Product details:

The Electro-Harmonix EL34EH is an extremely musical and predictable power tube with a sound that rich, smooth, detailed without being edgy. It the perfect EL34 for vintage equipment sure way to improve performance of modern equipment.According technical journal, Vacuum Tube Valley, "The balanced throughout entire music spectrum. Bass goes deep tight, mids are sweet well defined, highs extended." These EL34EH's in platinum matched sets. Their matching process consists 24-hour burn-in period followed by bias (plate) current measurement milliamps.