The big day arrives!

Actually it was yesterday, but I finally managed to complete a fully-active speaker project – yay!

This is a “2+1” design with SB23NBACs in sealed enclosures as bass modules and then a sealed 2-way top using the SB Acoustics MW19TX-4 and the Mundorf AMT25, both of which I have shown off earlier. The whole thing is activated with Hypex Fusion plateamps (FA251 + FA122) – one in each enclosure.

The idea is that right now it works as a set, but I can then experiment with adding other designs as the “top section” and keep the bass modules (which also function as stands) to provide the bottom end. This is similar to my previous passive design with Scan Speak 26W’s, but the SB23s should provide similar performance in a smaller box, and the built-in amp and DSP should of course improve the flexibility and performance as well.

When I say the project is “completed”, what I really mean is of course that I managed to assemble and set up the speakers, load some very basic filters into the amps and do some testing. Soundwise these are very far from where I hope they will (eventually) be, but even so I can still get an impression of what the drivers should be able to offer. Especially the AMT tweeters seem to be every bit as good as I expected them to be – nice!

As the pictures reveal the finish is clearly still “work in progress” – raw MDF and a bit rough at that – but it still looks much better than my previous attempts at enclosure building, so I am making progress there as well. I did not want to wait to properly finish the enclosures because any painting/veneering will have to be done outside, so it would have meant a delay of at least a couple of months. The speakers are made to be disassembled enough to allow getting back to painting/veneering later on anyway and another option is to build a proper “revision 2” of the cabinets instead.

Other lessons learned so far:

  • I’m still perfecting my cabinet build sequence, but the only thing I think I forgot this time was to chamfer the inside of driver cutouts on the 30mm front panels – not the biggest issue in the world with the chosen drivers.
  • Active speaker cabling really is a PITA! With power, signal and control signals to every speaker it really is a mess now, so to use this as a permanent setup will require some “optimisation” here.
  • As much as I like and admire the Hypex plateamps for their functionality and sound quality, experimenting with different sound settings is a royal faff when you have to update 4 plateamps manually via USB. I think I’ll try and get my “proto-amp” finished and then find a suitable front end that allows me to do all the tweaks from one place instead.

This is of course not my only “in-flight” speaker project (not by a long shot), but it’s still a good feeling to get something mechanically completed and finally be able to start the journey of tuning the sound 🙂

Monkey first!

I don’t normally make new year’s resolutions, but if I did…

In my professional work I have often used the principle of “Monkey first” to describe to others how to approach complex and costly IT or business projects. If this saying is meaningless to you, it comes from the head of Google X, Astro Teller (yes, I believe that is his actual name). He uses it as a metaphor to explain that you should always start with the most complex and risky part of a project – because if you can’t accomplish that part then the simple parts don’t matter.  (My paraphrasing – read the full story here)

What does this have to do with DIY audio I hear you asking?

Only that I actually tend to start a project by making a lot of the ”easy” tasks (like coming up with new ideas, designing PCBs and front/rear panels and – especially – buying parts for projects) instead of focusing on the “hard” work of building projects to confirm that they work. This means that the project pile grows and grows, and it also means I commit money and space to things that can’t really be finished – although to be fair that is probably the reason I’ve been able to keep this blog going for ten years… 🙂

To be perfectly honest this new and sudden level of insight hasn’t really been triggered by a new year, but more by a few recent less-than-successful designs where the time and money committed to the project on “simple” tasks turns into a bit of an annoyance when a “hard” task then trips up progress.

One example is the picture below, a simple TDA7294-based amp that is (so far) refusing to work, while the $100 chassis and the $60 transformer I have already bought for it are waiting patiently on the shelf…

So, maybe in 2023 it’s time I started following my own advice? 🙂

Happy New Year!

The time has come to close another year. For some I guess 2022 is a year best forgotten, but luckily not so for me.

My posting-pace on the blog has slowed yet again, partly a reflection of other commitments, and partly because it’s getting harder and harder to justify spending time and money on building stuff I don’t need. I’m not done yet though, so expect I will continue to post from time to time.

2023 is also the year of a pretty bit milestone for this blog – it’s tenth anniversary!. On one hand I am surprised, because ten years is a long time. On the other hand I had been involved with DIY audio for more than ten years when I started the blog, so it’s probably not so surprising I’ve kept at it.

