Cathode Bypass Capacitors: How they Affect Gain and Tone

In this milestone video (Rusty and my 100th) Cathode Bypass Capacitors (CBC) are discussed, with emphasis on their influence upon both gain and tone. Audio spectra associated with several values of CBC are demonstrated, utilizing the Amp Books Cathode Bypass Capacitor Calculator (see link below), and the diminishing returns associated with higher value CBC's is discussed. As usual, the language is basic and best suited for those seeking a fundamental understanding of tube amplifier circuits.
Link to Amp Books site: www.ampbooks.com/mobile/ampli...
If you enjoy videos featuring classic vintage tube amplifiers, jukeboxes, astounding home-built marvels, and clear, concise technical presentations, then please subscribe to my channel. You will gain immediate access to 100 videos, and (if you activate the service) you will be notified each time a new video is posted. Thanks for watching !!!

[@TucsonBillD]

Thanks again, Doug, for the well thought out and presented tutorials on demystifying the tube amplifier.

[@UncleDoug]

+Bill Daniels You're welcome, Bill.....glad you enjoy the videos :)

[@johnchase8510]

Happy 100th Doug, What a cool video, and explains the CBC very elegantly.

[@UncleDoug]

Thanks, John. Glad you liked it :)

[@carvingbone]

Excellent again and thanks for sharing your wisdom, congrats on 100 videos!

[@UncleDoug]

You're welcome, CB. Rusty and I really appreciate your kind words :)

[@murratosmani6517]

Hi Dough, a warm thank you taking so much time to produce all this videos! I really like it and it inspired me to build my own amp. I'm desperately waiting for your next meeting!

[@UncleDoug]

You're welcome, Murrat. I'm glad to hear that the videos have been helpful. I have posted 100 videos so far and hope that you'll get a chance to watch them all if you have the time. The next new video should be posted in a week or two.

[@charris939]

Wow! Congrats on the 100th video Uncle Doug, I must say I've seen and enjoyed most of them!

[@UncleDoug]

Thanks, Charris. Rusty and I really appreciate your loyal viewership (if that's actually a word :) We'll now focus on the next 100.....best wishes !!

[@ChickenStripped]

Another excellent piece of teamwork! Thanks Uncle Doug for the very pleasant lesson and Rusty for the solid camera work.

[@UncleDoug]

+KT88 You're welcome, KT.....glad you enjoyed it :)

[@AdamRainStopper]

Happy 100th anniversary to you and Rusty!

[@UncleDoug]

Thanks, Adam. We really appreciate your time, interest, and input :)

[@earworm]

Your videos are the best Doug. You explain so well even I can understand. Thank you

[@UncleDoug]

You're welcome, EW.

[@dbhguitar13]

Congratulations on passing the 100 mark. Really enjoying your videos and appreciate Rusty's contribution!

[@UncleDoug]

Thanks so much, DBH. I would definitely be lost without Rusty's support and guidance:) ^. .^

[@64mung]

Watching these videos all night..good stuff! Well done too.

[@UncleDoug]

Thanks, 64. Don't overdo it.....you need a good night's sleep.

[@charisjapan]

100th Congrats, Doug!! And thanks always for making amp goings on understandable to folks like me. ;) Cheers from Japan!!

[@UncleDoug]

Thanks, Charis. It's great to hear from you. Rusty and I are pleased to hear that our video was helpful......and wish you all the best !!!

[@MrTartlet]

Congrats on the 100th video! We love you! Send Rusty my regards. =)

[@UncleDoug]

Thanks, AR. The feeling is mutual.....and Rusty says, back at ya !! :)

[@Krolic5]

Thank you for going into this in detail. Very much appreciated!

[@UncleDoug]

You're welcome, K. Rusty and I are glad to hear that it was helpful :)

[@guitargeeknwa]

Great video Uncle Doug, keep up the good work & congrats on the 100th video milestone! Now I am anxious to start tweaking the values of the cathode resistors & bypass caps on my amp.

[@UncleDoug]

Thanks so much, GG. Rusty and I are still celebrating. By all means, do a little experimentation with cathode bypass caps. Although the value of bias resistors is strictly dictated by the plate current and plate dissipation of the tube, the value of CBC's is dictated by the ear :)) Good luck !!!

[@ZLUNION]

Congrats on the 100th video and thanks for another clear and concise tutorial. You are, as already stated, a gifted teacher.. Thank you.

