And this is when the light came on for me - no pun intended. You can read forums for hours, observing well intended people argue back and forth. It becomes a battle in my mind between trying to grasp the information itself and then sorting thru the emotion to see if there's a consensus of some kind buried in the arguments of the "experts." Save yourself weeks, maybe months, of forum scrubbing and please just watch this video. The Air Force paid good money to send me thru electronic principles and I still have a massive 3 ring binder full of my notes, but none of that helped me as much as this video. Bravo - well done my friend! Thank YOU AGAIN! *And my Champ thanks you too. 👍

@UncleDoug

2 жыл бұрын

Wow....thanks so much, Chad. We're really glad to hear that the video was helpful :)

I appreciate his ability to explain things in a way that’s interesting and easy to understand.

@UncleDoug

3 жыл бұрын

......and I appreciate your nice comment. :)

@Noah-gq7pq

3 ай бұрын

military training is best,,you know your shit ,you forgot more than i know

Uncle Doug's videos are a masterclass collection, I love watching them and learning. And then there are quotes like these: "the last thing you want to do is die, while you're trying to bias your single ended amplifier"..

@UncleDoug

9 жыл бұрын

cmpmuller Greetings, CM, and thanks for the very kind words. Rusty and I are glad you enjoy the videos. I guess dying is indeed "the last thing" we'll ever do.....it would just be a shame to hasten the process ;)

@jmg9808

6 жыл бұрын

Uncle Doug toujours clair Net et précis! Thanks !!!!

@frank1623

6 жыл бұрын

c'est absolument la vérité

@iangray7410

5 жыл бұрын

I'm wondering if anyone has systematically assembled his videos to construct a primer on all things amplifier for the beginner ? I have begun such an endeavour, but KZread seems to revel in scattering stuff all over the map. Here's what I've got so far (unedited): UNCLE DOUG NOTES How Tube Amps work ‑ HOW THE AMP WORKS 1,2 kzread.info/dash/bejne/qmmHta2RZ5eqe8o.html kzread.info/dash/bejne/a2Rly8OJhrngiZM.html TONE STACKS 1,2, kzread.info/dash/bejne/dJWo2aaSdq2fpco.html kzread.info/dash/bejne/p458r5d7p7Oygto.html CATHODE BYPASS CAPACITORS kzread.info/dash/bejne/eqafu7eJnai7mM4.html OSCILOSCOPE BASICS 1,2 kzread.info/dash/bejne/p5mD19JmiKXLqLg.html kzread.info/dash/bejne/h6erza-Be5Wddps.html OSCILOSCOPE AC/DV TRACING, RMS OUTPUT MEASURING kzread.info/dash/bejne/gqGK05mHfNmZYdY.html TUBE REVERB 1,2,3,4 kzread.info/dash/bejne/d45617ZtnMyycdo.html kzread.info/dash/bejne/ZX95y7N7kbzAdMY.html kzread.info/dash/bejne/qYirtsWjfbzUcbw.html kzread.info/dash/bejne/op6I0suKd5DVppc.html IISOLATION TRANSFORMERS kzread.info/dash/bejne/Z4eeuM9moqmZaaQ.html TRANSFORMER IMPEDANCE RATIOS kzread.info/dash/bejne/Z56Jy9apnMbOn84.html CAPACITORS IN AUDIO CIRCUITS kzread.info/dash/bejne/nmGpmqxmqcufiqQ.html kzread.info/dash/bejne/a4mJrtpsXcuuppc.html kzread.info/dash/bejne/i4x3ysuofqabfrw.html RESISTORS kzread.info/dash/bejne/fnao0cOrk5m0nNY.html kzread.info/dash/bejne/aqap3NCCeNjOZ7A.html kzread.info/dash/bejne/g3p8xc-MhJqnipM.html kzread.info/dash/bejne/gYae1bWfkcWYZ5s.html kzread.info/dash/bejne/hqqFubppfZnOerw.html POWER TRANSFORMERS kzread.info/dash/bejne/f4ybqY9pfayod6Q.html PT BASIC DESIGN AND FUNCTION kzread.info/dash/bejne/mn6nsrOdccu6m7Q.html GUITAR AMP VACUUM TUBES kzread.info/dash/bejne/iqNo0Lijmpe0g6g.html kzread.info/dash/bejne/jJyTl5OLgJe8Zqw.html PHASE INVERTERS kzread.info/dash/bejne/h2p225VqhpzMdNI.html BUILD A CURRENT LIMITER kzread.info/dash/bejne/qYZ6tNmInq_Ziqw.html HUM AND ITS POSSIBLE SOURCE kzread.info/dash/bejne/eaaK1rppgaq0nNY.html BIASING DOUBLE-ENDED AMPLIFIER OUTPUT TUBES, PART 1: BASIC EXPLANATION & METHODS kzread.info/dash/bejne/qW12krShosK_Xag.html

@daleburrell6273

4 жыл бұрын

...thats a GOOD one all right-!!!