So, slow pace aside, I wish everyone reading a very happy New Year, and I fully expect to be able to close out next year as well here 🙂

Gold glitter Happy New Year 2017 background. Happy new year glittering texture. Gold sparkles with frame. Chic glittering invitation template for new year eve.

Project files: B1 R2 buffer/preamp

It’s been a while since my last project files-post, so it’s a good feeling to get this published – and on Christmas eve to boot! 🙂

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Improving the B1…

If you’ve been following the blog for some years, you’ll likely know that I am a big fan of the Pass B1 buffer. I’ve built several versions and my own board layout has been one of the most popular designs shown here. It’s also almost 15 years old now (!) – oh how time flies!

The reasons for my fascination with the B1 are many: It’s a simple and elegant design; it sounds very good; and the lack of extra gain is very often a big plus because many modern signal sources have a high enough output level as-is. However, the single-supply original version of the B1 requires bulky/expensive/poor-sounding capacitors in the signal path, and so a DC-coupled version with a dual-rail supply that doesn’t require capacitor coupling seems an obvious next step.

There have been a few of those (for example the “DCB1”) but they’ve been more complex and so in my view don’t have the same appeal as the original. However, it turns out Nelson Pass also did a ”B1 R2” version with a complementary JFET pair (SK170/SJ74). I think I saw this some time ago, but I was a bit shocked to learn that it is actually much older. Since it’s possibly even more simple and elegant than the original B1, it was the perfect project to restart doing PCB layouts for the winter season (as described here).

The result is one of the cleanest PCBs I can remember doing, and fortunately it also works as expected. The version shown here has an onboard volume pot to make it a complete preamp, but there is also a version without the pot that should be even more versatile (and usable e.g. as a class D input buffer).

I don’t need this right now, but as it is a very versatile design it’s a good one to have in the arsenal for future use. Project files coming soon, probably just after X-mas 🙂

Change of pace…

All summer long it’s been really motivating to stay outside and do woodworking or house DIY projects. Now it’s dark and gloomy outside, so for some reason sitting at the desk doing electronics or PCB layout work seems a lot more attractive – good!

Also, Christmas is of course coming up. That inevitably means a) enduring a few weeks of pre-Xmas panic at work and b) a short – and much-needed – break is on the horizon. If all goes to plan I’ll be away for some of the time, but I should still get a few days at home where I can focus on some DIY-projects.

I’ve already started preparing a little by doing some PCB layouts and making some board orders. After not really feeling like doing layout work for a while, inspiration has been pretty good over the last month or so. I’ve received a couple of board orders already and I hope to maybe squeeze in one more order before the break.

As for what’s included, I’ll start off by showing you the least interesting board I have received so far. However, rest assured there are a few more designs that are a bit more exciting still to come 😀

Taking stock…

The summer is definitely over in Denmark, and after the switch to standard (winter time) at the end of October it’s quite obvious that the “long winter nights” are very near. That means that after a long period of mostly outdoor projects, the desire to start on more “indoor” projects is coming back.

This year I have decided (or rather, the ambition is…) to tackle the pile of unfinished and half-finished projects, which to be honest has grown to an unsustainable level (hence the post title – something must be done!). Top of the pile for now is still to finish some loudspeakers (which is going OK) and there will – inevitably – also be some “quick wins” in the pile. Basically projects that I have paused with so little work missing that it seems stupid not to finish them.

I also have quite a few class AB amp designs that I want to try, both discrete and chip-based. Ironically, the speakers I’m building are mostly active and don’t require outboard amplifiers, but I think that’s just a minor issue 😀 Also, I guess I am not the only trying to clear out stock, because lately I have been able to pick up a few missing pieces (transformers and PSUs) which will allow a couple more of these projects to move forward.

Onwards and upwards! (or something like that…)

Getting lost?

Another long-ish dry spell. Not because nothing has happened, but because nothing worth reporting has happened 🙂

The last few weeks I have mostly managed to lose myself in combing through my parts haul from a few weeks ago. There was more stuff that I anticipated and while that was sort of a plus it also took lots of extra time to go through. Found some good stuff though, and of course also found a lot of stuff that will just take up space until I – eventually – decide to get rid of it …

Another thing I have managed to lose myself in is old Elektor schematics. I started reading Elektor Magazines in the mid-1990s more or less as I became old enough to understand them (in English/German). I recently saw that Elektor advertised their full “Archive” collection in digital format for a special price and I decided to buy that. Elektor is not primarily about audio, but the collection includes magazines dating all the way back to 1974, so it’s definitely possible to lose yourself for more than a few hours in all that content – and sometimes hard not to laugh out loud at how much things in audio, computers and electronics have changed over those years.

