Rebuilding a 1977 Luxman L-30 Stereo Amplifier

My uncle asked me if I could repair his Luxman L-30 stereo amplifier, circa 1976-78. I said I could, so I did!

The L-30 is a 2x35W integrated amp made by Lux corporation in Japan. The company is still around, making hifi products.

When Uncle Pete brought over his amp, it was dirty from sitting around, unused, for many years. One of the knobs had come apart. Turning the knobs while the unit was powered on produced some awful scratching noises, and the knobs were stiff and difficult to manipulate.

I took the amp apart for the first time and cleaned the potentiometers with DeoxIT, a miracle contact cleaner. After turning each knob back and forth about a hundred times, the crackling was eliminated. I also blew out a cubic foot of dust and made some observations about the electronic guts.

Many of the original electrolytic capacitors had leaked their electrolyte gunk (see the big black one in the image below).

I found a great resource on repairing this exact amplifier. The author advised to check the small signal transistors for a "silver oxide creeping disease". The problem was that in the 70s, Hitachi "tinned" the leads of many transistors with silver (instead of tin). Silver oxidises over time, and the rust creeps up the legs of the transistors and eventually rots the guts.

It's hard to tell that the leads of the smaller transistor (installed back-to-back with a larger one) has blackened legs, not silvery/metallic like the other components.

I found some great supporting resources:

• Luxman L-30 Service Manual - circuit schematic, parts list, circuit board layout diagrams, and re-calibration info. Absolutely critical! 
• Hans Hilberink's Luxman Vintage Audio Website, specifically this page about the L-30. 
• Vintage Audio Repair L-30 - Dutch website with great before-and-after pictures of an L-30 rebuild. 

So, what's the final scope? I decided to: 

• Replace 42 electrolytic capacitors, same specs as originals. I am not savvy enough with analog circuits to contemplate upgrades;
• Replace 17 small transistors (TO-92 package); 
• Replace the factory speaker terminals with newer, nicer binding posts with banana plug connectors;
• Do a nice cosmetic cleanup of the knobs and faceplate. 

What I did, and what I learned. 

I spec'd and ordered all my parts from Digikey. My parts list is here on Google Sheets. I ordered Nichicon brand capacitors (UKA, USW and UKT series) and ON Semiconductor transistors. For the capacitors, if I couldn't find an exact replacement, I spec'd the same capacitance at the next-highest voltage rating. 

I splurged and bought wire labels for disassembly. This was probably the best idea I had for the entire project. The kit of professional wire labels kept me organized and made re-assembly a cinch. (the link to the kit is in my parts spreadsheet, linked above). 

Mistake #1: Instead of desoldering the wired pins from the circuit board, I desoldered the wires from the pins, instead of the pins from the board. This made reassembly WAY harder than it needed to be! In fact, to reassemble, I desoldered the pins from the board, soldered the pins to the wires, then soldered the pins back into the board. I doubled my work for no reason. 

Top: Desoldered pins from wires. Mistake! Bottom: Pins soldered to wires, with nice labels. 

First up for replacement were the capacitors. They were simple to replace because the polarity is printed on the circuit boards. 

Another great purchase for this project was a solder-sucker. Previously I'd only used desoldering braid (copper braid that absorbs solder when heated). A solder-sucker makes it SO EASY to remove components - suck off most of the solder with a puff of air, then remove the tiny remaining bit with braid. The sucker I got is on my parts list too. 

Top: New capacitors in blue (bigger ones) and gold (smaller ones). Bottom: Original PB-1009 circuit board. 

Next up were the transistors. They are trickier than capacitors:

1. They have three leads (leads);
2. The pin-out of the new transistors (Emitter-Base-Collector) is different from the old (Emitter-Collector-Base), and; 
3. They must be installed correctly or else they won't function as intended! Funny things will happen. 

Top: PB-1008 with new capacitors (blue, gold) and transistors (black). Bottom: Original circuit board. 

The last upgrade was replacing the old wind-only speaker binding posts with modern banana jacks, where you can wind or insert your bare speaker wire, or plug in a cable with a banana plug. 

Top: New binding posts. Bottom: Original speaker terminals. 

Next up: testing and reassembly.

I carefully reconnected the pins and wires to the two main circuit boards and arranged them back in the case. I followed the instructions in the service manual to do the 2-step calibration. Step One was an "Idle [current] adjust"; you remove a pair of fuses and measure the current between two terminals. If, after a minute of power-on time you're reading 45mA, you're good to go. I was fine. A good start! 

Mistake #2: The second step is to check the "Zero DC [voltage] offset". You want the reading across each channel's speaker terminals within +/- 50mV (millivolts). I measured the right channel at about 25mV. I measured the left channel at 33V - over 600 times what I expected! 

Disappointed, I pulled everything apart and started hunting for mistakes. I knew it was going to be a transistor installed incorrectly because one channel was good, one bad, and capacitors don't amplify voltages. After a few minutes of searching, and double- and triple-checking my work, I found one transistor (Q202a) installed incorrectly. 

