Thursday, 9 November 2017

Model 9 SUTs

Newly completed and ready for delivery, three SJS Model 9 SUTs, including:

  • Hashimoto HM-7 transformers
  • Pure silver wire with ptfe insulation
  • Dual primaries can be switched for high/low impedance carts
  • Ground connection on the primary can be isolated for floating the MC coils
  • MuMetal lined aluminium casework
  • WBT NexGen sockets and WBT silver loaded solder





The Hashimoto HM-7 transformers, which have dual primaries and may be switched in series or parallel, for matching medium (7 - 40 ohm) or low (2 - 7 ohm) impedance MC cartridges, providing gain of 15 times (23 dB) or 30 times (29 dB).

Wednesday, 5 April 2017

North West Audio Show 2017

WE ARE PLEASED TO ANNOUNCE WE WILL AGAIN BE EXHIBITING
AT THE NORTH WEST AUDIO SHOW ON 24 - 25TH JUNE 2017 


We are delighted to announce that we will again be exhibiting at the 4th edition of the NWAS which will take place in Cranage Hall and will run over 2 days.


THE SHOW

NWAS 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.

IT'S FREE

Free entry, free parking, a day surrounded by the best in audio and all in the beautiful setting of Cranage Hall, Cheshire. Book your free entry ticket(s) and enjoy a great audio festival at Cranage Hall in 2017 with best HiFi, live music, Audio Talks and more. Register and secure your free tickets today.

20th anniversary 20% discount offer

To celebrate 20 years since the first sjs arcadia Model 1 preamplifiers were delivered, we are pleased to announce a special 20th anniversary 20% discount on confirmed orders for any new sjs arcadia valve amplifier


This offer includes all current designs: Model 3 riaa, Model 5 se 300B, Model 6 riaa, Model 7 line, Model 8 se 300B amp, Aoide headphone amp

Thursday, 23 March 2017

SJS Arcadia Model 7 Line Pre-amplifier

Following on from the successful launch of the Model 3 riaa, and the Model 5 power amp, SJS Electroacoustics are pleased to present the new Model 7 line stage pre-amplifier. The Model 7 has been designed as the 20th Anniversary re-imagination of the original Arcadia Model 1 line stage pre-amplifier, which was first delivered to customers in early 1997.


The Arcadia Model 7 line stage is based upon the same 6111wa NOS military valve and has been specifically engineered for sonic performance rather than technical specification, and fulfils all SJS Electroacoustics primary design criteria:
  • Single Ended circuit topology
  • Pure Class A operation
  • Zero negative feedback
  • Valve rectification and choke-input HT power supply
  • Custom made HT T-network power supply capacitors with silver leads
  • Point-to-point circuit wiring without PCBs
  • Hand built
  • PTFE board for component mounting
  • High quality components throughout
  • Custom made aluminium chassis


Design Options
The Model 7 line pre-amplifier is hand built to order in England, and therefore we are bale to offer customisation to meet your sonic preferences. Bespoke customisation of the internal components is possible to meet our clients' specific requirements, whether it is replacement of the Audyn capacitors with Dueland RS or CAST or possibly even using Tantalum film resistors, for example, these can be discussed at the point of ordering.


Technical Specifications
Input Impedance
100 kOhm
Gain
12 dB
Frequency Response
+/-3dB 3Hz-100KHz
Valve Compliment
2 x 6111WA
1 x EZ80
Max. Power Consumption
100 Watts
Unit Weight
10 kg 
Shipping Weight
15 kg
(Original Packaging)
Unit Dimensions
100mm (h) x 450mm (w) x 400mm (d)
Shipping Dimensions
180mm (h) x 545mm (w) x 500mm (d)

(Original Packaging)
  

Each amplifier comes with 2 years parts a labour warranty, except for the valves which have a 6 month warranty.

SJS Arcadia amplifiers are available from Definitive Audio in Nottingham.

Monday, 6 February 2017

Model 9 SUT

I have just finished this little project making up some nice MC step-up-transformers (SUTs) using the fantastic Hashimoto HM-7 transformers from Japan.

Hashimoto Electric have been making audio transformers since 1958 and was a transformer supplier to Sansui Electric until 1979 when they took over the entire Sansui transformer business, including patents, blue prints, designs and personnel.

Little known outside Japan until the past few years, their transformers are winning a lot of admirers, and the HM-7 MC stepup transformers have gained something of a reputation for outstanding performance.

The HM-7 has dual primaries which may be wired in series or parallel, for matching to medium (7 - 40 ohm) or low (2 - 7 ohm) impedance MC cartridges, providing a gain of 15 times (23 db) of 30 times (29 dB).

The lower cost HM-X has very similar specifications, and trades some low frequency performance for high frequency extension. The HM-3 model is almost half the cost of the HM-7, it offers 20 times (26 dB) or 40 times (32 dB) gain but has less high frequency extension than either the HM-X or HM-7.

