Good rev eng vid of chinese 'valve' device

[chief mushroom cloud]

https://www.youtube.com/watch?v=coSt5HWRvv4

[martin manning]

Very entertaining, thanks!

[Leo_Gnardo]

https://www.youtube.com/watch?v=coSt5HWRvv4

Hosts voice = chihuahua on bad speed w/ annoying accent. Could not listen.

[xtian]

Here's the TL;DR: Yes, the valves work. They're pentodes, wired as triodes, and they're the first stage of the amp, so they barely color the sound at all, until gain is maxed. Second and third stages are solid state amps.

Looks pretty nicely constructed, though!

[JMFahey]

https://www.youtube.com/watch?v=coSt5HWRvv4

Hosts voice = chihuahua on bad speed w/ annoying accent. Could not listen.

Same here.

Mind you, nothing against Oz people, and in fact (True Story ), I learnt "Australian" before actually learning English; my later Oxford/Cambridge English teachers were *horrified* with my pronunciation and vocabulary and had to "unlearn" it before going on with their teachings.
Oh well.

EEV's videos in general are interesting but ... the way he speaks (which is clearly overblown) is nothing but unbearable.

That said, check *this* video on fake tubes.

To save you (some) of the annoying whine, it starts straight at the adequate moment, he's reviewing the then current Scam in Australia: you arrive to some Shopping Center parking lot and a couple guys in a parked "white van" (which happens to be rented) offer you an "Incredible 7.1 Sound System and matching bright-as-the-Sun video Projector" for a true Theater experience at home, for half the price, because "the shop owner didn't have the cash and they sell it for the real Factory price just not to take it back to the warehouse".

Of course, the sound system "has tubes" , for a truly miraculous sound:

https://youtu.be/i3B_KKyntQE?t=21m58s

watch only until 23:50 so just less than 2 minutes total

[rp]

Everything else in our lives is now fake, down to our food, why not fake tubes? "Something doing nothing". I blame these damn kids today!

The guy does sound like a cartoon character.

[John_P_WI]

As my Ex Chinese wife used to say... "Ah China King of copy" insert your own accent...

I actually like Dave Jones, I guess as a fellow engineer I have been exposed to engineers idiosyncrasies for the past 30 years and take him as the norm lol...

[SilverFox]

Here's the schematic shown during the video for those interested. Must be running "Starved Plate".

silverfox.

[JMFahey]

Thanks for capturing that schematic.

Very sharp image, way cleaner than expected fom YT, how did you do it?

As of the tube, not even starved plate , since it produces no gain at all.

As of fakeness, respected SWR and Eden Bass amps show basically the same tube "un-use" , they just hang 12AX7 as do-nothing unity gain cathode followers , again at the input, only they string them from +/- 45V to +/-67 V rails ... the power transistor main power rails by the way, not something they have to create specially.

I have done a similar thing in my amps, in this case from +/- 40 to 65V ones, but at least I use them in the output, before a master volume, and if driven hard they add a little assymmetry.

The (standard) tube of choice for very low voltages is 12AU7 , which can provide decent ~10X gain and clip/amplify like a real tube in a regular amp.

[xtian]

The (standard) tube of choice for very low voltages is 12AU7 , which can provide decent ~10X gain and clip/amplify like a real tube in a regular amp.

Well, there's a decent use for the piles of unloved 12AU7s in my closet...

[chief mushroom cloud]

As of fakeness, respected SWR and Eden Bass amps show basically the same tube "un-use" , they just hang 12AX7 as do-nothing unity gain cathode followers , again at the input, only they string them from +/- 45V to +/-67 V rails ... the power transistor main power rails by the way, not something they have to create specially.

I have done a similar thing in my amps, in this case from +/- 40 to 65V ones, but at least I use them in the output, before a master volume, and if driven hard they add a little assymmetry.

The (standard) tube of choice for very low voltages is 12AU7 , which can provide decent ~10X gain and clip/amplify like a real tube in a regular amp.

My Trace Elliott has a 12AU7 in the 'tube' path....70V on plate, and one triode unused. It does sound different than the FET pre (you can blend them)...I cut traces and paralled the triodes...waste of effort, but not degrading. Not real 'tube' sound like old DR103s, but...meh.

I like Dave, and his voice is radical....but try to understand an Iraqi EE/Phd explain how his lasers work w/o creating thermal problems.....I'll take Dave any day (sigh, too many JPL meetings).

My point w/ the vid is the rev eng task. I'm called on to do this all the time w/ 'legacy' industrial and aviation pcb designs and found it interesting that there was a vid showing one process. But I have remove and measure the smd components!

[martin manning]

Dave is clearly hamming it up a bit, with his outrageous accent, quaint Aussie expressions, and the huge Mick Dundee "knoif" his missus uses to open mail-bag items. He seems to know his stuff, though.

[SilverFox]

Thanks for capturing that schematic.

Very sharp image, way cleaner than expected fom YT, how did you do it?
.

With the video paused, I used Gimp. Under File, Create, Screen shot. There are options to pause the Gimp program capture process for x number of seconds and I select that option, then, minimize any other process window so only the image I'm after is on the screen. Then just wait for the timer to expire and select a region of the screen to grab. As I mentioned first I paused the video at the point of interest then started Gimp.

If you haven't used Gimp it's not that complicated for the basics and it's a free program with lots of plug-gins There are both Linux, (my choice) and Windows versions..

silverfox.