This is by far the best explanation on how tube amplifiers work and Mark explains in plain English on not only explaining how it works , but what each component does and why its there. Thank you very much, I finally fully understand how everything works together!
Mark, I was fortunate to have several outstanding instructors in my EE classes. I put your style of instruction above theirs. Thanks for sharing the knowledge, it was like a great refresher course for me.
This whole series has been phenomenal, but this presentation and the detailed and annotated BOM you posted really take it to a much higher level. The work you've put into this is incredible and much appreciated by audio hobbyists such as me. Thank You.
An excellent explanation of what everything does in a tube amp. Learned a lot especially the section on the ultra-linear / triode setup. Do remember you doing a video on how the DC voltage rides on the AC filament voltage, but for the life of me cannot remember when, but it explains/shows this extremely well. Thank you again for the wonderful video and it wasn't that long went by very well!
Wow...Mark, I am only 8 minutes into this video, I paused to download the schematics and BOM. You have gone WAY over the top on this. The comments on the spreadsheet on worksheet 2 and 3 are amazing, I can't wait to digest this walkthrough on the video. I deeply thank you for this effort, I know this took some work. I also know I am not going to be the only one building this amp. Man, I could go on and on, but...Just thank you. Thank you so much for this.
thank you, you are so good in explaining everything here , although I came back a few times and watched these again and again, and surprisingly, every time I learned something new.
I heard you mention C-R-C filter. its a C-L-C filter, otherwise known as a Pi-Filter. Anyways, I loved the detailed explanation of the amplifier, You pretty much hit it all on point.
Thank you so much for this whole series! I am semi retired and beginning to resume this hobby which I did in my 20's. In doing that I have purchased and read over 30 books on the subject this year, I've analyzed countless schematics, I learned a lot... But it also made me very aimless as to what I should build! There are so many choices. Ive decided to start here because this amp is so simple and classic, my reading has brought me to studying such things as high voltage regulators, DC filaments, etc. nice but I need to step back with a basic build like this. Again thank you so much for doing this. One question about the power supply... You strapped the two 100uf capacitors outright. But for only the cost of a low ohms 12 watt resistor you could have added an additional CRC stage and only lost 10 volts or so. Would strapping the two 100uf sections as an additional CRC given you much better ripple rejection than a single 200uf?
I thought I knew almost everything about this design, but again, it turned out that I've got something to learn. Thank you Mark for your time & efforts you put in this video series and Merry Christmas!
Thanks. I have enjoyed watching this project come to completion. This last walk through was a very nice recap, and the BOM with descriptions tied to the schematic is very informative.
Thanks Mark for all your efforts on this. I have done many a Bill of Materials myself and I know the level of effort they take. I'm looking forward to digging into this design and trying it out, got the schematics yesterday off of your Google drive as per the link. Happy Holidays and Cheers, - Eddy
Thanks so much for your video series on amp building. It's a real eye opener! One thing I can't get my head around is how the DC from the plate of the kt88 isn't affecting the DC at the plate of the input triode? I understand that the shunt resistor is feeding back ac signal but isn't it feeding back DC also?
I am a struggling beginner and I appreciate the time you have taken to walk through this circuit. I try to visualize what is happening with the electricity as it moves through the components, but I am really having a hard time visualizing "current" versus electron flow as you used those terms. Is there any way you could describe this circuit all in terms of electron flow (like you did when discussing tube amplification)? The convention of current moving in the opposite direction as electrons really messes me up. P.S. - I hope you are feeling better each day and that your heart will get back to full strength soon.
There should be an input decoupling capacitor between the pot wiper and the 3k resistor otherwise the potential divider formed by the 3k and 1meg resistors will be affected by the 100k pot.
Good night ! My friend looking at this tube amp I liked the project. what you set up works without problems? I'm wanting to build one for myself because I'm passionate about valves. I thank you for the attention. Adriano from Brasil
Good video Mark, for the output stage could you use 4 leds with the same voltage drop in parallel to set the voltage or a different diode maybe or a voltage regulator like the lm317hv? What about using a constant current source?
I notice that the voltage applied to the 33uF cap number 9 is 442 volts while the cap is rated for 400 volts. Seems like that might be pushing the limit a bit. Is there any typo here or are we just living on the edge?
Does this single ended configuration invert the output phase from the input? Maybe I missed that somewhere along the way, regardless, thank you Mark - I think this build series is awesome.
Thank you Mark, I learned a lot from this series of videos. I have heard a number of single ended amps, all of them flea watt, and loved how they sounded through horn speakers. One question: why do rectifier tubes require a separate winding for 5V when every other tube uses 6.3V?
