Dynakit ST-70 Reviews

February 2, 2009  |  Amplifier Reviews

The Dynaco ST-70 is probably one of the best amps for individuals new vintage tube amplifiers. The first kits were introduced in 1959. The Dynaco ST-70 provides 35 watts continuous, with a peak of 80 watts for each channel. The unit comes with a 4 el34 tubes and 2 gz-34's. The overall unit comes in at a hefty 32lbs measuring 13 inches by 9.5 inches by 6.5 inches high. The ST-70 provides taps for 4, 8, and 16 ohms.

Many say that the sound is not all the great, but can become much better with some modifications

dynakit-st70

Dynaco Dynakit ST-70 Power transformer amp upgrade 1 for Dynaco EL34 tube PP amp
Dynaco Dynakit ST-70 Power transformer amp upgrade 1 for Dynaco EL34 tube PP amp
Paypal   US $72.00
 CAPACITOR CAN 30/20/20/20 µF @ 550 VDC Dynaco ST-70
CAPACITOR CAN 30/20/20/20 µF @ 550 VDC Dynaco ST-70
Paypal   US $69.50
SUPER SOFT START & VOLTAGE BUCKING 4 DYNACO ST-70 MARK III, IV FISHER SCOTT
SUPER SOFT START & VOLTAGE BUCKING 4 DYNACO ST-70 MARK III, IV FISHER SCOTT
Paypal   US $62.00
1 set Parts Components Resistor Capacitor Diode for Dynaco ST70 Dynakit ST-70
1 set Parts Components Resistor Capacitor Diode for Dynaco ST70 Dynakit ST-70
Paypal   US $18.50
Dynaco ST-70 Tube Amp PA060 Power Transformer
Dynaco ST-70 Tube Amp PA060 Power Transformer
Paypal   US $59.95
NEW 6GH8A STUFFED BOARD Dynaco ST70 Stereo 70 Dyna Amp
NEW 6GH8A STUFFED BOARD Dynaco ST70 Stereo 70 Dyna Amp
Paypal   US $65.00
tubes4hifi   new OCTAL driver PCB for Dynaco ST70  - full kit, with CCS
tubes4hifi new OCTAL driver PCB for Dynaco ST70 - full kit, with CCS
Paypal   US $99.00
ORIGINAL DYNACO ST70 STEREO EL34 AMPLIFIER ORIGINAL BLACK CATS AND CLOTH WIRE
ORIGINAL DYNACO ST70 STEREO EL34 AMPLIFIER ORIGINAL BLACK CATS AND CLOTH WIRE
Paypal   US $550.00
Dynaco ST-70 Stereo Tube Power Amp
Dynaco ST-70 Stereo Tube Power Amp
Paypal   US $202.50
Dynaco,Dynakit ST-70 tube amp
Dynaco,Dynakit ST-70 tube amp
Paypal   US $102.50
Vintage Classic 1960s Dynaco Dynakit ST-70 Stereo Tube Amp Amplifier
Vintage Classic 1960s Dynaco Dynakit ST-70 Stereo Tube Amp Amplifier
Paypal   US $276.00
(2) Knight Output Transformers UL for 6CA7/EL34 Tube Amp Dynaco ST70 8Ω Tap Only
(2) Knight Output Transformers UL for 6CA7/EL34 Tube Amp Dynaco ST70 8Ω Tap Only
Paypal   US $119.99
Siemens/RFT EL34 Matched Quad + Siemens 6U8, NOS. Ultimate set for Dynaco ST-70
Siemens/RFT EL34 Matched Quad + Siemens 6U8, NOS. Ultimate set for Dynaco ST-70
Paypal   US $199.00
Dynaco St-70 Tube Amplifier
Dynaco St-70 Tube Amplifier
Paypal   US $549.95