[@UncleDoug]

You're welcome, John....and thanks for your kind words. Rusty and I really appreciate it :) ^. .^

[@randyj1833]

Congrats on the 100th vid! I am happy to say that with the great information from your videos and hours of research, my own Champ clone will be coming to life pretty soon. Thank you for the the high caliber videos and wealth of knowledge that you are passing on. Keep up the great work, and pass on my compliments to your outstanding videographer, Rusty. Best Regards!

[@UncleDoug]

Thanks so much, Randy. It's great to hear that our videos were helpful and your project is coming along well. Rusty sends his regards....in between sneezes :)

[@traktorboris]

These videos are amazing, thank you so much for your effort! There is something about the way you explain things that makes it so much better for me to understand than any other resource I have found! Greetings to Rusty and Jack

[@UncleDoug]

Thanks, Boris. We're glad the videos are clear and helpful.

[@donaldfilbert4832]

Great video Doug !! I learned a lot !! Thanks a ton for all you do !!

[@UncleDoug]

Thanks, Don. We really enjoy hearing from you and are glad to know that our videos have been helpful. Best wishes to you and yours.........

[@corneliusschulman6551]

i never said thank you for all of this, you really helped me out in the earlier days.

[@UncleDoug]

You're quite welcome, Cornelius.

[@kevinkraushaar5655]

Thankyou so very much for all your video's Uncle Doug - All of us amp building madmen appreciate your contribution to this beautiful art form.

[@UncleDoug]

You're welcome, Kevin.

[@basildouglas855]

Excellent video's, well presented, and a world of information. I have looked at many of your videos on the subject of valve amplifiers and written pages of notes from them. My regards to Rusty and the cat.

[@UncleDoug]

Thanks so much for all your very nice comments, Basil. Rusty has passed away, but Jack and I really appreciate hearing from you.

[@jeffreyhamer3107]

The last part of this video, with the screen shot of the calculator program with graph, was fantastic. Thank you for all of your work.

[@UncleDoug]

You're welcome, Jeffrey :)

[@ix-Xafra]

Thanks again Uncle Doug for your relaxed matter-of-fact deliberation style. I always learn something significant from your videos.

[@UncleDoug]

You're welcome, Vinny. Thanks !!!

[@Headwind-1]

Thanks again Uncie Doug you are an excellent teacher!

[@UncleDoug]

You're welcome, H-1 :) Thanks !!!

[@jjheaphy]

Another good one! Thanks Uncle Doug and Rusty!

[@UncleDoug]

+John Heaphy Thanks, John :)

[@BenSWilliamson]

Hey Doug and Rusty, congratulations on the 100th video! I came across your channel a few weeks ago and was instantly hooked. I think I must have watched nearly all your videos! With your help and a bit of my own research I've been able to have a look around inside my current amps (nothing vintage but still a learning experience) and have started sourcing parts for my own vintage clone. Just wanted say thanks. Keep the videos coming!

[@UncleDoug]

You're quite welcome, Ben. It's great to hear that the videos have been instructive and that you are planning your own amp clone project. Be sure to let us all know how it turns out.

[@jeffbrooks7246]

Thanks a whole bunch for the link to ampbooks.com - great resource!

[@UncleDoug]

Jeff Brooks You're welcome, Jeff. I hope the link is helpful.

[@huberttremaine8343]

Thank you TubCal for that wonderful explanation. Through Uncle Doug and his subscribers I think I have found a tube amp Gold Mine!

[@UncleDoug]

Yes, TC is a great source of info. It's nice that we can use this as a forum to share knowledge :)

[@GregsGarage]

Man. These videos are great. I have about 1,000,000 noobie questions I'd like to ask. Thanks for the vids and congrats on #100

[@UncleDoug]

Thanks, Greg. I'm glad you are enjoying the videos :) ^. .^

[@danielsauriol]

...........always happy to see rusty provide his usual assistance and supervision........ ;-)

[@UncleDoug]

We'd be lost without him, Daniel.

[@govelamo]

Not just "a 100th video"... 100th of 100 awesome, super helpful, videos!! Crank it up Uncle Doug and Rusty, all the way up! :)

[@UncleDoug]

Thanks so much, G. Rusty and I really appreciate your interest and support.....and we promise to keep the volume cranked to 11 :)

[@abeleballestri612]

Congratulations for your excellent 100th video which you performed beautifully well described with very practical examples , as usual. Thanks .

