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 »
I bought an AD9833 DDS module from China – you know the one: I wanted to control it from an Atmel ATtiny and my weapon of choice was the ATtiny44. Now I could just have easily used an ATtiny2313 (both devices are 14-pin), but I didn’t – and I went on and built a PCB.… Read More »
Alan Wolke (W2AEW) has posted an excellent tutorial on YouTube covering an introduction to the theory and operation of JFETs and MOSFETs. I highly recommend this video.
Following on from my previous blogs about Connecting Loudspeakers to Amplifiers and Passive Dummy Loads for Amplifiers here is a project for a modest passive dummy load with a twist – I have included a differential ‘scope probe to facilitate monitoring of the signal on an oscilloscope. I managed to score a new-old-stock Grayhill switch… Read More »
Following on from my previous article on matching amplifiers and loudspeakers, this article offers some ideas for making passive dummy loads. Active dummy loads are fine, but if you need to test an expensive amplifier at full load, you do need to be pretty confident that you are connecting a load which is going to… Read More »
Note: Some amplifiers will be very unhappy if you max them out without an appropriate load – and inappropriate could mean open-circuit, short-circuit or just too high or too low. This article covers the basics of connecting loudspeakers to amplifiers – in this case I am thinking of solid-state guitar amplifiers which are generally going… Read More »
We don’t do much SMD (surface mounted) work here at Stompville. When it comes to the True Bypass Relay however, smaller may just be better, so we designed and built a surface-mount version to see how small we can realistically make it – and the answer is about 30% smaller. That is 30% smaller on… Read More »
Update: Please see also Phantom Piezo Preamp revisited Update: Phantom Piezo Preamp modules are available for purchase in the shop here. A few years ago, Alex Rice put a design up on the internet for a phantom-powered JFET piezo preamp. Here’s the schematic of the original design as reported by Zach Poff: So far so… Read More »
Idss for the 2SK596s JFET – as introduced in my previous blog – is an order of magnitude lower than (say) a 2N5457, so I have been revisiting the design of my Arduino-based automatic JFET matcher to be sure that I can use it to characterise the 2SK596s with good resolution. Along the way, I… Read More »
UPDATE: The 2SK596S is discontinued from OnSemi. I bought some 2SK596S-C low noise JFETs. The device comes in a type SPA (SC-72) package similar to TO-92 (shown above on the right for comparison) and is otherwise notable for having very low Idss. It seems there were originally two versions of the 2SK596S (ranks A and… Read More »