My post a few days back highlighted the work on the Stealth GM70 project as noted here:
“Just a quick update on the “Stealth” project.
We have a fully working single channel prototype now working on the bench. To recap this is a GM70 triode tube based project.
High voltage 850 volts DC is fully regulated and has a peak current delivery of 300 milliamps (mA) and its short proof!
Front end is of a unique dual Triode topology fully DC coupled to output tube, extremely low impedance at all frequencies.
Full symmetrical DC drive topology with bandwidth in excess of 650 Khz. In addition can drive grid current for linear operation in excess of 10 mA
measured power full class A 23 watts / class A2 33 watts, no feedback
hum and noise wide band less then 100 uV (Micro-volts) (This may improve when we go to proper physical layout)
extremely low distortion (THD) will list up full measurements soon (HP Spectrum analysis) real photo Truth not doctored claims like others)
bandwidth of the amplifier is 5 Hz to 105 KHz +/- 3dB
this will be one incredible amplifier (safe to say one of the best on planet earth for an SE Triode)
Here are some updated measurements now that we have “fine tuned” it a bit and added some magic fairy dust (9-22-2020)
Measured power output:
13 watts @ 1% THD -52 dB down 2nd harmonic -80 3rd 4,5, others in noise floor
power in full class A output 29 watts (nearly perfect spectrum)
power in light class A2 38 watts (extremely linear)
all readings zero feedback
full bandwidth hum and noise 100 uV (micro-volts) (This may improve when we go to proper physical layout)
clipping is even on both end of sine wave (symmetrical)
square wave at 1 Khz very little ring and same on lead edge as well trailing edge. (Real and 2X scope pix to document)
bandwidth 5Hz to 105 Khz +/- 3dB (Tracking gen on spectrum analysis photos)
More to come with photos of breadboard amp and all scope and instrument readings to validate the performance as this is some of the best performance of any Class A SE amplifier on the planet for the tube types. Far better then any 845 or most other tubes in the same family ever dreamed.
“Always True to the Music”
Why you might ask do I post about a design that will not go into production?. Simple further technical design advancements that will trickle down into our line of production products.
and the fact the naysayers claim it can’t be done that never stopped us. “The relentless pursuit of audio perfection”