The way you brought the amp into its full potential by changing the value of a few components is the icing on the cake to a fantastic educational series. Thank you!!!
Great series Tony, learned a lot. Now that it's done I'm going to have to binge watch it a couple more times to get some of it to stick into my sieve of a brain.
This was a great series Tony. Very educational and informative. I admire your ability to explain in terms that make complex theory much easier to understand. Thank you.
Thanks for this btf. Amp-series Tony. It has been interesting to listen and watch.. specially with schematics, measurements & tuning/valueReplacements etc. Have nice week over there. br, from norway.
It's been a few months, but I just wanted to say how much I enjoyed this series. Your pedagogical approach of getting an ambiguous JABOP kit was great! The fact that viewers were unlikely to get exactly the same bag, even from the same supplier with the same SKU, was the perfect amount of requiring thought to follow along and adapt with personal work. This deserves many, many views and I hope these comments are helping you out.
Beautiful work as always, and thank you so much for another wonderful series to watch! I picked up a few little tips here and there, which I will use in my future vacuum tube amplifier builds and restorations :) I love the way you demonstrated how to get better performance by tweaking the feedback network, that is something I will have to try on my homebrew audio amplifiers, but first I need to get my hands on a distorion analyzer hehe :) I really loved this video series, and I love your other videos as well, looking forward to your next projects both solid state and tube!
Nice and learning video series. Very good you adjusted the pre section and negative feedback. I have a Push-pull amp made with 12AX7 to 6sn7 fase inverters to 6550 ofcourse two completely mono amps with there own psu and don't use negative feedback at all. When I open up the volume I measured the B+ at the output transformers and I loss 1v of the 390v DC like you said the psu is very important to be stable. To come back to your Kitt build. You did the right thing to avoid the pcb board. I love this kind of build. Thank you for your effort to give the viewers a taste of tube amplification. Love your channel🎷🎺
I REALLY appreciate this video series. I have ALWAYS wanted to build an amp and I love tube amps, so this kit seems like a great place to start. My amp is slightly different (no PCB board) but similar enough that this video gives me hope. I will try it and see what happens, but I didn't think I could do it at all with a one sheet schematic. Now at least I have enough confidence to try! That's awesome. Until someone opens a Tube Amp School that I can attend, this is my best shot at getting started.
Tony great job on this project! I enjoyed every one of the videos. Thanks for doing this and I would very much like to see you do a solid state amp that is equivalent to this project.
I put kits together to learn, not to save money on gear. I think this prevents me from getting impatient when putting them together -- in the case of this kit I would do what I knew I could do, and set about researching the parts I don't know --- and perhaps practice those new skills on a DIFFERENT kit or two ...
Thank you very much for this series. I enjoyed it very much. After each part I was looking forward to the next one. That's called "Vorfreude" in German.
Great series Tony 👏 👍another thing to add to my would like to do list. Need to get my new workshop done first though so I can get to my test gear and bench.