I find myself referring back to your videos often. You’re still the best Doug! 🥇

@UncleDoug

3 ай бұрын

Thanks so much, Tony :)

Thank you very much for your videos. You explain things so clearly that even people that don't have English as their first language can understand everything very well.

@UncleDoug

25 күн бұрын

You're welcome, Ed. Thanks for your very nice comments.

I am going through these videos slowly (about one every 2-3 days) and they're helping me get through these days, while educating me at the same time. You're a great teacher, and I appreciate you sharing your knowledge. Thanks Uncle Doug! :)

@UncleDoug

4 жыл бұрын

You're welcome, Kenji. Thanks for watching :)

Uncle Doug, I completed this procedure successfully today without incident, thanks to your excellent teaching. When I measured 450 volts after switching on my Vibro Champ, I felt a good amount of respect, but I didn't quake in my boots because I had watched your video. I did the measurements for several 6V6 tubes and found the newer ones (JJ) were running much hotter than an old GE tube (which was at 12.5 W with the original biasing). I also liked the overall sound better with the GE, so left it in there. Once I have to switch to JJs, I will have to rebias the amp because they're running at 15.5 - 16 watts of plate dissipation. I know how to do that now. The measurements were interesting. I also took the opportunity to glue the tolex back down and polish the front, using methods I learned from your videos. The amp is shiny and sounds great. I'm using a step-down transformer with this US-made amp, since I'm in Europe. I ran into some interesting polarity issues with that. If one turns the (Schuko) plug the wrong way around, the step-down transformer outputs 234 volts instead of 117. Not very nice. I believe many people aren't aware of this. I got myself a model with a polarity check so this doesn't happen anymore (it didn't hit the amp, I measured first). What is the result of running an amp made for 117 volts on 234 volts instead? I wonder.

@UncleDoug

17 сағат бұрын

Greetings, KD. A PD of 12.5W is still excessive and 16W is crazy. I tend to keep the cathode-biased 6V6's at around 11W. If 115VAC input can produce 450 plate volts, then 234V would yield close to 900 PV......which would breach all the capacitors and destroy the tubes.

@kneedeepinthedoomed

12 сағат бұрын

@@UncleDoug I guess I might change the resistor then. I suspect previous owners in Europe didn't pay any attention to the plug orientation, so I'm surprised the amp still works and nothing looks destroyed inside... I should probably measure all the caps, though.

@UncleDoug

7 сағат бұрын

@@kneedeepinthedoomed Plug orientation is a safety risk but does not threaten the circuit components, KD. Increasing the bias resistor value will result in better tone (in my opinion) and longer tube life.

Uncle Doug, thanks for putting up this very helpful video. I refer to it often.

@UncleDoug

Жыл бұрын

You're welcome, Denis.

"It's a real Downer when your heart stops!" Lol, I have to agree Uncle Doug!

@UncleDoug

4 жыл бұрын

Trust me, it's scary as heck, especially when you feel it struggling to regain its proper rhythm.

@Tonetwisters

3 жыл бұрын

@@UncleDoug I had A-Fib for six years. THAT is like an earthquake going off in your heart, and it is horrifically miserable. Got that fixed. Now I just have six blown discs in my lower back. It's been a good past 15 years ...

This is the best explanation on biasing I've ever found on YT.. and the whole Internet..

@UncleDoug

5 жыл бұрын

Thanks, Ivan. One change is that it's better to measure the plate voltage between the plate and cathode....not ground.

@ivanmilenkovic4324

5 жыл бұрын

So the actual plate voltage is voltage at pin 3 minus the voltage drop value?

@UncleDoug

5 жыл бұрын

Yes, I guess you could look at it that way.

Just wanted to thank you for your awesome videos! An electrical engineer friend of mine (guitarist, electronics tinkerer) recommended your channel as the best way to learn tube amp electronics--he was totally right. You're a fantastic educator.

@UncleDoug

9 жыл бұрын

Andy Reeves You're welcome, Andy. Rusty and I are really glad to hear that our videos have been helpful and informative. Thanks for watching :)

@diy-speaker

7 жыл бұрын

Thanks to you, i've build 2 amps for my self. One SE and one PP. You've opened a whole new world of me.

Years of confusion cleared up in 20 minutes.

@UncleDoug

6 жыл бұрын

That's good to hear, Jan :)

@fullwaverecked

5 жыл бұрын

@@UncleDoug Amen to that.

Good information Doug. Safety, safety safety.

@UncleDoug

2 жыл бұрын

Thanks. Yes sir, Amo :)

Uncle Doug, I wish you'd been one of the instructors when I through tech school!! Thanks bloke!!

@UncleDoug

4 жыл бұрын

I wish I could have been there for you, Vinny :)

@ix-Xafra

4 жыл бұрын

@@UncleDoug well you're here now and digital communication allows us to be in contact. I quit working as a technician 30 years ago. Digital technology made myself a thousands of other guys redundant. I worked maintaining telephone exchanges which were mostly relay switch operated. I also worked on big dc power supplies and have melted a few tools - lol

@UncleDoug

4 жыл бұрын

@@ix-Xafra We retired guys have to keep busy :)

Just turned on to UD! wow, Doug these are the Feynman lectures on valve amps! Thank you!

