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Old 5th Dec 2020, 1:44 pm   #1
Petedox
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Default Effect of output bias on tone, gain and headroom

I guess many of us here are devotees of Uncle Doug's Youtube channel. I found this recent one to be an excellent examination of the above, conveyed in his usual articulate style:

https://www.youtube.com/watch?v=hgyQ2scnLJY
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Old 6th Dec 2020, 3:10 am   #2
Herald1360
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Default Re: Effect of output bias on tone, gain and headroom

Pity he doesn't seem to understand the distinctions between voltage gain (as a ratio) and power gain in dB. Why he had to bring dB into it at all made no sense, he could have simply quoted (voltage out)/(voltage in) figures for the hypothetical amplifiers without confusing anything or anybody.
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Old 6th Dec 2020, 5:13 pm   #3
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Default Re: Effect of output bias on tone, gain and headroom

I managed to hold it together for the first 15 minutes then....zzzzzz.....started to set in, at that point I noticed that it was himself again in the next up in the play list describing how an amplifier works, I got so far as the point where he was explaining how an untapped primary of a single ended output transformer magically removes the ripple voltage, at that point I decided to go and do something more useful instead.

Lawrence.
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Old 10th Dec 2020, 7:37 am   #4
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Default Re: Effect of output bias on tone, gain and headroom

Quote:
I managed to hold it together for the first 15 minutes then....zzzzzz...
Uncle Doug does tend to cater for beginner's and guitarists, who're let's face it are not known on the whole for their electronic nous. If you want something more challenging Lawrence try - https://www.youtube.com/channel/UCKx...hF1Mt-2vbPug-g Sharia has a similar effect on me, mainly cos I haven't a clue wot he's on about. His fault finding video's are worth watching though if only for tips.

I found the video in question a bit subjective as the examples were audio, I suggested using FFT and a scope, easier to "see" the difference. Still, that said he puts effort into his video's, isn't on the cadge every five minutes and doesn't have ads turned on, kudos.

Andy.
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Old 30th Dec 2020, 3:28 pm   #5
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Default Re: Effect of output bias on tone, gain and headroom

I re-did a YT Playlist for my Google related account , mostly of the Uncle Doug videos, yes they are interesting, particularly if you are going to make (guitar) tube amps, or a comparing old (or new/reissues) amps etc. The vids can be watched speeded up which might help . and their claims as to output etc. He appears self-taught, but looks to have worked in the juke-box repair industry in the past. If you read any of the text books they wander between understandable and confusing too , so while it should not be the main source of understanding is certainly useful for refreshing knowledge, or a starting place. My actual playlist I have attempted to put into some kind of order following the analysis videos and the principles videos , something which maybe that, and other channels, should attempt to do themselves , if anyone wants to see the ordering I have done PM me and I can email a link.
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Old 30th Dec 2020, 10:48 pm   #6
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Default Re: Effect of output bias on tone, gain and headroom

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Originally Posted by Diabolical Artificer View Post
try - https://www.youtube.com/channel/UCKx...hF1Mt-2vbPug-g Sharia has a similar effect on me, mainly cos I haven't a clue wot he's on about. His fault finding video's are worth watching though if only for tips.
Shahriar, I think his name is.

That's a very nice website. He's into interesting things and has good understanding. Well presented and intelligent. The URL went straight into my favourites

David
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Old 1st Jan 2021, 3:35 pm   #7
dave cox
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Default Re: Effect of output bias on tone, gain and headroom

The 'signalpath' is 1st rate, it must be the best on youtube for test equipment. Personally, I kinda prefer the range of equipment on 'mikeselectricstuff' eg luggage x-ray machine, quadrupole mass-spectrometer ...

dc
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