Join me as I repair and completely resurrect an incredible Technics SE-A100 power amplifier that had been to just about EVERY Perth repairer before me. This is quite a story, so grab a drink…

Actually, I need a drink after how long this article has taken to put together. That’s right, folks, I’m following up on my 2021 teaser about repairing this absolute beast and my promise to write what I knew would be a hefty Technics SE-A100 resurrection article. Hey, it’s only taken me five years, but we are finally doing this epic story!

Why so long? The biggest and most complex jobs are the hardest to write up, often taking me a couple of days to put together, as this one has, with 100 images and video clips. Just editing and uploading the video took hours, and given how busy I am doing work like this, you’ll understand why some of the best stories are the ones I find hardest to bring to you.

If you’d like to see a video companions to the job, albeit a rather long and involved one, check it out:

Background

Keep in mind that I’m writing this almost five years on, but I recall the basics of the story pretty well. This beautiful but broken Technics SE-A100 had failed with what was likely a simple fault, throwing it into protection. The problem was that, instead of having that fault repaired, the amplifier made its way through various repairers, including the infamous Mr RadioWaves, all the way to my friend Jason @ The Speaker Doctor, and was still broken!

I can’t recall why the owner didn’t contact me initially, but he may not have realised that my business existed, or that I specialise in this type of work. He’d unfortunately contacted all the wrong people until he spoke to Jason, though, which came to haunt me whilst repairing this amplifier. Each of the four or five repairers who’d touched this amplifier before me gave up on it, handballing it back to the owner, after installing additional faults.

I’m sure Jason could have repaired this SE-A100 if he had wanted to, but he dislikes dealing with equipment that has been messed with by others, as I do, especially complex pieces like this one. Repairers, whether DIY or supposed technicians, often add problems rather than solve them, and that was absolutely the case here.

So, whilst Jason refused to touch the SE-A100, Jason also knew that I love a challenge and helpfully suggested that the owner’s last useful option might be to take the amplifier to Liquid Audio. I’m grateful for that referral and for whatever faith Jason has/had in my ability to help with this one.

My ‘problem’ in cases like this is that I find it hard to say no to:

1. Beautiful/interesting/serious equipment
2. The challenge of fixing equipment others couldn’t
3. Helping people who particularly need my help

This Technics SE-A100 certainly ticked all those boxes, and so, for better or worse, I took it on. This is something I came to regret for a while, but I eventually fixed the bloody thing when nobody else who’d tried could. I don’t mind saying that I’m proud of that! Oh, and it’s STILL working, five years on. Read on to find out more!

Technics SE-A100 Features

The Technics SE-A100 is, in my opinion, one of the most beautiful power amplifiers of all time. Others I like as much or more, featuring moving coil meters, include the insane Technics AE-A1 and SE-A3, the Onkyo M-504, which was my first serious power amplifier, the lovely Sony TA-N77ES, and the Accuphase P-360, another beauty I’ve owned.

This is a dual mono power amplifier with a class A driver amplifier and solid construction quality. There are some hokey elements that Technics always seem to include, like the wobbly card edge connectors and flimsy boards, but overall, these are good designs, if perhaps a little fragile. Certainly no Accuphase, but good.

There is a handy speaker selection switching from the front panel and even a handy headphone socket, for late-night listening perhaps. Best of all, though, are those massive moving coil ‘VU’ meters, and their unmistakable ‘Technics’ styling. This puts these and other related amplifiers into a unique category in terms of beauty.

I’ve summarised some additional details from the Technics literature, for your enjoyment:

Technics’ Class AA circuit design places the voltage and current drive amplifiers into separate blocks and boards. This frees the voltage control amplifier from the current supply, reducing distortion. The SE-A100 has two voltage control amplifiers and two current drive amplifiers for the left and right, for a total of four.

The voltage control amplifier employs a Darlington configuration with a differential amplifier FET input stage, and is a complete class A, ultra-low distortion amplifier. The current drive amplifier consists of a FET differential amplifier input, a high-speed amplitude amplifier stage equipped with a Darlington output stage using 3-parallel output transistors.

The power supply section has a 3-transformer configuration, equipped with a power transformer for the left and right current drive amplifiers and a transformer for the left and right voltage drive amplifiers. Fully symmetrical construction is employed to eliminate interference between the left and right channels. In addition, the power supply capacitor is equipped with 91,200 μF of total capacitance.

The power transformer uses oxygen-free copper wire and is sealed with special resin in a total of three layers of magnetic shielding case to reduce adverse effects such as mechanical vibration and magnetic flux leakage. The top plate is 3 mm thick and magnetic radiation and mechanical vibration are suppressed by a 2 mm thick high-rigidity chassis and 2 mm thick insulator rubber under the transformer.

Technics SE-A100 Specifications

Courtesy of Audio Database and HiFi Wiki, adapted by Liquid Mike

Problems

The biggest issue with this beautiful Technics SE-A100 was the poor previous work the amplifier had seen at the hands of those who’d worked on her. I won’t pull punches here, because this needs to be said: most of the ruined equipment I see has suffered the greatest damage in the hands of those who’ve tried to repair it. I’ve lost track of many cases like this SE-A100 I’ve come across over the years, and it’s appalling.

This teaches us a simple lesson that must be learned and one that I won’t stop trying to educate people about: Very few of the folks who might want to look at an amplifier like this should ever take the lid off one, and most folks who say they can fix something like this cannot. This shouldn’t be the case, and I know that pointing it out upsets some people, but it’s a simple statement of fact, and there is no better example than this SE-A100.