I don’t have the same attachment to the Elektor designs that I do to some of the designs from old Danish mags (like the NE headamp and the HF line stage preamp) but seeing some of those old magazine covers does bring back memories from many years ago. I haven’t found anything that I’ll go out of my way to build yet, but there are a few designs and ideas I’ve added to my list of projects to consider. In any case, It’s nice to have the whole collection to refer back to as inspiration and because the Elektor designs sometimes get quoted or resurrected in other places.

Lucky dip…

I’ve scored a few great deals over the years from my local classifieds site, and quite a few of those have made it to the pages of this blog – here is another one 🙂

It’s a (substantial) job lot of audio projects, PCBs and parts. It was on sale over the weekend with a “make me an offer” asking price and very little information except a few pictures that showed some audio-grade items and PCBs. That immediately caught my interest, because even though the prices of generic electronic components have shot up as well, parts that come from someone building audio things are much more likely to be interesting and usable for me.

I made the seller an offer on the box that was a bit low to compensate for the fact that not a lot of information was available. He responded with a slightly higher asking price, but offered me the chance to look at the box before committing to buy it. I only had a quick look and it was still a bit of a “lucky dip” as the post title says, but I could see enough interesting things to make it worth a punt. Most parts were in good packaging and also from sources that I recognize and generally trust (Mouser, TME, Reichelt etc.)

There is a lot of stuff here that I either have bought myself or looked at buying before, so the batch clearly comes from someone with good taste 😀 Now comes the fun part, which is to go through the things and inventory them in more detail and that might take a while. I was of course hoping for striking gold in the form of bags and bags of NOS Toshiba transistors or Semisouth JFETs and I haven’t found any of those so far, but even so I can already see that it was worth the investment 🙂

There is obviously also quite a lot of stuff here that I don’t need or want, so look out for some of that coming up for sale via diyaudio soon 🙂

The myth of “end-game”…

For as long as I can remember and in every hobby-community I have been in touch with (audio, watches, photography etc.) , people have been talking about “endgame” projects or purchases. “End-game” as in something that is so good that we no longer feel the need to build or buy anything new.

While the end-game concept persists and is often something that is discussed in forums, it doesn’t seem like it happens that often in real life. Part of the explanation is so obvious that people don’t really notice – if you are interested in something as a hobby, you’re likely not even looking for “end-game” in the first place, because you are driven by interest instead. You certainly don’t buy an expensive watch (or more than one…) because you just want to know what time it is, and as I have written about several times if I all I ever wanted from this hobby was a good-sounding audio system I should definitely have gotten out of DIY audio many years ago 😀

Among my own “end-game” purchases were my Sonus Faber speakers. These were maybe end-game from a sound quality perspective, but – and that’s the second “flaw” in the end-game concept – they still ended up being sold because the context around them changed (= the size of my living room increased after a house-move so I wanted floorstanding speakers instead). And so it goes on…

So, where am I going with this? Just that I recently bought another pair of (supposedly) end-game speaker drivers 😉 It’s a pair of slightly used SB Acoustics Satori “Textreme” MW19s and I bought them partly because they were around half price which seems excellent value, and partly because they solve a conundrum I’ve been having for some time. I am going to mate these with the Mundorf AMTs that I (still) have lying around, and then finish my Illuminator-project with a pair of Scan-Speak tweeters instead (which I then also bought…)

To be honest I was more than a little skeptical about Textreme (a special carbon fiber-based material) when people first started raving about it on and other places. This was partly based on the looks in the SB publicity pictures, and also the fact that the prices were much higher than the standard Satori paper/papyrus cones, which already have a fantastic reputation.

When I started looking more into it though, it seems that Textreme does actually have some advantages and even though the MW19s are on the large side for a two-way speaker design, it seems I can get them to mate well with the AMT tweeters and some active filtering. The SB Satori build quality seems to be top notch as usual so this time I am going to finish the speakers quickly (I hope!). I have already cut up some of the wood, so at least that is a start 🙂