Philips AH686 Rebrand, Restoration

Fredrik 1977

Super Member
Next up in my quest to restore all the 70´s receivers in the world is this.
its a DUX TA-12000, also named Loewe TA-12000 in germany.
it is a rebranded Philips AH-686 with a slightly diferent faceplate.

its a quite nice receiver, japanese made, Sanken outputs. its the biggest in its series.
very robust looking, and quite good build quality, its also pretty powerful too!

will recap the PSU, pre and main amp, replace a lot of 2sa725 and replace the 4 broken lightbulbs.
and we will see maybe i´ll come across some more work in here.

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the inputselectors sits in the back at the terminals (upper right pcb), nice!
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the mainamp pcbs, the psu, and Riaa has some neat connectors for easy service, just pull the cards and stick em back when done, very easy unit to work on.

Right amp pcb with stock components
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after replacing 2x 2sa726 and a bunch of caps its back in its place.
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regulator pcb, just pulled right out of the unit. no cables to worry about, awesome.

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it did run somewhat hot so lets hope that piece of copper will cool it down a bit.
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i hope so:)

pre-amp, nothing unusual here. looks just about the same in every damn receiver:)

stock
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recaped, 2x A725 replaced along with 4x C1313, and of course MKT filmcaps
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i pulled the phono eq, and recaped it, i am about to replace the 8 transistors, A726/C1313 four of each.

decided to go clean the faceplate and knobs instead of finishing the riaa pcb, i wish i hadnt!
be cause disaster and his gang of thugs was lurking around the corner and hit me where i least expected!

i put the parts in water with dishsoap and when i pulled it up the printed text on right side of the front i partially/mostly gone.
never had that happen before!

well i kinda knew something was about to go south since the recap went a litle too smooth.
does anyone know a way to get some text back on there?

i will try to take a better photo than this.
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well dispite the above drama i have replaced those phono transistors and played music for an hour or so.
and since i fail to find the correct idning current values in the manual i have adjusted it for 25mV i suspect that is not the proper value.

maybe i should go higher? better to have too high than to low?
 
You can make custom waterslide decals with a laser printer and special paper (~USD 1 to 2 per sheet, check your local modeling hobby dealer). I did this for a unit where the volume control labelling always wears off.

The hard part would be mostly in matching the font and size to look good.
 
Thanks!
thats a great idea!
as a kid i was crazy about building model planes. i didnt know you could print your own sheets,

i found some sheets for laserprinter and have placed a order.
 
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yes it will be a fun project.

i think the original text on the faceplate is similar or same as those water decal sheets. thats why they fell of when i tried to clean it.
bet i have to try a couple of times to get the right size and to get it in the right place and so on.
and i thought this was gonna be a easy receiver:)

so whats left now is the maincaps to be replaced and to come up with a good idling value. now its set for 20mV across the 0,47ohm emitters.

pics of the phono eq

stock
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4x electros , 4x wimas and 6x A726, 2x C1313 later
note: the upper right cap is mounted the wrong way in the pic, just so sombody doesnt do the same thing :) it pops! trust me:D
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and back in its place!
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well i got the papers in the mail so now im having some fun deciding what to print on them.

this is new territory in receiver repair for me lol

think i´ll make a smaller "12000" or "TA-12000" that matches the text "sound project"

the stock font in word (calibri) was pretty good match to the rest of the text, PHONES, VOLUME etc..
i´ll have some work to do here!

not gonna use any of those "12000" :)
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and maincaps was replaced! now playing some music on it and its one helluva receiver!

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soo nearly finished

keep in mind that this is the first time since the late 1980´s i use this material. then on plastic 1:72 WW2 Fighter planes. :)

first i cleaned all broken text so not much left
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new Logo, power, and phones in place. i chose the Loewe logo since the dux is suppose to be a bit of plastic mounted in the 2 holes.
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its a TA-12000 again!:) i chose a diferent font for the "sound project ta-12000"
some of the smaller ones on the toogle switches was badly printed so they look a little worn already:)
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i havnt put on the smaller stuff on the the input and tapemonitor switches yet.
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Very cool!

By the way, we had amps from that line - an A-8000 (which is TA-12000 without tuner) and an A-12000 (which is TOTL amp, more power than TA-12000) and I to my ears the A-8000 sounded better. The brands were Erres and Loewe in our case. We did wash the face and did not have a problem with letters washing off, but we used hand soap, not dish soap. Maybe that made a difference, maybe we were lucky.
 
Looking good Frederik - repairing front fascia graphics is always a problem, but of the possible options in this situation, I'd say it's looking like a very workable solution.

If I recall, the original 'Airfix' waterslide transfers from the 70's used to be varnish sealed after application - is that needed here, or does the newer material seem thicker / more durable ? I've used various transfers on classic M'cycle restorations, but they were all varnish sealed anyway, for weather protection. Maybe a very light (and localised) spray with something like the varnish used by artists to protect pencil sketches would be an option here ?
 
To me it seems to be the same material as in the 80's. Was thinking about sealing Them in some way. Not really shure how yet.

This solution would be perfect for fixing 1 or 2 text markings on an old amp. Not the whole front as in this case. A Little to much!

This receiver is a keeper anyway so it doesnt matter if its not exactly original. It will do mainsystem duty for awhile.
 
Well done! Been toying around with a Philips 793 myself, and all is working now except for the tuning meter. So I can relate to the sheer amount of effort you've put in.
 
well thanks all!

i have replaced some of the badly printed "stickers" now and i did the ones around the input and tape switches

here she is playing pointer sisters - slow hand
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the input selector wasnt easy but i guess that will work. and yes AUX/CD on a 1979 unit will arouse some suspicion.:)
now in day light i see the loudness sticker isnt exactly level, and the "input" has a broken T. but even the sun has its dark spots lol
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yeah i wont get a job as a photographer any time soon! thats for shure! :)

and a page out of the swedish "hifi handbook" 1979
swedish hifi institutes tests in red and factory specs in black
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Final Thoughts about the receiver: Unbeatable in bang for buck department! i bought it "broken" for next to nothing, but nothing was wrong with it, except the light bulbs. it sounded pretty damn good as i was, but after recaping/replacing all a726/c1313, and MKT´ing the signalpath wich was very easy on this unit, just WOW! it totally sweepes the floor with my KR-8010 (stock) i currently have set up in my main-system. will give it a try against some others later.

these units seems to be serious sleepers!

and since im gonna do a thread about recaping low-esr (UPW class) vs audio-grade (UKZ class) i need 2 amps. i think i´ll pick up 2 DUX,Loewe TA6000, its the 30W version.
 
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