[Richard]

I've now got my TX102 TVC's operational, and thanks to John for his help in supplying them after S&B decided to stop selling direct to the DIY market. I'm using reed relays for switching, operated by a PIC16F877 microcontroller which responds to up/down pulses from the remote control receiver or from a quadrature encoder on the front panel. If anyone wants a copy of the beginner's code I used to achieve this, just ask.

My question is whether there is an ideal load for the secondary of the TX102. The S&B data uses 10k as typical, but doesn't say whether this is optimum. Anyone done any measurements on this, or does it just vary with the setting?

[John Chapman]

Hello!

Glad it alive - sounds like it was a really fun project!

The TX102 is rather load tollerant - especially once you are running a few steps or more down from the topmost settings. Even at the top 10K or a bit lower is fine but once you get down a few steps it can handle really low loads. A while back I did some testing at 600 ohms for a customer and I was surprised how well it did! Going up above the 'typical' 10K point it will still behave just fine - I test at 100K typically on my analyser when I do my qc tests here on finished pre-amps.

Many Thansk!

John

[Richard]

Thanks for the reply. As I'm driving a tube amplifier, I can provide any load up to 1M or so. I know that many, if not most, transformers do sound better with a particular load. I haven't experimented yet, and was hoping that someone else had either done some measurements, or had a strong opinion based on listening. The character of my transformers is still changing with use at the moment, so it's a bit too soon for me to judge.