Because the 5V winding is referenced to the B+ voltage. The 6.3V windings need to be referenced to ground (or to an 'elevation voltage' not more than 50V or so above ground).
SE and especially SE-triode opens a window to the music that can not be matched by PP operation/complementary transistor /class AB , class D and even PP in class A....... But it will let you hear the sound of EVERY component you will use.......just like a chef does his cooking with the choice of his ingredients. It will also reveal that modern speaker are build for amplifiers with very high damping....and the single ended will reveal it's real nature with larger coned speaker of higher sensitivity and small cone excursions....... One's you tasted high quality food , there is no way back...........only more power but less reality and room filling presence.....closer to what is real music. I heard a lot of bullshit about tubes............and believes ( believers with there technical arguments).............i would rather talk about semiconductor sound than of tube sound...........silicium dveices are made out of sand and the current flow through a cristalline substrate..........it will always be a grainy sound how well this may be masked by FB and other techniques.......so will it be with smaller modern loudpseakers......it all sound good untill you experience a quality SE amplifier.
Enjoyed all of your videos and learned a lot.I was online and found this 300B design.I wanted to know if this design needs bias and how to go about it or is it a fixed that do not need bias www.euskalnet.net/smoky/index.html
This is by far the best explanation on how tube amplifiers work and Mark explains in plain English on not only explaining how it works , but what each component does and why its there. Thank you very much, I finally fully understand how everything works together!
Mark, I was fortunate to have several outstanding instructors in my EE classes. I put your style of instruction above theirs. Thanks for sharing the knowledge, it was like a great refresher course for me.
This whole series has been phenomenal, but this presentation and the detailed and annotated BOM you posted really take it to a much higher level. The work you've put into this is incredible and much appreciated by audio hobbyists such as me. Thank You.
An excellent explanation of what everything does in a tube amp. Learned a lot especially the section on the ultra-linear / triode setup. Do remember you doing a video on how the DC voltage rides on the AC filament voltage, but for the life of me cannot remember when, but it explains/shows this extremely well. Thank you again for the wonderful video and it wasn't that long went by very well!
You got it right the first time about the cathode and grid. The cathode is at +2.7, the grid at 0, so the grid is -2.7 V relative to the cathode.
The only good amplifier explanation on the freaking internet! Thank you so much!!!
Wow...Mark, I am only 8 minutes into this video, I paused to download the schematics and BOM. You have gone WAY over the top on this. The comments on the spreadsheet on worksheet 2 and 3 are amazing, I can't wait to digest this walkthrough on the video. I deeply thank you for this effort, I know this took some work. I also know I am not going to be the only one building this amp. Man, I could go on and on, but...Just thank you. Thank you so much for this.
Thank you Mark. I was a bit sketchy on how tube amps work, and you cleared some of that up with your explanation.
thank you, you are so good in explaining everything here , although I came back a few times and watched these again and again, and surprisingly, every time I learned something new.
I heard you mention C-R-C filter. its a C-L-C filter, otherwise known as a Pi-Filter. Anyways, I loved the detailed explanation of the amplifier, You pretty much hit it all on point.
Easy to mis-speak when making videos. A lot going on.
Oh I know, I did it all the time back when I used to make videos.
Thanks for the wonderfully simplified explanation.
Thank you so much for this whole series! I am semi retired and beginning to resume this hobby which I did in my 20's. In doing that I have purchased and read over 30 books on the subject this year, I've analyzed countless schematics, I learned a lot... But it also made me very aimless as to what I should build! There are so many choices. Ive decided to start here because this amp is so simple and classic, my reading has brought me to studying such things as high voltage regulators, DC filaments, etc. nice but I need to step back with a basic build like this. Again thank you so much for doing this. One question about the power supply... You strapped the two 100uf capacitors outright. But for only the cost of a low ohms 12 watt resistor you could have added an additional CRC stage and only lost 10 volts or so. Would strapping the two 100uf sections as an additional CRC given you much better ripple rejection than a single 200uf?
The walk-thru is so informative. Thanks.
I thought I knew almost everything about this design, but again, it turned out that I've got something to learn. Thank you Mark for your time & efforts you put in this video series and Merry Christmas!
Thanks. I have enjoyed watching this project come to completion. This last walk through was a very nice recap, and the BOM with descriptions tied to the schematic is very informative.
Wow you've been busy! I've been building amps for years now, but I still learn so much from your videos. Merry Christmas, and thank you Mark!
Thank you for spending the time on this video Mark, it really has helped with my understanding of valve amps. Merry Christmas
Thanks Mark for all your efforts on this. I have done many a Bill of Materials myself and I know the level of effort they take. I'm looking forward to digging into this design and trying it out, got the schematics yesterday off of your Google drive as per the link.
