Here is a pair of output transformers from Danbury Electronics in the UK. Model is DM53-DB425. 6.6k primary with 43% taps, 8ohm secondary. They were used in the Maplin Millenium 4-20 amplifier and have exceptional HF characteristics. Just give them a paint job and they're good to go! Asking $90 for the pair + shipping. Shipping should be $13.45 to most places in the US via USPS flat-rate priority box.