Dynakit (Dynaco) Premium ST-70 Tube Amplifier

Dynaco / Dynakit Premium Series ST-70 Tube Amplifier "Special Order"

This is a special order unit. Our "special order" ST-70 Amplifiers require a 3-4 week production period. Each amp is custom built. We need time to order the components and of course time for assembling and testing the unit. Often there will be a few orders to complete before we get to your build

The legendary PA-060 power transformer is made for modern day voltage so you don't need a voltage reducer (variac, bucking transformer etc.). You'll appreciate and enjoy the velvety smooth, highly musical output, thanks to the new, highly regarded A-470 output transformers.

The ST-70 is engineered to faithfully and precisely reproduce the input signal without any modification. Consequently, its performance should be evaluated simply by its capacity to accurately amplify the signal.

Video Review of This ST-70 

The (included) capacitors and resistors are key to this particular amplifiers sound and performance so there are no alternatives or options offered for them on this Premium Series ST-70 amplifier.

The coupling capacitors are Amtrans AMCY "Golden Black" audio grade films and provide excellent music reproduction with a magical holographic three-dimensionality and exhibit outstanding tonal balance. The two .047uF bypass caps are NOS Goodall/TRW pieces. 

The resistors are Amtrans ARMG Carbon Film, KOA Speer Carbon Film and Arcol Carbon Composition. 

The PC-3 Dynakit circuit board uses the genuine Dynaco 6GH8A circuit.

Tubes are not included

You are not required to purchase the tubes from us, but we'd appreciate it. Your amplifier will still be fully tested, but it will ship without tubes, unless you purchase the tubes from us. We sell Apex matched tubes.

An article about tube selection can be viewed here

The ST-70 uses the tubes and quantities listed below. Click the links to shop for tubes.

(when you add tubes to your amplifier order, an automatic 5% discount will be applied to the amplifier + tubes order)

The filter capacitor and filter choke are both brand new OEM Dynakit parts. The filter cap has Panasonic/Matsushita industrial grade metal film resistors. The capacitor is hand polished for a nicer appearance.

The upgraded (included) bias supply uses Nichicon electrolytic and Kemet audio grade film capacitors for super quiet and reliable power. The 390pF mica caps are rated for 1000 volts and the 82pF caps are 500 volt.

The inputs are upgraded (included) to high quality RCA jacks with gold plating and spaced slightly wider than stock to allow more room for modern interconnects to fit.

The outputs are upgraded (included) to binding post type terminals that will accept standard banana plugs or bare wire. These are gold plated to resist corrosion and provide superior contact/signal transfer. The amp can drive 4 or 8 ohm speakers, there are no 16 ohm outputs on this unit.

The stereo to mono switch is fully functional. (included)

The rectifier socket has flashback protection diodes installed (included). The bias pots have safety resistors installed (included). These are great "bullet-proofing" features you do not find on most ST-70's.

This is one beautiful sounding and great looking ST-70. It is built to impress you sonically and visually, it will not disappoint.

If you are looking for a Dynaco 70 that sounds like heaven then look no further.

Still want to know more? Click Here

Manuals, biasing instructions and initial set up printouts / diagrams all included. Email and phone support provided if needed. 

Specifications: (for an all original stock unit)

• Power Output: 35 watts continuous, 80 watts peak each channel
• Frequency Response: ±.5 dB from 10 cps to 40 kc
• Power Response: 20 cps to 20 kc within 1 dB of 35 watts at less than 1% distortion
• Intermodulation Distortion: Less than 1% at 35 watts Less than .05% at 1 watt
• Hum and Noise: Inaudible; better than 90 dB below rated power
• Sensitivity: 1.3 volts rms input for 35 watts out
• Output Impedances: 4, 8, and *16 ohms each channel
• Damping Factor: 15
• Minimum Channel Separation: 55 dB
• Power Consumption: 190 watts 50/60 cps
• 13" Wide X 9.5" Deep X 6.5" Tall
• Height may be slightly higher (+1/2") with larger feet installed
• Weight (unboxed) is about 38 lbs