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Thread: The Bug is back

  1. #51
    Join Date: Mar 2010

    Location: Sheffield

    Posts: 2,898
    I'm Simon.

    Default

    Lol
    Kuzma Stabi/S 12", (LP12-bastard) DC motor and optical tacho psu, Benz LP, Paradise (phonostage). MB-Pro, Brooklyn dac and psu, Bruno Putzeys balanced pre, mod86p dual mono amps, Yamaha NS1000m

  2. #52
    Join Date: Sep 2018

    Location: Liverpool

    Posts: 14
    I'm Paul.

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    BKsabath powered this amp up last night and it sounded amazing, even in its raw form, What an amazing build you've carried out on this f5t amp.

    Thank you so much for all your hard work.

  3. #53
    Join Date: Mar 2017

    Location: Liverpool

    Posts: 766
    I'm Sandro.

    Default

    You are welcome I really enjoy doing this and as I said the bug is back, so tank you !
    I most probably rebuild mine after
    It will really start to sing when the Bias is set properly and the presentation, imaging and so on will be much better whit the 2 running

    at the moment it was just 250 mV across the 0.5 homes resistors, could same one cek my maths please , that is about 500 mA from Papa notes it should go to around 350, this said, most of the builds out there do not have your heat sinks so there is plenty of head room to play whit

    they where running at about 32 C and if the above is correct we where only pushing 35 W on each

    I was going to post same pictures of the night, sorry I am to tired after a 12 hour shift

    I most probably get same in for Monday

  4. #54
    Join Date: Mar 2017

    Location: Liverpool

    Posts: 766
    I'm Sandro.

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    I was going to post same measurement of the Mule last week new job and other things in the way …
    And now the Toroidy have landed
    so I toke the mule apart and started to put things back again
    Those from last week


    DSCF2286.jpgPaul and Martin listening to the Mule





    DSCF2287.jpgMartin having a play whit his capacitors (well You quite open minded here so I hope I am not going to get banned)


    DSCF2288.jpg and here the Mule in my system



    DSCF2289.jpgAnd a close up of the Mule

    Bias is about half of what it is meant to be and it sound better than mine already

  5. #55
    Join Date: Mar 2017

    Location: Liverpool

    Posts: 766
    I'm Sandro.

    Default

    This was yesterday Martin 100W Turbos
    at last the Toroidy are here


    DSCF2299.jpg


    DSCF2298.jpg



    DSCF2297.jpgThis is an Idea for Martin lay out the traffo will be bolted to the sink

  6. #56
    Join Date: Mar 2017

    Location: Liverpool

    Posts: 766
    I'm Sandro.

    Default

    and this is today
    Dressing up the cable
    We got the base plate optional extras, IMO they are not optional at all trafo fit there nicely whit a M8 bolt





    Attachment 24290


    This is Paul power supply
    His requirement are that all should be pretty small so this lot is going inside a 300 mm deep U3 enclosure and then a length of cable to take the DC to the second bank of capacitors. we are using the cable as R in the CRC
    At the moment I am thinking about 2 meters of 2.5


    Attachment 24291

    Look like the box just fit whit a bit to spare
    DSCF2304.jpg
    I am making new plates to keep the capacitors together 40 mm wide X 3mm Brunel will be proud of it and we may cut down in width a bit

    DSCF2305.jpg
    Going for 50 mF or 40 mF for the second leg of the CRC ? we are stuck whit only 40 mF in the first as there is no space left
    DSCF2306.jpg

  7. #57
    Join Date: Mar 2010

    Location: Sheffield

    Posts: 2,898
    I'm Simon.

    Default

    Jesus wept, what size VA are those?
    Kuzma Stabi/S 12", (LP12-bastard) DC motor and optical tacho psu, Benz LP, Paradise (phonostage). MB-Pro, Brooklyn dac and psu, Bruno Putzeys balanced pre, mod86p dual mono amps, Yamaha NS1000m

  8. #58
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,757
    I'm Chris.

    Default Slow turn on likely to be needed

    Hi
    Large toroids can be quite problematic when first turning on - some good instruction here to follow to overcome that difficulty.
    http://sound.whsites.net/project39.htm

  9. #59
    Join Date: Mar 2017

    Location: Liverpool

    Posts: 766
    I'm Sandro.

    Default

    Hi Simon

    They are only 600 VA
    Martin was going to get the 800 but then he got 600 as well
    Size would have been the same from the speck

    One wonder what discount he got for the 4 ?
    Not told us jet

    Tanks for the link Chris

    I always enjoy reading Rod pages he has a nice understandable way to put things across, not like in same forums where Learners are just a pain in peak hour traffic and same gang up on them.
    I can certainly say to many, if you have not been there you are probably missing out (the Rod Eliot site)

    I am using one of such soft starters whit CL 60 I may double up on them but it seems ok on the Mule ( was using a spare 1000 VA traffo)
    Paul and Martin got the official soft starters and speaker protection.

    I use home brewed one on my F5 which IMO are better but being home brewed they look ugly I will post a bit more about that later ( I am thinking about building F5T for myself)

    I forgot to mention the speaker protection circuit …

    I got it working but whit a LM 317 for a 24 V supply they are fine this way but certainly do not like the 35 V, cant complain about the boards as they take a loot of punishment while swapping blown transistor

    they work fine and switch off the speakers whit about 3 V DC but I will change the Blink rate and increase the switch on delay

    They are there to try and save the speakers if one of the Mossfet blow up and go shorth circuit (soon followed by the others ) and stop rail voltage getting in the woofers

    I much prefer the NTE7100 or UPC1237 (very similar beast's)

    I have NTE7100 whit Amplimo speaker relay in my F5 and not a problem in the last 8 years.

    As I mentioned earlier we had one of Pauls amplifiers on the Right channel of my system and I don't think we could do that later this afternoon as Paul is popping down


    I live to him and Martin to post first impression …
    Just worth a mention I had a 2.5 A fuse on the mains and it gave up soon after we put same pressure on the pedal
    Last edited by Bksabath; 30-09-2018 at 11:53.

  10. #60
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,757
    I'm Chris.

    Default 24 volt regulator

    LM317 should be OK with 35v and 24v out, as they rely on Vin/Vout difference which is only 11v , perhaps a heatsink is needed

    I would in the circumstance arrange an initial 317 or LM338 TO3 as a current regulator, taking output from its adjustment terminal and
    have resistance between output and adjustment as Vref/ r which is 1.25/R

    Attached schematic shows a 24 v regulator using current regulation of 463ma ( hopefully that is enough ) then voltage regulation, and I added a IRF4905 mosfet
    working nicely off the resistive divider with its gate from the 338. 24 volt regulator.pdf

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