Oh, and this one is also for sale! 🙂

Do you love amplifiers with a little ‘wood’ in their design? Do you love a classic, discrete phono stage? How about machined aluminium knobs and a timeless design that is emulated some 50 years on? Welcome back folks to another article about a beautiful piece of hi-fi equipment I’ve saved and am selling, an iconic Luxman SQ507X integrated amplifier.

UPDATE: Sold!

The backstory around this one is much simpler than the one accompanying the Sansui AU-11000 integrated amplifier I wrote about last time. That beauty sold within 24 hours, congrats and thank you to my customer, Brett, a Sansui collector who added it to his collection.

Luxman is a brand I don’t discuss as frequently and yet work on a ton of. For example, I co-own, with the Speaker Doctor, two end-game Luxman L-550 class A integrated amplifiers. I’ve repaired one and will soon list it for sale. Then I need to fix and sell the second! I recently repaired a gorgeous Luxman 5L15 integrated amp and I have a beautiful Luxman M-4000 here for work. I have repaired and restored C-1000s, C-5000As, M-4000s and M-4000As, a statement Luxman M-10II power amp and C-10II pre-amp, etc, etc. This is an amplifier article, so I won’t even start on the Luxman turntables I’ve worked on over the years.

Luxman SQ507X Features

Like the Sansui before it, the Luxman SQ507X is a full-featured integrated amplifier with a discrete phono stage, utilising high-quality components. That phono stage is configurable for loading and gain and like most integrated amplifiers from this time, overall build quality is exemplary. There’s a ton of wood, metal and scarcely any plastic to be found here. These things came with a 5-year warranty, something Luxman doesn’t even offer now, despite all the supposed ‘improvements’ in modern gear.

Everything is serviceable and repairable and one thing I love about the SQ505X and SQ507X is that the amplifier modules are, well, modular in the sense that they can be removed in minutes. This lovely model also features connectors, allowing for easy disassembly, tone controls, filters, a tape loop, a headphone socket and a nice incandescent lamp to indicate power is on, in the warmest period-correct way.

By the way, the Luxman SQ507X cost a staggering $458 AUD in 1973. Adjusted for inflation, that equates to $5,150 AUD, not only a great number in musical and amplifier terms (my Perreaux PMF-5150B power amplifier will also be sold soon), but an incredibly large amount for an integrated amplifier as I’m sure you’ll agree. This was Luxman’s best effort at making a mid-sized integrated amplifier, back then and it holds up remarkably well.

Even though hi-fi equipment keeps ‘improving’ every year, going back at least 50 improvements would mean gear from the early ’70s would be absolute garbage and sound awful compared to the improved gear we have now, right…? Isn’t it strange then that this lovely amplifier and others like it sound so good..? When I say good, I mean better than modern gear that you might be able to afford. Yes, a $5000 amplifier might sound better, but I’m not sure about that, and it will not last 50 years, I am sure about that! I mean, it’s almost as if there’s a marketing ruse at play, designed to sell new gear and devalue older gear. Surely not?

Hans over at Hiberink has a great page about the SQ505X and 507X so go and check it out. The only thing I’ll politely disagree with Hans about is tantalum capacitors being no good. On the contrary, tants as we call them are/were used because they’re very good. You’ll find tants in stratospherically priced test and measurement equipment, some of which I own, specifically because of their improved high-frequency performance vs wet aluminium electrolytic types.

I haven’t removed the tantalum capacitors from this Luxman SQ507X, and I suggest nobody else does either unless they need to be. They can and do fail, and this can be tested. There are of course improvements that can be made here, but I’ll leave that up to her next owner.

