Jolida Foz SS-X

Jolida  Foz SS-X  Sound Stage Expander  A 2 dimensional sound in your stereo system. Flat sound from your sound-bar. Lacking bass in your monitor speakers. Bit of edge in your high notes. Need some more space and dimensionality in your headphones. Your speakers too boomy. Gaming sounds lacking excitement. Common problems without an easy one stop fix. That was the past, now there is an elegant affordable solution to any and all of these issues.

The author of this solution is Jim (Foz) Fosgate, who has spent decades designing, building and auditioning every possible circuit approach to tube amplifiers, preamplifiers, phono preamplifiers and other accessories. You may know him in relation to his company Rockford Fosgate or his collaboration with Ray Dolby in the ground breaking development of surround sound.  

Long an aficionado of vinyl’s and reel to reel tape’s three dimensionality and weight, Foz has designed the SSX; an effective, efficient and low cost solution to glare, limited soundstage and bass. The SSX circuit is a single stage between your source and amplifier and can improve the performance of your audio system with tube buffering to clip the edge off the highs, add or reduce your bass, focus or expand the three dimensionality of your soundstage.

3 Major Design Components

Initially, the signal passes thru the tube which buffers and cleans the signal. 

The bass equalizer circuit is designed to increase up to 9dB low bass impact without bass boom. Conversely, in the event of boomy bass, the bass equalizer can reduce the boom up to 9 dB. (based on Fosgate US patent 3,883,832).

The dimensionality circuit adds a greater sense of depth, space and helps pull the soundstage outside of your head. It is part of a Jim Fosgate US patent (number 5,307,415) originally used in surround processors. It was called a “panorama control”. It cross feeds signals between the channels so each channel has a signal from the other which is out of phase. Negative feedback is applied around this stage in a single loop. Output offset is controlled with DC servos allowing the video buffers to directly drive the signal path with no output capacitors. There is only one coupling capacitor per channel in the signal path, and it is enclosed within the feedback loop, thus capacitor colorations are eliminated. Separate, oversized storage capacitors on utilized on each channel to provide a rock solid supply voltage without voltage regulators to affect the signal. The circuit is configured so that audio signals from the one channel cannot couple to the other, preserving soundstage width and depth. 

Distortion and noise are below the threshold of hearing. The bandwidth is very wide allowing audio signals to pass through without colorations. Bandwidth is an amazing “ten times” threshold of human hearing 2 Hz to 200KHz at -3Db.

Another benefit SSX is that is can be used to test the phase of a recording and also can test to see if your system if is in or out of phase.