Dave's (Osprey1000's) Claymore

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Comments

  • Is it ever worth fixing a transformer? Is it most likely the windings shorted?
  • No,
    Yes.

    You need a replacement.  My previous comments were based on a different design amp I recently brought back to life which had a shorted transformer, shorted rectifier diodes and a couple of other problems.

    Colin seems confident it's just your transformer (his design after all!) so worth going for...
  • The problem is nothing off the shelf will fit.

    Terry @ Canterbury windings will make you one, but wont be cheap.
  • Might be worth asking Toroidy as well, but don't think they offer different core sizes.
  • I'll contact Terry @ Cantebury windings tomorrow. I am not entirely sure what I am asking for... I'll quote the specs Colin gave me and point him to this discussion. At this point do people think the amp is worth reserecting? 
  • Thank you Colin,

    I'll order one now!
  • Good luck getting either of those to fit :)
  • Yes do check diameter and height first please. As I forgotten the size, to long ago.
  • They are too big but trying to think of possible modifications to fit in 110mm dia by 50mm high. 
    Would 50mm be full height of mounted transformer above board surface?
    I can't find smaller transformers at this spec anywhere.
  • Original transformer is 90mm by 60mm.
  • I would need 10mm extra space all round it.image
  • 110mm by 50mm? I wonder if raising the transformer by the 10mm difference in height gives me some space underside of the transformer to do some modifications to the closest components and connectors.
  • edited November 2015
    Another thought, how about contacting Toroidy & Canterbury and seeing if either of them can work within the physical limits?
    You have pretty much zero lateral wiggle space but a little vertical. Give them the max. height (remembering the mounting nut CANNOT touch the lid) and see if you get lucky.

    If all else fails you could make the transformer outboard in it's own box?
  • Thanks again, I'll buy one now.
    Out of interest what are the consequences of being pushed into 4 ohm? 
  • Transformer dispatched. 
    I am a novice but I have soldering equipment (tampered with game consoles in the past). 
    Would this installation be reasonably straight forward? 
    I suppose which wire goes to which connector etc will be the main thing for me.
    Oh and what was meant by "being pushed into 4 ohm"?
    I appreciate all the help I have received already.

    I am enjoying all this! 
  • Osprey,
    I fiited the transformers in a recent amp build and its very straight forward from a practical POV. I had never done anything like that before (not even games consoles).
    Getting the colours connected up all right is obviously the important bit. There was some sort of diagram on the side of the tranformers I used, which made little sense to me. If you ask here what goes where, or post some pics here, I'm confident that someone will answer... :-)
    You may need some heat-shrink to insulate the connections, once made.
  • I have heat-shrink from my console days.  
    I have been promising to practice and improve my skills for years now but with children and recently a new baby boy also being very busy at work it's been hard finding time as there is always another priority. 
    I am now making time for this project. 
    I always crave to learn new things and the mix of electronics with the art of sound very much appeals to me.

    ..........but I do have a lot to learn!!!
  • Satisfaction awaits...
  • I have the transformer. I have been struggling to find time to approach the task.

    There are four spade connectors on the board. I imagine they are positive and negative for each of the stereo channels, and requiring 30v dc across them.
  • If I remember correctly the two centre pins of the 4 are ground/earth/0 and the two outer pins positive 30VAC. At this point you are still dealing in AC electricity as it has not yet passed through the rectifier.
  • "There are four spade connectors on the board. I imagine they are positive and negative for each of the stereo channels, and requiring 30v dc across them."

    NO not DC but AC now the side of the transformer has a colour code to tell you what is what please tell me what it says.
  • edited November 2015
    imageimageSorry about the dirty keyboard. I have a mobile office in the back of a van... and I am currently working in muddy conditions on a building site.

    So this is starting to make more sense. The 230VAC goes through the fuse to the switch. Then from the switch to the transformer Blue-Brown. Then out to the board at 30VAC. It's just the order of the wires. I suppose the switch will be brown above brown and blue above blue and then its a case of getting the ground the correct way round on the two pairs. 

    The new transformer seems less substantial than the original transformer.. The gauge of wire etc. What, if any, would be the potential consequences of that. Could it effect the sound quality or would it just affect the longevity of the transformer for being worked a little harder? 

    Again, thank you for your help.

  • Right the winding look ok the original transformer was on iron core like this one but the Flux Density could not be pushed high it can now because of better material. So do not worry about it too much it will work fine.

    From the front of the Claymore near the transformer mounts on the PCB there is 4 spades
    Spade 1 is Black
    Spade 2 is Red
    Spade 3 is Orange
    Spade 4 is Yellow

    When you have done this post photo so I can check please.

    Col
  • Hi Colin,

    My work and home commitments are so great at the moment and so I have not had a chance to give this a go. I hope to find a chance this weekend. 
    I am desperate to get it fixed but being the novice I am, I want to give this plenty of time to get it right.

    Thanks again,

    Dave.
  • Thank Dave if you get stuck PM or Paul.

    Col  
    >:)
  • image
    Hello Colin,

    Finally I have found time to put it together. I think that is the order of wires. Could you please look at the brown and blue wires to the switch as well, although I imagine they are obvious.

