What are Valve Rectifiers? | Too Afraid To Ask

This video is sponsored by Skillshare.
Click here to explore your creativity and get 2 free months of Skillshare Premium Membership: skl.sh/csguitars5
Rectifiers are vital for your amplifier to operate correctly. While most amplifiers today feature solid state rectification, there is still a big deal made of Valve Rectified amplifiers.
But what exactly is a rectifier? Is there a difference between valve and solid state rectification? and what does it mean for your sound?
Let's dig into this Too Afraid To Ask episode to find out.
More from CSGuitars:
Gain access to exclusive content at: / csguitars
Buy CSGuitars Merchandise:
www.csguitars.co.uk/store
Website:
www.csguitars.co.uk
Contact:
[e-mail]
Purchase my music at:
Amazon: amzn.to/2HUdXgV
iTunes: apple.co/2JvpCjp
Google Play: bit.ly/2KgSzkl
Or stream on Spotify: spoti.fi/2HuYPTP
CSGuitars uses:
Rode Microphones:
www.rode.com/
Hoffnine Cabinets:
www.hoffnine.co.uk/
Hosa Cables:
hosatech.com/
Dragon's Heart Guitar Picks:
www.dragonsheartguitarpicks.com/
Title graphics and logo by:
www.studiosmithdesign.co.uk/
Join the discussion at:
Facebook:
/ csguitars
Instagram:
/ csguitars
Twitter:
/ csg_scotland

[@ScienceofLoud]

This video is sponsored by Skillshare. Click here to explore your creativity and get 2 free months of Skillshare Premium Membership: skl.sh/csguitars5 Rectifiers are vital for your amplifier to operate correctly. While most amplifiers today feature solid state rectification, there is still a big deal made of Valve Rectified amplifiers. But what exactly is a rectifier? Is there a difference between valve and solid state rectification? and what does it mean for your sound? Let's dig into this Too Afraid To Ask episode to find out. More from CSGuitars: Gain access to exclusive content at: www.patreon.com/csguitars Buy CSGuitars Merchandise: www.csguitars.co.uk/store Website: www.csguitars.co.uk Contact: [e-mail]

[@gorbrushthreepwood]

@@BeckyYork That is a shame. I also try to avoid adverts or people requiring financial income, which is why I don't go see movies at the cinema, open a newspaper, access the internet, go grocery shopping, step outside, or breathe.

[@ScienceofLoud]

Maybe if you didn't use adblock I'd earn enough that I wouldn't have to embed sponsor ads directly into my videos. You enjoy your ad free existence, good luck with that.

[@iliasliakos6692]

@@ScienceofLoud Maybe if you got like a more interesting sponsor it would be better, every youtuber has skillshare, dollar shave club etc etc, if you had a more interesting sponsor like a haggis company or something it would be better.

[@ScienceofLoud]

Welcome to the world where some companies see the benefit of advertising on social media and others don't. Skillshare wants to work with me because what they do is relevant to what I do: it's education. Our demographics align and they can see a return on their investment. A haggis company would have no interest in advertising on my channel because: 1. My channel has nothing to do with food. 2. Over 40% of my viewer base is in America where there is a ban on importing haggis. It would be a financial waste of time for them. Also, the reason you are seeing a lot of similar sponsors is because you are watching a lot of similar content. They are targeting channels with similar demographics.

[@Skagb0y]

@@BeckyYork what a knob.

[@ChaosPootato]

Dang, you know it's serious when Colin swears at you :(

[@mk_rexx]

*SO DEWNT FOK UHROUND WIDIS SHET*

[@_RLP]

@@mk_rexx Perfect translation, dude.

[@ValerieWarner1]

Ya know, in case anyone is looking for the timestamp. kzbin.info/www/bejne/qqqbqaZpmK-ebq8

[@yogurtlurker]

He protecc

[@Admill15]

3:16

[@itai.617]

Whenever I hear rectifier I think of electroboom lol

[@ChaosPootato]

F U L L B R I D G E R E C T I F I E R

[@matteocristini6221]

Speaking of ElectroBoom, did he just say DC is way more lethal than AC at high voltage? Should watch some more videos... ;-)

[@Jimbodaddy74]

@@graxjpg Damn near killed 'em!