I actually bought this kit as a experienced amp builder, it is a really good bang for your buck and I figured I would build it and have some fun with is aswell. I also could use a small stereo amp, and this is more or less exactly what I need for my PC Speakers. I wanted to build it point-to-point as well, but for some reason, the prices have skyrocketed like crazy on parts such as terminal strips, etc. And It is not worth buying them from ebay for me since shipping to here is very expensive, so I think I will give the PC Board a shot, even though I am not 100% a fan of PC Boards. I will try to do some modifications to make it easy to take measurements etc though! I don't like how the designer of the board didn't make a solder pad for the pin in the middle of the tube sockets. That pin is for structural rigidity when pulling tubes in and out. It helps prevent stress on the solder joints for the pins themselves. Other than that, I think the board is laid out decently enough. My filter capacitors that came with the kit are unfortunately unuseable, they came dented... Looks like someone has pulled them out with pliers. Surprisingly enough, they test fine, both capacity wise, and leakage wise. but I don't know the reliability of dented capacitors, they could short out at any moment. The rest of the capacitors look to be brand new though, so I will use a vintage (but very good condition both physically and electrically) RIFA, made here in sweden, capacitor can for the main filter instead. When I first unpacked and looked at the kit, I was very confused where they intended you to mount the filter capacitors and rectifier, since there is no space for it on the main PC-B. They did not punch any holes or include any holders! That would make it difficult for people without the equipment to punch holes etc, ultimately making it harder for a true beginner to build this kit. For me it is not a big deal since I have been building my own tube amps for years, but I can only imagine the frustration a beginner might encounter with this kit :) I also pondered the idea of adding a vacuum tube rectifier instead of the solid state one, because I prefer everything to be vacuum tube based in my vacuum tube amplifiers, but there would be nowhere to mount a seperate filament transformer, not enough space anywhere! Maybe a small switched mode power supply could be installed... If I chose a 5Y3, I would need 5V @2 Amps, which most modern cell phone chargers can provide. I could take the circuit out of the housing, and mount it up inside the chassi somewhere, and have a 5V supply that way. :) Lovely video series, Tony! Even I, as a experienced builder/repairer, learned some things here and there! Things I had never thought about before :) I will wish you peace, hapiness and good health in your life back to you! :)
Tony ! Is the Bill Evans Trio YT safe ?!?! 😂 Thanks for your work ! I've learned more from you and this series than any other videos I've watched ! KUDOS 👍
I have built this exact kit a couple of years ago, and just like many of your patreons/viewers, the first thing out of the speakers was a horrible noise, which is referred to, as I learned as "motorboating" - the output trani wires are reversed, but I don't think you did anything wrong - I believe it is wrongly depicted on the schematic and on the MB. reversed it, and I am still enjoying this little thing till this very day.
I watched all eleven episodes in two days; getting a case of information overload. I especially like the fact that commercials didn’t interrupt very much, if at all. I was given a large guitar amp that blew fuses and now blows smoke. Trying to figure out how the circuit is organized, but the tone controls, reverb tank, hybrid construction (ICs and tubes) make it a bit difficult for a newbie. I may have been mislead by one ‘expert’ who counseled, “It’s OK to turn it on without the speakers attached, if the volume is turned down.” I had inadvertently left the reverb circuit on. No real schematics either. Oh well.
Great lecture and demo on how to "tweak" negative feedback resistor values to expand linearity. I did something similar with my SONY pre-amp re-design, but I cheated..I used a software circuit simulator first. I ended up sacrificing 2db of gain (from 20 to 18db) in order to get a flatter response and less THD. Who needs 20db of gain in a line-amp anyway ?
really a great video series 👍👌 thanks i have build same kit using the PCB but after a 1 hour of use at 1/4 volume the metal case is very hot (where the PCB is and the case mounted resistors is and power transformer) about 70 degrees celsius... is that normal i have checked my assembly many time all seems right 230v on main secondary 230v i have 315v dc out ( after the 2 big caps) and on schematic to 6p1 pin 1 says 278v there i have 310v so think i run over its "safe" limit ??
How does that triode take the big grid voltage at startup? ( For example in many guitar amps (Marshalls, Fender Bassman etc.) which feature direct coupled cathode follower, DCCF tube can fail at startup when the grid to cathode voltage of the CF goes to full B+ at startup if you do not preheat tubes using stand by at first.)
Technically this is know as a split load phase splitter. The load resistor is divided in half with half in the plate and half in the cathode. The plate is 180 degrees out of phase with the grid and the cathode is in phase with the grid.
