London DIY HiFi

Andy's System

The system, with cat

Lets introduce me and my system to you. I'm Andy and I'm a vinyl classical music freak. Now that's enough said about me so now to the system.

The Record Deck

Turntable and rack I struggled for some years with a record deck atop a stand. Even good stands are poor when placed on suspended wooden floors, which are common in older houses in the UK. When we decided to extend the house the second priority (the first was the kitchen for the wife) was to have the music room extended and a concrete floor in the extended part. This was a great decision! A large sand box using dry silver sand (it does not clump nor encourage growth of plants), 130kg in all, was used as the base for the record deck. Atop this is a sandwich of two layers of slate epoxyed together (originally I had used chip board but slate sounds better) - then four Newport Systems air suspension pucks - then another smaller sand tray then the Michell Gyro deck. I guess by now you can tell I'm a bit over the top, but more of that to come! My stand can withstand a fair sized kick without any noticeable sound coming from the speakers and I regard this as a "key test". 

Gyro deck The deck is fitted with a DC motor, rather than the standard AC one. An SME arm and a Clear Audio Gamma cartridge finish the vinyl front end. The DC supply for the Gyro motor comes from a rechargeable battery followed by two voltage regulator stages. Oddly enough, it is important to have two voltage regulator stages. I used a 7809 and an LM317. A small adjustable pot is available for speed adjustment but, to be honest, I don't tweak it more than once a year. 

The Pre-amp

Preamp Rack The pre-amp is a two box affair. One box houses four transformers, each 250VA, for the HT and heaters configured as a true dual mono unit. The other box houses the pre-amp proper. Each box is about 10" high, 20" wide and 19" deep. Construction is MDF with some lead lining. This provides RF attenuation and deadens the ringing nature of the MDF. I would not use MDF again. Instead, I would use beech and a constrained layer approach. Each box is far too heavy - I split my trousers trying to move the power supply from my desk to the floor! 

Preamp from above Circuitry is actually simple, 6 separate HT regulators based on a no feedback design, 6 HT buffers, 12 heater regulators again using no feedback technology. Huge numbers of FKP1 caps - about 250 in the pre-amp box! 

The Power Amplifiers

Power amps are based on a design published in Glass Audio, Volume 1, Number 5, 1993. Recently, they have been rebuilt with a few mods, most of which have also been in GA. Once again, large and heavy construction. 

The Speakers

The speakers are ESL63s supported on big stands 18" off the floor. Not the greatest speakers, but I don't know of anything I could live with and maintain a comfortable relationship with my neighbours.