Happy Holidays and Cheers,
- Eddy
Maybe you could do a short video on what Ultra Linear mode is? It seems to be a negative feedback system but separate from the signal grid circuit.
Thanks so much for your video series on amp building. It's a real eye opener!
One thing I can't get my head around is how the DC from the plate of the kt88 isn't affecting the DC at the plate of the input triode? I understand that the shunt resistor is feeding back ac signal but isn't it feeding back DC also?
I am a struggling beginner and I appreciate the time you have taken to walk through this circuit. I try to visualize what is happening with the electricity as it moves through the components, but I am really having a hard time visualizing "current" versus electron flow as you used those terms. Is there any way you could describe this circuit all in terms of electron flow (like you did when discussing tube amplification)? The convention of current moving in the opposite direction as electrons really messes me up.
P.S. - I hope you are feeling better each day and that your heart will get back to full strength soon.
if you use EL34..., the grid g3 pin 1 must connect the cathode pin 8 (not internally connected)
so soldering a short as possible jumper wire basically from pin 1 to 8 would be good for swapping any of the mentioned tubes then?
@@jakep8484 yes
Great tutorial Mark. Merry Christmas!
Outstanding video Mark!
If I eliminate the volume pot, do I replace it with a 100k resistor? Thank you for for this series and all the other videos you do.
There should be an input decoupling capacitor between the pot wiper and the 3k resistor otherwise the potential divider formed by the 3k and 1meg resistors will be affected by the 100k pot.
This was really great, thanks so much!!
Hallo verry nice tube amp👍 can you use a normal diodes in-sted of the led if it have 1.4v drop?
Good night ! My friend looking at this tube amp I liked the project. what you set up works without problems? I'm wanting to build one for myself because I'm passionate about valves.
I thank you for the attention. Adriano from Brasil
Good video Mark, for the output stage could you use 4 leds with the same voltage drop in parallel to set the voltage or a different diode maybe or a voltage regulator like the lm317hv? What about using a constant current source?
Perhaps add a document/plan detailing the layout of the chassis and the holes you drilled?
I did it all by hand so I don't have a measured out template sadly.
Hello. Anyone know what Vq of the KT88 is? Im trying to see how the power tube is biased and analyze the graphs with the vtadiy calculator. Thanks!
В драйвер можно еще поставить 6n5p ....очень хорошая лампа
I notice that the voltage applied to the 33uF cap number 9 is 442 volts while the cap is rated for 400 volts. Seems like that might be pushing the limit a bit. Is there any typo here or are we just living on the edge?
An estute catch. As Scotty would have said "Captain, she's gonna blow!".
Does this single ended configuration invert the output phase from the input? Maybe I missed that somewhere along the way, regardless, thank you Mark - I think this build series is awesome.
Thank you
Very nice and informative!
One question: Is the UL tap 43 % of the way from the 460V end or from the other end?
Thank you Mark, I learned a lot from this series of videos. I have heard a number of single ended amps, all of them flea watt, and loved how they sounded through horn speakers. One question: why do rectifier tubes require a separate winding for 5V when every other tube uses 6.3V?
Because the 5V winding is referenced to the B+ voltage. The 6.3V windings need to be referenced to ground (or to an 'elevation voltage' not more than 50V or so above ground).
SE and especially SE-triode opens a window to the music that can not be matched by PP operation/complementary transistor /class AB , class D and even PP in class A.......
But it will let you hear the sound of EVERY component you will use.......just like a chef does his cooking with the choice of his ingredients.
It will also reveal that modern speaker are build for amplifiers with very high damping....and the single ended will reveal it's real nature with larger coned speaker of higher sensitivity and small cone excursions.......
One's you tasted high quality food , there is no way back...........only more power but less reality and room filling presence.....closer to what is real music.
I heard a lot of bullshit about tubes............and believes ( believers with there technical arguments).............i would rather talk about semiconductor sound than of tube sound...........silicium dveices are made out of sand and the current flow through a cristalline substrate..........it will always be a grainy sound how well this may be masked by FB and other techniques.......so will it be with smaller modern loudpseakers......it all sound good untill you experience a quality SE amplifier.
Hi 474v i presume its the amp loaded
Thank you !!!
Power supply ............this is not a direct heated rectifier ( GZ34 - 5AR4 ) .....
I use 6sn7+6550..
Enjoyed all of your videos and learned a lot.I was online and found this 300B design.I wanted to know if this design needs bias and how to go about it or is it a fixed that do not need bias www.euskalnet.net/smoky/index.html