This series, on the build is very informative , I am building a parallel push pull amp with 4 output tube EL34’s and 2 12AU7, the problem I am facing is in the biasing of my tubes as it is fixed bias and the circuit is such that 2 tubes are on one bias pot the anode voltage is 441v and it is a 50watt amp can you tell me If there is a different logic to the parallel push pull config where bias is concerned.. Thanks in advance cheers
I have a question about tubes. I've watched your channel and Carlsons lab channel. I haven't seen these particular output tubes mentioned anywhere. I have an older McIntosh 30 watt receiver built in 1965 and it has 4 output tubes with the following number "7591" Are there any tubes comparable to these?
I thought it would be good to know what brand needle nose pliers you use to secure the wires onto the terminal strips. They appear to be very effective . Are they serrated? What size are they? Do they have side cutters? I hate to see the wiring get nicked up. Thank you for your response!
Hi thanks great series.The only thing I don't like is you saying that "you are not professional" you are and more you are doing the series that more of us can become better in the hobby we all love.I have a question is it possible to get flat to 10Hz in a tube amp and how thanks
I have one more question, is it safe to connect a computer or iPod sound output to a tube amplifier sound input? I wondered because computers use low voltage and tubes use high voltage. Does music from a computer or iPod sound good played through a tube amp?
The control grid is a low voltage and you have a coupling cap at the input. If you like tube sound the output from your ipod should sound great as well. Actually looking at the schematic for this, might be a good idea to have an input coupling cap on this amp as well.
Great video -- confused about driver tube(s) -- where is it ? I see 4 output tubes, and 2 phase inverters ... the schematic shows 4 tubes per channel - am I missing something here ?? (
Tony, there's something that has me puzzled. I have a 'fairly' good understanding of how tube circuits work, but what has me puzzled about this amp is why is there not a decoupling capacitor between the first two tubes in the circuit. What's keeping the first tube from red plating without it? I thought you ALWAYS had to have decoupling capacitors between 'stages'. Thanks in advance, great series! :)
because the cathode of tube 2 is at a higher dc voltage than the anode of tube 1. therefore the grid of 2 is negatve relative to the cathode of 2. This explained in the video.
First of all, why should it matter? I don't recall asking you for any money, yet you are still welcome to freely watch all of my videos. UA-cam allows creators to post their videos at no charge. The ad revenue helps them to keep it this way. As for what I get from ad revenue (very little) and from Patreon, I return everything back to the channel to help fund all of the projects that I post. Everything else in funded personally by me. If you are asking about Patreon, I suggest you watch the video I released at the time the Patreon account went up. I hope that answers your question.
The way you brought the amp into its full potential by changing the value of a few components is the icing on the cake to a fantastic educational series. Thank you!!!
Great series Tony, learned a lot. Now that it's done I'm going to have to binge watch it a couple more times to get some of it to stick into my sieve of a brain.
This was a great series Tony. Very educational and informative. I admire your ability to explain in terms that make complex theory much easier to understand. Thank you.
Thanks for this btf. Amp-series Tony. It has been interesting to listen and watch.. specially with schematics, measurements & tuning/valueReplacements etc. Have nice week over there. br, from norway.
Hi Tony,
Thank you so much for a really great series. It was super informative and inspiring!
Your channel is my favorite online hangout!
Cheers,
Mark
Great series! Enjoyed it very much, so thank YOU. Looking forward to the next! Wish you all the best.
This has been a lot of fun, and learning. Thanks for putting this tutorial together for us!
Xraytonyb your Amp kit that you are building is cool
Xraytonyb your utube videos are awesome keep making new videos
It's been a few months, but I just wanted to say how much I enjoyed this series. Your pedagogical approach of getting an ambiguous JABOP kit was great! The fact that viewers were unlikely to get exactly the same bag, even from the same supplier with the same SKU, was the perfect amount of requiring thought to follow along and adapt with personal work.
This deserves many, many views and I hope these comments are helping you out.
Nice job Tony ! I watched all videos about this project. Gratitude and regards.
Thank you Tony. Very enjoyable series.
Thanks so much for this series, Tony. Right on time for this newbie trying to process the basics of this crazy hobby.
