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Thread: SJS resuscitated

  1. #1
    Join Date: Nov 2011

    Location: Manchester, UK

    Posts: 266
    I'm Simon.

    Default SJS resuscitated

    Following a number of requests for service, repairs and upgrades to the original SJS Arcadia line level pre-amplifiers, the time has come to declare that SJS Electroacoustics is once more operational

    The following services are currently offered:

    - service, upgrades, repairs and general tlc to the original SJS Arcadia amplifiers,
    - bespoke commissions for single ended valve phono, line, headphone and power amplifiers

    Many thanks for looking
    Simon
    SJS Arcadia Line Level Pre-amplifiers, Headphone amps, MM Phono Stages and SET Power amps - service, repairs, upgrades.
    Designed and hand-built in England.

  2. #2
    Join Date: Nov 2011

    Location: Manchester, UK

    Posts: 266
    I'm Simon.

    Default

    A couple of weeks ago an original SJS Arcadia Model 1 line stage preamp last seen in 1997 came in for a service and full set of upgrades.

    It was an early model built with 5687 valves and was in original condition, apart from a thick layer of dust throughout. The volume pot had become rather noisy,but otherwise all was good.



    It went through a full strip down, clean up, and complete rebuild:

    • Change to 6111wa valves
    • Tantalum resistors
    • Hovland, MusiCap and ClarityCap bypass caps on all electrolytics
    • Pure silver solid core signal wire with ptfe insulation
    • Alps Blue volume pot in shunt mode
    • NOS 5Y3GTA rectifier




    Should be good for a few more years
    SJS Arcadia Line Level Pre-amplifiers, Headphone amps, MM Phono Stages and SET Power amps - service, repairs, upgrades.
    Designed and hand-built in England.

  3. #3
    Join Date: Nov 2011

    Location: Manchester, UK

    Posts: 266
    I'm Simon.

    Default

    WE ARE PLEASED TO ANNOUNCE WE WILL BE EXHIBITING
    AT THE NORTH WEST AUDIO SHOW ON SUNDAY 26TH JUNE 2016



    THE SHOW
    Now in its third year, the Northwest Audio Show is set to become one of the highlights in the audiophile calendar. With great exhibitors, top brands and a superb venue, we believe that the North West Audio Show gives attendees the opportunity to hear the very best audio in surroundings that are second to none. Register and secure your free tickets today.

    IT’S FREE
    Free entry, free parking, a day surrounded by the best in audio and all in the beautiful settings of Cranage Hall and Wychwood Hall, Cheshire. The event organisers will also be laying on a free shuttle bus between the venues.
    SJS Arcadia Line Level Pre-amplifiers, Headphone amps, MM Phono Stages and SET Power amps - service, repairs, upgrades.
    Designed and hand-built in England.

  4. #4
    Join Date: Nov 2011

    Location: Manchester, UK

    Posts: 266
    I'm Simon.

    Default SJS Aoide headphone amplifier

    The first prototype SJS Aoide headphone amplifier is assembled and undergoing final testing.



    It is effectively a mW level integrated SET amplifier using triode strapped E55L valves, with custom designed and made HiB Double C core output transformers. These have secondaries which enable switching for low impedance (30 to 100 ohms) or high impedance (120 to 600 ohms) headphones, and either balanced or unbalanced connection. The PSU is valve rectified with choke input filter and second stage LC filters per channel. There are 3 line level inputs, input selector and volume control.

    It came about as a result of a commission from a long time Model 1 preamp owner who has switched over to using Audeze headphones. It was designed to be an integrated amp, but a "power amp" version could be made for use with an existing preamp.

    It's a prototype at the moment, and I need to sort out the switching arrangement and possibly get different wooden frames, but otherwise it's up and running quite nicely.

    Almost forgot, it can also be built as a line stage pre-amplifier by changing the output transformers. I have this version built in another box which greengoblin heard recently when he visited.

    The design was developed to match the phono stages built a few years ago



    Any AoS members in South Manchester who are big headphone users and interested in hearing the prototype, please contact me
    SJS Arcadia Line Level Pre-amplifiers, Headphone amps, MM Phono Stages and SET Power amps - service, repairs, upgrades.
    Designed and hand-built in England.

  5. #5
    Join Date: Nov 2011

    Location: Manchester, UK

    Posts: 266
    I'm Simon.

    Default

    Last year I was asked to revamp a stereo SE 300B amplifier

    It is the classic 6SN7-6SN7-300B circuit which has seen many implementations over the years, and for good reason because when it is well executed it can provide great results.

