Dynaco ST-70 amp
Here we have an extra clean original Dynaco ST-70 Tube Amp, with cloth transformer leads,NOS dynaco branded 7199 Driver Tubes. a NEW Sovtec 5ar4 and a matched quad of Electro Harmonix el-34’sOverall Electronic Condition :
Amp has had 2 caps changed on the driver board; and were replaced with matched orange drops.on the underside of the amp you can see there is some slight discoloration on the bottom of the driver board from the heat generated from the 7199 tubes,
Also you will see a small amount of wax that has leaked out of the choke transformer, it has no effect on the discoloration.
- Since this is a Kit, the build quality is top notch, all heater wiring was routed in the correct way and twisted to ensure quiet operation; the layout was done correctly and the soldering looks very professional.
- The lettering is all intact, and the chassis plating is in VERY good condition with slight pitting by the center power transformer.
- The bottom as a few scratches and as you can see from the photos the rubber feet are missing.
- The Tube Cage is clean; however there are a few scratches on the top surface, as well as a few minor paint chips.
- The NOS 7199 tubes test Very Good / Strong + on my B&K tester(100 is new and these test 98+)
- EL 34 tubes have about 20 hours on them and were purchased as a matched quad, they hold bias well.
- 5AR4 tube has also about 20 hours and tests strong / new
- This is my second ST-70 and by far the better sounding, it also is the most original, I have played it using a Dynaco PAS2/3 preamp with an audio lab dac and the sound is fantastic, transparent and clean, it can compete with my vintage Scott in clarity and warmth. overall this is a great example of vintage American Tube Technology from the Golden Era of HiFi.
- Click here to see the review from Audiomagazine –
- Click here to see the review from Stereo Review both from 1959!