Luxman SQ507X Specifications

As always, courtesy of HiFi Engine

Power output: 50 watts per channel into 8Ω (stereo)

Frequency response: 10Hz to 60kHz

Total harmonic distortion: 0.04%

Damping factor: 40

Input sensitivity: 2.2mV (MM), 90mV (line)

Signal-to-noise ratio: 63dB (MM), 80dB (line)

Speaker load impedance: 8Ω to 16Ω

Semiconductors: 33 x transistors, 2 x diodes, 4 x varistors

Dimensions: 450 x 160 x 268mm

Weight: 11kg

Issues

I’d like to thank my kind donor Kurt for this one. Kurt donated two pieces of hi-fi gear, the other one being a gorgeous Hitachi HT-460 direct-drive, fully automatic turntable, currently available in the store. Both pieces needed TLC. The Hitachi ran slow at first and then stupid-fast, but I fixed that and she runs perfectly now. This beautiful Luxman SQ507X needed some fairly typical age-related cleaning and maintenance, after which she also now runs superbly.

There is a service record of some attention being given to one channel long ago, but based on what I know about that repairer and my close inspection of what was described as having been done, my conclusion is that nothing at all was done. Sorry Kurt, at least that repairer no longer ‘repairs’ things.

Resurrection

This Luxman SQ507X only needed deep service to bring her back to life and is now purring once again. A deep clean, attention to connectors, wiring, DC symmetry and quiescent current along with some deep service of switches and controls saw this amp back to normal again and ready for a new home. I also replaced the mains plug as the wiring was frayed and a new rear entry style plug is better in most cases anyway.

Let’s take a brief look at some of my work on this old girl. If you don’t want to miss equipment for sale and new articles, consider subscribing:

The first steps always involve a visual inspection and careful assessment of the state of things before proceeding. From there, with old, dirty pieces like this one, I tend to proceed with my deep chassis cleaning process.

Results

I think this beauty turned out well, and I’m especially pleased with the wooden cabinet, which looks like a million bucks, and how she sounds, which in a word is stunning. Overall, she performs flawlessly, with a warm, punchy sound we expect of good gear like this. This SQ507X also has an effortless quality to it, with lovely detail resolution.

Let me tell you, if you’ve never heard a really good older piece like this you ought to because you’ll no doubt be very surprised. Listening through headphones is just fantastic. Even though hi-fi equipment “keeps improving each year”, this lovely amplifier sounds so damn good and I can confirm that when you listen to as much older gear as I do, this becomes obvious very quickly.

The penny drops for most people regarding older gear like this after hearing a good handful of older pieces that they probably never knew existed. Marketing and advertising have a lot to answer for and I’ve explained this folly so often that I’ll spare you another sermon. Suffice it to say that this Luxman SQ507X sounds awesome, and this is entirely predictable as it is with all hi-fi equipment.

For Sale

This rather special Luxman SQ507X is also looking for a new home. Unlike most, she’s not been tinkered with and contains all her original parts, ready for whatever her next owner would like to do with her. Also unlike most, this SQ507X comes with the original owner’s manual, warranty card and a selection of original period reviews. It is very rare to find the amplifier and paperwork together in this condition.

This Luxman SQ507X cost $460 AUD back in the early ’70s and was a serious piece of equipment at the time. If anything, gear like this and the Sansui AU-11000 I recently sold only becomes more collectible due to raised awareness and appreciation, and the neverending sea of modern plastic gear. The other good news, to use some amusing terms commonly found in Japanese listings, is that there is no gully noise! She is 50 years old though, so, as they say in Japan, “Please don’t buy if you are nervous!”. Not much to be nervous about here though.

These days, Luxman SQ507Xs often sell for around $1000 USD / $1500 AUD, plus shipping, and import duty (10%) from sellers you’ve never heard of and rarely in this condition and so carefully serviced and never with a warranty. If you’d like to adopt this one-owner original, with original documents, manual, serviced and with no shipping or import duty, she can be yours for $1650. Local buyers preferred.

UPDATE: Sold!

As always friends, thanks for visiting and for supporting Liquid Audio’s endeavours in cherishing classic audio. Please like, comment and subscribe, and if you own some classic hi-fi gear that needs a little TLC, don’t hesitate to get in touch!