Here is my diagnosis, taken from my original 2021 invoice/report and tidied, for clarity:

• Amplifier has various issues caused by poor previous work and parts failure.
• Unit stays in protection due to various failed parts and a vaporised trace in the driver and current stages of the R/H channel.
• Voltage driver boards have been incorrectly rebuilt using inappropriate transistors and many previously replaced parts must be replaced again.
• Card-to-board connectors need attention.
• Faults are nested and interact with one another, but the design makes diagnosis and troubleshooting difficult.
• Several lamps are blown.

I explained to the owner that no factory hard copy manual or service aids, like extenders or jigs, were available, making the job harder again. In the old days, one would order a board or boards from Technics and be done in an hour or two. These days, repairs like this require painstaking component-level repair, without many of the service aids to help.

So, to summarise: I needed to repair the various faults introduced by the previous repair attempts, and then find and fix any remaining original faults.

Lets go!

Repair

As usual, my approach is to disassemble and then carefully inspect, clean and repair things linearly, one board at a time. Also, as usual, I’ll annotate each image, as this is the easiest way for me to explain and remember what I’m doing.

A quick note on repair costs for jobs like this, something I’m often asked about. Not long after repairing this old girl, I was approached by a gentleman arriving in a Bentley, who wanted me to repair his Technics SE-A3. There was one problem – he wanted to know how much the repair would be up front. I told him I could not estimate that, but there would likely be several days’ worth of labour involved.

For the record, there is absolutely no way to know how much a complex, multi-faceted repair like this will cost until you are doing the work. I could not know what I would find inside this SE-A100, and there is no way to predict what each unique case will involve.

I’ve written more about this concept in FAQs about amplifier repair costs and the need for inspection. Up-front quotes for complex repair work like the job I’m writing about today are impossible, due to the large number of unknowns in each case. Estimates with price ranges are the norm.

Results

Wow, well, what can I say that I haven’t already and that you haven’t already understood from this lengthy article?! I will say this: the very patient owner was absolutely ecstatic about the result. I don’t know who was happier: me or him, but when I explained the complexity of the work involved and the multiple faults that I repaired in the process of resurrecting this classic Technics SE-A100, and how much hair I’d pulled out doing it, he understood.

Here is a message I received from the owner I did the work for, the day after writing this article and nearly five years after completing the repair:

Still running Mike, still love it with my JBL-4344s. Thanks again for all the efforts getting her back to life!

Paul S

I thank Paul for the update because it says something about the type of work I try to do here: proper repairs that remain reliable for their owners, years on. I can’t fix everything, like worn-out hardware, poor design, and build quality issues. But what I can fix, I try to fix in such a way that it is unlikely to fail again.

An additional note about my happiness with the repair: I was ecstatic, because these are complex technical puzzles that others hadn’t/couldn’t solve. I was also incredibly relieved to finally fix this thing. This was, in some ways, what we call a ‘hospital handpass‘ in Australia, due to the complexity of the design and layout, serviceability issues and because the poor quality of the previous repair work had created an unknown number of new faults.

In other words, this was a risky job to take on. This type of work is stressful, and the stakes are high, so there is an inevitable sense of elation when you fix equipment like this. One should never gloat, and I hope it’s evident that I’m not doing that here. I do think it really is important, though, to delineate the differences between repairers and how we all work, and what that means for jobs like this one.

We (repairers, technicians) are absolutely not all the same. We have different backgrounds, approaches and philosophies, and we do very different work, with different results. I hope that is clear from articles like this one and others I’ve written. Others could have fixed this, I’m sure, but nobody else did, and quite a few tried.

I can’t solve all of these sorts of cases, nor do I want to. Others can and do take on jobs like this, so check in your local area. I’m proud I was able to fix this one, though, I’m thankful that Jason and my customer trusted me with this fabulous SE-A100, and I firmly believe we should embrace the wins!

As you might be able to tell, even from the YouTube video, the amp sounded wonderful after the repairs and some much-needed overhaul work. That was just on my pair of Yamaha NS-10s; I’m sure she sounded incredible in a full system, driving big speakers as she was designed to.

In terms of further work, a little more could still be done, but we replaced so much of the guts of this one that I’d not suggest doing much more here. Most of all in cases like this, I think that once they are repaired properly, they need not be over-finessed. This old girl has been through enough. Now she needs to play music, and I hope that’s what she’s been doing these last five years!

Anyway, if you’ve made it this far, well done, because this one was an epic. Writing this up and being as tired as I am reminds me why I don’t do big articles like this that often. But I hope you, maybe the owner, and some other SE-A100 owners, have seen and enjoyed it.

Thanks!

As always, thanks for visiting. I hope you enjoyed this article and found it informative. If you’d like me to look at your Technics SE-A-100, SE-A1, SE-A3, or any other lovely Japanese power amplifier for you, don’t hesitate to contact us, because this sort of work is right in our wheelhouse. The only problem is that there is only so much of it that I can do, because it’s exhausting and highly technical work.

Sidenote: As you know, very little original, quality content like this exists, which is partly why I go to the effort of creating it. I was recently asked: “Who pays you to write these articles?” My surprised reply was “Nobody!”, though that would be nice, especially after an epic write-up and video like this one.

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