Lesson learned: the calibration procedure was critical. If I had just plugged it into my speakers to test, I'd be shopping for a new pair of speakers. 

Work bench during one disassembly. 

Excited, I put everything back together for final testing. Both calibration checks checked out. All good. It's time to fire this baby up! 

I assembled the amp and took it inside. I powered it on. I queued up a record, dropped the needle, and....

Nothing.

Not a sound came out of the speakers. I turned up the sound just a bit. I heard something - so I maxed it. Terrible, choppy, intermittent sound. I could hear all the loud bits but the quiet parts of the song just dropped off. Stuttery. 

My heart fell - I really thought it was going to work. I had no idea what the problem might be. Disappointed, I went back to the garage for disassembly #3. 

Mistake #3: Since the problem was present on both channels, I reasoned that I had a serious issue with parts/components. I printed out 7 transistor data sheets (4 old types, 3 new) and started comparing specs.

After a few minutes of comparing data sheets I realized that I did something so dumb that I had to quadruple-check to be sure. Everywhere I wanted to install a BC550 transistor, I'd installed a BC560, and vice-versa. 

How did I manage something like this? I looked at my parts list, and from Day 1 I'd spec'd the wrong transistors. 

I figured it out later that day. Looking at Hilberink's website again, he says: 

The 2SA836 and 2SC1345 made by Hitachi will sooner or later add a lot of noise and even storm and thunder to your RIAA amp. [...]
Replace with modern BC550C/BC560C and all noise problems are history. 

I read these two sentences, and without even thinking to double check, noted to replace 2SA836 units with BC550, and to replace 2SC1345 units with BC560. In fact, it should have been the other way around (2SA836->BC560, both PNP type, and 2SC1345->BC550, both NPN type). This was totally my error - rushing, misunderstanding, and not double checking. I only had to replace 11 transistors and I'd be all set.

One more set of calibrations as a sanity-check, then I assembled the L-30 for the last time. I'd cleaned and polished the faceplate and all the knobs. The volume knob, which had fallen apart, was securely glued back together.

I plugged the unit it and dropped in an Ella Fitzgerald & Louis Armstrong album that I found in my parents' collection. I don't have the musical vocabulary to describe it as anything other than AMAZING. Superb warm sound.

That warm sound... get it?

That was Sunday night, and over the next few nights I listened to all kinds of stuff. It's hard to explain how the Luxman L-30 drives my KEF LS50 speakers in a totally different way than my NAD 3020 (rebuilt 2 years ago, and going strong). I was in love.

My Uncle Pete came over tonight to pick it up, and I think he was blown away. He brought over a record (I don't recall which one!) and we listened to most of the A side. Then we listened to tracks from The Sword, The Rolling Stones, Yngwie Malmsteen, Tony Bird, Eternal Champion, Iron Maiden, and Buffalo Springfield.

He was excited to be leaving with it, and I was sad to see it go! This was an exceptionally fun project, and challenging because I make some mistakes along the way. That's OK because I learned more than I would have otherwise.

What's next?

Full album/gallery. 

Re-cap on NAD 3020 Stereo Amplifier

A few weeks back I started hunting for a turntable and amplifier. My dad had his old kit boxed up in my parents' garage and he was happy to give the NAD 3020 amp and Onkyo CP-1010A turntable a new home!

After connecting all the gear, everything sounded good (so, so good), but occasionally the right stereo channel would drop out. A sharp tap on the amplifier would bring it back. Apparently this is symptomatic of failed or failing capacitors, because electrolytic capacitors are generally not designed to last 30 years or more.

I found the service manual for the NAD 3020 online and was amazed to find a full design circuit diagram, parts list, and labelled circuit board wiring diagram. Replacing the caps was going to be easy.

I put together a quick parts list of all the capacitors I had to replace - 42 in total. Only the electrolytic capacitors required replacement because the conductive electrolyte inside them can (and did) leak over time. The ceramic and mylar capacitors inside all passed a visual inspection.

I placed a Digikey order (~$60 for the bare minimum parts but I ordered spares and ended up around ~$90) and warmed up my soldering iron. Sure enough, a good number of the caps were trashed:

One daugherboard with caps removed. You can see the gunk where the electrolyte leaked in at least two places.

The order arrived and I started installing new caps Here's that daugherboard back in place. Anything blue or gold in this pic is brand new:

These 2200 μF caps were the biggest, and replaced 4 completely trashed caps on the input power filtering (I think). All the new parts were different brands and dimensions than the old ones, but that's okay. For cap replacements, as long as the capacitance is the same and the voltage rating matches or lightly exceeds the original, you should be good. Or so I read.

Powered back up!