Power Supply Delay Board Dynaco ST70 EL34 6550 KT88 6L6 6V6 El84 tube amplifiers
Power Supply Delay Board Dynaco ST70 EL34 6550 KT88 6L6 6V6 El84 tube amplifiers
Paypal   US $56.99
Dynaco ST70 Stereo 70 Amplifier NEW BASIC BARE PC BOARD (7199), Made In USA
Dynaco ST70 Stereo 70 Amplifier NEW BASIC BARE PC BOARD (7199), Made In USA
Paypal   US $18.00
Transformer Bundle w/ Free Choke for Dynaco ST70 240V
Transformer Bundle w/ Free Choke for Dynaco ST70 240V
   US $409.95
 CAPACITOR CAN 30/20/20/20 µF @ 525 VDC Dynaco ST70
CAPACITOR CAN 30/20/20/20 µF @ 525 VDC Dynaco ST70
Paypal   US $49.50
DYNACO ST 70 6GH8 TUBES DRIVER PC-3 TUBE AMP CIRCUIT BOARD POWER AMPLIFIER MOD
DYNACO ST 70 6GH8 TUBES DRIVER PC-3 TUBE AMP CIRCUIT BOARD POWER AMPLIFIER MOD
Paypal   US $69.99
Dynaco Dynakit ST-70 ST70 PC-3A Stereo tube Amp EL34 6CA7 PC-3A Stereo PCB Board
Dynaco Dynakit ST-70 ST70 PC-3A Stereo tube Amp EL34 6CA7 PC-3A Stereo PCB Board
Paypal   US $13.00
Dynaco ST-70 Rebuilt, SS Chassis, New Board, Rebuilt Power Supply, Mullard EL34
Dynaco ST-70 Rebuilt, SS Chassis, New Board, Rebuilt Power Supply, Mullard EL34
Paypal   US $1,095.00
TWO NOS DYNACO A470 PP OUTPUT TRANSFORMERS/DYNACO ST70*BRAND NEW*
TWO NOS DYNACO A470 PP OUTPUT TRANSFORMERS/DYNACO ST70*BRAND NEW*
Paypal   US $229.00
Dynaco Dynakit ST-70 Amplifier Assembly Instructions
Dynaco Dynakit ST-70 Amplifier Assembly Instructions
Paypal   US $9.00
Dynaco ST-70 tube amp cage.
Dynaco ST-70 tube amp cage.
Paypal   US $45.00
DYNACO ST-70 SUTHERLAND MOSFET JFET TUBE LESS DRIVER BOARD
DYNACO ST-70 SUTHERLAND MOSFET JFET TUBE LESS DRIVER BOARD
Paypal   US $99.99
NEW STUFFED BOARD Dynaco ST70 Stereo 70 Dyna Amp (7199)
NEW STUFFED BOARD Dynaco ST70 Stereo 70 Dyna Amp (7199)
Paypal   US $65.00
Dynaco ST70 ST-70 Amp Fully BOARD PC3 PC-3A SOLEN CAP
Dynaco ST70 ST-70 Amp Fully BOARD PC3 PC-3A SOLEN CAP
Paypal   US $44.99
* NOS DYNACO ST70 10K LINEAR BIAS POT CLAROSTAT 1960's
* NOS DYNACO ST70 10K LINEAR BIAS POT CLAROSTAT 1960's
Paypal   US $45.00
DYNACO ST-70 STEREO TUBE AMPLIFIER DYNACO PAS3 TUBE PREAMP DYNACO TUBE TUNER
DYNACO ST-70 STEREO TUBE AMPLIFIER DYNACO PAS3 TUBE PREAMP DYNACO TUBE TUNER
Paypal   US $1,499.99
Choke for Dynaco ST70 Mk2 Mk 3 c354 NEW & Sunn Tube Amp
Choke for Dynaco ST70 Mk2 Mk 3 c354 NEW & Sunn Tube Amp
   US $21.95
 CAPACITOR CAN 30/20/20/20 µF @ 525 VDC Dynaco ST-70
CAPACITOR CAN 30/20/20/20 µF @ 525 VDC Dynaco ST-70
Paypal   US $49.50
Vintage Dynakit Dynaco ST 70 Amp Amplifier Cage   Only
Vintage Dynakit Dynaco ST 70 Amp Amplifier Cage Only
Paypal   US $45.00
Power Supply Delay Board Dynaco ST70 EL34 6550 KT88 6L6 6V6 El84 tube amplifier