[@UncleDoug]

You're welcome, Abele. Thanks for your nice comments. We are now up to 150 videos, so you have a bunch more to watch :)

[@bullthrush]

Congratulations on 100 of the best videos about tubes and related! A surprising amount of emotion shown by Rusty, whose camera work is first class. The hand acting with dramatic backlighting has reached a new zenith! :)) I might have to add a bypass cap to my 5F1 now.

[@UncleDoug]

Thanks, Andrew. The video is never official until I hear from you. I agree that Rusty (and my hand) rose to new levels of cinematic glory in this epic.....and we strongly suggest that you add that capacitor ASAP !!

[@DennisMurphey]

I am going thru your older videos and trying to absorb all your lessons. I think i will need multiple inoculations as it is pretty new to me, but you method of sharing is just so damn good. it is a fun learning experience. Thank You Dennis

[@UncleDoug]

That's great to hear, Dennis. Thanks so much for your kind comments and best of luck with your continuing self-education.

[@davidtaylor9508]

Great teachings on tubes and amps. You have really helped my understand the mechanics. 72 k subscribers in 2020, Glad your channel is still here!

[@UncleDoug]

Thanks so much, David.

[@FRRRRAAANNK]

Great video and thanks for the link. Very helpful to many of us I'm sure.

[@UncleDoug]

You're welcome, Frank. I hope it is helpful :)

[@mendamp1715]

Excellent explanation, Thanks!

[@Lynn4510]

Excellent Vid! Wow, 100th video and still no ads! Very generous of you Doug. I once aquired an early Mesa Boogie schematic and found the first two gain stages had diodes in place of the Cathode resistors. So I tinkered with my 65' Deluxe Reverb using 1N914's with different capacitors (the schematic did not show any part numbers for the diodes). Using my Telecaster, I found some interesting gentle overdrive and sustain effects.. Eventually I went back to stock preamps but the OT-NFB circuit is another story...:) Still enjoy giging with my little sweetheart!

[@UncleDoug]

Thanks, F. Glad you liked it :)

[@Ivyhurster]

This is one of the most informative KZbin channels I've ever seen. I'm just getting started repairing old amps and would be totally lost withOUT these videos. THANK YOU!

[@UncleDoug]

You're quite welcome, Scott. It's great to know that our channel is helpful :)

[@timbones59]

I just wanted to say congratulations on your 100th video and thank you for your time and energy, and knowledge you put in to making these videos. I spend way too much time on youtube watching videos that interest me. Might I say, I have learned a lot watching your videos and I look forward to each and every one. I don't know you, but I like you. Thank you friend!

[@UncleDoug]

The feeling is mutual, Tim. Rusty and I really appreciate the time you take to watch our videos and post comments. You are definitely part of our "family" and always welcome :) ^. .^

[@palpater]

Rusty steals the show. Not just for guitar amps, your videos have helped me understand important concepts that apply to stereo and radio tube amplification. Eagerly awaiting each of your next 100 videos, congrats.

[@UncleDoug]

Thanks so much, Brad. Judging from your icon, you too have experience with four-legged scene-stealers :)) It's great to hear that the videos have been helpful. Thanks for watching, and for your input.....best of luck !!!

[@akxeman]

My Quest has ended. Perfect information presented perfectly! Thank you very much.

[@UncleDoug]

You are quite welcome, Luke.

[@dwightbehm4747]

Hi Uncle your info and teaching on guitar amps is very helpful. I have been adjusting things in my 1960s blackface fender champ. I use it. At mass in church so I can hear every one else through it by putting a low signal to the amp from the sound board. Works good as an extra monitor. Thanks for all your Help. Dwight Allenpark,mi. near Detroit

[@HammerToneAmps]

Nice job Doug .. a very informative vid for #100. Looking forward to the next 100.

[@UncleDoug]

Thanks so much, HT. It's always good to hear from you. Hopefully our second 100 will be equally informative :)

[@tiranosauriorex7513]

thanks to u uncle doug for sharing your knowledge this is my favorite channel on youtube btw

[@UncleDoug]

You're welcome, TRex. We're glad you enjoy our videos :)

[@iangomes]

That sneeze by Rusty had me giggling. A very late congratulations on 100!

[@UncleDoug]

Thanks, Ian :)

[@isaacg6967]

Wow... to think I was gonna leave that out of my 5f1 champ build... I probably would've been pretty disappointed with the sound. Very helpful!

