Surrey electronics mic pre 1983

[gary o]

Anyone got one of these or used one

 

[gary o]

 

[ruffrecords]

I rememeber seeing them advertised many many years ago but never actually got my hands on one. They were a well respected company.

Cheers

Ian

 

[emrr]

The varying compensation caps in the gain control are rarely seen. Over and above. The only other place I can think of seeing that is….another preamp with 10dB steps. R2 makes actual input Z 470/1880 for 150/600 switch, maybe 30-50 ohm mics in mind? A 150 source into a winding expecting 600 is also a way to force greater bandwidth.

 

[gary o]

Two Sowter input transformers built like a tank

 

[gary o]

 

[Matt Syson]

Surrey also made disc preamps (phonograph)! and PPM meter drive cards among other bits of gear.
From the written description it seems the 5534 actually fed the 'hot' side of the output directly (presumably through a lowish value resistor to isolate output cabling capacitance). personally I would have used a second chip to provide a 'buffered' output as it is being pushed to give most of the gain and to then drive cable seems a touch harsh. I would guess the 'cold leg of the output would be a second 5534 as an invertor with 10K input and feedback resistors ? (inverting gain of unity.
The compensation caps on the different gain settings was typical of the 'better quality' designed equipment. As a gain stage it is basically the same as used by Neve and Audix at that time.

 

[ruffrecords]

I seem to remember one of their unique products was an anti howl round device for live applications that shifted the pitch of a signal by a few Hertz. I believe it used SSB (single side band) techniques to achieve this.

Cheers

ian

 

[Mixermend]

Trevor Brook wrote a number of articles for Wireless World, including the pitch shifter mentioned by Ian, but also stereo multiplex encoders. The Company still has a working web site - specification information leaflets for their old products can be viewed - and service info is available for a small fee apparently.

Surrey Electronics

Trevor is also involved in radio - it is worth looking at the 'radio oddities' link at the bottom of the web page.

Wonder what he is doing now?

 

[abbey road d enfer]

I seem to remember one of their unique products was an anti howl round device for live applications that shifted the pitch of a signal by a few Hertz. I believe it used SSB (single side band) techniques to achieve this.

I had dealings with Surrey Electronics, as I was an employee of the company that distributed them in France.
The only product we had success with was the Spectrum Shifter. It used phase-shift circuits to provide quadrature outputs of the input signal and analog multipliers to provide the two side-bands (upper and lower) in combination with the LFO.
The proposed usage as a feedback eliminator was instantly rejected by musicians because they heard the disastrous change in pitch.
It did not succeed in address either, because it gave the speaker's voice a warbling quality that made them appear slightly sick, or tipsy.
It was used in music production, where it created some kind of phasing effect. Unfortunately, the stereo outputs contained the same effect with opposite polarity, which made it disappear when collapsed in mono.

 

[gary o]

I've had two of these stereo preamps sitting around for a while now I picked them up for only 20 pounds of the pair... Seeing each preamp had one transformer and 2 ICs I became a bit of a preamp snob and left them alone in favour of my two transformer and valve preamps... It was only after researching focusright ISA pres seeing they only have one transformer and same IC.... So I dug these out they have a very warm sound quite surprising