    Having seen that work I was ask if I could implement the same amplifier in one of the chassis used for the Model 3 phono amplifier

    After designing the layout and panels, the work of bringing it all together began





    after completing the work on the top panel



    the next step was to mount the top panel into the chassis and wire up the back panel



    Finishing touches, and it is up and running nicely



    SJS Arcadia Line Level Pre-amplifiers, Headphone amps, MM Phono Stages and SET Power amps - service, repairs, upgrades.
    Designed and hand-built in England.

  6. #6
    Join Date: Nov 2011

    Location: Manchester, UK

    Posts: 266
    I'm Simon.

    Default

    About 15 years ago I was presented with a DAC built for me by a good friend who used to work at Audio Note, I have been using as-is ever since however I realised that it isn't the most handsome of DACs, nor the safest :shock: so it was time for a make over

    Here is the customary before shot



    I decided to change to a valve rectified, choke input psu for the HT, and then separate mains tx for the heater supply and DAC board. some components upgrades throughout and a bit of a rearrangement to fit into a new chassis





    overall seems like a worthwhile effort, bass impact has improved significantly and the midrange is cleaner with better depth and finesse
    SJS Arcadia Line Level Pre-amplifiers, Headphone amps, MM Phono Stages and SET Power amps - service, repairs, upgrades.
    Designed and hand-built in England.

  7. #7
    Join Date: Feb 2013

    Location: W Lothian

    Posts: 99,005
    I'm Grant.

    Default

    Some pretty impressive handiwork there... All look lovely... The dac bar the 2 boards and 1 tx is completely changed lol
    Regards,
    Grant .... ؠ ......Don't be such a big girl's blouse

    I've said it before and I'll say it again: democracy simply-doesn't-work
    .... ..... ...... ...... ................... ..... ..... ..... ..... .....
    FIIO K7 BT, M11 PLUS, BTR7, KA5 - OPPO BDP-103D - PANASONIC UB450 - PANASONIC 4K ULTRA HD TV - PIXEL 6 - AVANTREE LR BLUETOOTH - 2* X600 SOUNDCORE - HEADPHONES INCLUDE, FIIO, NURAPHONES', FOCAL, OPPO, BOSE, CAMBRIDGE, BOWER & WILKINS, DEVIALET, MARSHALL, SONY, MITCHELL & JOHNSTON - 2*ZBOOK'S- MERCURY BD ROM, ROON, QOBUZ, TIDAL, PLEX, CYBERLINK, JRIVER - MULTI HDD'S -

    Oh my god! There's nothing wrong with the bidet is there?

    “Nothing discloses real character like the use of power. It is easy for the weak to be gentle. Most people can bear adversity. But if you wish to know what a man really is, give him power. This is the supreme test. It is the glory of Lincoln that, having almost absolute power, he never abused it, except on the side of mercy".

    “You see these dictators on their pedestals, surrounded by the bayonets of their soldiers and the truncheons of their police ... yet in their hearts there is unspoken fear. They are afraid of words and thoughts: words spoken abroad, thoughts stirring at home -- all the more powerful because forbidden -- terrify them. A little mouse of thought appears in the room, and even the mightiest potentates are thrown into panic.”

    "You don't have free will. You have the appearance of free will.”

    “There's a war out there, old friend. A world war. And it's not about who's got the most bullets. It's about who controls the information. What we see and hear, how we work, what we think... it's all about the information!”


    ***SMILE, BE HAPPY***

  8. #8
    Join Date: Nov 2011

    Location: Manchester, UK

    Posts: 266
    I'm Simon.

    Default

    This week I have been enjoying a very nice Border Patrol P20 power amplifier.



    2 x 300B per channel for around 18W of push pull goodness. This is the "low gain" version with a 6S45PI input/driver valve per channel and interstage driver/phase splitter transformer.

    It has two outboard power supplies, making it effectively a three-box-dual-mono-amplifier



    6 valve rectifiers each channel has a separate valve rectifier feeding a choke-input power supply for the output stage, driver stage and negative bias supplies, nice!

    The amp came in for a check over, service and a few component upgrades. It was fitted with new 6S45PI valves*channel matched to within 0.1 dB, tantalum film resistors in the audio circuit, carbon film resistors in the PSU, new HT caps for the output stage and driver stage, and Elna Silmic II bypass caps for the driver stage and bias supply and quite a bit of re-wiring with solid core silver.



    Overall a really nice improvement in clarity, tone and soundstage depth, whilst retaining that strength and dynamics the Border Patrol philosophy delivers.

    Really nice sounding amp.
    SJS Arcadia Line Level Pre-amplifiers, Headphone amps, MM Phono Stages and SET Power amps - service, repairs, upgrades.
    Designed and hand-built in England.

