Giant killer (including naim)

Discussion in 'British Audio' started by Superampman, Feb 14, 2018.

  1. Superampman

    Superampman AK Member Subscriber

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    3,304
    Location:
    Kitchener, ON.
    Some of you may remember the early Boothroyd Stuart Meridian line. The 105 monos at 100w@8ohm were considered high power back then. And they were quite capable, rivaling the top dog. But when all was said and done, it was power that limited the performance of both. The Meridians were faster, more up front while the Naim was a bit more relaxed. I've always wondered how a truly high power 105 would fare. Say, 400wpch? Two pairs bridge paralleled should do the trick? I would really love to hear that. Question is, how would that change overall specs/sq? Are there any techs here that can shed some light on the prospect.
     
  2. bimasta

    bimasta Super Member

    Messages:
    1,732
    That first Meridian line was also amazingly compact, and very pretty in a minimalist form-meets-function way. Incredible how they put all that SQ into such tiny boxes. That tiny tuner was one of the best. All my friends wanted that system. Me too.

    Why do you want 400 Watts, if I may ask?
     
  3. Superampman

    Superampman AK Member Subscriber

    Messages:
    3,304
    Location:
    Kitchener, ON.
    Well, as good as they were, they lacked that last bit of bottom end thunder. Consensus was that it was a bit too compact for it's own good. Mind you a pair of good subs takes care of that these days. Just a fun experiment. I was thinking a separate bridging circuit to plug them into like the old Ampzilla had.
     
  4. bimasta

    bimasta Super Member

    Messages:
    1,732
    Please keep us informed. I have some power amps which have the bridging option built-in, and I use them bridged. It's not just the increase in power (from 80W to 225W) but the amps sound so much better! They were the best amps I ever found to drive my Quad 63's — and I tried lots of amps, from Krell to Audio Research to VAC and many in between.

    But I had other amps that sounded worse when bridged — more power yes, but a severe loss of SQ.

    So I'm very interested in your Meridian project. I envy you for even having them. I had many chances to get that first series by Meridian but never did, and I really wanted them. I do have an even earlier design by the Meridian team, a power amp called Lecson, housed in a beautiful fluted cylinder that serves as a heatsink — cool looks were a hallmark of Boothroyd-Stuart designs. I can't use the damn thing because it needs a really weird cable and I can't find that cable anywhere, or a schematic or even the pin-layout to make my own cable. Maybe someday.

    I'm just running on now, so I'll stop — but I wish you the best results, it will be an exciting and totally unique component if you succeed.
     
  5. cpt_paranoia

    cpt_paranoia Active Member

    Messages:
    132
    What purpose does the connector serve?

    If it's the signal input, you could probably trace the connections to the circuitry. Then replace the connector with something more conventional.
     
  6. bimasta

    bimasta Super Member

    Messages:
    1,732
    I don't have it here to send you a photo, it's at my son's house. It has a DIN with 8 or 9 little sockets, some are input, some are output, some may be for power. Here's a pic from the web...

    images.jpeg

    As for tracing the circuits, here's the amp itself...

    images-1.jpeg

    Internally, it's a power supply, and dual-mono power modules (output I think is 80W). To fit all that into that 4" cylinder means every part of it is totally unlike any circuitry I've ever seen, and tightly crammed into a very small space. I look at it and my eyes go blurry. I'm sure someone smarter than I could do what you suggest.

    But I don't even know if it works. When I got it there was tinfoil stuffed into the fuse sockets. I put real fuses in, and they blew. Then I did something (I don't remember what, it was years ago) and I could turn it on without blowing the fuses. The first sign of life! Will it produce sound? I don't know, and can't know without that cable.

    I found a site in UK offering £80 for the cylinder. I contacted them and got no reply. I contacted them again about the cable, and again no reply.

    The cables sometimes appear on Ebay.UK and go for £50, but they only connect to the matching preamp, which I don't have. So I'd have to figure out two bizarre connectors so I can connect to a normal preamp. The matching Lecson preamp is also unique...

    Unknown.jpeg

    Both units are on offer for £1,400 on Ebay.UK. Here's the description —

    For sale, my beloved Lecson AC1 preamplifier and matching AP3 power amplifier. I'm sure that if you are looking at this listing then you know what you are looking at. I am reliably informed, by Meridian Audio that there are approximately 30 of these units left in the world in working order. One is in MOMA in New York. One is in the V&A. One is in my Dining Room!

    I bought these units in 2013 and immediately had them serviced by an engineer at Meridian Audio who used to hand build them for Lesson in the late 60s/early 70s. I have a transcript of his service notifications and works carried out. So in full working order. He had previously seen the preamplifier in 2003 when he converted one of the DIN inputs to accept a more normal, modern day CD player at 2mV.


    I'd love to have the set but I don't. I'd love to use the amplifier I do have. The fact it's in two of the world's most prestigious museums is a real incentive. But not even knowing it it works, or how to find out, or if it's worth the effort, is a disincentive for me.

    Any ideas? Anyone?
     

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    Last edited: Feb 20, 2018 at 10:44 AM
  7. Superampman

    Superampman AK Member Subscriber

    Messages:
    3,304
    Location:
    Kitchener, ON.
    This is not rocket science. The key is to do your homework and find a capable/competent tech. Most importantly, one who's heart is in it. Otherwise keep looking.
     
  8. cpt_paranoia

    cpt_paranoia Active Member

    Messages:
    132
    I did a google image search earlier, and came up with similar pictures. The preamp is very groovy...

    I did notice that a lot of the image hits are on www.lecsonaudio.com which seems to offer repair advice:

    "This site provides the history, product, performance, and repair information to complement the Lecson Audio Google Group".

    I suspect if you contact them, you might find the info you're looking for.

    The image of the open case shows what look like two very clear signal cables. Not sure what the other connector pins are for, though...

    [edit] here's the technical manual:

    http://lecsonaudio.com/wp-content/uploads/2011/10/AP3-MK11-Technical-service-manual.pdf
     
    Last edited: Feb 20, 2018 at 7:26 PM

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