[@Mauitaoist]

Doug, this is fantastic you give us private lessons on something that we could never learn any place else! Simply amazing, I can't thank you enough. Keep up the good work..... and make Rusty do something okay

[@UncleDoug]

Thanks so much, Cory. I'm glad you enjoyed the video :)

[@robertbarcus2008]

Thank you for all of your time and knowledge

[@UncleDoug]

You're welcome, Robert.

[@jonnybeck6723]

If I've not said it before, just wanna say your vids are clear, beautifully done and even make me feel I may still have a workable brain... Thanx so much and best to all of you and yours from us and ours... cheers

[@UncleDoug]

You're welcome, Jonny. We're glad you find the videos clear and helpful :)

[@4brewman]

I know next to nothing about electronics, but you explained this in a very understandable and educational way. The link to the other website is appreciated. I will be subscribing to your channel and look forward to learning more!

[@UncleDoug]

Thanks so much, Ken. Welcome to our channel :)

[@raulmontesdeoca7843]

Congrats on your 100th. Love the website calculator. I unusually use a decade box. This is much easier. Plus it has more choices than the box.

[@UncleDoug]

Thanks, Raul. We're well on our way to 200 videos now. Please take the time to watch them all :)

[@brentstewart59]

Very useful stuff here. Thank you Uncle Doug

[@UncleDoug]

Glad to hear it, Brent :)

[@Ideal1980]

Thank you for this video, it was very informing, I had never thought of this online calculator before

[@UncleDoug]

You're welcome, Ideal.

[@bondsongmusic]

Another great and informative video!

[@UncleDoug]

Thanks, BSM :)

[@wildhogdog]

Hey, loved the video and Rusty didn't do too bad himself.......I also caught the trailing value that persuaded me to go ahead with what I was considering, and yes, it gave the desired blues sound I was after.......Thank you

[@UncleDoug]

You're welcome, WH.....we're glad it was helpful :)

[@tubical71]

I forgot this: *celebrating your 100th episode!* and *bless you* Rusty! Excellent video -- as it is a nice and easy lesson about of what a common cathode operation point is basically all about...!

[@UncleDoug]

Thanks, TC. No video is official until I get your seal of approval :) Rusty's allergies are doing much better now, but the camera lens is a mess. I'll have to clean it off for video number 101. Thanks again for all your excellent input and continued support.......U.D. & R. (the Wonder Dog)

[@tubical71]

Uncle Doug If you need a hint for 101....(you know what 101 involves...?;) Show us all your Instrumental Amplifiers, and say what your like best on that particular Amp and why you have it....i´d love stuff like this as well...

[@UncleDoug]

That's an interesting suggestion, TC. I have featured just about all the amps individually, but never in a group. Let me think about this.......

[@alvagoldbook2]

Another great vid, Uncle D! I've never thought too deeply about this, but now I understand exactly why the income signal is almost always connected to the grid of the triode, and why your signal gets hotter (or louder) the harder you strum the guitar, due to the signal becoming more positive, which caused the grid to do less suppressing of the signal. Prior to this vid, my only thought on this was "signal hits the grid, amplification happens". I'm always surprised by what I learn watching your vids!

[@UncleDoug]

Yes, Alva. Small signal fluctuations on the grid become large fluctuations on the plate, and after several stages of amplification, the plate signal becomes strong enough to drive the speaker(s). It's great to know that the videos have been helpful and informative. Thanks for watching :)

[@citizencyclops406]

Congratulations UD. Your first hundred have been invaluable for all us circuit board curious musicians.

[@UncleDoug]

You're welcome, CC.

[@roscocsa]

I'm slowly gearing up to build my first tube amp. A champ with your variable feedback modification. These series of videos have generated many pages of notes and many more ahhh moments. Thank you!

[@UncleDoug]

You're welcome, Rosco. Please let us know how it turns out.

[@roscocsa]

I shall, plan to film and upload some of it at least. Thank you for all the knowledge. I think you and my electronics teacher would get along.

[@heinbldski]

Doug and Rusty :-). your lessons are just rocking. Totally focused on the spot. Not the usuall blabla. You have deep, very deep knowlegde about the stuff you are talking and you have the gift to explain complex things in an easy way and not "oberlehrer"- ly (you have to look that word up). I appreciate all your videos and keep the good work up... you guys are just AWESOME !!!