The first thing I noticed was that everything sounded a bit sharper, but the amp still has a beautiful warm tone. When I listen to music on this setup, I am amazed to hear new details in songs I've heard hundreds of times - instrumental trills, soft vocals, basslines, and more.

New Guitar! So Metal.

I bought a new guitar today with some money I got from my parents for Christmas!!!!

It is a Jackson Rhoads RR3, made in Japan, with a Floyd Rose licensed tremelo and Seymour Duncan humbuckers (pickups). The guitar was designed by the late Randy Rhoads, who played with Quiet Riot in the late 70s and Ozzy Osbourne in the early 80s, before a dying in a plane crash in 1982.

Although Randy Rhoads designed the Jackson Rhoads guitar, he (tragically) never played it. He played the prototype and sent feedback to the guitar makers, but died before the revised prototypes were completed. Although Rhoads was only 25 when he died, he had a massive impact on the metal scene with some original guitar work in classic songs like Crazy Train, Diary of a Madman and Mr. Crowley.

I bought the guitar from Italmelodie in Montreal where a guy named Dino was super helpful, letting me play on a crappy practice amp (to simulate the crappy amp I have here in Montreal) and a huge Marshall stack in a soundproof room. He was great - he left me alone to play for 40 minutes or so, stopping by every once in a while to ask how I was doing or tell me he liked a song I was playing (I was playing a lot of Randy Rhoads stuff, and he's a huge fan). A+++ would shop again! 

It is hard to take a picture of yourself holding a guitar and also looking cool.

Here's a little video I recorded this evening. I'm playing part of a song called Paraphrase by Swedish guitar sensation Yngwie Malmsteen. I couldn't get an cut with no mistakes so I said "eff it" and uploaded this version. 

I've only put a few hours of play into this guitar but I already love it. The action is super low and the notes just jump off the fretboard. My Gibson SG has no tremelo/whammy bar so it will take some time to get used to the whammy on the RR3. The only downside: it's not easy to play sitting down. But that's okay, sitting is not very metal. I might upload a few more videos of me playing guitar in the future, we'll see! 

Thanks Mom and Dad! 

Petition to rename February "Metaluary"

BECAUSE I'M GOING TO SEE SO MANY HEAVY METAL SHOWS!

Feb 3 - Megadeth & Motorhead
Feb 5 - Iced Earth & Symphony X
Feb 15 - In Flames & Trivium
Feb 27 - Children of Bodom (it will be my fourthtime seeing these guys - they tour a LOT)

Here are some samples.

/!\ Pro-click zone /!\


Trivium - The Crusade - An 8-minute thrashy instrumental metal epic. Even if you don't like metal, click this link and just listen to all the different guitar, drum and bass parts throughout the song.

Children of Bodom - Bodom After Midnight - I like this one because I can understand the vocals of the refrain. Also, they're the title of the song.

/!\ End Pro-click zone /!\


I missed a ton of awesome metal shows in Montreal in July due to a friend's wedding, and a ton more in October when I was in Saskatoon. Metaluary is going to make up for that. Metal!!!

SLOWTALLICA

My friends.... we have invented something amazing. Picture Metallica's crunchy riffs - yes, even if you're a Metallica hater, you know there is that one song you still like - and now picture them slowed down and pitch reduced by 25%.

Yes... enter SLOWTALLICA.

I was at a buddy's house, playing some video games and having some beers. We through Metallica's Master of Puppets 45rpm LP on his record player, without realizing the turntable was set to 33rpm. Dismay and annoyance at our so-called "error" immediately turned to PURE JOY as we realized just what we had discovered*.

*Technically, Slowtallica has already been discovered. But we'd still like credit for an independent discovery. 

I can barely express how awesome Slowtallica is without extremely profane and emphatic language, but I will do my best to keep this clean.

Slowtallica takes Metallica's thrash hits and turns them into crunchy, deliberate pieces of low, heavy metal. In some respects, Slowtallica sounds like the slower, incredibly low and crunchy viking metal songs of Amon Amarth. And like Amon Amarth, James Hetfield's voice is transformed from his normal pseudo-raspy mid-range "Yeaaahhhh!"s and "OHhhhhhh!"s to awesome, demonic, hellspawn vocals - the way heavy metal was meant to be delivered.

Don't believe me? I took the liberty of including a few samples in the 1-minute-30-second video below:



I kept the sound clips to 30 seconds to minimize the odds of the video getting flagged for copyrighted content. We start off with a Metallica song that everyone should know: Master of Puppets. We then slow it down 25% and therefore make it 25% better. We move on to a sampling of Leper Messiah, which sounds absolutely, insanely deadly with your speakers or headphones maximized, and finish it off with an instrumental sampling from Orion.

Wow, just wow, right?

If you want a Slowtallica album all for yourself, I can't give it to you! But, if you have some legally-acquired mp3s (or any mp3s, really), you can download Audacity then follow this tutorial to create some Slowtallica of your very own. Tip: -25.9% is the perfect slowing factor.

\m/