Music Stuff

Zygote Fuzz Pedal

Germanium. It sounds exotic. It’s an inferior material for an electronic part but something makes it desirable some 50 years after its original use in guitar effects.

So of course, I had to build a fuzz based on this element. These are not good starter projects for a few reasons, one being the polarity is opposite from other projects (it uses negative 9V power) and another is that germanium transistors are notoriously finicky, you have to get jusssst the right ones, and set them up in jusssst the right circuit. So I got a few other projects under my belt first.

The PCB
Not my board

First thing I did was order a PCB through MadBeanPedals.com – of course by the time I decided to do this the project & board had been discontinued. One of the forum regulars was kind enough to send me one he had etched for his own use. It looked awesome. I already had a “RoadRage” board from the same site, so I knew I could provide the -9V easily enough.

Black dot specials!

Next was getting those finicky transistors! I ordered the cheapest set I could from SmallBear. This is highly recommended for anyone building this project! Steve at SmallBear tests each set, finds the ideal resistor matchups that give just the right sound and electrical response (based on the official Dunlop/Arbiter Fuzz Face) and supplies both the transistors and the resistors in clearly marked baggies. It’s definitely a deal, even though it seems rather expensive for a couple of little parts.

The next part of the project always comes all at once. Building! I usually start by saying “Well, why don’t I just solder on the sockets” and then say “While I’m here, I’ll put the caps on. Easy enough” and that ends up with “resistors are easy too…” and before you know it the thing is assembled. Mind you, with this one some of the holes were too tiny for the 22 AWG wire I like to use, as well as some of the thicker leads on some of the caps. I ended up using the point on my X-Acto knife to ream them out bigger. That took longer than I’d like.

The board assembled

The next part that also usually takes longer than I’d like is the pots, switches and jacks. Cut, strip, tin and solder way too many wires to get it to a point where I can test it. It’s a healthy afternoon’s work, anyway. I tested it first with some PNP 2n5087 silicon transistors which I already had – I figured I would know if it worked and risk a few cents rather than a few dollars. They were way way too quiet (and didn’t fuzz at all) but at least I knew it worked! I plugged in my precious germaniums after giving them some socks to keep warm and safe, and it became loud and raunchy! In this case that’s a good thing.

At this point I have a working pedal though it’s hardly a pedal. Can’t stomp on it, you see. I have an enclosure set aside for it, but I need to figure out how to drill it and what color to make it (I have gold paint but that may be a bit too flashy).

As for the controls, I could have 6 knobs (input attenuation, power sag, transistor bias, fuzz, output volume, and boost level) and two switches (boost only or boost + mids and a “fat” switch). I clearly can’t fit all of those on the size enclosure I have in mind. I will likely leave out the power sag, since I don’t really like that sound.

In the meantime, I have set up two or three dummy layouts using cardboard. At first I was convinced that I would have to lay out the board in landscape orientation, that way the pots would line up all along the top, ZVex style. That leads to too many compromises and there is less room inside for other components like jacks and switches. it looks like I will have to put the switches at the top face of the box, like “eyebrows” above the knobs, and will probably fit just around the DC jack.

Knobbed and switchedWell, I did the drilling.  I started with the DC jack, fit the two switches around it, and worked my way downwards, but I didn’t quite get the centers exactly right, for some reason…  I tried to measure very carefully, but the rounded edges and the fact that the bottom is wider than the top make it really hard to measure. I may be able to make it not as obvious with the painting, and putting the center knob’s label above instead of below.  In any case, it’s good.  Now, what color?

I have to debug the grounds on this unit and my silicon fuzz. I can’t seem to have them both plugged in to the same daisy chain, though I have a bunch of other negative ground ones on the same chain that don’t cause the same problem.  At the moment I have it working with a separate DC power supply, and sometimes it works off the same daisy chain, but it’s a bit flakey.

This sounds much more overdrivey and aggressive.  The silicon one has more of a buzz. I can get extremely similar sounds out of both, but this one can get… “looser” – more grainy, perhaps and I suspect it gets more gain, though the silicon one definitely has more volume. The input trim control was definitely worth putting in, it really helps balance the guitar volume to have a smoother taper instead of the “cliff” I was finding earlier.  It’s also fun to dial it up, the fuzz way down and crank the boost.  Very tasty dirty boost.

