Suv450

Discussion in 'General Electronics Chat' started by R!f@@, Dec 12, 2010.

  1. R!f@@

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    Apr 2, 2009
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    This is to u kermit2

    see below is a Technics SUV450 VC4 Class AA Amplifier

    [​IMG]

    Another one of the same series but more power, a SUV650

    [​IMG]


    First off the photo's are not the real thing, it's just to show you what I have, Yes, I have a SUV650, my friend, a customer has, a SUV450. But actually my one belongs to him too but I bought it from another low life.

    Confused. :D

    First off, these babies are like gold. They have the lowest THD I have ever seen, Plenty of Power and a wide dynamic range. They sounds just heavenly. I have seen these during those days, and I always wanted one for my self.

    Here's what Happened. I saw an auction some where here in Male'. They were throwing away lot of junk, electronics items and boards. It seems who ever he is, has decided to give the work and start something new, so he is throwing away everything. Selling the more, good stuff.
    As Usual, this guy ran a "Sub Electronics" ( something we call to the wannabees here)
    As I remember it was around 2 years back, but he was running the workshop for like forever. Since technology advanced, the uneducated techs that then ruled this country, robbing every one during my School years are giving up due to the fact they can't seem to get anything fixed that has a digital circuitry. Now I guess.U know how the story goes.

    Anyways, this junk is what he said and I quote" No one can fix this", "no parts". are items that got left by customers who paid good and lotta money to buy them. What can the customer do. All he can do is, scratching his forehead, say "keep it".
    So Like the rest these too gets piled up, and one day the tech throws them away or sells them for scrap.

    I happened to drive by during the cleanup and seeing the SUV650 one on the pavement. This was too good to be true, someone throwing away a hefty Technic Amp. It did not take 5 minutes for me to grab it from that looser. For 30 Bucks this is a gold mine. He said it's IC's is gone and had ashed resistors. But I knew I can fix it, cause it is highly unlikely that the Hybrid Chip would blow, it is always the Voltage amp that dies. Something I studied during the repair days.

    I took it apart and didn't take me long to get it working. I got the parts from Srilanka. I went to lanka to buy some parts. So I got all the components, plenty of 'em, of the Voltage Amplifier.

    One day I was just relaxing in my workshop then, listening to the newly repaired amp, when an old friend of mine dropped by. He was passing by and hearing the beautiful music he peeked.

    Seeing the Amp he was like :eek:..& said that's mine. I went like :confused:..WTF.

    I never argue, so naturally I told him how I got it and that I fixed it. You know what he said...He took this same amp to that repair guy to fix it when it started to shut down every now and then. The amp belongs to him years back. It was around 5 or 6 years as I remember. That no good son of gun said that it cannot be done and since then he never heard of it.

    What can I say..his loss..my gain...

    He stood their a long time looking at it, but what can I do.
    After a long time he said that he has a smaller one. a SUV450 that he showed the same guy after having no luck on the big one. This time he did not leave it there, when he said ..no parts...
    I agreed to fix his, after all that's the best I can do.

    Problem is this Amp is missing the complete Voltage Pre-Amp Assy.
    The Japs never made these any easier. Every unit is different, although they have the same pre drive and voltage amps. Layout is different and of course the final Out put stage which it get's it's famous name for, the Current drive, the Hybrid Chip made by Matsushita, Panasonic. This chip is what it is all about. The Pre drive and the Pre-Voltage amp uses the same components for all of these series which has a VC4 drive. ( I really have no idea what that means ).

    For commercial one, this design is so quite and produces the lowest distortion I have seen in an amp at the rated Power.

    Hence it's infamous name Class AA. The Japs makes the most advance equipment overall.

    As I said the problem lies with a missing card, which the 450 series has. A plug in PCB Assy which has the Pre Drive Voltage amp.
    Then I have no Internet like now but I am very good at drawing and duplicating such circuits. What I did was I compared the two, the 650 & the 450. The Major difference is the PSU Voltage level and the Output Current driver.
    SUV 650's one is Massive compared to the 450. So After a thorough study, I gathered what I can then (components) and I came up with what you see below

    [​IMG]

    Yes...this is what I came up with what I have around couple of years back.
    Not bad huh!!...The good news is that it worked. The amp never sounded better.

    And now the problem is that it sometimes gives cracking sound, it started after a heavy moving. Probably a loose connection.

    I said to him to bring the card, Now at least I can make it far better than before since I have all of you.

    This is what I was referring to when I asked whether you can do a transfer for me. The netlist and all those thingy's are too much for me during these days. My friend is very anxious, and restless since his Sony amp is also crackling. I can draw the schema and provide the part numbers of what I will be using, cause I have almost all the components, except for a few SS diodes that these things use. I have to find them and buy them from digikey or mouser.

    I dunno what program you are using. I am familiar with eagle. But I haven't tried to transfer the PCB to the copper clad layout yet, cause I never get such a job. And when I got it, I dunno know how to do it yet.

    What do you say.....could you do a gerber, or drill file thingy for me.
     