[@UncleDoug]

heinbldski Wow, thanks so much Hein. The gang here at UD's Ancient Amp Emporium really appreciate the very kind words. In fact, Rusty says that YOU rock :)

[@johnzook7533]

Hi Doug...and Rusty too, This reminds me when I owned a Sunn Sentura II and was in the process of replacing some bad caps with audio grade caps which were somewhat expensive. Anyway after talking with an Engineer at Fender/Sunn I discovered the use of a bypass cap at the cathode. I don't recall what value was used but after I installed it I noticed a marked improvement in the high end response. The amp sounded much clearer and had some sparkle to it that it did not previously have. These were all audio grade caps that I bought at some expense...they still are expensive and really don't recommend using them unless you want to end up with something like an overpriced boutique amp. Anyway, I appreciate all your videos as they fill in a lot of blanks compared to when I went to school for electronics. Cheers and Merry Christmas.

[@UncleDoug]

+John Zook Greetings, John, and thanks for your input. Rusty and I are glad you enjoy our videos and wish you a very Happy Holliday Season !!

[@td7456]

Another great informative vid! Plus, Rusty juice too! LOL! Happy 100th, now on to the next 100.......

[@UncleDoug]

Thanks, Tim. Yes, cleaning the camera lens (and my face) took a while, but now we're ready for the next 100 :) ^. .^

[@chrislangdell117]

Very cool stuff once again

[@UncleDoug]

Thanks, Chris.

[@Byron_Blue]

Thank you for a very informative video. I’ve bookmarked the calculator.

[@UncleDoug]

You're welcome, BB :)

[@gustavcida2987]

Congrats to the 100th from Austria.

[@UncleDoug]

+Gustav Cida Thanks, Gustav. We're now up to 127 videos and invite you to watch them all :)

[@gustavcida2987]

+Uncle Doug Thx Dude. I'll watch them all! Since I'm involved in a own project, modifying an Austrovox 50W from the early 70's. The Amp has 2 ECC808s in the first stages, (looks like a echolette derivate), and a step-up PS. Thx again!

[@UncleDoug]

You're welcome, Gustav. Good luck with your project.

[@ianwatkin5452]

Just subscribed thanks so much for sharing your knowledge. I will be spending a lot of time learning from you.

[@UncleDoug]

You're welcome, Ian, and welcome aboard :) I hope the videos are helpful and informative.

[@robertjacko1718]

Enjoyed the video very much!Bob

[@UncleDoug]

We're glad, Bob. Thanks for watching :)

[@ben-7403]

Thank you for the video! The info was very useful for building a Eurorack-format tube preamp module.

[@UncleDoug]

You're welcome. We're glad it was helpful :)

[@zyadnob5449]

Uncle Doug, I appreciate greatly your videos as all of them are intelligent and genuine as well as hilarious at times..when you explain, we understand. I have builds many tube amps thanks to you. we want more of your superb videos..(Y) thanks loads..

[@UncleDoug]

Thanks so much, ZN. We will comply :)

[@zyadnob5449]

@@UncleDoug Thanks for your reply Uncle :) ..Cant wait for your new videos.. by the way even your vintage cars builds are awesome.. ingenuity is what ingenious people do..:)

[@UncleDoug]

@@zyadnob5449 We appreciate the positive input, ZN.

[@mosfet500]

Thanks, great calculator link!

[@UncleDoug]

You're welcome, Mos :)

[@briguy1960]

I'm retired now and finally getting back to trying to teach myself elctronics. Your vids are the best. You sir are a great teacher

[@UncleDoug]

Thanks, Brian :)

[@flynscot]

Doug- As luck would have it, I've been trying to find info about the relationship of cathode bypass caps for days, and here you are with the perfect video! I'm a visual learner and thinker, and I have to tell you, I've been reading and studying theory of amplification for a while, but I've gained more practical knowledge from your videos than from any other source. This gives me the best overall comprehension when paired with the theory I've been trying to grasp. Thanks!!!

[@UncleDoug]

You're welcome, Flyn. The greatest reward Rusty and I ever get for posting these videos comes when viewers tell us that they were really helped by them. That's what we're here for. Please keep watching.....and posting such kind and rewarding comments :) ^. .^

[@tinkerer570]

Dear uncle Dough, thank you for all of your videos, especially educational ones. I had at home old, rotten music box: Jubilant 1101A made in 1958 by Tesla. And thanks to you, I was able to fix original final amp stage and even build my own preamp and tone stack for it. It is no masterpiece by any means, but it freakin' works and I am thirlled with joy, especially when a few months back, anything more complicated than a switch was out of my league.