@UncleDoug

3 жыл бұрын

Glad you enjoy them, JR :)

Doug you hit it out of the park. Love your videos. Great explanation of the process

@UncleDoug

2 ай бұрын

Thanks, Paul. That's great to hear :)

Very helpful. I am writing notes as I watch to keep this all straight in my head. Have been away from tube amps for a while, so it's good to refresh. I learn more each time I visit.

Awesome info , I have a bit of learning of electronics and this is much more straightforward than other biasing issues, also more understandable, thanks.

Hi Doug: I was about to correct you on a couple of points but I read the description and see that you cover them in your notes. Excellent tutorial and WOW what a clean little Gretsch! Usually the ones I've seen have been shall I say "faithful companions". Cheers Mike.

@UncleDoug

11 ай бұрын

Thanks, Mike :)

Holy moley UD, I went to the URL you suggested and boy do I have a lot more studying to do. But at least I'm seeing a little light the further down this rabbit hole I go. Or should I say rabbit tube? It's like an alternate universe down here. The more you learn the more you need to learn... magic... And a little trippy too.

@UncleDoug

5 жыл бұрын

Indeed, if you really want to go into detail on topics like this, the depth of information is almost unlimited. You need to ask yourself.....how much do I really want and need to know ?

@fullwaverecked

5 жыл бұрын

@@UncleDoug I've said this before, and I'll say it again. Your advice is always spot on. At this point in time this is a perfect fit for me. I hobble around some, but I will soon get my ankles fused and after that I should be walking around normal. No worries :) until then I have some vintage test gear to work on and plan on repairing electronics for a living. Doing some of that already, mostly computers, but there is something about the sound of my guitar playing through that crazy Eico Signal Tracer... sounds strange good. But your right, this bunny hole is bottomless. So I've decided to focus only mostly on the Fender 5F1 & the Eico 147A schematics. So that is why I am very grateful for your first rate "tubetorials". Keep 'em comin! BTW I will be happily throwin down some well spent clams on your patreon as soon as I am able! Thanks again!

@UncleDoug

5 жыл бұрын

Thanks so much, FWR. Best wishes for a speedy recovery and good luck with all your projects.

Thanks Uncle Doug, this is the clearest explanation of cathode biasing of single ended amps that I've found so far. I really like the way that you explain things. I know have a much better understanding of biasing and it's relationship with headroom.

@UncleDoug

10 жыл бұрын

Thanks so much, David. I'm glad to hear that the video was informative and helpful.

Hi Doug, this is the first comment I have ever posted. I wanted to thank you for this video and the follow-up video. I have been playing guitar for 30yrs and during the last few years learning about amps. I had found it very hard to find a thorough demonstration of the biasing procedure even though I understood the theory around it. Its really good that someone with your experience is posting this type of experience. Warm regards John C

@UncleDoug

7 жыл бұрын

You're welcome, John. We're glad the videos were clear and helpful :)

Thanks Doug, helped save my StewMac Champ project. She was running way too hot from the get go.

@UncleDoug

5 жыл бұрын

I'm glad the video was helpful, Tom.

@blazer6248

3 жыл бұрын

Apparently my little Monoprice 15w is set cold. It's got a test point and adjustment pot inside, from what I understand. Headed to watch the double ended vids next in hopes of learning to check and adjust mine. The last post I found at TDPRI said this guy's was around -5.86v and he set it to -12v but I'm not just going to accept that as correct until I learn how this all works and whether it actually is correct for 2 EL84s Edit: so I found the schematic and it plainly says 'set to -12.5V' at the bias pot. So I guess that settles that?

excellent doug,,this is the best i have seen,,i worked in electronics production,but i forgot all this stuff,,now im ready to get in there and test my amp,,i want a warmer sound and mabey this amp is set different,,thankx again do more old school electronics,,no one knows much about this stuff in the computer age we live in.

@UncleDoug

2 ай бұрын

You're welcome, Noah. Good luck.

your videos are gold for all of us. thank you very much.

@UncleDoug

2 жыл бұрын

Glad you like them, Ivan :)

I'm so glad I found your videos, clean cut and to the point with laymans terms. Im hoping to build a BFPR soon for my next build and I loved your two recent videos on your BFPR

@UncleDoug

10 жыл бұрын

Thanks, Lego. I'm glad the videos were helpful. Good luck with your project.

Thank you for taking the time to explain all this.

@UncleDoug

2 жыл бұрын

You're welcome, MP :)

This video brings back a lot of memories of back when I was a U.S. Navy electronics technician...it has been a long, long, time since I worked on any tube type equipment(!)

@UncleDoug

4 жыл бұрын

We're glad to help you reminisce, Dale. Please watch more of our videos.

Outstanding video. Thank you so much. I just built my first champ from a kit. You're helping understand so much. I can see how addicting this can be. Bart

@UncleDoug

9 жыл бұрын

redfishbum You're welcome, Bart....glad the video was helpful. A Champ built from a kit is a great way to start what may soon become a very addictive hobby. Welcome aboard :))

Hi Uncle Doug, Thank you for the video. I am an electrician and guitar player. Loved watching ohm's law in action. Your safety measures and explanation were awesome. You have renewed my fascination with electricity. Thanks again. You have a new fan.

