Dynakit (Dynaco) Classic ST-70 Tube Amplifier

Dynakit / Dynaco (Stock) ST-70 Tube Amplifier

This is a "Special Order" Unit. Our "special order" 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.

This "classic build" ST-70 is built to order and is assembled entirely with the standard parts provided with the kit. We do not offer options for this model aside from the choice of a Brown or Black cover. It's an "out of the box" offering.

If you want something fancier, please choose one of our other "Special Order" Builds with options, or use the contact form to open a conversation about our completely custom build services.

Priced without tubes - the ST-70 uses the tubes listed below, however tubes are not included. Use the link at the top of this page to shop for and purchase tubes. You are not required to purchase tubes from us, although we'd appreciate it. We sell Apex matched tubes

• (4) EL34 Power Tubes 
• (1) GZ34 / 5AR4 Rectifier Tube
• (2) 6GH8A or 6U8A driver tubes 

This ST-70 has the following features:

The legendary PA-060 power transformer by Dynakit is wound for modern 120 volt operation so you do not need a voltage reducer like a vintage (117V) unit would require, this amp is ready to plug in and play. The A-470 output transformers are also current production, brand new stock direct from Dynakit.

The circuit board is the latest revision from Dynakit using the 6GH8A tube where the original amps used a 7199 tube. The 7199 tube is long out of production, scarce and expensive. 

The board is populated with the standard capacitors supplied in the kit. The resistors are all metal film and metal oxide types for clean and reliable operation The 390pF mica caps are 1000V rated and the 82pF mica caps are 500V rated. The 9 pin tube sockets are from Belton.

The gleaming trophy quality non-magnetic polished stainless steel Dynakit chassis is brand new, it is just a work of art.

The included cover comes in Original Dynaco Brown or Black.

The bias supply is built with 100uF electrolytic caps rated for 100 volts. The resistors are 1 watt metal films for super quiet and reliable operation.

All of the wiring is 600V rated stranded and soldered with Kester 63/37 solder.

The output terminals are traditional screw terminals that will allow the use of the 4, 8 and 16 ohm taps. Thes screw terminals will accept bare wire or spade fork terminations.

This amp sounds great and looks beautiful. Dead quiet and very musical, just like it should be. Built right and built to last, you'll love it.

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

Specifications:

• 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.