Luxman LV103 Conclusion Fixing the bad phono preamp stage

แชร์
ฝัง
  • เผยแพร่เมื่อ 8 ก.ย. 2024
  • Part 2, replacing the bad parts and full test run.

ความคิดเห็น • 77

  • @BoB4jjjjs
    @BoB4jjjjs 4 ปีที่แล้ว

    I watched both your long videos thank you. I would rather watch a fault finding video than one that says "This was what is wrong and I am going to replace them, then a shot of the thing working. I have no idea what went wrong and what anyone found when it is done this way! I will sit for an hour, before I start to think "Does it need to be this long, they have not found the fault yet?" However, you were finding faults, so I am happy to watch videos this long when you find faults and explain what you find along the way, so thank-you for the interesting video. Plus Pt1

  • @oldguy8177able
    @oldguy8177able 4 ปีที่แล้ว

    wow what a massive job i'm sure most people would have given up,so well done

  • @iwanssw
    @iwanssw 3 ปีที่แล้ว

    Exactly the same problems as mine, I'll try to fix it. Hopefully I'll succeed. BIG BIG BIG thanks

  • @dblaandy
    @dblaandy 2 ปีที่แล้ว

    i have that amp beautiful sounding amp had to take it in for repairs but was well worth it in the end thanks for the vid very insightful !

  • @basilsaverimuttu682
    @basilsaverimuttu682 4 ปีที่แล้ว +15

    keep the troubleshooting videos long and detailed!!!

  • @CliveTrezona
    @CliveTrezona 4 ปีที่แล้ว +3

    Nice repair thanks. I love the long vids. You always learn more from the long ones.

  • @australianbloke3934
    @australianbloke3934 4 ปีที่แล้ว

    Oh dear, the poor old vinyl has seen better days, as you say.

  • @GeorgeGeorge-xj2bc
    @GeorgeGeorge-xj2bc 4 ปีที่แล้ว +1

    The double jfet is a differential ampilier that adjust the gain according to the feedback circuit which is the RIAA compensansated frequency filter.Q2103 along with LD2101led form a constant current source that drives the dual Q2101 jfet differential amplifier.And finally the IC2105 is a dual operational amplifier common in both channels.

  • @jameskrivitsky9715
    @jameskrivitsky9715 4 ปีที่แล้ว

    Glad you show the lengthy original version of "A Day in the Life of DAVE " so viewers can see that sometimes it takes a twist and delays to fix a quality piece of valuable equipment. Always a learning process. Thanks J K

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      Another one on the way. Finished that NAD and more parts were found bad after the 3 new transistors installed. A total of 4 transistors in 2 resistors.

  • @Asriazh
    @Asriazh 4 ปีที่แล้ว +1

    At one point i was wondering if i should switch the caps in the audio path on my stereo amplifier to "audio grade" quality ones, in particular the Elna Silmic II ones until i saw their estimated lifespan. It's a joke compared to other quality capacitors! Also they're just rated for 85°C. After i saw that, i did a big "Nope.." and kept my 105°C ones that have 4 times the expected lifespan :p

    • @PhuckHue2
      @PhuckHue2 4 ปีที่แล้ว

      You read wrong information. Those Elnas are high quality that last at least 20 years

  • @saarike
    @saarike 4 ปีที่แล้ว +1

    Excellent repair and information about feedback! Thank you.

  • @Budro4764
    @Budro4764 4 ปีที่แล้ว

    I got a question for you , is there a solvent that will make the circuit glue soft and make it easier to get off the parts ???? I have a couple tiny ferrite beads with some tiny copper winding's on them in my HR 2510 ham radio...... Those tiny ones are like Hen's teeth , and have to be wound by hand nowaday's.... I don't know how many winding's are on there....

  • @pahrumpauto
    @pahrumpauto 4 ปีที่แล้ว

    LOVE LUXMAN I HAVE LUXMAN R404 AND RIGHT CHANEL COMES AND GO,S I CAN,T FIND A WIRING SCHEMATIC FOR IT WHERE DO YOU FIND YOURS AT. PS LOVE YOUR LONG VIDEOS THERE IS SO MUCH TO LEARN.

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      Hifi engine and vinyl engine is where I find them.

    • @pahrumpauto
      @pahrumpauto 4 ปีที่แล้ว

      @@12voltvids you are the best thank you but they don,t have any of my stuff on there. my luxman or fosgate first gen. i will keep looking or maybe draw it out my self thank for help

  • @skip1835
    @skip1835 4 ปีที่แล้ว

    The length of this vid is no problem on my end - very interesting all the way through - kind of a "bummer" that you weren't able to change out the "red" caps - regardless, I'm not surprised that your Luxman sounds so good, some viewers may not be aware that Luxman is still producing some of the finest playback equipment out there - they're ultra high end stuff is coveted by those audiophiles that put together playback systems where cost is practically no object - their M900U amplifier would fall into that category, it's considered to be one of the finest performing and sounding at any cost level - - thanks, enjoyed every minute.