@UncleDoug

4 жыл бұрын

Thanks, Steph. Welcome to our channel :)

I really appreciate your videos. They are incredibly helpful in helping me to understand these concepts

@UncleDoug

9 жыл бұрын

You're quite welcome. It's great to hear that the videos are helpful :)

Great video with very simplified explanation. Been trying to understand this topic for a while, this is the best video that i have come across so far.

@UncleDoug

3 жыл бұрын

Glad it was helpful, Bijay.

Uncle Doug-I don’t have my RCA Radio Tube book yet, so these tutorials are essential to first pique one’s interest, then draw us in with some basics that don’t clutter our heads and obscuring our understanding in the process. Very skillfully presented. Getting close to pulling the trigger on the book!

@UncleDoug

5 жыл бұрын

Don't wait, John.....the manuals are readily available on Ebay and not expensive.

I have to say this was fantastic information delivered in the most professional and entertaining fashion. I'm hooked !

@UncleDoug

8 жыл бұрын

+thebuzztone Thanks so much, TB. We have posted over 135 videos so far, so there are lots for you to watch :)

Excellent presentation, I will go home and try this soon!! Thanks, Uncle Doug!!

@UncleDoug

7 жыл бұрын

You're welcome, Eric. Be careful and best of luck.

Thank you, an excellent Video! Perfect timing too, as I am ready to start soldering a scratch built 5F1 with a solid state rectifier. Thanks again.

@UncleDoug

10 жыл бұрын

You're welcome, BT. I'm glad the video was of interest. Keep us posted on your project.....it sounds like an interesting one.

Nice look and its got that Gretsch sound too!

@UncleDoug

5 жыл бұрын

Thanks, Dave. Yes it does :)

Well I have watched this a few times and I'm starting to get it. My 6V6 on the 9002 is perfect and removing the strange air gap resistor caused the thing to just start working. I am amazed, I actually fixed this thing... ;) Thank you Doug

@UncleDoug

4 жыл бұрын

Congratulations, Anthony. This should give you confidence to continue your new career in amp repair :)

What a fabulous lesson! I really like it because it offers constant safety reminders, an easy-to-follow, logical procedure, AND it explains how to voice (in part) an amp for more or less distortion. (Hope I'm not over-simplifying). Thanks Uncle Doug ! I'm feeling even more ready for my amp build with Bruce Egnater on Saturday coming.

@UncleDoug

5 жыл бұрын

Thanks, Ian. I hope your amp building session is a total success.

@iangray7410

5 жыл бұрын

@@UncleDoug I'll do my best to remember your tip about one hand only in the chassis. I can be impetuous and would hate it if my darling wife had to travel to a Detroit suburb to collect my ashes.

@UncleDoug

5 жыл бұрын

Yes, it would be a shame to have a good viewer, like you, incinerated, Ian. So for heaven's sake be careful :)

Thank you!!! You are the best Amp Teacher

@UncleDoug

4 жыл бұрын

We're glad the videos are helpful, Michele.

I really enjoy your videos! Great slow speech and thorough explanations without being too slow and never boring. I've built a similar amp using a 6L6 driven by a 12AX7. I'm using solid state rectification and resistors for voltage regulation- no chokes, just simple. The output transformer is rated at slightly higher plate impedance than what this tube is rated at using 292 volts on the plate. It dissipates about 11 watts bias and sounds great! I can't seem to find many 6L6 single ended amps.

@UncleDoug

3 жыл бұрын

Thanks, Ryan. I too have found very few SE 6L6 circuits. A PD of 11W is rather low for a 6L6 in fixed bias and real low if cathode biased.....yet it sounds good. That's the most important criteria ;)

@W1RMD

3 жыл бұрын

@@UncleDoug I only used the 6L6 because I bought several at a yard sale for 50 cents each! I'm curious how it would compare to a 6V6. I didn't have any until yesterday I bought a Challenger HF8A which uses a pair of 6V6's in P.P. Can't wait to get started on the 1950's gem!

I am not into guitar amps; the plan is to build some HiFi tube amps, but principles stay the same - please correct if am wrong. However, your videos do help me understand what is going on in those circuits, how the electronic parts work and why. At school was I never really interested in physics (… it's just stuff that happens to some other stuff and it'll still happen without me understanding it …), but now, I want to know about it, and your videos do help a lot, they're epiphanic to me. Thank you very much for your effort in spreading knowledge in such a comprehensive and kind way. Please give your four legged companions an extra treat from me!

@UncleDoug

3 ай бұрын

Thanks for the very nice note, EW. Yes, the fundamentals are all the same. We're glad the videos have been helpful. Best of luck with your projects.

Excellent! Thanks Uncle Doug! I understood everything. Well taught!