    Also which is the best fuse  - fast or slow burn?

    Many thanks,

    A nervous Dave!!
  • Dave the dimple in the transformer cap fits down into the transformer not up.

    Wiring look OK from up here, but twist the Orange, Black, Red and Yellow gentle this will reduce noise a bit onto the phono stage.

    The mains fuse should be slow blow.

    :)
  • Hello again,

    Is that better?

    Thanks again.image
  • edited January 2016
    Does the twist of the wires matter whether it is clockwise or anti-clockwise? I have now twisted the brown/blue wires from the switch also.image
  • Does the twist of the wires matter whether it is clockwise or anti-clockwise?
    It will be cool if the answer is "yes".
  • Docfoster said:
    Does the twist of the wires matter whether it is clockwise or anti-clockwise?
    It will be cool if the answer is "yes".
    ....and the Ausies had to do the reverse twist :D


  • only that I remember in physics the right hand rule... something to do with shielding...motion, field, current are all at right angles to each other so it was important to twist the shielding depending on the direction of current.. or something like that.
  • edited January 2016
    the amp is now working, thank you Colin and everyone else!!!!

    It sounds so good and my son loves it. "Even old music sounds special" he said.image
  • the amp is now working, thank you Colin and everyone else!!!!

    It sounds so good and my son loves it. "Even old music sounds special" he said.image
    That is good to read, twist direction no matter a bit tighter would be good.
  • the amp is now working, thank you Colin and everyone else!!!!

    It sounds so good and my son loves it. "Even old music sounds special" he said.image
    Great quote from Osprey Jnr.
    Lovely pic. :-)
  • edited January 2016
    needs the audio to truly make the scene.

    Thank you again.
  • I tightened the twist and have been listening to the amp this evening with the cover back on. It sounds brilliant! 

    I have noticed that it is very warm to touch underside. Is this normal? I can't remember how hot it used to get. There is a slight smell but I think that is the new transformer burning in.

    I am guessing its the cooling for the fet chips after looking inside. After blowing the transformer previously I am a little paranoid! It had been in storage for a long time.
  • only that I remember in physics the right hand rule... something to do with shielding...motion, field, current are all at right angles to each other so it was important to twist the shielding depending on the direction of current.. or something like that.

    The right hand rule was for generators- First finger; Field. seCond finger; Current. thuMb; Motion. You can use your left hand for motors!

    https://en.m.wikipedia.org/wiki/Fleming's_right-hand_rule
  • Are yes, thanks. Why are some audio cables directional? Is that to do with the shielding?
  • edited February 2016
    Hi Colin,

    Tonight I have been enjoying and showing off the amp using a pro-ject elemental turntable as my source, to my son and my father in law. Found a local store that sells new and second hand vinyl ...brilliant! 

    My friend who came with me to JRC hifi in Torquay back in 1990 when I bought this amp, is coming round tomorrow to listen to it again..... and to watch the rugby!

    I have a slight background hum which is only noticeable between tracks and on phono. I have twisted the wires quite tightly as advised. Did I read somewhere that you said rotating the transformer can reduce this hum?

    It's not a major problem and I am thoroughly enjoying the sound quality of my old amplifier but my OCD tendencies kick in occasionally and if I can make any improvements I will try.

    Also, the amp is in an open backed cabinet with space around it.  The whole case has become very warm to touch, I can't remember how hot it used to get. Do I have to be careful as I know the transformer spec wasn't your first choice because your preferred transformer wouldn't fit? 

    Thank you again,

    Dave. 


  • Hi Dave,


    "I have a slight background hum which is only noticeable between tracks and on phono. I have twisted the wires quite tightly as advised. Did I read somewhere that you said rotating the transformer can reduce this hum?"

    Yes you do but be gentle and slowly.

    Heat sounds has if it is

    a) to loud or heavy load
    b) the bias needs to be reset
    c) a possible sidk fet

    I would look at (b) has this could have killed the last transformer so turn it off.

    Then we can see who is near you with a signal gen and scope.

    Col 
  • Hello Colin,

    Thanks for your quick reply. I live in Torbay and will spend a lot of time camping near Dorchester on a permanent pitch from March onward. I will be patient and I am prepared to travel to make sure I get this right. 

    Your direction has got it working and producing beautiful music again via this welcoming and enthusiastic forum. This experience has been very rewarding.

    Vinyl really has a wonderful presence. I have never used the phono stage until now.

    Thank you,

    Dave.




  • Hello Colin,

    Thanks for your quick reply. I live in Torbay and will spend a lot of time camping near Dorchester on a permanent pitch from March onward. I will be patient and I am prepared to travel to make sure I get this right. 

    Your direction has got it working and producing beautiful music again via this welcoming and enthusiastic forum. This experience has been very rewarding.

    Vinyl really has a wonderful presence. I have never used the phono stage until now.

    Thank you,

    Dave.




    Most welcome, camping! god I doubt I could get of the floor now from a sleeping bag, I try later I get Dave UglyMusic to rescue me if I get stuck.
  • Camping from March??? You do know which hemisphere you're in? :-)

    BTW thanks for your nice words about Chews. It's exactly what we want Chews to be.
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