I'm no blogger, but very occasionally I'll add bits of news below:
Why I probably won't answer your email
As anyone who's looked at my contact page will know, I do my best to discourage folk from getting in touch. That's not because I'm rude or antisocial; it's because I get a lot of email and really struggle to find the time to reply properly. I feel constantly guilty about this, not least because I've had some fantastic conversations in the past with a large number of people. But those positive interactions mostly pre-date social media. It's really sad to watch the trends that have emerged since then - a decline in the quality of written communication along with an increase in expectation and entitlement. I'm generalising - a lot - but also not imagining it!
A few weeks ago I recieved an email that I really should have just ignored. I very nearly did. But I happened to be in front of the computer at the time, and knew that I would have pockets of time during the day, so decided to try to help. It didn't go well.
After dwelling on it for a while, I've decided to publish extracts from the exchange. The consent box was ticked, but even if it wasn't, I have reserved the right to publish emails that violate the terms and conditions of the contact form.
Here's what arrived:
Subject: MF preamp schematic
Good effort but too many errors to be taken seriously let alone trust it. Most opamps (including the psu) are drawn without proper closed loop fb , the IRAA stage has no defined gain blocks etc
If you have a corrected schematic please feel free to let me see it.
G-----
079--------
The confrontational tone of this message would normally be enough to prompt me move the message to the "Ignore" folder. But as I say, I had the bandwidth to have an email conversation at the time, so thought I'd give it a go - partly to see if I'd misinterpreted the tone in this opening salvo. I won't publish the whole exchange at this stage, but would consider doing so if enough people request it.
Two things were obvious to me: firstly, G doesn't understand how it works, and secondly, G hasn't read the explanations on the webpage. However, I patiently explained that my sketch does indeed match the official schematic, and yes, all op-amps do have closed loop negative feedback, and yes, the IRAA (sic) stage really does work properly. I also asked G to list the other issues, but despite repeating that there were many, we never did get beyond these two points. I don't think G really did have any more, and was merely grandstanding.
Credit where it's due - I was thanked for my time more than once during the exchange. But at no point was any sort of appreciation shown for the insight. Perhaps that means that G still didn't understand? Or was too proud to admit that they'd misjudged something that was relatively straightforward after a taking a minute or two to think about it? That's a common human reaction that I try my best (not always with 100% success!) to check myself for. I happily admit on the webpage (and in the email exchange) that I'd had similar moments of confusion when I first produced the schematic, but that experience has taught me to not dismiss unconventional things out of hand - instead, there is often much to be learnt from such circuits. A bit of humility and an open mind goes a long way.
I was asked to call G's mobile number more than once. But I'm not a helpline! Quite apart from the time it would take, why would I call a complete stranger, thus revealing my mobile phone number? Plus, from the tone of the communications so far, I feared that I would be on the receiving end of a rant. Or worse. To be honest, that felt rather "pushy" to me!
Once we got to the point where we'd established that there were no mistakes in my 25 year old hand-drawn schematics - schematics that no-one else had ever complained about over the last quarter-century, including Tim de Paravicini (RIP), who of course was the original designer - I very gently suggested that G might wish to reconsider the tone of the opening message. I'm not sure what I was expecting here. Perhaps an apology, but even I'm not that naive! But I made sure the door was open for a graceful climbdown, perhaps something along the lines of "Oh, now that you mention it, I can see how that could have come across as a little brusque, but that's honestly not what I intended". Whatever I might have been thinking, I certainly didn't anticipate this:
Mark
you should learn to draw accurate schematics mate you are obviously not an engineer never leave things to interpretation: be factual and unambiguous.
I don’t like your attitude so lets just leave things as they stand and forget it.
Thanks for your time.
G-----
I'll be honest here. I thought this was absolutely hilarious! Perhaps on another day I might have taken offence, and reckon I'd have every right to do so, but I'm not that thin skinned. Sorry, G, but this reply says almost nothing about me, and everything about you.
Even though the schematic was only sketched out for interest, there is nothing that is ambiguous about it. The point G is referring to is how the PSU connections to the op-amp sections in the phono PSU are shown. But these are done using a kind of "call out", which is completely industry-standard. In fact, I made it even more obvious by putting these immediately adjacent to the relevant op-amp section, which emphasises how IC2b controls the positive rail and IC2c controls the negative - in my line of work, I draw schematics in a way that assists understanding, which is in contrast to most manufacturer's schematics, where getting it on as few sheets of paper as possible is the main objective.