@UncleDoug

6 жыл бұрын

You're welcome, Wally :)

Uncle Doug, I'm way in over my head & know nothing about electronics but I really enjoy your teaching & explanation. I play pedal steel guitar and appreciate a good amp my amp is a solid state Peavey Session 400 but a lot of players prefer tube amps. Your teaching gives me a better understanding when I listen to guys that work or have work done on their amps and just wanted to Thank you for these vids!

@UncleDoug

2 жыл бұрын

Greetings, John, and thanks for the nice comments.

This is great my understanding expand 's every time I watch one of Uncle Doug's video 's

@UncleDoug

4 жыл бұрын

That's our goal, Dain. Thanks !!!

Wonderful demonstrations and information as always with your videos, Uncle Doug. You make all these tube amp mysteries very clear to me, after struggling with understanding this material for years! Thank you very much for these invaluable videos, as cmpmuller said, they are truly a master class collection.

@UncleDoug

6 жыл бұрын

You're welcome, Jason. Thanks so much for your very nice comments :)

Doug, all of your videos are great but this one is fantastic! I can't wait to use what you've shown here in my own builds. Oh yes, great advice: "Don't die while biasing your tubes. It's a real downer!"

@UncleDoug

2 жыл бұрын

Thanks, Jeff. Glad you enjoyed it. Be safe !! :)

Great video series for a very well done amp. I am really impressed!

@UncleDoug

4 жыл бұрын

Thanks, Bob.

Another great video! Please continue.

@UncleDoug

10 жыл бұрын

Thanks, DN. I will start production on a sequel, probably detailing the biasing process for dual output tubes. Stay tuned.......

Great intro video. The KISS [Keep It Simple, Shtupid] principle is a very good one. When is comes to math for electronics, it cannot be too simple for moi. Thanks to your well-presented tutorials, I am beginning to grasp and actually understand the mysteries and vagaries of audio electronics. Thank ya ver' much, Unca Doug Now, on to double-ended output biasing , where the fun really is.

@UncleDoug

3 жыл бұрын

Thanks, Antonio. We're glad the videos are helpful.

This is what people need to learn especially if they rebuilt the amp or if it's been used heavily... Great video

@UncleDoug

7 жыл бұрын

Thanks, Mr. B :)

This was incredibly useful and helped me a lot to comprehend many things, thank you so much for the video, cheers!

@UncleDoug

9 жыл бұрын

You're quite welcome, DM. Glad the video was helpful :)

I am new to vintage tube amps and found this lesson to be of great value. I always wondered how one would modify an amp to have more or less "head-room". I always wondered what caused an amp to distort with manipulation of the electrical components. Now I know, thanks to Uncle Doug. I really appreciate your lessons, videos and topics covered.

@UncleDoug

9 жыл бұрын

You're quite welcome, Daniel. It's great to hear that the videos are helpful :)

Great video.Anyone can understand everything.Thank you Uncle Doug.

@UncleDoug

9 жыл бұрын

You're welcome. Glad you liked it :)

I just found you the other day. Im loving learning about tube amps. I would never try this at home but its fun to know how the things work. I have a marshall DLC5 , fender blues jr and a boogie mk5 35. cheers

@UncleDoug

2 жыл бұрын

Welcome aboard, Steve.

One of the things I really appreciate about these videos, besides the learning opportunity, is the fact that you leave your mistakes to be seen. The disclaimers and corrections are added later over the top. It greatly increases my faith in your presentation and adds to the humanity of the whole process. Good stuff.

@UncleDoug

6 жыл бұрын

Thanks, Keith. Unfortunately, KZread has decided to eliminate any notes or corrections within videos. So I guess the mistakes will have to go uncorrected :(

@keithblaney9064

6 жыл бұрын

Yikes! (I know you will continue to make things right, in spite of ewetoob...)

@UncleDoug

6 жыл бұрын

We'll try, Keith. I will never understand the compulsive need to constantly modify systems that are working just fine.

Excellent. Love this stuff. Yes... I am just learning. Keep on Rock`en! From Sioux City,Iowa.

@UncleDoug

9 жыл бұрын

Thanks so much, Ronnie. It's great to hear that the video was helpful. Best regards from UD & Rusty :)

Thank you Uncle Doug for sharing your knowledge Uncle Doug without charge you've been very helpful to me your friend Dwight from AllenPark Mi. I'm 62 now but I wish I would have been a student in your class. Your worth listening to thank you for teaching the wright way. You R A presious. Joul. Thank You.

@UncleDoug

4 жыл бұрын

You're welcome, Dwight. Thanks for the very nice comments.

thank you for taking us through...

@UncleDoug

2 жыл бұрын

You're welcome, Gaurav.

Hope this is not getting redundant, but thank you so much for all these great videos. I/We really appreciate your love of teaching, and all the little gifts you give us!

@UncleDoug

7 жыл бұрын

Appreciation can never be too often received, Ken :) You're quite welcome.