  • @docfoot316
    @docfoot316 4 ปีที่แล้ว

    Great repair ,enjoyed watching ,many thanks for sharing .

  • @chuckchar
    @chuckchar 4 ปีที่แล้ว

    You can join the Neg. lead on two S.P. caps to have a B.P cap , it halves the rated capacitance so you need two 2uF s.p to = 1uf b.p. Also sometimes both the schematic and silk screen on circuit board can be wrong for S.P and B.P markings (among others) I did a Marantz 1070 recently, ordered parts based on schematic and parts list , the pre-amp board S.P indicated and I replaced with a S.P , sounded OK testing . Recapping a second 1070 a couple days later I see the cap I removed was B.P so I replaced with B.P , went over to the first Marantz 1070 customers house and swapped the caps out for B.P and man it was night and day , he did not notice it first because the large amount of hard dirty hours on the amp beforehand ( blown outputs main reason for recap). I would swap all the B.Ps with B.Ps on yours IMO.
    Thanks again for the videos , long format is good 👍

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว +1

      Yes I am fully aware of this. Have done it before, but this is a critical low signal area so I wanted the correct value. The smallest I have is 2.2, so that would give 1.1, and these were 1.0. Again not much of a difference but this is the critical RIAA equalization circuit so any drift is going to present itself as a change in the response.

    • @chuckchar
      @chuckchar 4 ปีที่แล้ว

      @@12voltvids Yes but to be fair these are probably 10 to 20% rated caps anyway, I always measure caps when mirroring channels , not so much for spec but to get them as close to equal values per side.

  • @alexispieltin9379
    @alexispieltin9379 4 ปีที่แล้ว

    Good job, even if it took two videos to show most important and interesting phases. It's a good tribute to the real time spent to apparently simple projects like that, that can last a great amount of unedited time to complete. And once again, the brown glue problem is here present in some limited extend. Few understand this can ruin part of expensive equipment as it can trigger corrosive reactions, eating components, pcb copper, solder...
    We also all share the same problem with components sourcing and the limited number of shops remaining. Covid crisis has only complicated things with distances and stress for everyone. And you have the chance to live within an hour of a shop (even if it's a pain in the a..). If I have to ask for bipolar audio caps, I must order them in Berlin Germany (living in Burgundy, France!).
    I was a retail seller of Luxman HiFi back in the late 1980's, and these LV 103 and 105 were aliens in the all solid state production of the era. Luxman also produced laser players, with the same intention. Sound was beautiful, but budget was huge, even with the high watts offered with MosFets output stages. We were selling one for a thousand, but it sounded really better than LV113 of the same series, (this amp included more power and a DA converter). For audiophiles, Luxman (founded 1925!) has a long history of top quality tube amps, and having the opportunity to test one, it sounded really impressive. The hybrid approach is seen as "a good compromise", as you can have the tube sound without the expensive tube output power stages. Of course nowadays PS audio is a US reference manufacturer (is it known outside US and audiophiles?), but you can also find some pretty well made Chinese "replicas", and why not try some sort of blend of your own, with a tube preamp and a high power class whatever you like output stage. If you're rich enough, multi stage tube amps have always been in production (Carver...), but if your needs are for more power for the bucks ratio, or if your loudspeaker system has a poor rendering (watts for dB ratio), these "compromises" are perfect solution. Back in 1989, I had the opportunity to ask some senior Japanese Ingenior from Lux corp, about the life expectancy of these solutions. He argued that you can expect a very long life of these preamp tube,as they are generally used within their best operating condition. They use low stress heating circuitry (your pre heating operation!), and as these tube are designed to get their best linear operation, they are not stressed with high Mu tubes selected for power usage, with very high grid voltages and enormous heath to evacuate! If your decoupling caps are fine, they can last...forever! However, these amps were perhaps too expensive (you could buy an Accuphase or a Studer for that budget) and commercial up and downs from the early 1990's made these a dead end in further series and designs. Many of these top quality products (and even brands) disappeared from market at the same time, as Japan had to endure a severe economic and political crisis, aggravated with Kobe earthquake. Note, many of these HiFi manufacturers also left their original production country at the same time. Most of what is left, is now Chinese owned or name brand only. You cheap vinyle player is something far better than most entry level today's production. Of course Technics made pretty good machines, specially for DJ use with their robust direct drives, but early top end models specially designed for Japanese markets never ended in foreign markets. Sony and Denon also produced fabulous full auto direct drive machines, some even used a "computerized" arm balance and tracking control. Technics, Sony and Pioneer also produced tangential arms mechanisms, an idea still used (with far more complexity and precision) in top end linear laser driven arms accompanying 100000$+ engines!

