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After all these years, still love this amp...

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  • After all these years, still love this amp...

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Name:	Antique Sound Labs MG-SI15DT-S.JPG
Views:	173
Size:	3.44 MB
ID:	115690
    This is my Antique Sound Labs MG-SI15DT-S (the -S designated it has the triode/pentode switch). I've had this since new, about eighteen years. It was only about $700 back then. This is a very early production model, that had an error in the placement of a grounding wire that left it with two big issues:

    1. it is unstable in high impedance loads in pentode mode. Found that out first time I hooked it u to a pair of Gregoire Ikonoklast 3 speakers (about 12 ohm). Scary, but nothing was damaged. Switching to triode mode worked fine.

    2. It will instantly toast itself if you power it up with no speakers attached. It was in fact my first sample where this happened that caused them to replace it and analyse the issue. A quick mod (rerouting the ground wire internally) fixed the issues.

    15 wpc in pentode, 5 watts in triode. In most cases I prefer the sound in pentode mode. Very dynamic, gorgeous tone and very powerful tuneful bass. I still use it as my primary amp with my Tekton Lores or Sound Dynamics 300ti. It can't really drive my Maggie .7 and struggles somewhat with my Tekton Double Impacts.

    Though it is technically an integrated amp with three inputs and level control, I always use it as a basic amp (leaving the level up all the way) and control volume and switching through either diy a passive device or an active preamp (currently a Burson Conductor Virtuoso). It just sounds better that way. Even the designer of the amp seemed to feel that was a better option.

    I just use basic JJ 12AX7 and stick with the ValveArt KT88 that the designer recommended, though I plan on replacing the 12AX7 with JJ 12AX7 Long Plate Gold Pin (ECC803) that George Counas of Zesto recommended to me. It is stable, easy on tubes, and rarely ever needs bias adjustment. It is a workhorse.

    I really love this amp, though I have no idea what makes it sound so good. Simplicity of the circuit possibly.

    Running $700 through the inflation calculator from 2001 to now puts it right about at $1000. What's out as a current model that would compare, if there even is anything?
    Steve Lefkowicz
    Senior Associate Editor at Positive Feedback
    --------------------------------------------------------
    http://www.audionirvana.org/forum/ti...ounding-system

  • #2
    Steve. Thank you. Will you email me at jonathanhorwich@me.com I have a question for you. Thanks. Jonathan
    JLH

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    • #3
      I built two of the AS USA kits back in the '90s, with a lot of part upgrades since I was building them as kits. One was a KT-88 ultralinear amplifier, and the other was an EL-84 ultralinear amplifier. Both still work fine and sound good today! Antique Sound USA was great!!!

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      • #4
        Originally posted by chrisfromri View Post
        I built two of the AS USA kits back in the '90s, with a lot of part upgrades since I was building them as kits. One was a KT-88 ultralinear amplifier, and the other was an EL-84 ultralinear amplifier. Both still work fine and sound good today! Antique Sound USA was great!!!
        Pretty sure AS USA and Antique Sound Labs from Hong Kong were two different companies. Might be wrong, but wasn't AS USA based out of Washington or Oregon?
        Steve Lefkowicz
        Senior Associate Editor at Positive Feedback
        --------------------------------------------------------
        http://www.audionirvana.org/forum/ti...ounding-system

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        • #5
          Same Company as far as I know. Had a US office in Kirkland WA but was getting supplied from HK. Here's the front page from the one kit:
          AS USA Kit by c f, on Flickr

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          • #6
            Front Panel of the one completed kit (paid extra for the gold finish front panel and the chrome chassis). Can't supply the other basic black one as it's on loan to a friend.

            AS 102 by c f, on Flickr

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            • #7
              Maybe a split happened afterwards, maybe when Divertech started importing them for North America. I remember mid 2000 (maybe 2005-07) calling them. At that time they were not associated with ASL in Hong Kong.

              Regardless of all that, yours is a great looking amp. How difficult was the kit to build?
              Steve Lefkowicz
              Senior Associate Editor at Positive Feedback
              --------------------------------------------------------
              http://www.audionirvana.org/forum/ti...ounding-system

              Comment


              • #8
                The more I think about it, they had the US office to be able to sell the assembled and unassembled HK tube electronics back in the late 90s for some tax or import advantage. Then I think someone got sick or something happened and they sold out to Divergent. They were all the same back in the late 1990s but the part number was slightly different for the already assembled and the kit versions. Sometime after 2000 Divergent was running everything.

                I don't know if there's any truth to it but people were saying the earliest ones had the best sourced transformers. That picture is my more powerful Antique Sound amp and I could use 6550 or KT-88 tubes in the final. A nice feature was the switched grid bias meter and the individual pots to tweak the grid current for each tube so it was not necessary to buy matched tubes. It had solid state rectifiers and voltage regulation, and used a large circuit board inside. I used better connectors, Mundorf coupling caps, and some other upgrades. It was not very hard to build and I think it cost around $800 or $900 as a kit. It sounds like it should, like a high power ultra-linear amp. I loaned it to someone that messed it up by "tube rolling" and then I had to fix it. Servicing it was not so easy as you basically have to remove many connections on that circuit board to flip it over to work on it. It works fine now.

                The other one was basic black, with a black cage, and much less powerful as an EL84 ultra-linear, but was all point to point wiring. I used all REL Caps and also improved the connectors. That one I particularly liked because it used a tube rectifier for the B+ which is a feature I generally prefer with tubes - in that the B+ doesn't hit the finals until they're already warmed up (because the tube rectifier needs to heat up to conduct first). A friend of mine is enjoying that one now on his efficient speakers, but he frequently changes his setup so I expect it back in a few months.

                They were a good product, though I hardly use them anymore.

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                • #9
                  I believe the model designations with DT were the North America spec imported by Divertech. That’s why mine is an MG-SI15DT-S.
                  i thought they manufactured all their own transformers.
                  Steve Lefkowicz
                  Senior Associate Editor at Positive Feedback
                  --------------------------------------------------------
                  http://www.audionirvana.org/forum/ti...ounding-system

                  Comment


                  • #10
                    Steve, the closest thing I can come up with is the Jolida Fusion 3502S priced at $1875.

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                    • #11
                      Originally posted by Audioraven View Post
                      Steve, the closest thing I can come up with is the Jolida Fusion 3502S priced at $1875.
                      I have a Jolida JD1000P. It is a very nice amp, though when i don't need the extra power I prefer the Antique Sounds Labs.

                      Vista Audio used to make some nice under $1000 EL34 and KT88 amps, but they seem to be focusing on their phono stages and a $349 compact solid state Spark amp now.
                      Steve Lefkowicz
                      Senior Associate Editor at Positive Feedback
                      --------------------------------------------------------
                      http://www.audionirvana.org/forum/ti...ounding-system

                      Comment

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