24 December 2011

The Laney Gut Project pt2

Progress has been a little slow... mainly due to waiting for funds and deciding on parts. Let's take a look!

So, the INGO transformers are mounted. Power Transformer, Output Transformer and Choke in place of the original transformer set. These transformers are SLO100 replicas.

The rocker switches are a green illuminated power switch and a standby switch marked to show the on/off position. I thought that was a nice touch. with all these things, it seems parts from 1986 sometimes aren't QUITE the same size as what is available now. Luckily those switches JUST about fit. The illuminated switch (unlike the old Marshall rocker switches) just need to be wired to the mains voltage and a neon lamp inside the switch will light up. On the old switches Marshall used there was a 5th pin especially for powering the bulb from a different tap on the PT. Snazzy.

As for sockets... I really like to use Belton Octal & Noval Sockets. They feel decent. This time round I got the actual Belton shields to fit the preamp sockets. This things are tough! Not the flimsy metal shields you get sometimes. They also look awesome.

The pins on the Belton octal sockets can be hard to manipulate. They won't handle much bending and shaping before they snap or tear. It's best to be careful if you want to try lining up the pins like this. If you do break a pin, it's actually pretty easy to swap in a new pin on these sockets so all won't be lost. Just get a spare socket to steal the pins off, that's my advice!

The Screen Grid Resistors in the photo (Green things) are 1K 3Watt enamel coated resistor from Vishay's Sfernice range. They are small in size for their power rating and more importantly they look good!

The 'purple' wire... ok it's not as purple as the spec sheet claimed it would be... and the black wire is silver tinned copper stranded 20AWG Teflon insulated wire. It solders really nicely and the insulation can handle really high temperatures, so no need to worry about melting it during soldering. The wire is rated for 600V. Teflon sleeve is also used on the octal socket connections. The pins are wired with 18AWG bus wire and sleeved to protect against shorts.

This is some filament wiring. The wires are twisted to reduce any noise that might be radiated from the wires themselves. I do this by trapping the wire in the chuck of a small battery powered drill. Wiring over the top of the socket rather than around the pins reduces the risk of creating a hum loop. Only two of the 4 preamp sockets are wired here... in parallel with the octal base filament pins... because the first two preamp valves will be using DC heat.

One other thing I decided to try out, was an in line filtered IEC. This is rated for 6A and should provide some filtering on the raw AC is it comes into the amp before the power transformer. I've not used one before so this will be a test.