The transformers are supplied in cans with solder connections, so they need to be built into a case for ease of use.





The switches on the left select series or parallel connection of the primaries, and the switch on the right connects or disconnects the primary winding ground to the secondary winding ground, to enable the primaries to "float".

Between the input and output phono sockets are a pair of "load" sockets, which can be used to plug in secondary loading resistors if desired.



The inside of the case is lined with mu-metal sheet to help minimise noise and hum pickup.



The finished SUT can be supplied with any of the three Hashimoto stepup transformers, HM-3, HM-X or HM-7 to best match with cartridge and budget.

Friday, 5 August 2016

Arcadia 7W PSE 2A3 Power Amplifier Upgrade

At the end of last year one of the original SJS Arcadia 7W PSE 2A3 amplifiers, originally built back in 1998, came in for a major service and upgrade.

Following the terminal exit of the main power transformer the opportunity was taken to upgrade and almost rebuild it.

The main power transformer was replaced by an external dual mono PSU, containing 6 mains transformers; two for the HT to the 2A3 power valves, two for the HT to the 6072A-5687 input/driver stage, and two for the negative bias supply for the grids of the 2A3s.



EZ81 rectifiers, choke input and first smoothing cap for the input/driver stage power supply are inside the PSU case


Four umbilical cables connect the psu to the audio chassis



Independent left and right mains switches, with remote switching controlled form the audio chassis


Removal of the power transformer from the audio chassis allowed for a pair of larger chokes to be fitted for the 2A3 HT supply, each channel has NOS GZ37 choke input supply and Elna Cerafine HT caps in the HT, and NOS Mullard EZ81 and choke input supply for the bias supply


Inside there was a major component refresh and upgrade; tantalum resistors, Hovland Musicaps, lots of Black Gates, Jensen 4 pole HT caps, Kemet bias supply caps and silver wiring



Not looking to shabby for it's age, and now fit and ready to go



Arcadia Model 5 Stereo SE 300B Power Amplifier

Following on from the successful launch of the SJS Arcadia Model 3 MM RIAA Phono amplifier, SJS Electroacoustics are pleased to present the matching all new bespoke Arcadia Model 5 stereo singled ended 300B power amplifier.


In common with other SJS Arcadia amplifiers it has been specifically engineered for sonic performance rather than technical specification, and fulfills SJS Electroacoustics primary design criteria:
  • Single Ended circuit topology
  • Pure Class A operation
  • Zero negative feedback
  • Valve rectification and choke smoothed HT power supply
  • Custom made HT T-network power supply capacitors with silver leads
  • Separate mains transformers for HT and filament supplies
  • Point-to-point circuit wiring without PCBs
  • Hand built
  • Real solid wooden frame
  • 4mm aluminium panels, black or natural anodized
  • Soundcare SuperSpiked feet

The Arcadia Model 5 power amplifier is a modern implementation of the classic 6SN7-6SN7-300B topology with a few tweaks, mainly in the psu design, component selection and layout.



The standard version is supplied with large wide bandwidth multi-section IE core output transformers, carbon film resistors and high quality film and copper foil coupling capacitors.

It is possible to upgrade this is stages to the Premier version including:

  • tantalum film resistors
  • Black Gate bypass capacitors
  • Dueland CAST DC coupling capacitors
  • Custom HiB double C-core output transformers
  • Pure silver wire for all point to point connections

Inside an Enhanced version:

Inside a Premier version


Technical Specifications

Input Impedance
100kOhm
Input Sensitivity
400mV for full output
Power Output
8W per channel
Frequency Response
+/-3dB 8Hz-30KHz
Valve Compliment
2 x 6SN7
2 x 300B
1 x 5U4G
Max. Power Consumption
250 Watts
Unit Weight
30 kg 
Shipping Weight
49 kg
(Original Packaging: Customised flight case)
Unit Dimensions
300mm (h) x 450mm (w) x 400mm (d)
Shipping Dimensions
400mm (h) x 545mm (w) x 500mm (d)

(Original Packaging: Customised flight case)



Design Options

The Model 5 SE 300B power amplifier is hand built to order in England, and therefore we are able to offer customisation to meet your aesthetic and sonic preferences. The solid wooden chassis is available in a range of four standard choices; cherry, maple, light oak and walnut with others such as zebra wood available to special order. The chassis panels are available in either natural or black anodised aluminium as standard, with other colours, such as blue, red or gold, available to special order.

Bespoke customisation of the internal components is also possible to meet our clients' specific requirements, whether it be for use of a certain interconnect cable between the phono sockets and the circuit, or replacement of the coupling capacitors, power supply capacitors or resistors, for example, these can be discussed at the point of ordering.