[@nmr405]

Mesa Full Bridge Rectifier 🤔😂

[@jayden4244]

MESA BOGIE DUAL FUUL BRIDGE RECTIFIER

[@lucasvandekerkhove3769]

That moment Colin gets his video demonetised for the sake of warning us Damn

[@mcswordfish]

Absolutely loving the old-school STV advert warning

[@seanjohnson1988]

I just had to pause your video to tell you that the little black and white prompt for the ad in the corner was a nostalgic throw back to my childhood. It's that sort of attention to detail that will keep people coming back. Bravo.

[@priorsb11]

"so don't fuck around with this shit if you don't know what you're doing" I need this on a shirt, it would answer many questions in engineering asked by customers. For the love of God Colin! I need this!!!

[@theknifesedge57]

Colin, I hate to correct, but for the safety of others, AC voltage is always more deadly than an equivalent DC voltage value. The parasitic capacitance of the human body allows more AC current to flow through it (putting your organs at risk), and the rapid cycling forces muscles to contract, making it near impossible to let go. I've been caught with around 200vDC in amps before, and while it hurt, it (obviously) didn't kill me, and it wasn't too hard to let go. Comparatively, depending on frequency, it only takes around 10-20vAC for your body to start freaking out. Any higher than 50vAC, and you're looking at a bad time.

[@matteocristini6221]

Yeah, wanted to point that out too. AC is way more dangerous at high voltage. Stay safe kids!

[@johnyang799]

There is a curve. At 1khz it's most dangerous to interfere with nerves. At very low frequency (5hz eg) or very high (100khz +) it's similar to dc.

[@theknifesedge57]

@@johnyang799 true, I was specifically speaking in the context of mains voltage though, which is what you're going to see in your valve amps.

[@matteocristini6221]

@@johnyang799 You're right, but in this context, most amp heads run on 50/60 Hz, at least in the countries I'm aware of.

[@johnyang799]

I was just supplementing the information. We cool.

[@elliottallan337]

Always heard about rectifier lag, nodded my head, and pretended like I understood. Now I can nod my head and pretend with greater confidence. Thanks for the lesson

[@_RLP]

... And if they try to push you to actually enter the discussion, you can always say "don't fóckeround widis shyt!".

[@nooralamgir3703]

@@_RLP lol Colin, give this reply a heart

[@brutallyremastered4255]

Nodding my head in mature consideration.

[@bpabustan]

the guy receiving the box/tube rectification sag analogy FLOORED ME! You can't get any more clear than that!

[@dionr1168]

When I think of Rectifiers, I think of Mesa Boogie Duals.

[@surekhaahlawat6068]

Not triple recs?

[@hmtp177]

No shit

[@bauchbart]

03:15 Best advice EVER!

[@noashore2312]

Wow, I learn so much from you. Most of these TATAs I didn't even know I really wanted to know. And now I do (partially at least). Thank you 😁

[@bpabustan]

we can probably be competent repairmen just by watching Colin's videos!

[@yallevereatenbeans2723]

I'd love to see you make one of those kit amps you can buy, like a clone of a plexi with all the components, you just need to put it together, could be a good way to show off some of the mods you can do too.

[@malcolmhardwick4258]

Paul Blart Mall Cop great idea ☺

[@HalfBredReviews]

I have a dual rec roadster. I use solid state on all high gain channels and tube on my clean channel. Tube just adds that charm in the dynamics on a clean sound, which you don't get when you're highly compressed with distortion. Really gives a different feel that only the player can actually notice.

[@shovington67]

This is the best video "EVER", teaching the end user about tube and solid state rectification. You should be very proud. If the Academy gave out Oscar's for instructional/educational videos in guitar technology, this would have taken home the prize.

[@richardcatalinajr.369]

This was the best explanation on the subject matter that I have heard. Heavens, I was able to follow and understand all the way through. Many thanks.

[@hazrod13]

Cool video Colin, and I realized that you now use more sound effects, that's great !

[@wallywutsizface6346]

2:51 Don’t tell Edison, he’ll go killing a bunch of elephants to try to prove you wrong

[@zollnano3430]

‘Don’t F around with this shit if you don’t know what you’re doing’ As a sparky (electrician) I highly recommend you live by this rule.

[@vanessajazp6341]

I've always preferred the experience and sound of solid state amplification and drive over tubes. Now I understand why. Thx!

