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Thread: DCB1 trials

  1. #1
    Join Date: Nov 2017

    Location: Godalming, Surrey, UK

    Posts: 35
    I'm Dominic.

    Default DCB1 trials

    For my second adventure in the world of diy electronics Iím building a dcb1 preamp. Buoyed by the eventual success of my first project, a Bigbottle mc phono stage, which after a lot of help from Oliver has seen a great leap forward in my systemís musicality, I thought Iíd see if I could get a similar improvement in the next link in the chain.
    Iíve assembled two boards and plan to get it working unbalanced first, with provision to try a balanced arrangement in the future when I can afford a 4 pole Khozmo.
    Itís taken me some while to build as there were no parts kits left so Iíve had to source components individually. With my rather basics electronics knowledge (A level physics back in 77) and a bewildering choice of similar components available progress has been slow.
    So the big switch on today, andÖ. well, nothing. No lights no signal, nothing! Any. Thoughts on where to start looking would be very welcome. Measuring the input voltage 12.6V to signal ground or 25.4V across terminals. Also there is a very gentle Ďbuzzí to the touch on the casework. No J3 installed - is that right?
    Thanks for any help.







  2. #2
    Join Date: Jan 2014

    Location: london se6

    Posts: 639
    I'm AndyElectroNumpty.

    Default

    hi , Are the 4 big Fets on the side in the right places? I made that mistake and got no lights etc check the components are in the right place. the voltages seem high, on the V+- out should be at the 9-10 v mark.


    Don't worry I'm sure Steve Oliver and others will be along to help.
    At the cutting edge of Numptyness!

  3. #3
    Join Date: Jan 2014

    Location: london se6

    Posts: 639
    I'm AndyElectroNumpty.

    Default

    Looking at the board you have included the short jumper 2 - J2 by the V out , you don't need this it belongs to an earlier iteration of the board. . Take it out and it might work.

    Good luck.
    At the cutting edge of Numptyness!

  4. #4
    Join Date: Jan 2014

    Location: london se6

    Posts: 639
    I'm AndyElectroNumpty.

    Default

    Check my thread pics for board close ups for comparison see the J2 jumper slot is unused. .

    https://theartofsound.net/forum/show...pty-DCB1/page4
    At the cutting edge of Numptyness!

  5. #5
    Join Date: Nov 2015

    Location: Wolverhampton

    Posts: 9,017
    I'm Oliver.

    Default

    Dom,

    Have you got isolation pads under the fets? If they have exposed metal on the back, I would expect this to be the problem or a problem as I can't see the rest.

    Check the part numbers are in the correct places too.

    PS, feel free to share your thoughts on the BigBottle, no one has yet!!! I'm starting to wonder if it's shit!?
    Analogue: Technics SP10 MK2 > Phonomac AT-1010 MK6 tonearm > Ortofon Kontrapunkt b > Bigbottle Jfet MC Valve Phonostage (Telefunken Valves)
    Digital: Raspberry Pi 3+/Allo Boss 1.2/Isolator 1.3 & 2x LPSU's with Volumio & JRiver
    Amplification: Nelson Pass DCB1 with Khozmo 48 Step Series Attenuator & Krell KSA100 MK2 Amplifier
    Cables: SPOTFIRE Speaker Cable & SPOTFIRE IC Cables & SPOTFIRE Tonearm cable
    Speakers: Pioneer CS-77A

    Price List For SPOTFIRE Cables here:https://bit.ly/2Uxiv3j

    Alternative reading: http://www.audioaddictsforum.com

  6. #6
    Join Date: Nov 2017

    Location: Godalming, Surrey, UK

    Posts: 35
    I'm Dominic.

    Default

    Quote Originally Posted by smangus View Post
    Check my thread pics for board close ups for comparison see the J2 jumper slot is unused. .

    https://theartofsound.net/forum/show...pty-DCB1/page4
    Andy - looking at your thread pics I should cut J2 but install J3 - is that right?

  7. #7
    Join Date: Nov 2017

    Location: Godalming, Surrey, UK

    Posts: 35
    I'm Dominic.

    Default

    Quote Originally Posted by Bigman80 View Post
    Dom,

    Have you got isolation pads under the fets? If they have exposed metal on the back, I would expect this to be the problem or a problem as I can't see the rest.

    Check the part numbers are in the correct places too.

    PS, feel free to share your thoughts on the BigBottle, no one has yet!!! I'm starting to wonder if it's shit!?
    Oliver
    I only have clear mica TO220 pads in for isolation - theyre a bit small and I see one is a bit squiff, I see if I can get bigger ones to be sure.
    BTW really pleased with Bigbottle phono now. I'm not good at reviews, but it has a much more fluid and musical sound than my previous Dino - defo NOT shite at all....

  8. #8
    Join Date: Nov 2015

    Location: Wolverhampton

    Posts: 9,017
    I'm Oliver.

    Default

    Quote Originally Posted by Domg View Post
    Oliver
    I only have clear mica TO220 pads in for isolation - theyre a bit small and I see one is a bit squiff, I see if I can get bigger ones to be sure.
    BTW really pleased with Bigbottle phono now. I'm not good at reviews, but it has a much more fluid and musical sound than my previous Dino - defo NOT shite at all....
    Haha, thanks Dom. That'll do me nicely.

    I'd double check that there's isolation there. Get a multimeter on the connectivity setting and just check that centre screw and chassis aren't connected.

    Other than that, I'm at a loss.
    Analogue: Technics SP10 MK2 > Phonomac AT-1010 MK6 tonearm > Ortofon Kontrapunkt b > Bigbottle Jfet MC Valve Phonostage (Telefunken Valves)
    Digital: Raspberry Pi 3+/Allo Boss 1.2/Isolator 1.3 & 2x LPSU's with Volumio & JRiver
    Amplification: Nelson Pass DCB1 with Khozmo 48 Step Series Attenuator & Krell KSA100 MK2 Amplifier
    Cables: SPOTFIRE Speaker Cable & SPOTFIRE IC Cables & SPOTFIRE Tonearm cable
    Speakers: Pioneer CS-77A

    Price List For SPOTFIRE Cables here:https://bit.ly/2Uxiv3j

    Alternative reading: http://www.audioaddictsforum.com

  9. #9
    Join Date: Jan 2014

    Location: london se6

    Posts: 639
    I'm AndyElectroNumpty.

    Default

    Quote Originally Posted by Domg View Post
    Andy - looking at your thread pics I should cut J2 but install J3 - is that right?
    Hi Dominic

    By J3 do you mean the jumper that replaces the 2 resistors as per the note on the board? For the
    12v relay? I guess yes.

    J2 is the only jumper not used unless the relay is less than 12v.

    looks like you're using the same hook up wire as I did, it will sound fine then!


    Oliver I'll be building the Bigbottle over this winter, I'm sure it's not shit! Even if it is the board looks nice!lol
    At the cutting edge of Numptyness!

  10. #10
    Join Date: Nov 2015

    Location: Wolverhampton

    Posts: 9,017
    I'm Oliver.

    Default

    Quote Originally Posted by smangus View Post
    Hi Dominic

    By J3 do you mean the jumper that replaces the 2 resistors as per the note on the board? For the
    12v relay? I guess yes.

    J2 is the only jumper not used unless the relay is less than 12v.

    looks like you're using the same hook up wire as I did, it will sound fine then!


    Oliver I'll be building the Bigbottle over this winter, I'm sure it's not shit! Even if it is the board looks nice!lol
    Lmao, I know it's not mate
    Analogue: Technics SP10 MK2 > Phonomac AT-1010 MK6 tonearm > Ortofon Kontrapunkt b > Bigbottle Jfet MC Valve Phonostage (Telefunken Valves)
    Digital: Raspberry Pi 3+/Allo Boss 1.2/Isolator 1.3 & 2x LPSU's with Volumio & JRiver
    Amplification: Nelson Pass DCB1 with Khozmo 48 Step Series Attenuator & Krell KSA100 MK2 Amplifier
    Cables: SPOTFIRE Speaker Cable & SPOTFIRE IC Cables & SPOTFIRE Tonearm cable
    Speakers: Pioneer CS-77A

    Price List For SPOTFIRE Cables here:https://bit.ly/2Uxiv3j

    Alternative reading: http://www.audioaddictsforum.com

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