[@UncleDoug]

That's great to hear, Rene. Glad you're able to put the video knowledge to good use :)

[@scottmclennan692]

im late cause i just found you recently and im binging.. congratulations on 100 !!!!!

[@scottmclennan692]

and a thousand more . i hope :)

[@UncleDoug]

Thanks, Scott. We just passed 150 videos.....so there is quite a way to go :)

[@frankpennington]

Thanks Doug, as an Electrical Engineer (guitarist) your explanations are great and sometimes amusing but keeping away from the maths helps a lot. In my student days (50 years ago) everything started with maths making the understanding of what circuits did exhausting to understand. I love your method learn to walk before you can run, thanks again.

[@UncleDoug]

You're welcome, Frank. I'm glad you enjoy the videos :)

[@trackingstationneillindsay]

Another great job!

[@UncleDoug]

Thanks, Neil.

[@grahamduncam7375]

brill videos thanks for takeing the time so good

[@UncleDoug]

Glad you like them!

[@MichaelLloyd]

This was your hundredth vid and you were happy that you had over 4,000 subscribers. It's a tad more than that now :o) Great site. I visit it daily.

[@UncleDoug]

+Michael Lloyd Thanks, Michael. Yes, what started out as a couple of vintage jukebox videos has indeed "grown up" a bit. Rusty and I are thrilled and humbled by the response to our channel. We really appreciate your kind input :) Thanks for watching.

[@FistOfRuin]

+Michael Lloyd 22.736 now

[@UncleDoug]

Thanks for noticing, FoR. I guess 25K is our next big hurdle :)

[@Nooner2549]

+Uncle Doug Congrats. 25k subs. Well done.....

[@UncleDoug]

Thanks, RC. Rusty and I were celebrating this milestone with a couple beers and T-Bone steaks. I hope we both live long enough to see 50K :)

[@benoySimon]

Greetings Doug and Rusty. Your amazing videos from even a decade ago are still so very enlightening. You are the Guru in this amazing technology especially in the art of teaching in a refined simplistic style. Wonder how the superstars Rusty and Jack are keeping these days....

[@UncleDoug]

Thanks so much, Simon. Jack is just fine, but Rusty passed away several years ago. Thanks for asking.

[@benoySimon]

@@UncleDoug Thanks for the update Dough. Sorry to hear. Glad now Jack plays an active role in your videos…🙌🌈

[@ahmedkamiss7643]

Watching this in 2023. Congratulations on this significant milstone and thank you for being so generous with your knowledge!

[@UncleDoug]

Thanks for your kind words. You're welcome, Ahmed.

[@markschmitt5550]

You can effectively voice an amp without any traditional "tone stacks" simply by selecting the right cathode and gain stage coupling capacitor values. Tone stacks lower your gain and they dampen the amps chime. Single-Coil pickups require larger coupling cap values - 0.1, 0.047, 0.022 and humbuckers sound their best with lower values - 0.01, 0.0056, 0.0047. Fender built his amps for his single-coil guitar line, therefore the 1k5 cathode resistor and the 25uf bypass cap, so that they sound full and not thin. The Marshall line sounds best with humbuckers, hence the 820 ohm with the 0.68uf arraignment, in order to manage the low end harmonics, especially when pushed. I often place a switch on the first gain stage in order to select one or the other.

[@UncleDoug]

An excellent point, Mark, and one that is frequently overlooked. Amp circuits were often tailored to certain types of guitars and pickups. An amp voiced for humbuckers may sound shrill and strident with single coils......and vice-versa. I believe this explains the shrill, brittle sound of many of Gibson's mid-60's and later amps. They were designed for clarity with (Gibson) humbuckers and really sound awful with many other guitars and pickups.

[@markschmitt5550]

You are so very right, and I'm surprised at the number of guitar players that are unaware of this. I've built and modded a number of amps with two switches, sometimes something as discrete as a push/pull switched pot, that selects or shunts the coupling cap after the 1st gain stage and a switch for selecting or shunting the cathode resistor and cap on that 1st gain stage.... so that you can stab a Gibson or a Fender into the amp with desirable results. If you want to do that one better, you can also switch select a few of the other coupling caps farther into the amp's audio chain; before and after the phase inverter or the finals. I truly appreciate your wisdom and history points, and your experiences. Your YT threads are great talking platforms. BTW - I finally finished my super-deluxe Plexi/Bassman/Trainwreck build last night... with internal switching and features that will allow the user to select coupling and cathode cap options... and I'm tackling a sudo Fender 26 / Supro 24 build; your Fender 26 Project was inspiring... I plan on adding an intermediate driver tube between the 6n7 phase inverter and finals to give it a really clean hi-fi voice. We shall see...