The end of one journey is the start of another. 😌
Thanks for your professionalism on producing this educational series, Tony. Learned some good tips along the way.
Loved watching the series on this kit and your teachings. Thank you for time and sharing all this with us
Beautiful work as always, and thank you so much for another wonderful series to watch! I picked up a few little tips here and there, which I will use in my future vacuum tube amplifier builds and restorations :) I love the way you demonstrated how to get better performance by tweaking the feedback network, that is something I will have to try on my homebrew audio amplifiers, but first I need to get my hands on a distorion analyzer hehe :)
I really loved this video series, and I love your other videos as well, looking forward to your next projects both solid state and tube!
Superb series of videos. Thank you for all your great work. 👍
I really enjoyed this series Tony. I learned a lot as well. Thank you.
Loved the series! Always wanted a good tube amplifier for my records, now more than ever. Thanks!
Nice Amp! I enjoy watching your videos too!
Nice and learning video series. Very good you adjusted the pre section and negative feedback. I have a Push-pull amp made with 12AX7 to 6sn7 fase inverters to 6550 ofcourse two completely mono amps with there own psu and don't use negative feedback at all.
When I open up the volume I measured the B+ at the output transformers and I loss 1v of the 390v DC like you said the psu is very important to be stable.
To come back to your Kitt build. You did the right thing to avoid the pcb board. I love this kind of build.
Thank you for your effort to give the viewers a taste of tube amplification. Love your channel🎷🎺
I REALLY appreciate this video series. I have ALWAYS wanted to build an amp and I love tube amps, so this kit seems like a great place to start. My amp is slightly different (no PCB board) but similar enough that this video gives me hope. I will try it and see what happens, but I didn't think I could do it at all with a one sheet schematic. Now at least I have enough confidence to try! That's awesome. Until someone opens a Tube Amp School that I can attend, this is my best shot at getting started.
A high class lesson for those who want to learn how it works and how to build a tube amplifier. Thank you!
Very good job Tony!!! I liked how you got the amplifier to perform better by adjusting resistor values where it mattered.
I have enjoyed walking through this with you! It's stuff I know but don't use everyday. :)
More excellence, from TonyB! Woot! Thank you so very much.
Tony great job on this project! I enjoyed every one of the videos. Thanks for doing this and I would very much like to see you do a solid state amp that is equivalent to this project.
Nice series ! Thanks. It looks like a playlist is in the making...... good luck, move to top, move to bottom.
I also appreciate the length and teaching of your videos.
Really enjoyed the series thanks you .
I put kits together to learn, not to save money on gear. I think this prevents me from getting impatient when putting them together -- in the case of this kit I would do what I knew I could do, and set about researching the parts I don't know --- and perhaps practice those new skills on a DIFFERENT kit or two ...
Thank you Tony for replying to my question.
Thank you very much for this series. I enjoyed it very much. After each part I was looking forward to the next one. That's called "Vorfreude" in German.
I really enjoyed this series and learned a lot from it!!! Would be neat to see the same series using transistors and the differences.
Thank You again! Great job.
Great series Tony 👏 👍another thing to add to my would like to do list. Need to get my new workshop done first though so I can get to my test gear and bench.
Nice builder series, thanks Tony
I actually bought this kit as a experienced amp builder, it is a really good bang for your buck and I figured I would build it and have some fun with is aswell. I also could use a small stereo amp, and this is more or less exactly what I need for my PC Speakers. I wanted to build it point-to-point as well, but for some reason, the prices have skyrocketed like crazy on parts such as terminal strips, etc. And It is not worth buying them from ebay for me since shipping to here is very expensive, so I think I will give the PC Board a shot, even though I am not 100% a fan of PC Boards. I will try to do some modifications to make it easy to take measurements etc though! I don't like how the designer of the board didn't make a solder pad for the pin in the middle of the tube sockets. That pin is for structural rigidity when pulling tubes in and out. It helps prevent stress on the solder joints for the pins themselves. Other than that, I think the board is laid out decently enough.