[@edwardebel1847]

Mate, EXCEPTIONAL (!) exposition of tube amplification as applied to electric guitars! Especially explaining attack and sag (compression). So many guitarists do not understand why tube amplification has a different and (mostly) more desirable tone. And even though digital effects and digital amplification have come a long way, it cannot compare to the sound of a high end guitar played through a totally analog signal chain, terminating in a tube (valve) amplifier. Well, that's my opinion anyway. Cheers for this video

[@DennisTrovato]

How dare you trick me into learning stuff?!

[@spottswoode8122]

That was an outstanding, well organized presentation. Thank you!!

[@Mechanicthing]

FANTASTIC explanation - thank you very much for this!

[@scblds7496]

Colin, Awesome TATA, thank you. Your colloquial explanation of sag was the best I’ve encountered in my 53 “revolutions around our solar core”. Right on.👊🏻

[@CorvetteCoonass]

The biggest pro to tube rectifiers is how it affects the longevity of the components of the system. Because the tube rec introduces the voltage to tubes gradually rather than instantaneously, the tubes will last longer. Since there is sag when you try to push the amp too hard with a tube rec, it again raises the longevity of the tubes in the system. I have a 1964 Wurlitzer Electric Organ that uses tubes for oscillation. All the tubes are original and still work fine; it has a tube rec. It also doesn't have a standby switch which also prolongs tube life. Also have a 1958 Magnavox Stereorama console that also has a tube amp. Amp still works great with original tubes; no standby switch and uses tube rectification.

[@emiliano9321]

TATA: Why are SLO so praised? Excellent and informative video mate!

[@ScienceofLoud]

I'll ask Mike Soldano that when I meet him next week.

[@rickc2102]

@@ScienceofLoud !

[@davidfuller581]

Because essentially every popular high gain amp out there is based on the SLO. It's a really remarkable design, and arguably the first to really get high gain "right".

[@MrTheog1989]

Very well explained. Love your work!

[@nordicguitar8395]

I always love your TATAs Colin. Seriously your vids are really informative. Keep ‘em coming.

[@razek666]

Great video! Very informative!

[@johnmac8084]

Very clear explanation, thanks

[@chrisrose2730]

Love the video sir! Would love to see another guitar build video in the future as well!

[@jdiesel9048]

Excellent explanations!

[@reverendayglow]

3:15. Laughed out loud! But you're right.

[@BigEdWo]

very good explanation. thanks.

[@stevemaass3074]

Yes! I finally understand what sag is!! Well done as always, Colin. 🤘🏻

[@sbove]

Best explanation of rectification for guitar amps ever! Tx!!!

[@Poly6Groove]

Very well explanation and demonstration dude!

[@Bob48]

Love these 'too afraid to ask"...great job.

[@JackdeDuCoeur]

Great lesson! Thanks

[@jera2150]

This was great. Thank you!

[@cmartinrel]

Great video, thanks.

[@Sturgistube]

Thank you. I have always wondered!

[@lekmannen9990]

amazing video. thank you

[@j.thorgard]

Best video on the subject, thank you

[@OzziePete1]

Great video Colin. Thanx for doing it. Your comments about Rectifier valve sag reminded me of a show I went to years ago to see a well known Aussie pub rock band "The Celibate Rifles".... Their guitarist used a Mesa Dual Rectifier and I felt, from the sound I was hearing from the audience, that his rig wasn't properly biased or something, as every time he 'dug in' the volume wouldn't respond in a corresponding way....It was my first time hearing a Dual Rectifier live & it didn't impress me with the lack of dynamics heard. It might well have been the valve rectifier sagging....

[@RickHollis]

Colin teaches me stuff and things. Mostly stuff, but sometimes things.

[@montlejohnbojangles8937]

Cheers Colin, another thing I now understand much better thanks to your excellent videos! ❤️

[@MichaelSnidaro]

You made me more knowledgeable and I thank you for that!

[@EL34]

Thank you for this!

[@iNDERUdmg]

Thanks, this was so informative. I also asked about rectifiers on your last TATA video :)

[@montanaadams452]

So AC/DC: High Voltage? Got it.

[@tmitz73]

Great Video Dude!!