[@UncleDoug]

Thanks for your kind words and best of luck with your projects, Mark. The Model 26 I built is, to this day, one of my all-time favorite amps. It has no special features, but simply sounds wonderful. It's like a hearing a great singer.....you know immediately that you're in the presence of something special. I really think you will love the 26 you are building.

[@markschmitt5550]

Do you have a source for a decent low powered 15 speaker? What's your favorite? I've purchased quite a few from Parts Express, a few from Weber, and Speaker Warehouse... Your thoughts?

[@UncleDoug]

I've had the best luck with Musician's Friend and Antique Electronic Supply, Mark. You might check their inventory. Another great source of high grade vintage 15" speakers is old organ tone cabinets. Good luck.

[@jgalloway01]

Thank you Doug.. great info...

[@UncleDoug]

You're welcome, Rufus. I like your screen name :)

[@jgalloway01]

thanks, Here is a link to some amp projects my friend Rick and I have been working on. More to come. kzbin.info/door/EyiAQesucv4j8pYhdAfFOw

[@kevinholzer6244]

Awesome video! Thank you!

[@UncleDoug]

You're welcome, Kevin :)

[@60retired]

That you Uncle Doug and you to Jack, like all your video’s they are very interesting and informative. It’s amazing how much the cap values change so much in the way of tone. I just replaced all the 25uF cathode bypass resistors in my 67 Pro Reverb because the originals were all reading 36-38uF and now the amp sounds totally different. Previously I had to use the bright switch to get it to sound decent, it sounded muffled with it off. Now it sounds better without the bright switch. Highs and lows are so much defined and alive. Just figured out the bright switch isn’t heeded anymore and thats why I wasn’t happy with the results of the new caps. Everything is good now.

[@UncleDoug]

You're welcome, 60R. I'm glad the video was helpful.

[@donnyboy911]

this is REALLY helpful......thank...

[@UncleDoug]

You're welcome, Don :)

[@The_Absurdistt]

Curing cathode constipation without a laxative one cap at a time. Thank you Uncle Doug!

[@UncleDoug]

You're welcome, O. Glad you enjoyed it.

[@LowEndStrings]

Yeah! The 100th video. Time to party. Time to thank you again for your work, your just awesome! :)

[@UncleDoug]

You're welcome, Julez. Rusty and I really appreciate the time you spend watching and commenting on our videos. See you in the next 100 :)

[@LowEndStrings]

I'll be there commenting on the next 100 videos :) Give rusty a hug from me :)

[@UncleDoug]

I will....thanks again :) ^. .^

[@LowEndStrings]

Uncle Doug Hey I got a question, just to see if we share the same opinion: Would you think using a cap for letting enough of the signal (bass) through and then design the tonestack would be the best solution? Or would you cut the bass with the cathode bypass capacitor before the signal hits the tone stack? both versions of course only, if you wished to have less bass in the signal :)

[@UncleDoug]

Greetings, LES. I would let the bass get to the tone stack and then adjust the tone controls to reduce the bass. That way, it's not hard-wired, but reversible, in case someone else buys or uses the amp.

[@bustersinclair]

thank you for sharing your knowledge and wisdom kind sir.

[@UncleDoug]

You are quite welcome, BS. Thanks for watching....and for your courtesy :)

[@michaeld8975]

It's these little gems here that gets me through all the politics and current events stories THANKS for that Uncle Doug! If I ever get to put in an application at my holy grail (Marshall Amps) under education I'll put most recent - Uncle Doug/KZbin. All the best and Carry On Doug.

[@UncleDoug]

You're quite welcome, MM. It's good to hear that the videos restored your will to live in a world gone mad. Best of luck with your career at Marshall.....with your diploma (signed by Rusty himself) you'll be a shoe-in :) ^. .^

[@huberttremaine8343]

Just absorbed your latest video like a Cronut. If anyone can teach tube amp it's you. Thanks and tell Rusty to take care of those sneezes. I'm glad I have not started my next build, and am looking forward to your next tutorial. Thanks!