    Last edited: Dec 12, 2010
  2. Kermit2

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    I'll do what I can to make a proper layout. And I'm sure if it isn't 100% perfect more people will get involved until we get that way.

    :)

    It's the perfect little thing to get me busy and so not thinking about other conditions that plague me.
     
  3. R!f@@

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    The Schema is bad scan so I will clean it up for u guys....don't want to trouble you all too much :D
     
  4. tyblu

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    Nov 29, 2010
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  5. R!f@@

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    The electrolytes are old buddy....I am trying to remake this using quality parts.

    Guys.. I have q?

    I am drawing the schema. Since you can use this to readily transfer to PCB, what are the things that I should be concerned about.

    I want to use SMD components where available. I have most of the resistors and caps ( SMD ), the electrolytes will be standard ones.

    In short. The PCB will be a single layer, since I have single layer clads.

    This will be my very first design which will be ready made to PCB transfer.

    I like to to use the unused area of copper as ground shields where possible.

    As of right now I am using dummy symbols. I believe I can replace them without hassle once I got the components pin layout data. Right ?

    So any pointers on Eagle if you may. :D
     
  6. tyblu

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    Nov 29, 2010
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    It's best to choose the one with the correct layout in the first place, as it is a bit of a hassle to do pin swaps. It also takes a bit of getting used to searching for parts. If it's nowhere to be found, you can create your own. I find it best to have the PCB layout open while you do your schematic so you can get visual feedback on parts, as you place them.

    EAGLE tutorial: http://www.sparkfun.com/tutorials/108
     
  7. Kermit2

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    [​IMG]

    THAT is what you use when you don't have the proper part for the schematic and/or the PCB. Generic symbol-you name it-you decide what the pins are. :) Works just the same when you etch a board. It don't know any difference. Same as me.
     
  8. thatoneguy

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    Feb 19, 2009
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    That's pretty cool. Sucks that the guy couldn't get his amp fixed.

    I like Kermit's PCB method of "MeNC", a little more time than etching, but the drilling is right there. I hate drilling....
     
  9. R!f@@

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    Here's the complete V Amp




    Note* {supply line }
    Track connected to pin3 of J7 is + 45V
    Track connected to pin7 of J7 is - 45V

    High Res attached

    Checking to see what components I have

    {ed} there are 2 errors...correcting 'em :p
     
    Last edited: Dec 14, 2010
  10. Kermit2

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    C413 connected to base of Q401. This ties the emitter directly to the base. shorted.
     
  11. R!f@@

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    [​IMG]

    Schema Corrected
     
    Last edited: Dec 14, 2010
  12. Audioguru

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    Dec 20, 2007
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    One transistor has an emitter resistor but the other transistor has a collector resistor.
    Which one is correct?
     
  13. R!f@@

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    Shooooooot!! :p it shud be mirror image..


    {ed}
    Thanks guru...I missed tht. the pdf is corrected now....I think I'll leave the image
     
  14. Kermit2

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  15. R!f@@

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    Oooooooops !! I checked, the 82p is the C408
     
  16. R!f@@

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    Hey Guys...
    My primary concern was what to choose for a replacement diodes.
    The amp uses MA167A & MA4036M

    I checked digikey after looking at the data, but they don't have 'em

    I doubt that these are available.

    I like to know what would be the preferred replacement for these two diodes

    My Guess is for the MA167A, I can go for IN4148
    for the MA4036, which data says a 3.6V zener. So any 3.6V Zener would suffice. Right?

    note
    The ones I use before were 4148 and some "identical" looking diode I salvaged from my junk. I dunno why it worked. Or it may be the reason why the Amp is crackling now.
     
  17. Audioguru

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    Dec 20, 2007
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    Zener diodes less than 5V have poor voltage regulation and their regulated voltage is affected by temperature.
    Some little zener diodes are rated at 100mA but at lower currents their voltage is much lower if they regulate anything at the low current.
    Other little zener diodes are rated at a low current but at higher currents their voltage is much higher if they don't burn out.
     
  18. SgtWookie

    Expert

    Jul 17, 2007
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    The 1N4148/1N914 sounds good for the MA2C167.

    Consider a BZX79-B/C3V6 for the MA4036. IzT is the same (5mA); the rest of the specs aren't as tight but it would probably work OK.
     
    R!f@@ likes this.
  19. Kermit2

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    I've ruled out two simple layouts as impossible only one sided. The clencher is the 7 pin header. I'm trying some different layouts now keyed around the header. Also, I can't find the three pin header location from the picture you posted. I'm guessing it's the three parallel wires to the right of the 7 pin header? So both headers on one end of the board?

    I think you would be good at this R!f@@. It takes an artistic touch and plenty of fly by the seat of your pants decision making. AND the willingness to hit delete and flush the whole thing to start again.

    Eagles Auto router is helpless. next to useless(one man's opinion, who is not a master of the software) for anything I've ever put to it.
     
  20. R!f@@

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    leave the header for now...I need to collect the SMD's first...
    The header is single row, but it is shown separate in the diagram.

    I have to bring the amp and check the mainboard to see the track orders..