[@johnnycanosoda]

Another great in-depth video... Keep up the great work... \m/

[@hulkslayer626]

Hey Colin, love the content keep up the good work! 😊 My suggestion for a potential "too afraid to ask" episode would be eq utilization. For instance, I have an active bass. I have a couple pedals with eq on them(not talking about actual eq pedals). My amp has eq. Do I just use the eq on my guitar since it's closer? Do i use the one on my amp because it is more powerful? Do i use one individually and set the rest flat? Do i use them in combination? Like setting the eq a certain way on the guitar, then setting an eq that comes after distortion and then finally on the amp... I knew there are mo hard and fast rules and I should do what sounds best to me, but was just hoping for a little more info on the plethora of options available. Thanks 😁

[@0riole11]

Great explanation, you can really hear the sag in amps like the 5E3, but if you're not playing Blues or early Rock 'n' Roll, it may not be what you're after

[@dennispennell]

Great video!

[@jesuzleonardo]

Thank you so much!

[@SidewinderINC]

Absolutely love the curiosity box t-shirt!!

[@justinmcwilliams6759]

I have a 12AX7driven pre-amp overdrive that I built. I actually put it between my guitar and my Digitech RP50, and then the RP50 sends to the amp. Makes for some really cutting, sharp, hard distortion sounds.

[@MechMK1]

"Don't fuck around with this shit if you don't know what you're doing!" - Wiser words have never been spoken!

[@kristonterbutt7373]

Thanks mate, very good explaination of tube rectification and the terms Sag and Tight in relation to tone. Very helpful indeed as the term Sag in relation to bottom end tones has always confused me. Mostly, and i am not musically biased, i hear this as bad thing in relation to metal players who usually give me the wrong advice in regards to amps because we want different tones from an amp. it also helped me understand why i prefer tube rectifying amps such Fender 68 amps etc.. Cheers and thanks again for posting this.

[@burnbacktime]

Nice video man, as a amplifier nerd and Master Electrician / Power electronics technician I had to repeatedly push my glasses up the bridge of my nose while snorting uncontrollably during this video. 😃

[@ToroKchannel]

Thanks for those details and explanations Colin ! Now I know that Rectifier isn't just the name of a legendary Mesa Boogie amp ;)

[@lucashernandez8146]

*F U L L B R I D G E R E C T I F I E R*

[@throatsinginggambist8927]

Electroboom has joined the chat

[@Poly6Groove]

Lucas Hernández hehehehe fortunately I wasn’t the only

[@Totone56]

Came here looking for this, i imagined him screaming at me during the whole video

[@aliali-ce3yf]

your videos are awesome!

[@pip5528]

All the Mesa/Boogie amps have tube rectifiers. The Rectifier series does still have the solid-state option as mentioned and apparently only recommends the tube rectifiers be used for EL34s, not 6L6s.

[@czarofzonk1360]

My Silvertone 1482 uses a 6X4 (well, the tube is 6X4WA... not sure what the "WA" is). The wattage on this amp is inconsistently published, but I'm safe to say it's under 25 watts. I have this routed through a load box into the Pod Go instrument input, effectively making my amp both a bedroom level cabinet as well as a big-honkin "drive pedal" in front of the Pod-Go (all of which is "yummy"). As for the caps... I thought one day I might try my hand at building a tube amp, but decided against it: "Step 1: make sure you bleed the caps or you might die". I decided to not approach step 1.

[@vk3fbab]

I think you stated that rectifiers are responsible for the higher voltage after rectification. It's actually the capacitors that do this. The voltage rating of a transformer is RMS which is the average voltage. The peak value is 1.412 (square root of 2) times higher. When the caps smooth the voltage it increases towards the peak voltage. With silicon rectifiers (and probably valve ones too) they actually are responsible for a small voltage drop. Just thought I'd share. Also in high power power supplies they use MOSFETs as rectifiers. Turning them on for half the waveform. Almost no sag or power loss, but need to get the AC zero crossing right or bang goes the MOSFET. Great video.

[@silasfatchett7380]

Valve rectifiers have a much larger voltage drop than silicon diodes. Voltage is dropped across the valve's internal 'anode/plate resistance'. As more current is demanded by the power tubes, more voltage is dropped, resulting in 'sag'.

[@magutanko]

Hey, thanks Colin. I was just wondering about this, after years of playing guitar - and I thought "I wonder if CSGuitars...?" Yep. You've done it. Thanks for touching on my TATAs. 🤘

[@greatreset3]

Slight correction: U.S. normal wall socket voltage is 120v not the old 110v. Which is why some vintage amps don't always work right without modification in the states. 🎶🎸

[@thomaschilds8781]

Love the analogy. Good to finally know what sag is.