Very well presented Doug. Thanks a lot, Colin UK 🇬🇧

@UncleDoug

Жыл бұрын

You're welcome, Colin :)

Uncle Doug. This is just a general comment about all the videos you have posted. I was looking for a video on how to cover a speaker cabinet with vinyl and I hit 'Pay Dirt' as I want to build a small valve combo amp from scratch, but I have struggled understanding any electrical theory from books. The joinery side I am fine with Thank you very much for the most informative and easy to understand films I have watched in a long time. They are very inspiring. I have just watched your video on identifying the wiring on transformers so I am off to find a flea market that has old electrical items for sale. Rob

@UncleDoug

9 жыл бұрын

Thanks so much, Rob. Rusty and I really appreciate your very kind and favorable appraisal of our work. We're glad that the videos have been helpful and wish you the best of luck with your projects.

Thanks for another great video!

How does one dislike Uncle Doug? Not cool. The man is a treasure.

@UncleDoug

4 жыл бұрын

Thanks, B, but judging from the fact that I always get some thumbs down.....granted they are from slobbering cretins.....would indicate that not everyone is a fan :)

The best educational videovI have ever seen. Thanks Doug. I have built 3 amp learning from you.

@UncleDoug

3 жыл бұрын

That's great news, Petar. Keep up the good work.

One of the best clear vids I have ever seen. Thanks Doug

@UncleDoug

6 жыл бұрын

You're welcome, B :)

This was great. A very helpful refresher. And a new technique for me regarding measurement of the voltage drop. Keep up the good work, sir. (Also just a fun note - I picked up some parts off our local classified ad website last week, and the guy with the ad had linked to one of your vids as an example of a possible build using the parts. Of course I immediately recognized the Uncle Doug video. So just FYI, up here in Winnipeg total strangers are watching your videos, being inspired, and chatting about amps amongst themselves. Figured you might appreciate knowing that.)

@UncleDoug

10 жыл бұрын

Wow....thanks, Dr. S. It's good to hear that Rusty and I are now the spokespersons for a Canadian classified ad website. Today, Canada.....tomorrow the world :)) It's also good to know that people are chatting about tube amps. It's a great hobby and the more people who become involved, the better. Thanks again for a really nice comment :)

Thanks for the vids Uncle Doug.

@UncleDoug

9 жыл бұрын

You're welcome, BN. I hope you are enjoying them :)

Excellent Video ! Lots of great information . Thank you Uncle Doug

@UncleDoug

3 жыл бұрын

Glad you enjoyed it, Joey.

One of your best ever Doug! U.D. reigns supreme

@UncleDoug

3 жыл бұрын

Thanks so much, Austin :)

Wow!... I love that Gretsch. This video is special to me because I damaged my Fender HotRod Deluxe trying to dissipate the Caps. I still have to fix it too! Not having an alligator clip for support, I shorted on other components causing a bit of smoke...I think the output transformer. Thanks to you though, I no longer feel all that concerned - worst case scenario, I gut the chassis and handwire a new amp. Cheers from Ontario

@UncleDoug

4 жыл бұрын

Wow......I hope a complete rebuild isn't necessary, Dave. Best of luck.

Amazing tutorial! Please make more technical videos!

@UncleDoug

10 жыл бұрын

Thanks, AR. With such a favorable response, I can guarantee that sequels will be posted. :))

Amazing videos as usual! Thanks Doug :)

@UncleDoug

10 жыл бұрын

You're welcome, David. I'm glad you enjoyed the videos.

Ouch! my 40W (prowler) made an "impact" in the past; glad to be alive/learning now!!!, thx, bird.

@UncleDoug

8 жыл бұрын

You're welcome, Steve.

doug. brilliant video. exactly what i've been looking for. thanks a miilion!

@UncleDoug

9 жыл бұрын

Thanks so much, Greg.....glad you liked it :)

I use to dislike electronics, but I needed to know more and more. Lucky for me I found your channel. Now I find it interesting and intriguing and have already carried out some successful repairs. I would like to build my own amp someday, but I am a long way from that at the moment. Thanks for sharing all your knowledge.

@UncleDoug

7 жыл бұрын

You're welcome, GW. Best of luck with your continued study of electronics.

@TheGasWoks

7 жыл бұрын

Thanks, you explain topics really clearly, it's amazing how you improve circuits and your knowledge of electrics seems endless. I have learnt some really interesting topics here on your channel about tubes, love it. Having said that it remains a little abstract thinking about what electricity is and how it travels through copper wire. Hats off to Tesla!

i concur, another awesome video! it's great to finally see one on cathode biasing, rather than the typical Fender trim-pot videos (which are a dime a dozen.) i started a new thread and reposted the video over on the TDPRI amp forum: i think it'll help out newcomers quite a bit, since SE cathode biased kits are so popular, as well as stuff like old Champs scored off Craigslist and that sort of thing. can't wait for the next one!

@UncleDoug

10 жыл бұрын

Thanks, Cat. It's always good to hear from you. I think the next installment will be cathode biasing with dual output tubes. It's much the same process, but with a couple of extra steps. I also hope your Melodier project is going well.

@catdumpling

10 жыл бұрын

Uncle Doug my computer decided it needed a new hard drive, so i had to put off getting my transformers for a couple weeks. minor setback and no big deal though. who knows, maybe i'll get lucky and Triode will have some sale prices coming up (i can always hope ;) .

