You WILL hear a difference by replacing the GZ34/5AR4 w/a Mullard 5AR4(unless there's already one in the unit). Any improvements in the power supply will be very audible. Sylvania and Phillips ECG 7199's are the two cleanest(least colored) brands that I've tried in the ST-70's that I've worked on. Ditto- the Svetlana EL-34, from the St Petersburg plant(all that's now available at a sane price). If you're considering mods: Contact Joe Curcio (http://www.curcioaudio.com/) Here's been a major player in the Dynaco mods business for decades. Upgrade that pitiful AC cord too.
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- 19 posts total
- 19 posts total