[@autocratdaddyjones]

Enjoyed the old school advert warning :-) It would've been really helpful to hear the difference between an amp using valve rectifiers and an amp using SS rectifiers though... Even just a few power chords might have been enough...

[@ScienceofLoud]

Sound samples would be utterly meaningless without an amplifier that has switchable rectification options. I don't have one of those. Using two different amplifiers would result in two different sounds and it would be impossible to isolate what was the rectifier and what wasn't within the sound. It would be completely contrary to the scientific process.

[@autocratdaddyjones]

@@ScienceofLoud that's a very fair point.

[@vjc1630]

@@ScienceofLoud It could be done with a Weber Copper Cap.

[@djcanilla]

Hi Colin, thanks for your channel and the excellent informative videos. Got a TATA for you: could you do a video on preamp pedals, their uses, and comparison to actual amp preamps? Thanks

[@PierceThirlen2]

Rectifiers can DIRECTLY affect the sound in the analog signal path. As the rectifier switches on and off the sudden changes in current result in RF noise generation that is both radiated & conducted into the analog signal circuits & produce a glariness to the sound. Early solid state rectifiers with slow reverse recover time were especially bad sounding compared to tube rectifiers. The newest fast soft recovery rectifiers cause 20 times less RF noise and with proper snubbing circuits are a vast improvement upon vacuum tube rectifiers. Vacuum tube rectifiers are now obsolete for audio. If you want to make the power supply sag, just switch in a resistor. FYI, the first rectifiers were the commutators on DC generators.

[@jeffmariajenson9751]

Thanks Colin.

[@beaverrow9272]

saw the wee corner-of-the-screen barber poll advert warning and howled laughing until my partner pointed out how old it makes me Oo

[@NebulonRanger]

The other major notable use of rectifiers is in, big shock, standard ATX power supplies. Computer parts expect near-constant +12V, +5V or rarely, +3.3V. While this is *much* lower than an amp, it's still significant enough to cause a fire. Just ask NZXT.

[@androdid9249]

Now I understand the "sag" amp setting of my Helix and what it was meant to replicate. Thank you. Can you explain the "hum"?

[@pecenak21]

Can you make a TATA on biasing with tube amps? My amps has the ability to adjust the bias, but :shrug:

[@ScienceofLoud]

You mean like this video: kzbin.info/www/bejne/a4SvfKyde6uhobc

[@pecenak21]

@@ScienceofLoud :facepalm:, just like that! You are a beast.

[@JuveriSetila]

PATREON NOTIFICATION SQUAADDDDDDD 3:15 Glenn Fricker approves this sentence

[@hazrod13]

hello there

[@jumpnrun3368]

@@hazrod13 HOLO there

[@DavidGossettMusic]

Yeah, ummm... Was totally not expecting that... had this video playing on my monitors and not headphones. 😂

[@Yupppi]

It's surprising that people do remember the valve rectifier Marshalls as well, but they started phasing out GZ34 rectifier as early as 1966 in JTM50. Only ~4 years after the first Marshall. JTM100 from 1965 had a solid state rectifier from the get go already.

[@HaroonRahman]

I'd love to see a video detailing what a wet/dry rig is, and how it may be helpful in place of stereo!

[@Burnt_Gerbil]

0:18 The Wilhelm scream. That thing is everywhere! 😆

[@andyleibrook6012]

To be honest with you, as someone into electronics I came across this video by chance and was ready to just laugh at this. I totally stand corrected and my hats off to you on a great explanation of SS vs tube rectifier response. Spot on!,,But I still use tubes..lol

[@nathandrawdy]

3:16 = pure gold

[@stevenheinje181]

I’ve always liked Lee Ritenours tone and I often see a Mesa Rectifier behind him. I think I know why. And I think this helps explain why I like my solid state Bass amp.