I finally painted it.  I wanted a coppery colour, but all I had on hand was a gold and a red spray paint.  I thought I was so clever in that I could paint the gold base and just dust a bit of red on top.  They were different types of paint, which may have added to the difficulty!  The gold made this cool pebbled finish and the red caught in the grooves to make it look coppery, but this took me about two days to get just right!  Sadly, I don’t think it’s all that durable either, so I took pics quickly so that I could see it at its best. I don’t think I’ll ever do that again, I can probably get a copper textured paint for $7 or $8.

Ooh gnarly
iWatch

The rumor mills are ablaze. Two things bother me about this though.

1) available later this year, and
2) prototype has battery life issues.

Apple, as a rule, doesn’t let these two kinds of things go together. Battery life is almost certainly an early design goal. “Later this year” would mean “production now”. If something so fundamental is not ready, then they wouldn’t think of releasing it any time soon.

I just don’t see it. 

Mark this down, just in case I get it wrong. I will be deleting this post if I do! 🙂

New CRTC Wireless Regs

It looks like the new CRTC cell phone regulations have been enacted. We may still have 3 year contracts in Canada but with zero termination fees after 2, we effectively have the shorter period now.  It remains to be seen whether carriers will make up the difference with reduced subsidies (higher handset prices) or still requiring the full contract before upgrades are possible (almost a certainty).

Data caps at $50 and International data caps at $100 are great, though I’m sure they’ll be abused, sadly.

Phones may be unlocked but I think all carriers did that already.  The regs did not specify unlocking fee rates so Virgin is still likely to be the most expensive.

Whatever happens, cell contracts are more affordable and flexible now. Always a good thing.

The look of iOS 7

I agree for the most part with this post. I’m not crazy about the icons – I particularly dislike the settings icon.

Me: “I don’t like the settings icon”
Tina: “Yeah I preferred the gears better”
Me: “It is gears, see?”
Tina: “It looks more like the fan in the back of a computer”

But, as I posted earlier, I don’t care that much about how it looks.  I’ll get by with this, maybe they’ll fix it in the next version, or possibly even the release version.

I do understand the static weather icon though; updating that one would require regular network access.  Better “a stopped clock”, and all that.

(I was going to comment in that article’s discussion thread, but at over 1200 comments as of this post, it would have been pointless.  Probably 900+ smug Android user posts too)

Arc Reaction

I got myself a Kobo Arc when they had them on sale just over a week ago.  About 22 hours before they announced new ones.  Well, this time I don’t mind.

What I ended up getting was a pretty decent tablet/reader.  I got it primarily as a reader, though I recognize how much better e-ink is for that stuff in general, I wanted it for richer documents (i.e. PDF, picture-laden & color books) – for which e-ink isn’t as good.  I also wanted a decent Android device for browser and the occasional app testing.

That’s certainly what I got – a decent Android device.  My other option at this price range was an Asus MeMO pad, which also would have been very good, except this has a better screen.  1200×800 I believe, vs 1024×600.

For that screen I sacrificed a few other things; rear camera, GPS and bluetooth.  The CPU is 1.5GHz dual-core instead of 1.2 quad, but very very snappy, I have absolutely no complaints on the CPU (or anything else for that matter).  I have frequently been surprised by how quickly it accomplishes many tasks!  It may be anectotal, but it seems like the wifi is notably faster than my iOS devices.

I don’t really want a camera on a reader that much (just enough to read QR codes and in desperation use Skype), I don’t really ever use the rear camera on my iPad.  GPS only eats battery, and I prefer that on my phone anyway.  Bluetooth would have been nice but a very minor exclusion.

Kobo’s software is too intrusive to use.  Their launcher takes up an unacceptably huge area to promote their expensive ebooks. Their book reader, while it renders beautifully won’t synchronize sideloaded books.  I have relegated it, and chosen a much better solution.

At the sale price, this was a fantastic purchase.  Now that the sale is over, it’s too expensive. It’s too near to an iPad Mini’s price to even contemplate.  Maybe when the new ones come out the price/performance will be better.

Hardware vs. Software (Nikon)

This week I ran head-on into a fantastic hardware product (Nikon WU-1a) that is almost made useless by its software (Wireless Mobile Utility).

