Restoration of a Luxman L-58A

[syrjosh]

Dear tech-savvy audiophiles,

On the lookout for a great amp to play my vinyls and CDs, I spotted a Luxman L-58A on the second hand market.
Long story short: the guy was asking €150 for that amp that had not been used in many years, we tried the amp together at mine, it worked fine but obvious issue with the treble control (which still works but not like it should), at which point we agreed that I'd ask my tech a quote for a fix + full revision, further to what we can then decide what to do: my tech quoted €600 and the (definitely super nice) seller decided to give me the amp after hearing that...!

Here is the report I got from my tech:

"The amp might 'work' now, but it is basically a ticking timebomb if it doesn't get a full recap soon.
The steps are kind of labour intensive and basically break down into:
- Dissecting the amplifier into its individual sections and PCB's (7 in total)
- Composing a list of all electrolytic capacitors, their values, voltage tolerance ratings, width and footprint
- Placing component orders with (at least) two providers. The large (and bloated) power capacitors are really hard to find, so I'll have to see where they can be sourced.
- Replacing all Elco's & Tantalum capacitors on all boards
- Whilst we're at it, cleaning the switches and potentiometers. Only when the stuff is open I'll have good access, so this is an opportunity.
- Put it back together
- Resolve the issue with the treble control.
- Go through factory specification alignment procedure for the bias current and offset voltage
- Do some restoration on the wooden case, because it's scratched pretty badly

This would take at least three full days of work, plus a whole bunch of parts (Audiphiles dig Nichicon capacitors, which are a little more costly than your generic Chinese stuff, but do tend to stay healthy for at least 3 decades) and my count has me at around €600."

Now, what would you guys do in my place? Does this report sound reasonable to you? Based on my experience with my tech, I'd be surprised to hear overly negative comments about it, though you may have ideas / remarks / suggestions

If the amp fell on your lap like it fell on mine, would you drop €600 to bring it back to "factory specs" (or say, as close as possible to these)?
Is it worth it commercially speaking, and perhaps more importantly, sonically speaking (should I rather drop €600 on another, seemingly "better" amp)? Another option would be to resell the amp "as is" and leave it up to others to decide whatever they want to do with it, but I have a sense I got lucky and should rather leverage that luck.

I know this very model of Luxman is great, fairly sought after, can reach 1K+ in value or so, assumingly when in good technical shape...
This is an amp I would keep and make a long-time investment for (hoping it's worth even more in twenty/thirty years from now), but there may be aspects I fail to consider that may make this prospect unrealistic (for example: if modified/recapped/no longer original enough, value won't increase...) or undesirable (the amp is not so great all things considered -- we're in 2021 after all...).

Many thanks in advance for your feedback on this potential project
Cheers - Laurent

(PS: the amp's bloated caps ready to burst as illustration)

 

[Helicopter]

Congrats on the nice free piece.

No idea what 3 days is worth there, but sounds likely comparable to other high cost locations. 3 days sounds reasonable for a full recap.

You might want to look at a simple repair, or a restoration bringing it to spec without a full recap. I am sure other techs would offer either.

I agree cleaning all pots and switches is a good idea.

I disagree with the time bomb comparison. A full recap may be more reliable but that doesn't mean it is guaranteed to fail right away with less work done.

I am dubious about the big caps. I bet there is a new small cap or combination of caps that will work fine from a normal supplier. I am not certain, but I would look into it further. They will probably look different though.

Maybe just take it to another tech and get their opinion, or ask them what they typically offer for restoration or repair.

 

[DVDdoug]

but obvious issue with the treble control (which still works but not like it should)

I would try some control cleaner spray into the treble control and related switches.

Personally, I'd buy a new amp (or receiver or AVR) before paying someone to completely rebuilding the old one.

he (definitely super nice) seller decided to give me the amp after hearing that...!

...Another option would be to resell the amp "as is"

And then the "nice thing" would be to give the original owner the money.

 

[AnalogSteph]

Bloated-looking plastic on top of the big power supply filter caps is not unusual, it's just cosmetic. The vents on these are on the bottom side. Busting out the ESR meter would tell you a lot more about their health.

600€ is a bit steep, but then it does amount to a full restoration with case and all. I would have to be very much in love with the style and build of this unit to go ahead with this.

There are some Luxman series which are known to be ticking timebombs, but that's due to issues with bad solder joints (L-410/510 series). Going over those rarely hurts with a unit this old, it's a fairly common issue - apparently boards with through-holes substantially larger than the installed component legs are quite prone to this.

For the time being, I might look into options for a "small service" if possible - address scratchy controls as far as accessible, test electrolytics for ESR and swap out bad ones, look for dodgy solder joints.

I am not always seeing the value in Luxman's separates, but this integrated amp I must say features some pretty neat circuitry. I would think that Pioneer's SA-9800 may still have the edge (for one thing, MOSFET outputs are likely to benefit reliability but not so much distortion performance), but it's definitely not too far off. Certainly one worthy of considering doing a full restoration on. The MM/MC phono stage alone is likely to be about as good as any, though I'm not sure how RF-proof the whole construction is (easy enough to try out with your phone or a WiFi router, I suppose).

 

[restorer-john]

The amplifier was made in 1981 judging by the date codes.

As @AnalogSteph mentioned above, the main cap 'bulge' is purely cosmetic. The caps are soldered down and glued around the PCB and over the years, any gassing off goes up, under the outer sleeve and expands the top cap. You can pull off the bulged piece and have a look for yourself.

600E for a rebuild of that amp is a lot.

Personally, I'd clean the pots, switches if they need it and check bias and offset and listen to the thing before making any expensive decisions.

What is a "time bomb" however is this:

These are Rifa brand suppression 240Vac caps which are encased in epoxy. The epoxy crazes and cracks, air/moisture gets in and yes, they explode. There may be another pair in or around the main power switch. They should be removed and replaced pronto.

 

[Helicopter]

@restorer-john what about the assertion this needs special rare big caps that cam't be found at 2 normal electronics supply houses? Is that true?

 

[restorer-john]

@restorer-john what about the assertion this needs special rare big caps that cam't be found at 2 normal electronics supply houses? Is that true?

Most unlikely. That said, they are PCB mount, likely not snap in, but with old-skool lugs or pins, perhaps three pin (one for stability) and I don't know the pin pitch or overall length (vertical height) in mm. Not esoteric or expensive, but maybe height clearance could be an issue.

They will probably be fine, I'd test them for capacity, ESR and check to see what we are looking at in terms of ripple on the main rails before doing a thing to the amp. Right now, he has apparently zero $ invested. Why throw money at something without establishing a baseline performance?

That's the thing with "vintage technicians". They will tell people an amp needs this and that, or it might explode in a ball of fire and will need new caps as the old ones are deteriorated, and yet they will never test the amp, give some baseline figures and numbers and justify what they intend to do and what it will cost. And particularly, what improvements they expect to achieve.

 

[bloodshoteyed]

That's the thing with "vintage technicians". They will tell people an amp needs this and that, or it might explode in a ball of fire and will need new caps as the old ones are deteriorated, and yet they will never test the amp, give some baseline figures and numbers and justify what they intend to do and what it will cost.

well, yes and no, depends on who you stumble upon
just got a quite low quote from an authorized sony repair shop for restoring an almost 30 year old ta-f690es (which itself ain't really anything special, it just has sentimental value) including analisys and a complete explanation on what & why will be exchanged, cleaned, etc.

 

[Helicopter]

Yeah it depends, but anyone recommending a full recap of something under 40 years old that isn't a sticky mess inside, I would move on to another tech.