![]() ![]() When configuring a download, you get to select the output quality (highest, 4K, HD or regular with different resolutions) or choose to export only the audio to an M4A or MP3 file. PullTube will start fetching the video data right away so you can see the video name, duration, and a small thumbnail. Download videos hosted on YouTube or Vimeo to different output sizes and formats Worth mentioning is that, if PullTube detects that the video is part of a playlist, will offer to download the entire collection: will fetch the data for each entry and handle the downloads consecutively. Note that you can also add a video by dropping the link on top of the PullTube window. ![]() The PullTube user interface is represented by a small window where you get to quickly paste the video URL. Video downloader that can import links with drag and drop and can detect playlists Frustrating.Sharing videos via online hosting services, such as YouTube or Vimeo is a common practice, yet streaming the content might not work as expected if you have a slow internet connection. And I haven't since been able to reproduce this result using the H-P gear. Would this externally modified transistor amp now suddenly sound tubelike? Anyone care to try?įootnote 4: While measuring earlier with the Audio Precision, I did see a 1.4x increase in Vp with pulse-like signals, but as I was disappointed I made no printouts. But we already knew that, didn't we?įootnote 3: Compare this to fig.2 and note that, in both cases, the transient output level into a speaker load is almost the same regardless of the presence of the external 3.5 ohm resistor-nothing is gained, nothing lost. ![]() So tubes do something special transistors can't. Magnetic energy stored in the output transformer? Unlikely I would have seen it at work with an 8 ohm resistive load also, and I didn't (footnote 4). So there's more at work than just the output impedance. However, the little push-pull triode still fared better at 1.8x, and the 300B SE was supreme at 2.6x. The transistor amplifier's output at clipping had increased almost by a factor of 1.5.įig.7 25W transistor amp with 3.5 ohms in series with output, system into 8 ohms, sinewave just into clipping, 12Vp, 5V/vertical div.įig.8 25W transistor amp with 3.5 ohms in series with output, system into Audio Note E loudspeaker, 0:05 into track 1 of Touch, driven to maximum produced 17.5Vp, 5V/vertical div. But with a speaker hooked up, the maximum peak voltage on Touch was 17.5Vp positive (fig.8) (footnote 3). See fig.7: Vp is now 12V against the 17V measured earlier directly at the output. What if I added an external 3.5 ohm resistor to the latter? The output under steady-state conditions would fall, of course. Both tube amps operated without overall loop feedback, meaning that their internal output (source) impedance was about 3.5 ohms, compared to an effective 0 ohms for the transistor amp. The interaction between speaker and tube amp haunted me. (Not bad for a tiny triode, eh?) I repeated the simulation tests, but nothing new emerged.įig.5 4W EL84/triode-mode push-pull tube amp into 8 ohms, sinewave just into clipping, 8.5Vp, 5V/vertical div.įig.6 4W EL84/triode-mode push-pull tube amp into Audio Note E loudspeaker, 0:05 into track 1 of Touch, driven to maximum produced 15Vp, 5V/vertical div. With the Denton 2XP, the peak output was 15.5V-very close to that of the 25W transistor amp. ![]() Playing Touch at 0:05, the speaker load managed to produce fig.6, with a positive Vp of 15V-not as shocking as with the 300B, but this still implies almost a doubling of the Vp under steady-state conditions, and represents a quadrupled transient output power. Pushing further leads to hard clipping at 10.5Vp output. (As this is a lower-output amp, the vertical scale is again back to 5V/div.) Defining clipping as 3% THD, the 'scope indicates a 4.2W RMS power rating. Fig.5 gives the 8 ohm situation: Vp is about 8.5V. By now I had grown pretty curious about how my 4W push-pull triode would fare. ![]()
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