Nikon WU-1a
Objects in browser are smaller than they appear

I wish this sort of thing was rare, but it happens only too often. (I’m looking at you, Logitech)

In this case, the device is a tiny adapter that plugs into what looks like a micro-USB port on the side of a Nikon camera. And I do mean tiny. Think “dime-sized”. There is a single WPS button inset on one side, and the thing creates a Wi-Fi network for your tablet or phone.  On the hardware/firmware side, the only shortcoming I can see is that you cannot join an existing Wi-Fi network, you have to create a separate ad-hoc(ish) network with the dongle. This is too bad, but understandable to me, because even though there is a WPS button, I can’t imagine an intelligible interface allowing joining a secured Wi-Fi network on your camera.  Apparently the Wi-Fi has b/g/n support, though I highly doubt it has 5GHz support.

The transfers all take place over PTP/IP, which is a standard for this kinda thing. Standards often seems to enable better technology.  It supports picture transfer, but notably all of the other picture parameters such as ISO, aperture, shutter speed, focus, etc.

This is where the software falls over.  Hard.  I loaded the software on my iPhone and connected (after a few tries).  I can take a picture remotely (with live view), download pictures and… well, that’s it.  It was so weak that I basically decided to take it back.  But first, I googled.

I found a number of people who, like myself, were very underwhelmed.  What I also discovered was an Android app called DSLR Dashboard. I scrounged up an old Android phone that was compatible and tried it out.  This software alone turned around my perception of the hardware – it does everything, focus bracketing, intervalometer, histogram, RAW transfer (that’s gotta be slow), photo management on the camera and so much more.

I also found this forum thread with not only the common complaints, but the user that posted it decided to write his own iOS software to replace the pathetic first-party stuff.  The  release of said software is unfortunately, still pending.

The Nikon iOS developers are doing a serious disservice to the hardware engineers.  This device is apparently now integrated into the D5300, so the camera itself is going to take the flak for their junk software.

Please, companies, do TRY to make your own products look good.

Apple Watch

I, like others, was drooling when Apple introduced their new wearable.  They made the competition look horrendous.  (As a side note, when I first saw the Galaxy Gear S in pictures, I was excited – it too looked great, and not Android… until I saw the actual size.  It’s absurd.)

They pitched this at everyone.  It’s not a “geek watch” and another model is a “fitness watch” and another model is a “cool watch”.  They all have factors of each.  Sure, they have different versions but nothing’s stopping you from exercising with the Edition… uh… edition (that name!).  Or wearing the Sport edition with a suit.

The digital crown is one of those obvious things that nobody thought to use.  Why did it take Apple to think of this?  Because they’re never in a panic to release something.  They don’t iterate like Microsoft (used to) or in the extreme, Samsung.  Can you believe Samsung is (as of publication) on their sixth generation of smart watches?  Have you seen anyone wearing one?  Wanna know why?

Of course I want one, but the price is high.  They “start at” $350US.  Is that the Sport one with a basic rubber(ish) band?  What if you want the Sapphire crystal version?  How much will bands cost?  This is pretty much the definition of a luxury item.  You can get a pretty awesome regular watch for $350.  Are the digital additions worth the premium over a decent analog watch – one that, remember, will still be worth a respectable percentage of that amount (if not all of it) 5 years from now?

I won’t be getting one, but not because I disagree with them in any shape or form.  I’ll see what the next product cycle or two brings around.

Now, was that a working model that Tim Cook was wearing?  If so, I’m sure Apple execs can wear them in public now as test cases and get some real-life issues resolved even before release.

If you read this far, are you wondering what I think about Android Wear?  I won’t have Google touching my person or knowing my physical status or location at all times, thanks.  The “Ok Google” thing on the Android watches creeps me out.

Maglite Solitaire LED Conversion

I got a Maglite Solitaire LED flashlight this summer, but I already had two regular incandescent ones.  Once you get used to the LED one, the incandescent one is so… dim… and yellow.  It’s really really convenient, though, and I’d hate to just drawer it, or worse yet, junk it.

I got a cool little module from eBay that just plugs right in and you’re done.  About $7.  Is that as good as it gets?

I found a pretty good tutorial on YouTube about how to mod an existing one to LED, so I thought I’d try it, and what is explained below is that exact project, with some slight changes.  The main thing is that a 1.5v cell isn’t enough to drive a decent LED light, so I’d either need to build a teeny tiny booster (probably what was done in the module above) or change the source voltage.  Voltage it is!

The space is limited in the battery compartment.  So what to do?  Very small batteries with 1.5v… sounds like a watch battery.  Also sounds expensive… but, the YouTube video explained how you can get an A23 battery and peel it open to gain 8 LR932 cells!

