Since I bought my main system two years ago, my passion for vintage hi-fi has grown, and now I would like to assemble a good-quality 70/80s turntable, amp , and speakers on a budget of around £250.
Read MoreThe 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
 TWO NOS DYNACO A470 PP OUTPUT TRANSFORMERS/DYNACO ST70*BRAND NEW*  US $229.00
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 Dynaco Dynakit ST-70 Amplifier Assembly Instructions US $9.00
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 Dynaco ST-70 tube amp cage. US $45.00
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 DYNACO ST-70 SUTHERLAND MOSFET JFET TUBE LESS DRIVER BOARD US $99.99
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 NEW STUFFED BOARD Dynaco ST70 Stereo 70 Dyna Amp (7199) US $65.00
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 Dynaco ST70 ST-70 Amp Fully BOARD PC3 PC-3A SOLEN CAP US $44.99
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 CAPACITOR CAN 30/20/20/20 µF @ 525 V Dynaco ST70 ST-70 US $49.50
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 Dynaco ST70 ST-70 NEW Amp Fully BOARD PC3 PC-3 wima cap US $42.99
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 CAPACITOR CAN 30/20/20/20 µF @ 525 V Dynaco ST70 ST-70 US $49.50
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 upgrade 2x 120V 240V Dynaco Dynakit ST-70 power transformer amp hi-current 6CA7 US $90.00
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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.