[@davidfuller581]

By the way, other than the internal resistance of a tube rectifier causing sag under current demand, the "sag" also comes from tube rectifiers having limits on capacitance - with the best performing one in guitar amps, the GZ34, having a _hard_ limit of 60uF for the first stage and others being considerably below that (the 5U4GB Mesa uses in their amps with tube rectifiers, like, well, Rectifiers has a limit of 47 uF, and the ubiquitous 5Y3 used in old Tweed Fenders and others is around 33uF). A smaller reservoir capacitor value (i.e. the input filter cap of the power supply) will sag a lot more. Think about the difference between a Marshall Super Lead and a Soldano SLO (or for the sake of it, a Peavey 5150). The Soldano is stiffer, firmer in its response for a multitude of reasons, not the least of which is using four 220uF caps in series-parallel for 220uF of input stage filtering and reservoir.

[@goodun2974]

David Fuller, It is also worth noting that output tubed have a higher impedance at lower plate voltages, and so as the voltage sags momentarily when the amp is pushed hard, the interface and transfer function from the tubes through the transformer to the speaker is going to also be affected. A loss of some speaker damping seems likely. This is probably another reason why tube rectifiers affect tone and why many people prefer it that way

[@Chord_The_Seeker]

Mr Mike Soldano: “In my opinion, all amps should have solid state rectifiers. I don’t believe there are any really good rectifier tubes on today’s market and, even if there were, why use them? The technology is obsolete; they are horribly inefficient, and far more expensive and troublesome to build into an amp. These tubes, no matter how good, will routinely need replacing, adding to your maintenance expenses. Besides that, tube rectifiers kill the headroom of an amplifier. If you want that spongy, vintage sound, there are other ways to do it. I have successfully designed and built amps that have replicated that soggy bottom, vintage tube rectifier sound using solid state rectifiers and various circuit modifications.”

[@sparkplug1018]

Whats funny is, there are probably no end of people that would line up to tell us "yeah its close, but it still isn't a REAL tube rectifier". At this point even for classic rock id have to agree, but there will always be those that refuse to let it go.

[@PrinceWesterburg]

I used to work for a major valve hifi manufacturers and solid state is cold, dead and hard sounding. Nothing replaces a valve recitifier, its night and day. Some people say the contrary but invariably they are 'scope jockeys' with cloth ears. Emulating a valve rect. in a guitar amp isn't difficult, browning out the PSU and producing flabby bottom end is more to do with the voltages produced and not the reason to have a valve in the first place.

[@samomarincek478]

yeah that's thrue, but tube rectifier is still tube rectifier and match with others tubes in amplifier, because all thogether is still vintage tehnology. I's more matter of tast, seems to me...

[@bpabustan]

I agree. Brian May's AC30s mostly have solid state rectifiers and nobody says his tone stinks.

[@javiceres]

Bryan M. Pabustan He runs them quite compressed already.

[@silviopimentel7247]

Bravo brother 💯👌

[@CalvinBacon]

4:40 - Oh my Colin was right, how very much we all got lost this past year...

[@thegougler]

I know this would be a longer video or series, but I was wondering if you could do a series about an amp schematic breakdown where you highlight different parts of the schematic (e.g. Preamp, Poweramp, Power Section, etc...) and explain what they do or how they color the signal.

[@Christoffer83]

Hi Colin. And with an 3-phase power supply system the voltage ripple gets even smoother due to the fact that the 3 phases is 120 degrees mutually displaced.

[@Christoffer83]

But I think it's only used for big sound systems.

[@hunter5028]

Yeah, three phase power is usually only used in major high power devices.

[@malcolmhardwick4258]

So long you learned one thing a day then it's a good day ☺

[@TheWarped45]

well the Peavey 6505 and 5150 have 4 1n4007 diodes just in the high voltage section alone and 4 1n4007s in bias and low voltage rectification supply and it sounds kickass I also like triple rectifier amps.

[@chrisf6216]

tapadh leat (hope I am using this correctly. Pardon my ignorance and I thank you for yet another fantastic video, sir!)

[@firstnamehidden6514]

iMO, the EZ80 is improperly named. In my area in Can'tada, these certainly are not EZ to find. The nearly identical miniature 6X4 is easy to find, but IIRC, not pinout compatible. I was working on a pair of Heathkit EA3 monoblocs and had the toughest time finding required EZ80 rectifier tubes.

[@tyschuby]

Good stuff as always. Really don't want to use the silicon rectifier in my mesa

[@ronboff3461]

i enjoy all your "ta tas" and learn a lot.....your brogue is entertaining and your enunciation perfect....had a Scottish girlfriend back in the 60s, her name was Carol Cummings, did you know her?...just joking, love your lectures!!!