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      It took 2 videos as I make twice as much when you watch both. I ain't stupid. I know how it works.

  • @sonnylou8087
    @sonnylou8087 4 ปีที่แล้ว

    I like your long videos, it’s a good chance to learn something👍😆

  • @123clis321
    @123clis321 4 ปีที่แล้ว

    Love the choice of music.

  • @jazbell7
    @jazbell7 4 ปีที่แล้ว

    That's amazing that you have an electronics parts store. I live in a supposed high tech city (Columbus Ohio) and there are no electronics stores left. I have to use Digikey, Amazon, Ebay etc. and wait.

    • @pliedtka
      @pliedtka 4 ปีที่แล้ว

      How about Parts Express, for some stuff. Digikey, etc, shipping charges are insane to Canada, plus if over 100$ Can, they slap duty on us, plus tax ☹️. We have one store left in Ottawa, Ontario - better than nothing.

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      We have 2 retail shops that have limited parts, and a local mail order that has a good inventory but because he works out of his house there is no pick up possible anymore which is unfortunate because he is very local to me, like 20 minutes away local.

  • @jijzer3284
    @jijzer3284 4 ปีที่แล้ว

    ooh was that 1.5 hr

  • @Oufg103f
    @Oufg103f 4 ปีที่แล้ว

    Great video 👍 I'd love to own that luxman.

  • @pliedtka
    @pliedtka 4 ปีที่แล้ว

    2sk240 JFETs, try to find one these days. I would put 1uF film, polystyrene, polypropylene, mylar - stinking bypolars, I'm not big fun of them in NF leg, not that I hear differences, just for reliablity. Or 2x470nF small film caps in parallel. Some stores used to have them from time to time, if not Parts Express or someone dealing with crossover parts, because they are pain to find.
    I had Sima power amp from late 80s, the 470uF in nfb to the ground went bad and gain with it, took me a while to figure it out.
    I'm fighting with my Nakamichi deck, changed the capstan motor and belt, but it doesn't want to settle down on particular freq, wondering a bit. Strangely speed came down once I closed the chassis. Let it play for a while and see if it will keep steady speed.
    BTW, did you pick up the adjustable soldering iron at Princess, 70$ on sale, screaming deal.

  • @jdmccorful
    @jdmccorful 4 ปีที่แล้ว

    Interesting repair.

  • @dwoodog
    @dwoodog 4 ปีที่แล้ว

    Thanks for the long video. I for one like the long ones. I wanna see how you arrived at the problem not just the fix. Kinda like doing a long division math question and you didn't show your work, what good is that.

  • @johnb5519
    @johnb5519 4 ปีที่แล้ว

    I remember my old boss telling me to never assume anything when it came to picking up orders from the electrical supply . From then on everything was checked before leaving the parking lot.

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว +2

      Never trust mail order parts either. The problem there is even when they fuck up they charge you a new shipping fee.

    • @johnb5519
      @johnb5519 4 ปีที่แล้ว

      @@12voltvids Right on.

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      @@rusty1187
      "They f..k you in the drive thru, they f..k you in the drive thru they know you will be miles away before you realise you got f..ked so they don't care. Theh know you're not going to turn back so who gets f..ked Leo Getz that's who gets f..ked" sorry, couldn't resist that classic line from lethal weapon 2

  • @tyronenelson9124
    @tyronenelson9124 4 ปีที่แล้ว

    You know what i would do, go right back to the electronics store go in and tell them that they have supplied the wrong part and no you are not rushing me this time just to make another mistake.

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      And they would say. NEXT!

  • @MrRadioGypsy
    @MrRadioGypsy 4 ปีที่แล้ว

    When I'm done re-capping a board, then I will use the ESR meter and test them all just to see just how messed up they were - or not.
    Seems there is always a couple bad ones - or more.
    Says nothing about leakage - of course . . .

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว +3

      I did that, and in the opening to the next video I will show them. They were all perfect except for the red ones that I found were messing up the phono preamp.

  • @bretthibbs6083
    @bretthibbs6083 4 ปีที่แล้ว

    is it may imagination or is the preamp board warped a little or is it because of the lens on the camera? great video by the way. Oh I'm just wondering about the board is all i'm not criticizing at all. The length of the video is fine for me.

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      Warped imagination

  • @stephendeluca4479
    @stephendeluca4479 4 ปีที่แล้ว

    What's that ambient music at the beginning after you found the open capacitor?

  • @williamsquires3070
    @williamsquires3070 4 ปีที่แล้ว

    Hi. How come your mic gain (and frequency response) keeps randomly changing? Or are you just changing sound input sources during post-production? 🤔

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      I often dub in audio in the studio which will change the sound quality as the studio microphone is a much better one than in the camera in the shop.

