Contact Joe Curcio. There are a plethora of upgrades, that can be done to the ST-70's power supply(simple and complex). He's an expert on the piece. (http://www.curcioaudio.com/)
Output threshold using a Dynaco ST-70 amplifier with passive pre.
I am concerned with overdriving my recently refurbisher Dynaco St-70 amp. I is my understanding that the GZ34/5AR4 tube based rectifier is the 'weak link' regarding this amplifiers output power capabilities. Am I right on that (Question 1)?
I am using a HRT Music streamer Ii which has a maximum output of 2.25 volts. This is connected via short interconnects (0.5m or less) to a Schiit Audio SYS passive pre which is in turn connected to the amp via short interconnects. Source is Macbook pro via USB.
Question 2) At what input voltage might I be overdriving this amp? Sensitivity rating states "1.3 volts rms input for 35 watts out". I am thinking that the 1.3v may be at the upper limit given this amp is rated 35wpc.
Question 3) Can I measure the output voltage on the SYS pre at at various output levels as driven by the DAC using digital meter without harm to pre or DAC? I am thinking of using RCA connecters on pre outputs having striped wire ends for attachment of meter probes.
I am using a HRT Music streamer Ii which has a maximum output of 2.25 volts. This is connected via short interconnects (0.5m or less) to a Schiit Audio SYS passive pre which is in turn connected to the amp via short interconnects. Source is Macbook pro via USB.
Question 2) At what input voltage might I be overdriving this amp? Sensitivity rating states "1.3 volts rms input for 35 watts out". I am thinking that the 1.3v may be at the upper limit given this amp is rated 35wpc.
Question 3) Can I measure the output voltage on the SYS pre at at various output levels as driven by the DAC using digital meter without harm to pre or DAC? I am thinking of using RCA connecters on pre outputs having striped wire ends for attachment of meter probes.