+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 20 of 22

Thread: Buffer and reference power amp build.

  1. #1

    Default Buffer and reference power amp build.

    My latest creations

    First up my new pre/buffer stage. It's DC coupled throughout and is a development of the First Watt B1 buffer by Nelson Pass. The original was excellent, this is even better. It uses a shunt PS and strings of LED's for accurate voltage reference.

    I liked what my previous preamp did for dynamics but did not need the x3 gain, this buffer is the solution, wicked bass and very transparent sounding indeed.














    A mate gave me the board and the set of 4 matched transistors, I got the rest from the US. The case I reused from my previous preamp.


    Next up is my new power amp's. These are called My-Ref FE version. They are basically chip amps on steroids having on board PS, speaker protection & drivers before the main amplifier chips. They use some SMD components and it was fun getting back up to speed soldering them, they were too small to do without a magnifier.

    They sound like a large class A amp but with more pronounced fine detail and really tight deep bass, they produce 68 watts per channel and a sustained max of 9 amps per board and they sound absolutely stunning! I fitted a 300kva transformer for each board and I decided to build mono blocks.















    That's me pretty much finished with the electronics now, a set of Manzanita open baffle speakers is the next build plan but that's for next year now
    Last edited by davym; 28th November 2013 at 17:27.

  2. #2
    Join Date
    Oct 2007
    Location
    Lancashire.
    Posts
    4,134
    Blog Entries
    1
    Rep Power
    324042

    Default

    Clean build and I like the enclosures, nice and simple. You can't beat understated looks imo. I see Mr Salas's name cropping up again. Knows a thing or two that lad
    Si.

  3. #3

    Default

    Thanks Chops, I just wish you could hear this lot. Salas is a good man and quite an audio guru, he gave me tips to help me out a bit with my DCB1 build, I'm glad to count him as a pal.

    Mauro Penasa is also quite some designer, he is the man behind the original My-Ref design, this version is a development of that design by Dario Inserra aka Clave Freeman hence the FE (freeman edition) added to the amps name. He has the boards built locally in Milan, I took part in his last group buy for them. I ordered the components from mouser - 150 quid for them alone. The enclosures are from ebay (Hong Kong) and transformers are from Air Link (somewhere in England).

    This has been good fun but has to come to an end because of Christmas which is now too close for comfort!

    Speakers next year!

  4. #4
    Join Date
    Jun 2009
    Location
    glorious Devon
    Posts
    1,148
    Blog Entries
    1
    Rep Power
    3428822

    Default

    good work, Davy, excellent quality build. Bet those leds light up like a Christmas tree.

    I'm sure you mean 300VA, and not kVA Which chimps* have you used?

    I have similar boxes for my preamps, which are currently running at four boxes, although not finished yet (new year, at the earliest). The power amps (which are more a long term project) are two twin channel jobbies, for bi-amping, and the two channels will contain a total of 10 transformers, as the power amps each have three split power supplies. After all, power amps are just 'taps' for the power rails! And the circuits for the power amps are very simple, just 6 transistors per single channel.

    Still lots to do on mine, but I have music all the time, and "lovin' it".

    Next up for me on the electronics front will probably be to sort out some sub-bass units using a pair of 300 watt 10 inchers by Epos, so I will need to build a pair of 300 watt amplifiers!!
    That's 300 watt, not 300kwatts

    * chimps, contraction of 'chip amps'
    Last edited by cat's squirrel; 28th November 2013 at 22:55.
    cheers.....Bryan

    http://qualia.webs.com/

  5. #5

    Default

    Oops good catch Bryan, yup it should say 300VA transformers

    Although monobollocks with 300KVA each could be quite a set up eh

    The chips are LM318 and my favourite, the LM3886. Wicked bass power from a wee chip

    If you want to check them out more, here's a link to the group buy for the boards and design info - http://www.diyaudio.com/forums/group...ml#post3640615

    Quite a project this one and it doesn't sound like your typical chipamp. These have a full on sound more like you'd expect from a fully discrete design but with amazing detail and composure. Best amp's I ever heard by a long way. No wonder there are some real expensive high end versions around nowadays which use this chip.

    That sounds like quite a project you have going there Bryan! it'll be good to see some pics when you get finished.

    I had a 250w sub for a bit, couldn't live with it though, it was obvious where the sound was coming from (the corner) and if I turned it up to boost the bass on a recording, it made the doors rattle in their frames if I forgot to turn it back down when some heavy bass stuff started playing.

    I recon I'd have needed two of the things for balance and herself would object to that many boxes in the room

    I usually didn't need the extra bass anyway and my new setup produces wicked bass weight, a sub would be way overkill now.

  6. #6
    Join Date
    Jun 2009
    Location
    glorious Devon
    Posts
    1,148
    Blog Entries
    1
    Rep Power
    3428822

    Default

    that's why I have two bass 'speakers, or will have. And we have metal framed doors. Think I'm going to use the wee bass boxes as plinths for some of our extensive bowl collection, when not in use. As I listen a lot to Baroque music, I won't need them on most of the time!

    When I was looking at chimps, I bought four (for two projects) of the FET ones, TDA7294. Haven't fired them up yet, but I'm going to use them in what I call a pseudo-active configuration with one amplifier in each speaker, and one power supply. The neat thing about the 7294 is that it can have separate power feeds to the input and output sections, something I've carried forward to my main amplifiers, and some.
    Last edited by cat's squirrel; 29th November 2013 at 14:01. Reason: finger problems
    cheers.....Bryan

    http://qualia.webs.com/

  7. #7

    Default

    I was looking into building active speakers but it kind of limits you and I like to be able to change boxes including speakers, easily.

