOUND SYSTEM: Model S 311 Valve PA Amplifier

SSS S311 front 2521c726bb98

I picked up a couple of valve PA heads on the cheap, without valves, so jotting down a few notes for later.  I believe that this is almost the same as a Philips 982, based on early observations.  The preamp was converted to something very similar to the Marshall 18w, with two inputs, volume, tone … Read more

PHILIPS: Model 956B Valve PA Amplifier

Philips Model 9565 PA head front 07152dda5c2a

Yep, another valve PA head.  Adding details as I find out more about this one.   PHILIPS MODEL 956B VALVE PA AMPLIFIER I’m still looking for information on this one, apart from what appears to be an almost identical amp made by Steane’s Sound Systems, Model S304 amplifier.    Steane’s operated in Australia somewhere up into the … Read more

AWA: Model PA1003 25w PA Valve Amplifier

AWA PA1003 front panel 799835132a16

AWA was one of the big names in Australian electronics for decades.  Formed as Amalgamated Wireless (Australasia) in 1913, it went on to build everything from radios and communications gear to TVs and commercial audio equipment, so by the time this PA1003 was made in the 1960s, AWA was already a very familiar name in … Read more

VOX: Modded Vintage AC-4 schematic and tagboard layout

Vox Ac 4 schematic trem removed 589dc11164a1

While I’m in the process of modding / rebuilding some Vox amps, I thought I might try the original Vox AC-4 from 1962, or at least a simplified version of it.   Here’s a link to the full vintage Vox AC-4 schematic and amp details. Apart from the simplicity, I want to try something with an EF86 … Read more