Not recognising these call-outs demonstrates a lack of experience. A further example of this came earlier. After I explained how the op-amp was powered, G came back saying that they'd assumed the op-amp was actually powered from the unregulated ±24V rails. Needless to say, not many op-amps can run from that sort of voltage, and certainly not a TL084! This also proves that my existing explanations on the web page had not been read.
Just in case you'd like to take a look at the schematic in question, here's a link to the phono PSU. As mentioned, it was drawn over 25 years ago, and has been floating around the internet for all that time, and no-one, including the original designer, has challenged me about it before. Not that I would have minded, as I welcome corrections, but there are ways to go about it.
Being told I'm "obviously not an engineer" was a new one to me - I'd better get my resignation letter to my boss forthwith!
I get that no-one wants to be wrong. But when you are, doubling down on it is really not a good look - albeit one that seems to be the norm in some areas of public discourse today, sadly. Resorting to ad hominem attacks is also far too common now, and while it's a sure sign the argument has been lost, it doesn't change the facts. As I said originally, it was clear that G hadn't read the explanations and didn't understand the circuit. That's not my fault. But apparently, it is my problem. At least I tried to help.
For better or worse, I did reply. I remained fairly polite, but was a little more direct than usual. I doubt it helped.
So anyway, if you don't get a reply from me, it's possible that my radar has picked up the risk of another exchange like this. It might be worth considering this before trying again. But then, there's a host of other potential reasons - most of which are listed on my contact page. Of all those reasons, the most common one is simple: I don't reply because I don't understand why the person thinks I might know the answer - perhaps it would be obvious with a bit of context, but that's rarely included, so many questions just seem totally random to me. Another factor is that I don't expect to get a reply to many emails - it's usually obvious when the author is employing the scattergun approach to getting an answer by pasting the same text into many other forms and messages. For those, I usually reply with a quick line asking for more background and nearly all of those go unanswered. I learned a long time ago that sensible 2-way communication needs to be established with short messages before diving into the long, detailed response!
Finally, let me know if you think I'm being too sensitive and need to move with the times, or if you think I should go for broke and publish the whole conversation!
New ISP
I have changed my ISP. "So what?", you might be thinking... Well, given that I'd been with PlusNet for nearly 20 years it was a quite a big deal to me at the time, but let's not get into all that here. Perhaps I'll write about it separately one day...
However, this means 2 things. If you and I have exchanged emails in the past, my old Force9 email addresses were provided by Plusnet, so these will no longer work. To get back in touch with me, please go to my Contact Me page.
Next, my PlusNet webspace has gone - not unreasonably, of course. I flagged this up as a future problem back in 2014 when I took out my own domain name - at the time, I replaced the content on the PlusNet webspace with re-direct pages, and as a result there are generally fewer links to the old site than there used to be, but inevitably there will still be plenty out there. Many of these won't be easy to change - for example those on discussion forums - but if webmasters have sites with links to my old URL could update their links, I'd be extremely grateful.
Trialling a new contact mechanism - Update
Things seem to be working reasonably well. I have tidied up the code, and added some JavaScript to validate the form interactively before it is submitted (it's also checked on the server because some people disable JavaScript). I've also opened up the Guestbook. Thanks to the previous facility being disabled by my ISP, I haven't had a message left for me since June last year, so desparately need some submissions before the end of 2015 - I'd hate to have a blank year after all this time! Please, feel free to sign my Guestbook!
Trialling a new contact mechanism
For many months now, visitors have been unable to get in touch via the contact form. This is because I was using a simple script provided by my ISP, but they decided to take it down because of security concerns.
Since then, providing an alternative has been reasonably high on my priority list, but I can't pretend that the lack of messages hasn't improved my work-life balance! Still, I've just had a bit of spare time, so I've put something together. It is highly experimental, and no-doubt will need to be refined as time goes by, but let's see how it goes. Initial tests are encouraging.
As always, please understand the time pressures that I am under, so if you are asking a complex question, it will take a while to get back to you. But feel free to test the form, and if it seems to be working, I'll write one for the Guestbook as well.
I apologise for the time it's taken to get around to this, but in fairness, I can be found in a handful of forums if you look hard enough.
Go to the contact me page...
New Website Home!
