Saturday, 16 April 2011

Progress Build of TU882R

The main board, without the missing 4 resistors, tube
sockets and the wiring. 
Have had an opportunity to start the build of the TU-882R kit. The first thing I did was to clean the PCB with alcohol to make sure that the through hole enlargement and my handling didn't leave any foreign matter that may cause any poor solder joint. I was going to try the Mundorf M-Solder silver. This has 95.5% tin, 0.7% copper and 3.8% silver. Up until now, I was using the old Welborne Labs Silver solder, which had 2% silver. Initial impression was that I needed more time with the solder iron to get a good flow with the Mundorf. Setting at around 280 C, I needed around 5 seconds for the Mundorf to flow well. On the same component type, I only needed 3 seconds on the Welborne. I reverted back to the Welborne solder.

During the build, as per normal, I realised that I ordered the replacement resistors four less then what was needed. I was short 220k and the 3k3. So, immediately placed another order for these missing four resistors, but continued to build.

Close up of the signal part of the PCB. Note the
Mundorf caps and the Tantalum resistors 

Close up of the main PCB signal section, note that both
the Mundord caps and the Tantalum resistors stand off
the PCB by a bit, as they were larger than what was supplied

Have a look at the photos below of the progress. The instructions was simple to follow and straight forward. The PCB has good room, and the solder pads weren't too small. Everything fit and as you can see, I am just waiting on the replacement resistors before I do the assembly, wiring and chassis part of the kit.
The front panel sockets PCB.
Front Panbel sockets PCB showing the header pins.
The replacement Noble pot. This will be direct wired from
the pot to the PCB, not requiring PCB 'B'.
The PSU/Transformer PCB.


  1. Yeah, but it will be hard to finish off, since we are going to be moving house soon... Also waiting on the missing resistors from DIY Hifi Supply...