My filter capacitors that came with the kit are unfortunately unuseable, they came dented... Looks like someone has pulled them out with pliers. Surprisingly enough, they test fine, both capacity wise, and leakage wise. but I don't know the reliability of dented capacitors, they could short out at any moment. The rest of the capacitors look to be brand new though, so I will use a vintage (but very good condition both physically and electrically) RIFA, made here in sweden, capacitor can for the main filter instead. When I first unpacked and looked at the kit, I was very confused where they intended you to mount the filter capacitors and rectifier, since there is no space for it on the main PC-B. They did not punch any holes or include any holders! That would make it difficult for people without the equipment to punch holes etc, ultimately making it harder for a true beginner to build this kit. For me it is not a big deal since I have been building my own tube amps for years, but I can only imagine the frustration a beginner might encounter with this kit :)
I also pondered the idea of adding a vacuum tube rectifier instead of the solid state one, because I prefer everything to be vacuum tube based in my vacuum tube amplifiers, but there would be nowhere to mount a seperate filament transformer, not enough space anywhere! Maybe a small switched mode power supply could be installed... If I chose a 5Y3, I would need 5V @2 Amps, which most modern cell phone chargers can provide. I could take the circuit out of the housing, and mount it up inside the chassi somewhere, and have a 5V supply that way. :)
Lovely video series, Tony! Even I, as a experienced builder/repairer, learned some things here and there! Things I had never thought about before :)
I will wish you peace, hapiness and good health in your life back to you! :)
Excellent series! I learned so much, your circuit explanations really help. Wish you would build a tuner and do a series like this.
This amp looks delicious all done.
Multumim si felicitari!
it all made complete sense when you whipped out the blue sabre lightstick!magic! at that moment a cow flew overhead! :)
Always a great learning experience, "thanks" .
Very well explained, thanks❤.
Tony ! Is the Bill Evans Trio YT safe ?!?! 😂 Thanks for your work ! I've learned more from you and this series than any other videos I've watched ! KUDOS 👍
Xraytonyb your Amp sound good
Awesome series!!!
Xraytonyb my hobbys are painting pictures and lisining to shortwave and ssb iam thinking about getting my ham license
Awesome love it.
you're the best!
I have built this exact kit a couple of years ago, and just like many of your patreons/viewers, the first thing out of the speakers was a horrible noise, which is referred to, as I learned as "motorboating" - the output trani wires are reversed, but I don't think you did anything wrong - I believe it is wrongly depicted on the schematic and on the MB. reversed it, and I am still enjoying this little thing till this very day.
I watched all eleven episodes in two days; getting a case of information overload. I especially like the fact that commercials didn’t interrupt very much, if at all. I was given a large guitar amp that blew fuses and now blows smoke. Trying to figure out how the circuit is organized, but the tone controls, reverb tank, hybrid construction (ICs and tubes) make it a bit difficult for a newbie. I may have been mislead by one ‘expert’ who counseled, “It’s OK to turn it on without the speakers attached, if the volume is turned down.” I had inadvertently left the reverb circuit on. No real schematics either. Oh well.
Great lecture and demo on how to "tweak" negative feedback resistor values to expand linearity. I did something similar with my SONY pre-amp re-design, but I cheated..I used a software circuit simulator first. I ended up sacrificing 2db of gain (from 20 to 18db) in order to get a flatter response and less THD. Who needs 20db of gain in a line-amp anyway ?
really a great video series 👍👌 thanks
i have build same kit using the PCB but after a 1 hour of use at 1/4 volume the metal case is very hot (where the PCB is and the case mounted resistors is and power transformer) about 70 degrees celsius... is that normal i have checked my assembly many time all seems right
230v on main secondary 230v i have 315v dc out ( after the 2 big caps) and on schematic to 6p1 pin 1 says 278v there i have 310v so think i run over its "safe" limit ??