As of 2014, this website has a new location - http://www.markhennessy.co.uk/ - please update your bookmarks! Old bookmarks and links will be redirected to the new location for the foreseeable future, but if I ever decide to change my broadband supplier, the redirect pages will probably be lost.
And that's all you need to know - please feel free to stop reading now. But, this move has prompted a moment of introspection, which turned into the rambling thoughts that follow for anyone who might be interested in my little bit of the web:
I have had a website since 2000, and it has gone through many changes in that time - though fortunately for me, the Internet Archive hasn't captured the most embarrassing of the early versions!
In all that time, I've simply used the hosting that came with my ISP. Of course, back in those days, an amount of web space was an important part of the offering - even the free "pay as you go" dial-up accounts came with a decent chunk of webspace. The allowance was pretty generous back in those "Web 1.0" days - I think it was something like 25MB.
Anyway, that served me well. No pun intended! My early webpages were little more than experiments; I fancied learning a bit about HTML, and my learning style requires me to actually do something to figure it out, and to do that something, I need some form of motivation. Some pretty webpages that my friends could see (and mock!) did the trick, and I enjoyed it. Back then in those BC (before childen) times, not only was I building stuff, I had the time to write it up for half a dozen people to see. Happy days...
Then, sometime in late 2001, Google discovered it. And suddenly, I was on the front page of search results for a variety of obscure queries. Emails almost literally started flooding in. I exagerate only slightly! Emails that were from people I didn't know. Emails that were not mocking in any form. Suddenly, the word was out there, and I can't tell you how strange this felt at the time! Remember, this was 2001... Everyone has a website today - it's so very easy to throw together a Wordpress site or similar - no need to learn HTML or anything, but back then personal homepages were the preserve of a certain type of geek. What had I become???
So anyway, encouraged by feedback, the website gradually grew through several different styles, with a major relaunch in 2004. I remember how modern it looked back then, yet how dated it was when I finally refreshed it at the end of 2013! Sadly, I haven't had much time for the website in recent years because I've been so very busy with more meaningful things like moving house and starting a family. Hopefully, things will gradually improve as time goes by.
Anyway, I digress. Back to the hosting.
Towards the end of 2004, Force9 (Plusnet) had the audacity to start monitoring the traffic used by websites hosted on their servers. I mean! With the free service I was using, I was entitled to 100MB per day, but it turned out I was using well in excess of that. A series of measures quickly took place - reducing image sizes being one - which helped initially. The really sneaky move was to set up additional free accounts with Force9, and divide the website across them - Force9 had no problem with this, and eventually I ended up with a total of 4 free accounts, giving me a massive 400MB per day. This was quite a faff - making sure links worked correctly was awkward to say the least - but at the time I couldn't justify anything that involved paying cash. Remember that I make no money whatsoever from this website.
Despite this, however, parts of my site would occasionally get taken down, which required another round of grovelling emails to Plusnet technical support, giving them my assurance that it wouldn't happen again. But how in all honesty could I promise that? I'm not able to control who visits my site, and I'm not able to prevent links to my site being placed on popular blog sites like hackaday.com and instructables.com. Much as I like Plusnet, this aspect of their service is very poor, and with no sign of it improving any time soon, the move to a dedicated web host was inevitable.
For those who have never done this, it's an amazingly difficult consumer decision - there are so many web hosting companies out there, and it's nearly impossible to make a sensible comparison between them. I couldn't come up with a shortlist, and in the end went with a recommendation from a friend - although as you chase back that decision it sounded like it was pretty much a random choice at the time. Let's see how things go - it does seem reasonably simple to change web host if required.
I've registered this domain name via a different company. Although many of the hosting companies offer a domain name as a free part of their service, it seems to me that it's best to keep this separate - at the very least, that makes it easier to move hosts. A domain name company merely pays to register the name - once set up, there's actually very little they can get wrong (famous last words!).
Anyway, I now have "unlimited" bandwidth, so things should be rather more reliable now. It means that I can use more pictures, and rely less on the thumbnail-enlarge model that was appropriate in the dial-up days. And of course, I have the option of PHP/MySQL interactivity now, so perhaps a blog engine or image gallery could be used. We'll see.
I have lots of ideas for new content, but bitter experience has taught me not to make promises. I will say that I have about 4 half-written loudspeaker reviews and some basic electronics stuff that needs a lot of work to finish. I also have a house to fix and a day job!
Anyway, for anyone who has read this far, please update your bookmarks!
Thank you.