[@UncleDoug]

You're welcome, Hubert, and thanks for the kind words......I have to go now to clean the sneeze off the camera (and my face) :))

[@MinamiSen]

Thanks!! Great video!

[@UncleDoug]

Paul kan You're welcome, Paul......glad you liked it :)

[@rheidtech]

Rustys an awesome dog. Conrats on 100 great vids. Found a 1940s epiphone electar amp winter project.. Cant wait to work on it with help from your vids. Now just to locate a brass pole. Thanks ud.

[@UncleDoug]

Thanks so much, RH. I have never owned or worked on an Electar. You're a lucky guy !! Best of luck with your restoration, and quest for a brass pole. Be sure you don't buy one from a Russian girl named Anastasia......her poles are all badly scorched and worn out :) ^. .^

[@rheidtech]

Uncle Doug lol thx fir the advice ud.

[@djfrank59]

Congrads on your 100th! I look forward to seeing 101+ :) When you have professional techs following you, you're doing it right! :) Looks like Rusty needs to invest in a box of Kleenex :) It's snot a fun thing to get hit in the puss (LOL)

[@UncleDoug]

Thanks, Frank. It's always good to hear from you. Rusty and I really appreciate your input and comments :)

[@drfdfe]

There is a signal inversion from control grid input to plate output. The sine at the plate should be inverted! Good job, however, I do enjoy your videos. Happy 100!

[@The-Master-of-None]

Thank you so much. Amazing teaching indeed. I hope you also make a preamp gain staging. I highly appreciate you.

[@UncleDoug]

You're welcome, MT :)

[@postcrisp]

Hello Uncle Doug: Thank you for the engrossing, enlightening and illuminating videos. Learning Physics, Electonics and (a little History, too) with each view! Tell Rusty if he was not so handsome everybody would mistake him for the RCA dog and I think I saw Jack playing lead for," The Ventures". All the Best!

[@UncleDoug]

Greetings, PC, and thanks so much for the nice comments. I shared them with Rusty and Jack and they both gave you "two paws up" :)

[@postcrisp]

I realize this is a forum for Vintage (Guitar) Amps and the lessons here are stringent but, I wondered if there might be a universal source for contemporary, IC circuit diagnostic(s) and enhancements? In particular, the Class AB IC's...in particular, the TDA2030A? Does your channel speak to improving the tone of this type of ICC or issue a point-of-contact for a similar rendering?. Thanks, again.

[@UncleDoug]

Sorry, PC, but all my videos, experience, interest, and knowledge are focused entirely on tube circuitry and amplification. I leave integrated circuitry to those who specialize in it.

[@measter29]

I hope you're still working your trade uncle Doug. I'm 35 and I'm diving deep in your videos to really learn tube amps. Im an automation controls tech by trade and I love this stuff. You should be proud to know that your teachings will help the next generation learn this technology and keep it going.

[@UncleDoug]

We are indeed, M29, and it's good to hear that nice viewers, such as yourself, are benefitting from our videos.

[@measter29]

@@UncleDoug i am really going all in with my study. I understand the concepts and while I was never a small circuits with resistors etc. guy, I create and modify prints and I design and build analog relay control circuits. Your explanation is perfect and succinct. For folks with an intermediate electrical knowledge your videos are by far... The best instructional resource on the internet for this niche interest, in my opinion. Maybe ill be sending you a new question as I dive deeper. I just picked up the trickiest circuit for me yet. Its a was a steal at 150$. A b52 at112. Not well-known but a lil noisy and known to be a bit unreliable from the little I can find. But I hope to change that. It isn't that crazy of a circuit, but there are several gain stages. Thank you for your videos. I hope Jack and rusty are still around to keep you company and conduct experiments.

[@JivRey]

Amazingly useful and interesting. Thank you!!

[@UncleDoug]

Glad to hear it, JR.

[@JivRey]

@@UncleDoug these are topics that will never go out-of-date and sharing your knowledge the way you do is priceless for us who are interested in how an amp works. It made me smile at the end of the video when you mentioned you had 4000 subscribers at that time and here we are today, at 114K. Congratulations to you and thanks again for transmitting your passion while helping us understand

[@UncleDoug]

@@JivRey Thanks so much for your very nice comments, JR. We have been blessed with a whole bunch of wonderful subscribers......like you :)

[@Radio478]

Great video thanks 😊

[@UncleDoug]

You're welcome, RN.