This is a glorious little vintage Australian valve amp that's also a bit of a mystery regarding its brandname, Jason.
Jason guitars were the brand name used to market Japanese-made student-grade guitars in Australia in the 1950s and 1960s, and it seems that the Jason brand name was around at least in 1958 for a Jason Amplifier. There are mentions of other amps with Jason brand. It also seems Jason may have been the house brand of J Stanley Johnson, the music store in Park St near Town Hall Sydney (many thanks to James for the music shop details!)
The amp is the magic combination of valve-rectified (original Aussie-made AWA 6X4) power supply, EF86 pre-amplification (vintage Philips solid-plate made in Great Britain), and single-ended pure Class A output into a vintage Alnico-magnet speaker, and it sounds it!
The output valve is a Telefunken ECL86 (equivalent of the 6GW8 so popular in early Australian low-powered amps), a triode/pentode configuration within the one envelope. Therefore, the second gain stage (after the EF86) is handled by the triode section of the ECL86, before the signal is further amplified (to the 4 searing watts output!) by the pentode section of the valve.
A date stamp on the putput transformer indicates a May 1967 production date.
The speaker is an 8" MSP Hi-Flux (Sydney) Alnico speaker, with a DC coil resistance in the 2 to 4 ohm region. The amp has been fitted with a switched extension speaker socket (when an separate box is plugged in, the internal speaker is disconnected, effectively turning the amp into a head), meaning you can use any Fender-style cabinet with a 4 ohm impedance to make the amp sound a lot bigger than its 4 watts.
While it is possible this amp was made in Japan, I doubt it very much, with the high Australian content and the fact it has a 'cottage industry' look to the chassis. Was it an Aussie-made amp sold through Johnson's music shop in Sydney and branded accordingly? We may never know.
Sonically, this little amp is a ball-tearer! The overall character with the EF86 pre-amp is darker than an equivalent amp using a 12AX7 front end - quite British in character. Both channels have loads of gain, and each has a separate volume knob to allow both channels to be used at one time, and allows the amp to be driven well into class A overdrive heaven (loads of even-order harmonics, which sound oh-so-sweet) even with single-coil pickups. It's a surprisingly loud and efficient little amp.
This little Jason measures 37cm(W) x 31cm(H) x 21cm(D) and weighs in at 6.5kg. Shipping sizes and weight will be higher due to packaging.
I have been emailed by a Grouse Guitars customer with some interesting information regarding the Jason brand. Here it is in edited form;
Sold to Paul