    I suppose I'm now going the other direction with mono block amps and hopefully next spring, a set of open baffle speakers with 10" bass drivers and 3" full range drivers to cover the mid/high frequency's. Apparently they produce excellent bass for an open baffle design, we'll see!

    http://www.diyaudio.com/forums/multi...b-project.html

  8. #8
    Join Date
    Jun 2009
    Location
    glorious Devon
    Posts
    1,148
    Blog Entries
    1
    Rep Power
    3428822

    Default

    to get any bass from an open baffle design, you need LOADS of power, and BIG cones and LOTS of excursion.

    That's why I'm using tiny boxes (closed), 10" cones and LOADS of power.


    In your link, I only see a 12" bass unit and a tweeter, they will not sound good together, unless you only listen to boom and tizz muzik!
    Last edited by cat's squirrel; 29th November 2013 at 14:13.
    cheers.....Bryan

    http://qualia.webs.com/

  9. #9

    Default

    That was what I thought too Bryan, the small driver is full range (obviously bar the low frequency's). A lot of people have now built that design and given good feedback.

    All I can go on is my experience with installing drivers in saloon bulkheads on yachts, basically an open baffle and some of them were very impressive for what they were. The designer is fairly well known in the US and has got some cracking designs under his belt so he should know what he's at but I still wish I could hear a set of them first.

  10. #10
    Join Date
    Oct 2007
    Location
    Lancashire.
    Posts
    4,134
    Blog Entries
    1
    Rep Power
    324042

    Default

    Quote Originally Posted by cat's squirrel View Post
    In your link, I only see a 12" bass unit and a tweeter, they will not sound good together, unless you only listen to boom and tizz muzik!
    Tannoy don't seem to manage too badly Bry
    Si.

  11. #11
    Join Date
    Jun 2009
    Location
    glorious Devon
    Posts
    1,148
    Blog Entries
    1
    Rep Power
    3428822

    Default

    always an exception, Si, but most PA systems I've played through have a 12 or 15" bass unit, and some kind of tiny tweeter, and they completely miss the mid range!

    The problem is bass cone breakup, that is the cone is not acting as a perfect piston over a certain frequency. Usually, the bigger the cone, the lower the breakup region.
    cheers.....Bryan

    http://qualia.webs.com/

  12. #12
    Join Date
    May 2007
    Location
    Next door to the Clangers
    Posts
    11,940
    Rep Power
    40382553

    Default

    Quote Originally Posted by Chops54 View Post
    Tannoy don't seem to manage too badly Bry
    Yes, but they have midrange issues IMVHO, but I think it's less to do with disparaging tweeter/woofer sizes and more to do with the waveguide, which is constantly moving. Never heard a Tannoy DC that I could live with YMMV. Gordon's JBL's manage the driver sizes better, ie twin 12" bass, with a tweeter and a super tweeter, but the tweeters are both horn loaded, and the first tweeter goes pretty low, so no bass breakup.
    Last edited by The Professor; 30th November 2013 at 23:56.

  13. #13
    Join Date
    May 2007
    Location
    Next door to the Clangers
    Posts
    11,940
    Rep Power
    40382553

    Default

    FWIW I agree with Bryan re the OB speakers, to do bass on a level with the tweeters you really need very big drivers, with high excursion, usually need more than one, and high excursion brings other issues. ALL speakers have compromises though, you just live with the compromises that suit your taste.

  14. #14
    Join Date
    May 2007
    Location
    not far (enough) from Glasgow
    Posts
    5,565
    Blog Entries
    1
    Rep Power
    615848

    Default

    Looks very nice Davy.

    quick question regarding the blue ringed power switches, which look awesome.
    where did you get em?
    "It's ok your comments are noted, so if you want a war you've got one. Watch your back, ya !!!!...." in an email from Marco 3/4/09

  15. #15

    Default

    Just noticed your post, Cheers! you would never guess these were chip amps by just listening to them, they sound way too powerful.

    I got the switches from ebay, the blue ring is an internal LED, he also had red and yellow versions last time I looked.

    http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=171185821621

  16. #16
    Join Date
    Oct 2007
    Location
    Lancashire.
    Posts
    4,134
    Blog Entries
    1
    Rep Power
    324042

    Default

    No no no Kenny. Looks fine on the front of an up to the minute solid state amp but has no place on the front of a classic style valve amp
    Si.

  17. #17

    Default

    Kind of what I was thinking too. However if you don't connect the LED it looks quite classy, way better than a toggle.

  18. #18
    Join Date
    May 2007
    Location
    not far (enough) from Glasgow
    Posts
    5,565
    Blog Entries
    1
    Rep Power
    615848

    Default

    's ok, wasn't going to fit them to the 2A3... just curious about them.
    "It's ok your comments are noted, so if you want a war you've got one. Watch your back, ya !!!!...." in an email from Marco 3/4/09

  19. #19
    Join Date
    Oct 2007
    Location
    Lancashire.
    Posts
    4,134
    Blog Entries
    1
    Rep Power
    324042

    Default

    Quote Originally Posted by cartridgemangler View Post
    's ok, wasn't going to fit them to the 2A3... just curious about them.

    You had me worried for a while there
    Si.

  20. #20
    Join Date
    May 2007
    Location
    not far (enough) from Glasgow
    Posts
    5,565
    Blog Entries
    1
    Rep Power
    615848

    Default

    might fit one to the dual magic eye vu meter project I've also got on the go. now I have workshop facilities I can get the holes cut for mounting the boards in the lid and securing the traffo/psu into that old monolithic psu case I got from Paul...
    "It's ok your comments are noted, so if you want a war you've got one. Watch your back, ya !!!!...." in an email from Marco 3/4/09

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts