Building Colin's SECA kit



  • Sorry you're right there's a 100nF ceramic capacitor. Your reference to 470r threw me. I'm out at the moment and can't Check the part number, but I think I went by the 10nF part number and ordered 100nF of the same type. Hope that helps, Si
  • Thanks Si. I'll get my order in tomorrow. It's marked 470r on the PCB I have.
  • edited October 2015
    OK guy the 470R refers to the DC offset adjuster no a Cap.

    Here is the BOM again, the 470R adjustable preset resistor is the DC off set and the part number is there. 

    Now I was asked a question for a part number for a 1K resistor not a preset whoops so I have given the wrong Farnell part number.

    Here it is on the left pic.

    This is the part on Farnell.

    This one is nice if you can have a steady hand.

    This one will fit also.

    I do hope that helps, now the 100nF add on up date kit does fits in the spare hole behind the preset.
    In the photo (left hand) it would be away from us.

    This cap will do fine OK it legs will need spreading a tiny gentle bit.

    But you might find the use of this one will make the top end sound more detailed.

    I do this helps a little, sorry about the misunderstanding .

  • Sorry me again with a wiring question. My PSU boards are nearly ready for wiring. On the amp boards they are wired as if it was a centre tapped transformer. Is it the same for the PSU boards?
  • Yes it is see drawing/sketch 

  • Many thanks Col, I'd forgotten about that diagram.
  • While I'm still waiting for bits to arrive I thought I would partially put the Modushop case together to work out how it will all fit inside. I bought some toroid's through James(Sov), thank you, and they are pretty big so I'm having a few issues coming up with a layout that fits. Can the toroid's go on top of each other? That's one option! How do I post pictures?
  • Hi Chris, I'm on an iPad so I can't post pictures , but see the thread here where I built my Wonfor 40W amp using the same Toroids. They are big buggers, but worth it in every respect.
  • Badsoden,
    Is it this Modushop case...?

  • That's the one. The components will fit although not with everything laid out flat horizontally. Its just the question of how to lay them out. This is the one to confirm.

    James's build has them one on top of each other which I may go with but I quite like the idea of the boards being mounted flat on the heat sink and the toroids down the middle. I'll try and post some pictures when I have time but I'm watching the rugby for now!

  • How much stuff have you got in there? I was very self-conscious of how empty my modushop case was when I'd finished!
  • It does sound ridiculous given the size of the case!  :))

    I went for ready made up boards from Colin but both amp and PSU PCB's. The toroids are big you can see them in the build James did. Its not like it all won't fit in its just getting the right layout. I might be obsessing about it more that I should but as people are always telling me I'm a bit OCD!
  • FWIW, there's loads of space in my monoblock cases  :-\"
  • image

    There is look.
  • True, but then your toroids aren't the size of Range Rover tyres Dave...!
  • Size doesn't matter.
  • This is Justin SECA.




    PCB mounts on PCB to heatsink



  • Very nice, indeed.
  • The Red one is a soft start, PCB left is power amp, PCB right is the PSU. This Amp has soft start and a over temp setting that is set for 70C then all PSU's turn OFF.
     I have also set the PSU to shut down on clipping but I am going to turn that OFF it far too quick and you miss the punch.
    The IQ of this one after 1hr is 3.00Amps and the heat sinks still not 20C + Ambient
    That relates to about 120W idle each channel.
  • Quick question. Does the IQ have an effect on sound quality? I have mine biased at 1.5 amps, is this still in the right operating region.
  • Lubbly jubbly :D
  • edited October 2015
    Love the case when it's so full of stuff. Proper amp!

    What does that big red button do? Turn on the amp or detonate something destructive somewhere...?
  • Looks lovely Colin. I will have a look when I'm free to come pick her up. :)
  • Very nice Col.......Can you make me one :)

  • Can I have one too please?
  • It's all mine :))
  • Nice one Justin
  • Colins Class A are amazing
  • Thanks Mark cant wait to pick it up and get my sbl's singing with it. :)
  • I've had my TOCA for twenty odd years, Mr Quick has refurbished it very recently, it's now singing it's head off
  • Will be interested to hear what you think of a SECA with Naim SBL's.
  • I've been trying Chord Comp Odyssey 4,OMG,TOG loves it
  • My claymore plays them lovely at the moment. So I'm hoping the seca will.
    What speakers do you use.
  • I've been using Rogers LS7's for years, lovely deep bass, great mid, twinkling top
  • jsm said...
    "My claymore plays them lovely at the moment. So I'm hoping the seca will."

    You'll be in for treat then! If you think the Claymore does well on them (yes I've been there too) your jaw is going to drop with a vastly different league amp like the SECA on there.

    Then, you'll be wanting to build decent passive cross over for them instead of the basic ones that come in the box.
  • edited October 2015
    Mark you have a TOCA so NO :D
    Quickie you have to many amp and yous look good anyhow so a BIG NO  :D 

    I am keeping it MINE sorry.  
  • You devil Mr Wonfor :D
  • I all some good new , Audiochews has been read in Russia and I have had the first inquiry from a Dmitre.

    So OK whole speaks Russian here , Dave not Double Dutch or Klingon Alan., No not Raspberrypi either Dave.
  • Has digital hit Russia yet?
  • edited October 2015
    They do have light switches that go On and OFF so yes they have.

    Carry On Banned User what happen there it should read "Love TQ for Ever if you're Geoff  Deaf"
  • Love to make passive crossovers maybe next year see how things go.
  • Here is a amp/tuner I made in 1970. but not a SECA

  • Trouble with your knobs Colin? @-)

    Or were Farnell out of stock?
  • No the Old TV had only two.
  • And then it had none, by the looks of it.
  • edited October 2015
    I decided last night to try the Plasma Generator linked to Justin Amp and make a singing arc speaker.
    Here is the Photo.
    It sounded lovely deep bass and the screams were so life like. Somerset here I come.

  • Oh no. Colin's gone all Sauron on us X_X
  • I am just taking the Middle Earth point of view.
  • Soft Start PCB for SECA Kits is now available.

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