Unleashed the power.
Unleashed the power.

I found a double-pack of these batteries for just over $5.  Shop around, the prices can vary considerably.  Make sure it’s an alkaline battery, apparently there are some carbon batteries this size but they aren’t going to have anything near as tidy inside (i.e. “gunk”).

Note, If you do this, keep the positive and negative terminal bits.

You will only need 3 cells for one light, so put aside 5 of them.  Now we need to make a spacer so that the battery reaches both terminals inside the flashlight.  Get a pen tube and cut it to approximately 30mm.  You don’t need to be laser-precise, but get as close as you can.

Next, LEDs really should have a current-limiting resistor to prevent them blowing up.  Technically these cells probably have enough internal resistance to it’s not a problem, but I wanted to add a tiny amount of extra just in case.  The video suggested a 68 ohm resistor, but I didn’t have that, so I used a 51 ohm one.  I did say a tiny amount, didn’t I?  With a hammer and nail (or screw), poke holes in the top and bottom of the disassembled terminals you saved from before.  Solder one through the hole and then fish it through the pen tube and solder on the other end, again through the hole.

Spacer Age
Spacer Age

Note that the plastic may melt as you solder this, another reason to leave a mm or two to spare on the length of the tube.  With the cells and the spacer you now have a 4.5v “battery” the same length as a AAA cell.

Pop them into the battery compartment – pay attention to the orientation of the little cells, it almost seemed backwards to me at the time.  The flat side is positive and should be facing the bulb socket.

A thumbnail
A thumbnail of, well…

Now to get the LED bulb in there.  I assumed that I needed a really tiny LED, so I went and ordered some SMT ultra-bright LEDs from Amazon.  I just got them and yup they are really tiny.  These are designed for automated pick & place production but it’s not impossible to solder them manually!  I got two small cutoff leads from a capacitor and tried to figure out how to place them on this thing… first step was to get a ball of solder on each of the LED’s solder pads.  That’s fairly simple, just blob some melted solder on the bottom, and it will congeal on each pad as it should.

Lining up the leads, though, was another thing.  I decided to poke them into a cork, bend them over so they were going straight into the back of the LED and then just heat the blobs just enough to melt the leads into it.  Not too hard!

Soldered
Soldered
With a novelty size paperclip
With a novelty size paperclip for size comparison

Next, test it in the flashlight.  Remember that these are diodes, so if you plug it in one direction it may not work, even though the connection is perfect!  Try flipping the leads around and plugging it in the other way.  You too may be pleasantly blinded by the light.  (Curiously, that song was playing on Spotify just as I was doing this, and I only realized it now). If you are using needle nose pliers as I was to push in the diodes, grasping both of the leads, remember you are shorting the connection as you push it in.  It will not light up as you are doing this… so make a connection and then let it go for a second to make sure it’s working.

IMG_1964Now to trim down the leads.  I decided that the base of the LED should be at the same spot as the base of the regular bulb. Using that comparison, I snipped off the leads and then tried to carefully push the leads again into the light… and ripped the trace right off the SMT LED.  🙁

Oh well, I had ordered 50 of the little thingies (that’s the technical term), so I did it all again.  This time I was more careful, and taped off the jaws of my needle nose pliers so I could see if it was working as I was inserting it.  It worked, and blinded me again!

Factory LED (left) my mod (right)
Factory LED (left) my mod (right)

With my good eye, I could see that the tiny little LED fits through the bulb hole in the reflector with room to spare.  I actually realized as these were on order that I could have ordered actual 3mm ultra-bright LEDs and just cut and plugged it in.  Hm.  Well, let’s just say they’re on order now.  I will at least have a point for comparison (and 48 more SMT LEDs).  The connection point from the lead to the LED (say that out loud) is probably fragile, but it may have enough shock absorption in from the case and being suspended 1/4″ away from the body of the light.  In any case, I will use the spare bulb location in the base of the battery compartment for one of the other LEDs, so I will always have one even if it does break.

The result is pretty decent.  It looks like the first-party Maglite installed version is a fair bit brighter – and has the advantage of using standard AAA cells.  However, I am curious how the battery drain compares on these two, and how much different the 3mm LED is once I get it.

All in all, not too hard of a project.  The price was reasonable and the result is definitely superior to the original incandescent light.  If you had the LED and the battery on hand, you could probably do this in about 20 minutes to half an hour.

