Modular approach (Part I)

As time is very limited these days, I’m focused in continuing my modular building approach in LEGO style. I have developed several PCB modules which are flexible to be used in multiple amplifier and pre-amplifier designs. Now, I used the power of PCBs to build some additional supporting modules to speed up my breadboarding over the IKEA boards. Not the most elegant approach, but building becomes a very fast process this way.

You will see what I’m saying when you see a few of the following additions:

Turret and 2mm female connectors in a strip

Continue reading “Modular approach (Part I)”

DHT preamp “The Mule”

The birth of the Mule

The name I guess says it all. This is yet another DHT preamp with the gyrator PCB. So what’s different? Simply, a breadboard DHT preamp module ready to be abused.  I’m planning to mod this to death and try a long list of other DHTs with the gyrator load. 

I will only need to change the valve sockets (or build an adaptor) as well as the filament resistors and Rod Coleman filament regulators. Simple changes which can be done fast, will open the door to quick tests on my system.

In order to make this simple and a rapid build, I opted to use an IKEA chopping board. These are made of a laminated hardwood and are dirt cheap. A couple of hours are required to drill all the board like this:

Job done. You only need to do this once. Here is another look at the half-build Mule:

The initial sockets are NOS short pin UX-4/UV-4. I will play around with the 01a before I move to other DHTs. I still need to add the tag strips for filament resistors, output capacitors and the filament regulators. 

Wiring will take a couple of hours and we should have another DHT amp to play with 🙂

 

UV4 PTFE sockets

Looking to build a new 01a Gen2 preamp shortly. This time will be for the rare UV-201a valves. They need a special socket UV4 rather than the usual UX4. See width difference of both filament pins. In the UV4 all pins have same size as below:

image2 Weather they have brass or bakelite bases, the new UV4 sockets produced by Luciano Bandozzi (Jakeband) are of supreme quality. I highly recommend them:

image1I already reviewed these and you can see more info here. I hope to post some pictures of the new preamp shortly