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Scourge, Bulwark, Marauder, Dreadnought "front end" cards for DIY VFET amp
Scourge, Bulwark, Marauder, Dreadnought "front end" cards for DIY VFET amp
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Old Yesterday, 09:56 PM   #111
Mark Johnson is offline Mark Johnson  United States
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Scourge, Bulwark, Marauder, Dreadnought "front end" cards for DIY VFET amp
I bought the meter mentioned in post #103 above, it arrived today. Image attached, it's a small little booger.

Regrettably it did not correctly display the frequency of the Marauder card. It didn't even read a subharmonic or harmonic of the actual frequency. I tried direct coupling and AC coupling; wrong answer both times.

So it looks like you'll either need to use an oscilloscope to measure frequency, or else design and build a little buffer + attenuator on your solderless breadboard, which drops the peak-to-peak voltage swing to 9V or less, without loading down the Marauder circuit too much. Then a standard multimeter on frequency counter mode MAY be able to see it's 50 kHz. Unfortunately the best way to debug this little breadboarded circuit, is with an oscilloscope.

Sorry for the disappointing result. Glad I tried it, though.



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Old Yesterday, 10:18 PM   #112
Mark Johnson is offline Mark Johnson  United States
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Scourge, Bulwark, Marauder, Dreadnought "front end" cards for DIY VFET amp
A diyAudio member has asked
Quote:
However, I was wondering if either of the Dreadnought or Bulwark cards could be used in the MoFo as a front end -- is it possible given the MoFo topology? It's hard to find a good voltage gain pre-amp to drive a MoFo (I know my B1 won't do it and haven't even attempted it). Would either of these cards be able to provide that extra push and lift in gain? Or not recommended.
I suspect it is too early to ask or answer this question. People are not yet familiar with Dreadnought, and VERY few people have studied both Dreadnought and MoFo. Certainly I have not -- although I do know Dreadnought, I haven't read any MoFo technical info at all.

I suspect that over time, this may change. Gradually, more and more MoFo experts will have the opportunity and the desire to study Dreadnought. Eventually there might be one or more of them who can answer your question.

However if anybody does have an opinion or an answer today, please reply today!
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Old Yesterday, 11:07 PM   #113
RafaPolit is offline RafaPolit  Ecuador
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Scourge, Bulwark, Marauder, Dreadnought "front end" cards for DIY VFET amp
Quote:
Originally Posted by Mark Johnson View Post
I bought the meter mentioned in post #103 above, it arrived today. Image attached, it's a small little booger.
That is the multimeter I use for everything. It's the "best" thing I could find here... and it is your "trash" trial multimeter. LOL!

Ok. I was not hoping to measure frequencies, but at least I hope the voltage measurements and resistance are good enough!
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Old Yesterday, 11:28 PM   #114
Mark Johnson is offline Mark Johnson  United States
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Scourge, Bulwark, Marauder, Dreadnought "front end" cards for DIY VFET amp
I only tried it for measuring frequency on a weird waveform that no other meter seems to be guaranteed to read. This one is probably quite good otherwise and a screaming bargain for as many display digits as they offer. But it doesn't do the one thing I hoped it would.
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Old Yesterday, 11:41 PM   #115
RafaPolit is offline RafaPolit  Ecuador
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Scourge, Bulwark, Marauder, Dreadnought "front end" cards for DIY VFET amp
Hah! Found the photo I was looking for. It's from my ACA build and dates from August 5th 2018! There you can see my Multimeter. It bears a different brand, but it's the exact same thing! This one-model-multiple-branding habit is a bit annoying.

Click the image to open in full size.

Amp Camp Amp - ACA
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Old Today, 09:15 PM   #116
Citation19 is offline Citation19  United States
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This looks great...look forward to incorporating one of these into whichever Vfet/SIT build presents itself.
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