@UncleDoug

10 жыл бұрын

I never recall seeing any sort of sale prices from Triode. It's too bad that Musician's Friend doesn't sell transformers.....

@catdumpling

10 жыл бұрын

yeah, probably just a bit of wishful thinking. the combined price of the ones i'm going to get is only around $75, so it's still a great price!

@UncleDoug

10 жыл бұрын

Transformers are always a major expense in any amp project, but if you get them from Triode, it's less painful than from other sources. Also, If you get them around Christmas, they'll be a nice gift (to yourself)......way better than a lousy pair of socks or underwear.

Wow 👍 I picked one of those up at the goodwill store for 7 dollars awhile back soldered the speaker wire's back on and cleaned the controls and it sounds great

@UncleDoug

2 жыл бұрын

That has the be the best deal I've heard of in several years, DC. Congratulations !!

@doctorcircuit5338

2 жыл бұрын

@@UncleDoug and it still has the price tag on it 👍 just couldn't bring myself to take it off

@UncleDoug

2 жыл бұрын

@@doctorcircuit5338 I don't blame you, DC. Why lose evidence of your major coup ??

Excellent. Been eagerly watching many of your amp tech videos and learning a lot. Thanks so much for sharing the knowledge :)

@UncleDoug

10 жыл бұрын

Thanks, Necro (Rusty is a little nervous about your nickname :) and you're welcome. I'm glad the videos have been helpful and interesting. Please stay tuned for Part 2 on the topic of tube biasing.

You are the man, Doug! Thanks..

@UncleDoug

3 жыл бұрын

Thanks, Carlos :)

Thank You! Love Your Teaching! You Are The Best!

@UncleDoug

3 жыл бұрын

Wow.....thanks, Greg.

Ótimo vídeo mestre

@UncleDoug

Жыл бұрын

Thanks, Jorge. Glad you liked it :)

cheers, again Doug thanks for another great video, as always from you. very informative, toke me back to my collage days. it good to get a refresher on basic principals every now and again. after using transistor, and now IC chip you forget the basics. will deff help me in my projects.

@UncleDoug

10 жыл бұрын

Thanks, Ron. I'm very glad to hear that the video will help you and others with their electronic projects. Good luck !!

Very well done video! I learned something new. I thought by biasing the output tubes hotter, or with more plate current would actually cause amp to break up or distort / flattop a sine-wave at a lower volume level. Thanks for your explanation. I’m next looking forward towards seeing how you bias a tube amp with two or four output tubes with 4, 2 or 1 variable bias resistor in a amp that doesn’t use a fixed cathode bias resistor for output tube(s). 🙂👍

@UncleDoug

4 жыл бұрын

Thanks, Mike. The chart in the video was a bit misleading and I corrected it with graphics that are not visible on all viewing devices. Hot bias does induce earlier breakup, and cool bias increases headroom. I apologize for the confusion. This was one of my earlier videos. My knowledge and techniques have improved with time and my more recent videos are far more astute. I have posted a video showing double-ended biasing, variable resistor fixed biasing, installing of a variable bias pot, etc. I hope you enjoy them.

Very helpful. Thanks !

@UncleDoug

10 жыл бұрын

You're welcome, Kal. It's always good to hear from you.

Great video, a masterclass indeed. Thanks

@UncleDoug

4 жыл бұрын

You're welcome, Andrew :)

Uncle Doug once again great video thank you so much I hope you know how much you are appreciated for what you're doing for us noobs out here you are the coolest of the coolest

@UncleDoug

6 жыл бұрын

You're welcome, MM. Thanks for your very nice comments.

Hi Doug! I like the way you explained cathode bias! I need to show this video to some of my customers...I have a tendency to forget that almost everyone I explain bias to is NOT a technician...I always forget and think I'm talking to another tech (LOL)...If the amp you used in the video wasn't a collector's piece, I would say you could install a potentiometer to vary the cathode bias, which would make it a lot easier to tweak when replacing the output tube...I've done that to many newer single-ended amps with fixed bias...I've also used extra resistors to limit the pot's range in some cases...Keep up the good work and pet Rusty for me :)

@UncleDoug

10 жыл бұрын

Thanks, Frank. Rusty sends his regards. I agree with the benefits of installing a cathode bias potentiometer, in fact I posted a video about the "adjustable bias" concept a while back. In this case, as you said, I didn't want to alter what was otherwise a pristine original amp.

Great content Sir! And thanks for the safety tips. Be safe.

@UncleDoug

3 жыл бұрын

Thanks, you too!

Another vy good tutorial. Here's my vote for a dual pentode (PP) bias video..tnx!

@UncleDoug

8 жыл бұрын

Thanks, Chuck. The video you requested was posted a couple years ago. Please check my video list for Biasing Double-Ended Amplifiers.

yes this was a really informative vid for me. i have a hand made Purdy "tramp" and changed the power.tube in it. the manual says i dont need to get biased but does run hot aftef a few hrs playing. breaks up around 6 on the volume. i might just take it in to a pro and see where the voltage is really at. thanks Doug :)

@UncleDoug

7 жыл бұрын

You're welcome, Scott. If your amp's output tube is cathode biased (check the literature or ask the builder), then it probably does not require re-biasing......but, if it's fixed bias (the cathode is grounded, which is quite unusual in single-ended amps), then a new tube must be re-biased.

