Sound Impressions of the new Dynaco ST70x

Since we heard that Hafler was back and starting production of the most famous tube amp from the 70s and 80s we have been ecstatic to get this in to the showroom to listen too it. At The Show Newport we were so busy running our rooms that we didn’t have a chance to go listen to the Dynaco ST70x, so when Rutherford Audio told us we could keep it for a week, you could imagine the ear to ear smiles we had on our faces as we began planning the music and system we would listen to with it!


Through its long history the ST70 has proven to be one of the most reliable and heavily sought after products from its time. Hafler has done their best to preserve many of its original virtues that made it so reliable and loved, while still making the fullest use of modern parts and more advanced circuit techniques available today. When you compare the “old 70” with the “new 70” you will notice the external similarity of the metalwork but with an entirely new connector array and top cover. Internally, the design has most certainly changed by appearance and execution of design.

After admiring its beauty we finally turned it on for a listen and our impressions of this little amplifier were amazing!

Sound Impressions

20160610_160451As the this newly styled and reissue ST70x amp warms up the LED’s slowly come to life. A quick test with some rowdy music and the LED’s start to pulse. Punchy with healthy dynamics and a snappy pace. Our first impression was that the soundstage was deep and wide. This came from listening to BYU Vocal point, “Nearer my God to Thee”, as well as some other vocal arrangements. As you would expect the design implementation of the power supply lends itself to a beautifully rounded bass that is well rounded, taught,and just plain yummy. Listening to Donald fagen “Ruby Baby” and Shelly Lynne “just a little lovin” really showed off the bass. The overall character is reminiscent of of the pleasant and warm sound of many of the better EL34 amps of the past, not the least of which, the original ST70. Leaning ever so slightly neutral side yet still warm mids, silky highs. 

After 3 days of pleasant and non fatiguing listening with the amp powering up a pair of Magico S1 speakers and then with a pair of Spendor SP3/1r2 books shelf on stands. We couldn’t help ourselves and we rolled the tubes. Though the tubes the ST70x came with were certainly adequate, we had to roll them one by one. And with each new tube the sound became more relaxed, warmer, yet still capturing ever greater detail and articulation. By the end of our last evening we were particularly thrilled. This little amp played outside it’s expected price, and impressed like a high priced exotic. Final thought, it’s a winner.