Subjectivist thinking is flawed.   Subjectivist arguments always depend on a misrepresentation.   If a scientist is worth his salt he will defeat a subjectivist on a level playing field.   In order to maintain a subjectivist outlook a disorganized personality is required. A inconsistent...

I discovered this morning that my cancer is terminal, I have 6+ months to get my affairs in order.   I have been giving away intellectual property for a few years. I have some remaining circuits and code I intend to put into the public domain, and I may be calling your attention to the virtues...

I've seen a few requests for Cmoy power supplies. This is a subject I've dealt with before. Here's yet another idea... This can also be made to run off an AC wallwart by building a voltage doubler instead of using the bridge. Of course you can build it for a fixed voltage by substituting a...

I've just been reading some stuff on Roger Sanders site. http://sanderssoundsystems.com/technical-white-papers/esl-amp-bias-wp. Sanders Sound Systems make ESL systems, everything but sources. What particularly caught my attention was this... 'Keep in mind that for most humans, the threshold of...

Here are schematics and simulations of 2 electrostatic amplifiers. These amplifiers were previously posted both on esldiy and on my website on December 26th. 2013   The first uses DMOSFETS throughout.       This second uses both DMOSFETS and 6SN7 tubes.      The credit for one...

A few months ago I bought some 4P1L tubes. They're Russian, directly-heated pentodes with a plate dissipation of ~7.5W. With octal bases, they're readily available at reasonable prices.   I always had a fancy for building a hybrid with the solid state at the front of the amp. The usual thing...

'Merry' is not how I usually express myself, but what the hell, it's traditional.   Only just under an hour to go here. Wishing all the frequenters of the DIY section, and all the other Head-fi members without exception a good one.   Fred (w)

I've just been listening to / viewing the BBC production of the Rolling Stones playing Hyde park, which was re-released recently and was available via the BBC iPlayer. As the title says, I was using my recently acquired Tesco (brand) hudl tablet. I listened using my Klipsch Image S3 iems. Volume...

Since there isn't a thread on this, I decided to create one that I could point to...   People think, 'Soldering. How difficult can that be?'   The answer is, 'As difficult as you want to make it...'   The fact is, there's a wrong way to solder, and that's the way most people...

You may have noticed that some of my projects have become a bit erratic recently. This is in part because I have been distracted, waiting for the results of various medical investigations. A couple of days ago I discovered that yes, I have suffered from a recurrence of the lung cancer that I had...

I don't think much of virtual ground circuits, but I drew this:-     As drawn it draws just 1.4mA, has an output offset of 6 nanovolts, and an output impedance of ~0.1 ohms. Build it with the LT1097 shown for the best performance, pretty much any complementary NPN/PNP pair will do, the...

Here's an idea I've been playing with...     I recently 'discovered' how to make circular PCB features.   I used to make footprints for tubes by drawing a silkscreen circle, and then using trigonometry to calculate the positions for the pads to the nearest thou. It works, but...

In the UK we have a well-known radio program, Desert Island Disks.   A celebrity is asked to select 10 disks (single tracks) that they'd choose from all the music in the world, that they'd like to have if they were marooned on a desert island.   Now, you've probably seen this:-  ...

A little while back I made a passing remark about writing a programming example for Microchip PIC.   Avro_Arrow said at the time that he would be interested if I took it on. I've been a bit remiss in keeping up my discrete amplifier co-operative design effort with him, so I'm going to write...

I designed this:-       Bits came yesterday. This is just the trial fit for the parts.   It says lo-cost in the thread title, but that's comparative. The parts cost is at least twice what you can build a very good solid-state amplifier for, $220 - $250 including chassis.   I...

I bought some of this stuff (or similar):-   http://www.ebay.co.uk/itm/Conductive-Wire-Glue-Paint-NO-Soldering-Iron-Gun-Solder-/320599571856?pt=UK_Home_Garden_PowerTools_SM&hash=item4aa5393d90#ht_1416wt_1398   It's carbon loaded glue, the stuff I bought claimed to have carbon nanotubes...

Since I had an AD 8397 kindly supplied by Analog Devices, I thought I should work up a circuit.       The circuit is a compound design with 2 opamps, an LME49725 and the AD8397 in a global feedback loop in the amplifier proper and a third OPA2277 employed as a DC servo. A high...

I know this doesn't really belong in DIY, but this is where I mostly hang out. I don't really have anybody else I want to tell.     Tonight our beautiful grey and white cat Indigo Spatz, the Indysaurus, brought himself home for the last time, missing half of a hind leg and with the other...

Things rattle around in your head (they do in mine anyway), then eventually they fall out.   I'd really like a straightforward way of measuring THD, preferably one not involving spending a great deal of money.   It occurred to me to write a program to create some .wav files with tones at...

I guess a few people had the same reaction as I had when I first saw announcements about the credit-card-sized computer that would run linux with a full GUI. Cool. Where can I get one? When can I have it? Yesterday? Anyway it actually arrived the day before yesterday, but I didn't have all...

Here's the first:-     It's no more than the headphone amp reference design from the LME49600 datasheet with the addition of dual regulated power supplies. There is a slight departure in that the servos don't use amps from a second package, but rather each channel comprises one LME49600...

  A while ago I posted details of my first experiment with the TPA6120, a high-performance headphone amp IC from Texas Instruments.   More recently I have shown a design using multiple NE5532s in parallel, combined with a PGA2310 stereo volume control, a chip which again has an impressive...

Avro_Arrow suggested I post in the 'Rate My Etching Job' thread, but there's so much of this, I don't want to take over that thread.   I've seen a few posts about PCB fabrication. Many people use toner transfer, but I've always used photo-etch.   Here's how:-   This time I decided to...

I've answered a couple of questions recently about power supplies for low-power amplifiers such as cmoys.   It's better to use a supply with a true ground rather than the virtual grounds that are used with many amps which run off a single battery or DC wall wart.   I like to use a supply...

Thinking about paralleled opamps for a headphone output stage as I was, I suddenly remembered the Douglas Self power amplifier I have seen, which uses paralleled NE5532s. That was it, I had to draw up a few PCBs for a headphone amp.   Performance should be extremely good in theory. I can't...