As previewed in an earlier post, this is a preamplifier designed by Shaan and offered for sale in a group buy at DIY Audio. It is fully discrete, Class A with an integrated power supply. The twist is that it offers adjustable (from less than 0.001% to over 1%) single-ended, predominantly second harmonic distortion. In…
Category: Hardware
Elliott Sound Projects P113 Headphone Amplifier
I’m a fan of the projects on Rod Elliott’s ESP site as they come with lots of information to help you understand the circuit, and most are simple and robust enough for entry-level DIY hobbyists. Yet this does not mean these are low audio quality circuits, Rod specifies this P113 headphone amplifier as a very…
PeeCeeBee Preamplifier Preview
An envelope dropped through the letterbox yesterday morning containing a PCB I’m quite excited about, a preamplifier with a twist. In a similar vein to the Pass H2 harmonic generator, this preamplifier has a real-time, adjustable harmonic distortion level. The circuit was designed by Shaan and is offered for sale in a group buy on…
DC Splitter for Bench PSU
There is often a need for a dual voltage supply when dealing with audio (op amps often require dual supplies for example) but there may not be a suitable one at hand. There is, however, usually a single supply, a wall adaptor, bench supply etc. and, at its most basic, all that is required to…
Another buffered opamp headphone amplifier
For no particular reason I built another headphone amp. This one is similar to the Emmeline XP-7 clone I built, in that it utilises op-amps with buffers. The complete setup comprises three components; the amplifier itself, a dual power supply, and a delay circuit, all of which are slowdiyer designs. The amplifier is relatively straightforward…
Headphone amplifier power outputs
Following on from my last post where I showed the headphones dummy load, I thought I would post the measurements I obtained from the other headphone amplifiers I have built. It’s also an excuse to play around with my new toys. I knew that eventually I would end up with an oscilloscope, I spent a…
Headphones Dummy Load
A dummy load simulates your headphones by presenting the amplifier with an impedance as close to that of your headphones as possible, using high wattage resistors. There are a number of reasons you may wish to use this – but primarily you are able to protect your headphones and your hearing. You can use higher…
RJM Audio Sapphire 4 Headphone Amplifier
I came across this headphone amplifier project about a year ago on DIYaudio.com. Built using the default choices, the class A output buffer provides 30 mW minimum output power into all headphone loads between 30 and 600 ohms. One of the things that impressed me was the continual input the designer Richard Murdey had on…
Nelson Pass H2 Harmonic Generator – Update
The events unfolding around the world at the moment are having impacts unheard of for generations. I am lucky; I’m well, I still have a job at the moment and am working from home, but, like many, that job may not be there for much longer. Whilst I am probably busier than normal as I…
ICEpower 50ASX2(SE) based Integrated Amplifier
I bought an ICEpower 50ASX2 amplifier from Ebay in 2018. It was an impulse buy if I’m honest as it was very cheap, they retail at about £100 in the UK and I got it for £35, but it’s been sat in my drawer since then waiting for a purpose. I must admit, I’m running…