  • @sonhouse9636
    @sonhouse9636 4 ปีที่แล้ว

    The red capacitors, look like "black gate" audio capacitors, were they ?

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      No they were Elna audio grade

  • @zx8401ztv
    @zx8401ztv 4 ปีที่แล้ว +1

    I'ts never mattered to me how long your videos are, people are too picky.
    Shame about the stupid shop mistake, i have r.s semiconductors for parts but they are not what i call cheap.
    Just out of interest did you test one of those large caps to see how far they changed over the years?
    For some reason i thought about a norton amplifier when you were talking about gain selection, just rubbish that comes from memory, memory saves all sorts of crap lol.

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      The large caps I changed are well in spec as you will see in the next video.

  • @willtech1759
    @willtech1759 4 ปีที่แล้ว

    Sir i have a simple question regarding on multimeter, based in your exp. What is the best for you, analog or digital multimeter?

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      I use a fluke 12.
      It would be a fluke if it's accurate.

    • @willtech1759
      @willtech1759 4 ปีที่แล้ว

      So you mean digital multimeter is the best

  • @turntableman100
    @turntableman100 4 ปีที่แล้ว

    Nice amplifier you got but the sound quality is not my cuppa tea. For the money I rather buy cheaper marantz for the sound really. It's sound horrible it's sound like medium wave radio alarm clock 😂 but I will be very very disappointed for $2.000 back in the 80s I will be crying. It far too warm for me with the sound. Ok I understand is the tube sounds. I give it a pass but the bass is good.

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว +1

      Sounds like a clock radio? What have you been smoking. You can't tell how it sounds over the camera especially from the 6" whizer cone speakers in plastic box jvc ghetto blaster speakers I am using for test speakers. On my good speakers this amp sounds fantastic.

    • @turntableman100
      @turntableman100 4 ปีที่แล้ว

      @@12voltvids am agree with you now am sorry mate 👍

  • @williamsquires3070
    @williamsquires3070 4 ปีที่แล้ว

    The vacuum bulbs will warm up the front end... when the filaments get hot! Or you have the wrong bias on the grid and it red-plates! 🤣 That being said, I’d still rather have an old tube radio than an all solid-state one. 😁

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      These won't red plate. They are preamp stage only, and the voltage / current is not high enough.

    • @pliedtka
      @pliedtka 4 ปีที่แล้ว

      They actually don't run as hot as you may think. At least not in this amp. Don't remember what they use exactly but when they were selling them some 30 yrs ago I didn't notice too much heat coming from the front panel.

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      These don't run that hot.
      You want hot. Grab the el34 on my yaquin or the 6l6 on my elekit. Now those suckers will leave you with 3rd deg burns.

    • @williamsquires3070
      @williamsquires3070 4 ปีที่แล้ว

      12voltvids - I was just being facetious. 😜

    • @williamsquires3070
      @williamsquires3070 4 ปีที่แล้ว

      12voltvids - “voltage current” huh? Is that the same thing as volt-amps? Or a typo? 😋

  • @BoB4jjjjs
    @BoB4jjjjs 4 ปีที่แล้ว

    I just knew when I watched the last video, when you said "I will have to make a special trip to pick those up" that there would be a rant on this video about having to wait, getting the wrong parts and them rushing you out of the store after waiting. I just knew it! You are so predictable ha ha ha :-D Why is everyone so hung up on changing caps? Ok, some loose it but others work just fine and will keep working. I changed all the caps on a 40 year old amp and didn't notice any difference in the sound. Although I did notice a tiny bit of hum that might have been caused by two tiny caps leaking on a per-amp, other than that i noticed nothing. You could only hear the slight hum if you concentrated very hard at volume with no sound. If anything there was more problems with resistors and diodes burning the PCB than anything else. What a bitch the amp was to work on, they maybe sound great the Leak Amp, but I was so fed up working on it I sold it. I see they are making them again after a long break, but it looks crap, I hope the inside is better than it looks! www.whathifi.com/news/british-hi-fi-brand-leak-returns-with-its-first-product-in-40-years

  • @neverknowit11
    @neverknowit11 4 ปีที่แล้ว

    Thank you!

  • @larryshaver3568
    @larryshaver3568 4 ปีที่แล้ว

    This covid bs HAS gotten out of hand

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      It is what it is. I know people that have had it, and not all of them are with us now. Believe what you want but I have seen this one and it is nasty. You DON'T want it.

  • @Madness832
    @Madness832 4 ปีที่แล้ว

    Don't think I've ever heard "Zener" pronounced w/ a short "e."

  • @jasonthejawman5442
    @jasonthejawman5442 4 ปีที่แล้ว

    Complex is ls my language like it

    • @12voltvids
      @12voltvids  4 ปีที่แล้ว

      Wait for the NAD part 2 COMING UP NEXT