Kenwood KA-1000 recap?

Discussion in 'Kenwood-Trio/Kensonic-Accuphase' started by Cosmin2000, Apr 18, 2013.

  1. Cosmin2000

    Cosmin2000 Active Member

    Messages:
    194
    Location:
    China/Romania
    If I want to double the power supply capacity from what I have now, that is to say add another four 8200microF/71V in parallel with the current four Nichicon KS 8200microF/71V will I make a mistake?
    The rectifier diodes will withstand the augmented current? If I am not mistaking, the diodes are each 2.5A.
     

     

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  2. scimitar12

    scimitar12 AK Subscriber Subscriber

    Messages:
    246
    Location:
    Bettendorf, IA
    Great job restoring your KA-1000. The Sigma Drive is real and improves sound quality, at least with the speakers I paired with my KA-900; Polk Monitor 10s and Advents 1As. I've been looking for a nice KA-1000 with its tuner.
     
  3. Cosmin2000

    Cosmin2000 Active Member

    Messages:
    194
    Location:
    China/Romania
    The Sigma Drive is a very nice feature, which can be "felt" in the sound signature of these amps. If I were to describe that signature, I would say just one word: control.
    Especially in the bass department, but not limited to, the Sigma Drive makes the listening experience more involving.
    Now, I have spotted another candidate with this feature, L-06M mono amps.
    Although I own the L-05M mono amps, which are very much similar internally with the L-06M, I would really love to listen to the latter...
    The price for them is very good, they are very underappreciated amps...
    The thing is that after I bought the V-FET Yamaha B-3, I'm now in a big dilemma: two L-06Ms or another B-3?
     
  4. Bigdrive

    Bigdrive Active Member

    Messages:
    102
    Location:
    Kelowna
    @Cosmin2000 I also have a KA-1000 that was my first recap I ever did. How did yours sound after the recap? I want to redo some of the parts of the amp and was interested on your listening evaluation.

    Also what transistors did you replace if any?
     
  5. georg85

    georg85 New Member

    Messages:
    4
    Hi, since you have this amp, could you please do me a great favor? I bought one KA-1000 also, unfortunately without the power supply.. The device had only 4 burnt transistors, which I already ordered from digikey original sanken, I have already ordered two torroidal transformers 2x45V for the +-62 Volts (primary 230V). And I am a little confused about the third transformer that I want to order, that I want to use for the +73, -75 voltages (yes in the schematic it seems like -75 not -73, at least at my copy), So, if I am right I will need two secondaries, one 54 and one 52 Volts.. In the original power supply one transformer should have this secondary with violet/blue cables - I think this should be the 54V one, and the other transformer, with brown/blue, the 52V one... could you please measure the voltages at the transformers secondary outputs? and also with how many volts at the primary? (I will then calculate how much should the voltage be, with a 220V input, and order that value for 230V). You will help me a lot.
     
  6. Bigdrive

    Bigdrive Active Member

    Messages:
    102
    Location:
    Kelowna
    Hello,
    I have my granddaughter over right now. Give me a few days and I will try my best and should have some info by the weekend.

    The amp has a lot of power and I love the sound. I recapped it years ago around 2015, but someone had done it before me and posted it. I have since looked and never found a thing. I do want to make some changes to some caps that I did. The two 330@35 I think, they run real hot. I will be more specific when I get your info.

    Cheers
    Gord
     

     

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  7. Bigdrive

    Bigdrive Active Member

    Messages:
    102
    Location:
    Kelowna
    IMG_4827.JPG IMG_4828.JPG Hello,
    I have taken the ps apart and have looked at the schematic. Here is what I got. First, the ps I have is the x00-2130-10 a2 so there is a difference. For the two large main transformers, there is no violet wire coming out of outputs.

    For the small third transformer it's input is 121.8 line voltage. The two blue wires for output is 12.71 vac. The coil has 8 ohms across the coil with the wires still "in circuit" There is a green and a violet wire coming off of x00-2130-10 that goes up a 21 and 22 it them goes into the harness. From there, pin 15 and 8 go to power switch and back to ps to close rl1 and rl2 to turn the thing on.

    When I look at my schematic it is on a 150" screen at 250% and I only see two secondary voltages for the main transformers 63 and 100. There is c75 and c73 right above the voltage???? Could you be reading that by mistake?

    Finally here is a picture of the transformer if it helps. Hope I answered your questions.

    Cheers
    Gord
     
  8. Bigdrive

    Bigdrive Active Member

    Messages:
    102
    Location:
    Kelowna
    I will keep the unit apart for a couple of days, in case of any other questions. I looked at schematics again and it still looks like it's only function is to close those relays.

    Cheers
    Gord
     
  9. georg85

    georg85 New Member

    Messages:
    4
    Untitled.jpg First of all thank you for your answer and your time! Apparently you didn't understand me, and which windings I am looking for their voltages. Take a look at the posted picture of the schematic. X00-21-30-10, exactly like yours. You see three transformers in the schematic, one, only for the relays, marked with blue color on the picture, I am not interested in this transformer, and two other transformers with three secondary winding each. One double winding of each of these transformers is for the current amplifier, and should be approximately 2x45V since after the rectifier it says on the schematic 62 and -62 volts as you can see. Each of these transformers has an other extra winding, which is for the first stage of amplifier and voltage amplifier, as you can see on the schematic, it says +73 and -75. Because the schematic is not in the best quality, I may be mistaken and it could be +-73, but on any point of these two voltages on the schematic it looks like -75, the negative one, and +73 the positive one. If this is correct, the two main transformers are not alike, and one should have approximate 54 volts and the other approx 56 volts, and also that may be the reason, that one transformer secondary is marked on the schematic BLU VIO, and the other BRN BLU, different color coding for this small difference in voltage. I have marked these two secondaries with green color. These two secondaries I need. It may be that in the schematic it says violet but I may be reading that wrong because of the quality of the file, but anyway you know which ones I need, regardless of the color. Thank you very much.
     
    Last edited: Aug 10, 2018 at 2:58 PM
  10. Bigdrive

    Bigdrive Active Member

    Messages:
    102
    Location:
    Kelowna
    Hello,
    Thanks for the clarification and the highlighted schematic helps. The small transformer that you highlighted in blue is disregarded now as you are not interested in that one....got it.

    OK, the schematic is wrong. Front trans, BROWN wire to pin 30 1 amp fuse BLUE wire to Ground pin 34. Back trans BLUE wire to pin 27 1 amp fuse BROWN wire to pin 35 Ground. The label on the trans for p/n is the same for both transformers, making me think the output voltages are the same. When I really blow up the pdf the +/- for the 73 or 75 look the same. in other words I cannot tell if its 75 or 73 but they look the same.

    I of the belief that both transformers are the same and that those voltages should be the same, especially at the caps, and that if the number is different its a typo.

    Cheers
    Gord
     

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