Arduino.  Fine, and you?

I have long avoided Arduino, because “that’s hardware stuff”, and I just didn’t get it.  Based on a request from a friend, I looked at it and I just knew I could write the code to get him started.

Turns out I could and I did!

Now I’ve got loads of ideas, partly practical, partly (ok mostly) experimental… I was able to test my code on simuino in a Linux VM, and when we plugged it in to actual hardware, it was great fun!

I have ordered a SainStudio kit for more experimentation.  I’m already looking at how to make my own custom board for an ATmega chip.

AppleTV Updated

Finally, Apple decided to update the AppleTV – and promote it to the product menu bar on the main site!  This common, and popular, device had been overlooked for four years!

The changes are exactly what I was wishing for… but somehow not enough.  The main thing I wanted was apps.  It seemed kinda dumb that an iOS device (the previous AppleTV was running iOS 5) couldn’t run apps.

The internals have been improved significantly to support the load that modern apps will certainly give to the hardware.  An A8 processor (mostly the same in the iPad Air 2, with a different GPU), 2GB RAM, and 32-64GB flash storage.  Bluetooth 4.0 and WiFi 802.11 ac (along with the other letters).

But Apple has never been strictly about the internals.  You shouldn’t need to know exact RAM numbers to know how the experience will be 1.  Apple has always been about the experience, even if it causes the device to be a little more expensive.

So what is the experience?  Well, the existing AppleTV experience is a gimme.  It was already very good and uniquely seamless… playing iTunes content and receiving AirPlay streams is a very satisfying experience.  The downside?  The doors were closed to anything else.  So now with apps, the experience gets much wider.  Plex is better than iTunes.  2  TuneIn Radio would be nice to have on the same box.  And then there’s games!

<record scratch>. 3

Of course there’s going to be games, when people talk about the App Store for iOS, their first thought is GAMES.  But, the App Store games have been unique beasts until now.  Odd games with ridiculously simple controls and brief (seconds to minutes) of typical game time.  Games like Threes, Angry Birds and Plants Vs. Zombies really worked on a portable, touchscreen, battery-powered handheld that you had with you anyway.  Put it on a screen with three other bored family members watching and it won’t work.

The games have to change nature, obviously.  When you fire up a game in the living room, you do so with hours, not minutes in mind.  Solo games are still fine, of course (they already succeed on the consoles, so that proves that).  But the AppleTV as a gaming device is going into the arena with a handful of potential games worth playing.  I too loved the demo of Crossy Road, it looked great… but I think I would only play it on the big screen for 10 minutes.  The Apple ad highlighted Asphalt 8, and there’s also Real Racing 3, another graphics-beautiful game that lends itself wonderfully to the controller.  And with the In-App Purchases you can…

<record scratch>.  <audience gasp>. <crickets>. 4

I bought Real Racing 2.  It was fun, if a bit unrealistic.  It was self-contained and cost money up front.  Real Racing 3 came out, and was mostly improved except it’s now Freemium… so you can play for free as long as you stop playing every few races to let it recharge.  Stop.  Playing.  Tell me if that’s going to work when you’re on the couch with a cool drink and controller in hand.  I know, there are about 1% of the players that actually pay for cubits or gemoids or coinules or whatever they have 5.

The easy(tm) solution is to charge more for the games.  I’m actually fine with that, as I’d pay $5-$10 for a really good game.  That would be kinda the upper limit, the reason for which will I will explain shortly.  So maybe that will happen.  I’m actually pretty certain(tm) that it will, actually, though I think the prices will balance out at a little more around $10-$20.

Now back to the hardware.  It has the grunt to drive these games, but there are two significant problems that stand out right away.

First, controller support is restricted to MFi controllers, so those awesome and cheap USB controllers you already have (like the ubiquitous Xbox 360 controller) cannot be used.  So you can get an AppleTV for $149 plus a controller for $49 more.  $200 USD for an unknown console with a single controller… now that’s not too bad given new console prices.  Except I could pop out today and get a PS3 with 4 really good games (Lego Batman 3 and the Sly Collection) for $219 CDN.  With 500GB of storage.