  9. #9
    Join Date: Nov 2011

    Location: Manchester, UK

    Posts: 266
    I'm Simon.

    Default Snell A2 refurbishment

    In a slightly tangential move compared to the valve amplifiers I generally get to work on, I was approach by Phil, The Count, and asked if I could help with his Snell AII loudspeakers.

    In the time before marriage I was lucky enough to have a pair of Snell AII speakers for about 10 years, during which I refinished the wood veneer, replaced the grill cloth and worked on the crossovers, mainly replacing the old electrolytic caps with newer Black Gate bipolar caps

    Phil had a problem, one of the tweeters had died. He had hunted down the appropriate replacements and supplied a new pair along with the speakers. First step was the assess the current situation......

    Main unit with grill removed:


    Inside to uncover the crossover for the midrange and tweeter:

    Note the Audioquest speaker cable which is noticeably green under the clear cover

    Then inside the bass cabinet to uncover the crossover:


    Unfortunately, the "chuffing" noise in the low bass was caused by the perished foam surround on the bass unit:


    Not a great result overall, but for speakers originally built in 1983 they weren't doing too badly. The worst problems were the (1) dead tweeter, (2) perished foam surround on one bass unit, and (3) copper oxide cables

    Having one fully working unit, a bunch of measurements were taken to give an understanding of the baseline situation before any work was begun.
    Acoustic measurements were taken of all 5 working drive units, with and without crossovers.
    The crossovers were all taken apart carefully, the circuit drawn out and every component individually measured using an LCR meter.
    The crossovers were then modelled in LTSpice in order to understand how they worked, and what the slight differences between left and right did to the output of the filters.
    Very interesting

    First off, replace the dead tweeter, unfortunately this required a switch of face plate:


    Then strip down the bass unit to remove the perished foam surround:


    Which seemed to work out quite nicely:


    The bass crossover was then upgraded: replace the old cable; replace the inductor with a low dcr unit; and film caps to replace the old electrolytics:

    The reduced dcr should help re-align the bass to work more nicely with the valve power amps Phil favours, and the film caps help to really improve the clarity of the bass.

    Then the big challenge, the midrange and tweeter crossovers:

    The old electrolytic caps were replaced with a combination of new bipolar and film caps, the cement clad resistors replaced, and all the old cable replaced.

    All went back together, and it was then a long and careful process of integrating the new tweeters into the midrange. The new units were far more sensitive than the old ones, so they needed to be padded down, and it took a lot of measure/listen/tweak/repeat before the right balance was struck.

    Definitely one of the more challenging projects, but very interesting, and hopefully a nice pair of speakers ready for many more years making music.
    SJS Arcadia Line Level Pre-amplifiers, Headphone amps, MM Phono Stages and SET Power amps - service, repairs, upgrades.
    Designed and hand-built in England.

  10. #10
    Join Date: Oct 2008

    Location: Glasgowshire

    Posts: 9,651
    I'm Gary.

    Default

    Super work Simon, inspires confidence you know your onions!

    What trannies are you using in your 300B amp in the first photo?
    Also, what hookup wiring are you using...looks like silver with teflon sleeving?
    AC POWER
    Hardwired 10kVA balanced mains powering entire system
    AMPS
    Meridian 557 power Amp (Modded) / PS Audio BHK Preamp (Modded)
    SPEAKERS
    Wharfedale Evo 4.4
    DAC
    PS Audio Directstream (Modded)
    TURNTABLE
    Pro-Ject X8 balanced output via XLR / Ortofon Quintet Blue cartridge
    PHONOSTAGE
    Pro-Ject DS3 B balanced Input (TT and Phonostage powered by Pro-Ject Power box RS2 linear psu)
    DIGITAL
    OPPO 203 (Modded: Linear PSU, i2s output to Dac) - Roon Endpoint, HDMI input used for all things Streaming/ PS5 /AppleTV ... also good for movies apparently?
    MUSIC PLAYBACK
    Tweaked AP-Linux based Roon Server into Oppo 203 as Roon endpoint
    Ipad Roon Remote.
    Apple Music/ YouTube via AppleTV, fed to Dac via Oppo HDMI input/i2s output to Dac.
    SPEAKER CABLES
    Biwired: Duelund DCA10GA (Bass) Duelund DCA16GA (mid & treble) Duelund 12DCA used as jumpers (On
    "Blackcat Cable" Chris Sommivigo's advice - yup, even with biwire it sounds better - and it does)
    INTERCONNECTS
    All Balanced: Ghost+ recording studio XLR cables

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