I have a 1965 6150, I love it great video, keep it up.

@UncleDoug

6 жыл бұрын

Thanks, Raymond :)

Thanks, another great video.

@UncleDoug

7 жыл бұрын

You're welcome, Michael :)

Excellent.... I'm close to getting it.

@UncleDoug

9 жыл бұрын

Carl Rudd Thanks so much. Keep at it, Carl, and it will all become clear and comprehensible :)

Thanx for another great and instructive video/lesson... And, for me anyway the typos wind up forcing my brain to work a wee bit more, and odd though it may seem, the overall learning experience was enhanced... thanx again and cheers

@UncleDoug

6 жыл бұрын

You're welcome, Jonny

Thank you Uncle Doug A million times over! I've been ignoring this subject matter for 30 years for 2 reasons; at 13 years old I had better things to do, like learn my instrument (guitar). Now that I've kinda done that, I'm obsessed with finding that tone that gets to me down real deep and you are helping me understand how and why I'm on my quest and believe that I'm closing in on it.THANKS HOMEBOY! Now I'm one step closer to having a meaningful conversation with the other UNCLE, the one and only legendary "UNCLE ALBERT" here in my home town of INDIANAPOLIS. Some of you out there may have heard of him (heh heh heh) Thanks again Sir!

@UncleDoug

7 жыл бұрын

You're welcome, WT. Give UA our regards :)

@wtangodelta1715

7 жыл бұрын

Will Do UD! Might you inform us (if you can)a tad bit about U. A.'s recently patented 'Del Ray' tube amp? He told me he made 25 of them, all 10W amps, 8 or 10"(not sure which) with 'plenty of headroom" for my cleans. I could not get the $ quite fast enough, but I MUST have one. I WILL have one! HEHEHEHEHE!

@UncleDoug

7 жыл бұрын

Since they are so hard to get, WT, it sounds like you have a better shot at getting one than we do.....so if you do get one, please let us know what you think of it.

@wtangodelta1715

7 жыл бұрын

Will do UD- I will call UA first thing after he opens and ask (cross your fingers!) if he will let one go to me IF HE Has one. Very least Ill get more specs. Might get the link to the schematic. Peace on Earth okay? Later!

great video, i learned a bunch!

@UncleDoug

8 жыл бұрын

+Reginald Morton Thanks, Reginald. Glad it was helpful :)

Very educational video on biasing an amp. Thanks, I now feel comfortable in checking/adjusting tube bias on my BF and SF VibroChamp's, A good way to think of the bias resistor, for me, is to think of a dimmer switch for a light bulb. Increase resistance dimmer bulb= lower output, decrease resistance brighter bulb= higher output.

@UncleDoug

5 жыл бұрын

You're welcome, OAG. You're right, the Plate Current is indirectly related to the bias resistance.

@DChrls

5 жыл бұрын

@@UncleDoug I have a question for ya. My Blackface VC is alot darker sounding than my early 70's Silverface VC. The Silverface does have a Pyle Driver speaker, model MH810, in it. Other than that and new Tung Sol tubes both have all original components. Is that normal between the BF and SF VC?

@DChrls

5 жыл бұрын

Well I finally gave the Blackface VibroChamp a good going over to find out why it is so dark sounding. The problem is the speaker cone is shot, kaput, finished. Guess it's time to order a Weber 8A125

"I've got one hand ion my pocket..." and the other one in an amp circuit! Ok, I'll see myself out now, lol. Thanks UD!!

@UncleDoug

11 ай бұрын

Make sure it's YOUR pocket, Jack.

Hello Doug, I have a Vibrolux reverb custom amp which I converted to an eyelet board and have wired it like the AA964 schematic. Two weeks ago I wanted to check the bias to the tubes and found it cold, so I lowered my resistor value at the bias pot so I could get a higher current value and when I powered the amp I blew a fuse. Well when inspecting the circuit and chassis I found a piece of heat shield by the heater and pilot light section. This came off from above, I guess I caught a piece when pulling the chassis in and out. I then troubleshoot and found the power tranny was shorted. I then installed a vibrolux tranny that was a Weber brand and had to remove the end bell where the wires come out of in order for the tranny to fit. The amp powered on and my plate voltage was now 384 as opposed to the 430 volts I had on previous transformer. I like the lower plate voltage. I am running about 42 ma and using the power dissipation formula comes out to 16 watts for 6L6GC tubes. With the plate voltage running at 384 can I use the 5881 tubes? Thank you for you time and videos

@UncleDoug

2 жыл бұрын

Both the plate current and plate voltage are rather conservative for 6L6's, so I would say, yes, 5881's would be safe in this circuit. Simply recheck the bias with the 5881's installed and verify that the PD is within acceptable limits. Good luck.