Which leads me to my next issue.  There are only two levels of storage differentiating the $149 and $199 models Is 32GB enough, or is 64GB enough?  Right now very few know.  A high-end iOS game at the moment might push 2GB, or possibly more, but recently released developer information explains that apps for the AppleTV can only reserve 200 megabytes of persistent storage each.  They can download and cache a whole lot more than that, apparently, but given memory pressure (i.e. lots of different apps, not just games) using that cache, it will be dumped and you will have to redownload it.  So the snappy performance of the device when you first set it up will probably fade.  In practice, maybe you don’t notice this much, since you’d have to run a lot of different apps to create the memory pressure required to dump the cache of one.  Most people would focus around 4 or 5 apps each.  Unless of course you’re a family.

Oh… yeah, that 6.

It would be easy to compare this to the Xbox One, because it does much of what the Apple TV promises, without the Apple integration, of course… but it’s expensive, so I won’t do that.

Let’s go back briefly to the pricing of games…  It seems to me the big competitor they’ve just walked into the ring with is Valve.  Steam sales are ridiculous.  It’s not unusual to get a significant and excellent game on Steam for under $5.  Steam games are often cheaper than their iOS ports.  But, PC games and consoles are very different things.  The other key is the Steam Link hardware that is coming out next month.  A $59 CDN box will stream your PC/Mac games to your big screen.  It supports Xbox 360 controllers as well as a few others, and they are releasing a new $59 (CDN) controller as well, that is looking promising.  So for games, it’s $119 for a game plus controller, and a TON of cheap, high-quality games.  And an online store that works really well.  It will also stream your music if you really need to (MP3 only).  Maybe movies will come soon, who knows.  While it’s true it’s a streaming-only device, and you need your computer on… AppleTV is mostly the same for movies and music.  (Yes I know about iCloud)

I think the real potential competitor to the new AppleTV is the old AppleTV + Steam Link.  $89 + $59 = $148 CDN beats $149 US by a fair margin.  Enough to throw in a controller, if you really really don’t have one.

Comparing unreleased, unknown products is often an exercise in madness.  But at least my madness is well exercised.  I think we’ll know how this all shakes out in about a year.  Mark this down.

  1.  Quick, tell me how much RAM a PS3 has!  Whether you know that number or not, you realize it doesn’t matter as much as it would on a desktop
  2. There.  I said it.
  3. For the younger set, you might have to Google this
  4. You have to add your own sound effects here.  Work with me, people.
  5. For the older set, don’t bother Googling these
  6. Won’t someone think of the poor RECORDS?
M-Audio StudioPro 3 repair

First of all, let me say “hi there, Googlers!”

I owned the M-Audio StudioPro 3 speakers for quite a few years before they started to fail on me.  They were not too bad, gave decent sound at reasonable desktop volume.  In the last year or so, the right speaker conked out.  Well, it played, but was really really quiet.  I replaced the cable a few times, and tested with an oscilloscope that yes, it was actually receiving signal, but very weak.

I opened it up and couldn’t see any immediate issues, like loose connections or popped capacitors.  I tried making a better solder joint on the wire leading to the right speaker jack, but didn’t notice an improvement.

I would probably have been wise to obey this

Much of my research leads to the understanding that these units will eventually fail, even if I fixed it now.  I decided I might as well convert the speaker into a passive speaker, and bypass the amp entirely.  I first thought this was as easy as attaching the speaker terminals, then I realized I still need the crossover, of course.  I just needed to find it on the board.

With the help of this page (thank you Yashar), I found at the very bottom of the page a rough estimation of what the crossover will look like in this speaker.  It is slightly different from the AV40, but the general layout of the two inductors helped me locate the general area I was looking for.

Armed with that and a little function generator I was able to find the spot after the power amp and before the crossover.  Here it is, with the original output wire removed from its spot and soldered on to an existing joint.

I removed it shortly after and threaded the wire through the hole alongside the zip tie for a small amount of strain relief.  Now the 1/8″ jack, instead of sending amplified signal OUT to the right speaker, is an input for amplified signal.  In other words, it is now a passive speaker, just like the right side one.

I can leave it unplugged from AC and still use it, as long as I have a small amp, like the little LEPY amps on Amazon/AliExpress.  The speakers seem to be rated 10W and 4ohms so I certainly can’t drive them hard with that little amp, but I think I can easily get a lot more life out of them, especially with the right one being significantly less dead than before.

I can’t guarantee that I did this right, and maybe someone will correct me, but I think I found a simple solution to save these.

Here’s the full bottom side of the PCB