Power Supply Delay Board Dynaco ST70 EL34 6550 KT88 6L6 6V6 El84 tube amplifier
Paypal   US $29.99
2 Adapters 6AU8 6BH8 / 7199 + 2pcs 6AU8 or 6BH8  tubes for dynaco st70
2 Adapters 6AU8 6BH8 / 7199 + 2pcs 6AU8 or 6BH8 tubes for dynaco st70
Paypal   US $49.00
Dynaco ST70 ST-70 NEW Amp Fully BOARD PC3 SOLEN CAP
Dynaco ST70 ST-70 NEW Amp Fully BOARD PC3 SOLEN CAP
Paypal   US $44.99
Dynaco ST70 ST-70 Amp BARE BOARD PC3 PCB 7199 + EL34 PP
Dynaco ST70 ST-70 Amp BARE BOARD PC3 PCB 7199 + EL34 PP
Paypal   US $14.99
 CAPACITOR CAN 30/20/20/20 µF @ 525 V Dynaco ST70 ST-70
CAPACITOR CAN 30/20/20/20 µF @ 525 V Dynaco ST70 ST-70
Paypal   US $49.50
Dynaco ST70 ST-70 NEW Amp Fully BOARD PC3 PC-3 wima cap
Dynaco ST70 ST-70 NEW Amp Fully BOARD PC3 PC-3 wima cap
Paypal   US $42.99
 CAPACITOR CAN 30/20/20/20 µF @ 525 V Dynaco ST70 ST-70
CAPACITOR CAN 30/20/20/20 µF @ 525 V Dynaco ST70 ST-70
Paypal   US $49.50
Dynaco ST-70 Stereo Tube Amplifier, Exceptionally Clean, Retubed
Dynaco ST-70 Stereo Tube Amplifier, Exceptionally Clean, Retubed
Paypal   US $749.00
Power Supply Delay Board Dynaco ST70 EL34 6550 KT88 6L6 6V6 El84 tube amplifier
Power Supply Delay Board Dynaco ST70 EL34 6550 KT88 6L6 6V6 El84 tube amplifier
Paypal   US $99.99
DYNACO ST 70 7199 TUBES DRIVER PC-3 TUBE AMP CIRCUIT BOARD POWER AMPLIFIER
DYNACO ST 70 7199 TUBES DRIVER PC-3 TUBE AMP CIRCUIT BOARD POWER AMPLIFIER
Paypal   US $79.99
upgrade 2x 120V 240V Dynaco Dynakit ST-70 power transformer amp hi-current 6CA7
upgrade 2x 120V 240V Dynaco Dynakit ST-70 power transformer amp hi-current 6CA7
Paypal   US $90.00

When your buying a new Dynaco ST-70 you'll want to remember a few things: Make to sure to determine whether or not the amp is in working order. You'll want to know what work if any has already been done to the amp particularly if the work deviates for the standard schematic.

When you get your new amp some upgrades you may want to consider. This is assuming the no major repair work needs to be completed, like changing the driver board. You'll want to replace all resistors with MF-MO types. Definitely replace all capacitors with film types and replace the ceramic capacitors with Silver Mica. Put approximatelya 100ufd capacitor after the choke in the powersupply. Remove the cathode resistors or significantly reduce them by atleast 10 times in value. This one change will dramatically improve the bass output. I would then remove the mono switch and replace all of the RCA Jacks. Add a capacitor to the bias supply and replace all of the capacitors in that section.


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