How does that triode take the big grid voltage at startup?
( For example in many guitar amps (Marshalls, Fender Bassman etc.) which feature direct coupled cathode follower, DCCF tube can fail at startup when the grid to cathode voltage of the CF goes to full B+ at startup if you do not preheat tubes using stand by at first.)
Technically this is know as a split load phase splitter. The load resistor is divided in half with half in the plate and half in the cathode. The plate is 180 degrees out of phase with the grid and the cathode is in phase with the grid.
This series, on the build is very informative , I am building a parallel push pull amp with 4 output tube EL34’s and 2 12AU7, the problem I am facing is in the biasing of my tubes as it is fixed bias and the circuit is such that 2 tubes are on one bias pot the anode voltage is 441v and it is a 50watt amp can you tell me If there is a different logic to the parallel push pull config where bias is concerned..
Thanks in advance cheers
Cheers!
I have a question about tubes. I've watched your channel and Carlsons lab channel. I haven't seen these particular output tubes mentioned anywhere. I have an older McIntosh 30 watt receiver built in 1965 and it has 4 output tubes with the following number "7591" Are there any tubes comparable to these?
Both are great channels aren't they? Also, Trevors bench is good. Ahfixit is ok as well for specific models. Xraytonyb is my favorite.
I thought it would be good to know what brand needle nose pliers you use to secure the wires onto the terminal strips. They appear to be very effective . Are they serrated? What size are they? Do they have side cutters? I hate to see the wiring get nicked up. Thank you for your response!
The red handled ones were Knipex model 31-160 and the green handled ones were Diamond USA model NN55-1
Tony, I thought that amp sounded pretty good to me using my computer speakers.
Hi thanks great series.The only thing I don't like is you saying that "you are not professional" you are and more you are doing the series that more of us can become better in the hobby we all love.I have a question is it possible to get flat to 10Hz in a tube amp and how thanks
I have one more question, is it safe to connect a computer or iPod sound output to a tube amplifier sound input? I wondered because computers use low voltage and tubes use high voltage. Does music from a computer or iPod sound good played through a tube amp?
The control grid is a low voltage and you have a coupling cap at the input. If you like tube sound the output from your ipod should sound great as well. Actually looking at the schematic for this, might be a good idea to have an input coupling cap on this amp as well.
yea a tube amp would be cool but 50 watts rms is a min to me :LOl🥳
What? What did you say? I can't hear anything anymore! Lol 😆
@@dangoldbach6570 What shet i upgraded to 150 watts watts per channel 20hz-20khz hold my beer but i can not hear🤫🤨🤑
Great video -- confused about driver tube(s) -- where is it ? I see 4 output tubes, and 2 phase inverters ... the schematic shows 4 tubes per channel - am I missing something here ?? (
The 6f1 is a dual tube. It has a pentode as well as a triode tube in the same bulb
@@xraytonyb THX - That explains it !
Why not add a variable resistor in place of the 10k resistor in the feedback loop?
You can. You see it sometimes on guitar amps. I'm not positive, but I think Accuphase also had variable feedback on their solid state amps.
What size printer do you use to print out your schematics? Thank you for responding.
I'm using an hp inkjet printer that can handle tabloid size paper.
Tony, there's something that has me puzzled. I have a 'fairly' good understanding of how tube circuits work, but what has me puzzled about this amp is why is there not a decoupling capacitor between the first two tubes in the circuit. What's keeping the first tube from red plating without it? I thought you ALWAYS had to have decoupling capacitors between 'stages'. Thanks in advance, great series! :)
because the cathode of tube 2 is at a higher dc voltage than the anode of tube 1. therefore the grid of 2 is negatve relative to the cathode of 2. This explained in the video.
@@jonka1 OK, thanks, guess I missed that part when Tony was explaining it. I was thinking it was something on that order.
I don’t see a cap in the input, to isolate any DC …
👍
if it is only hobby, why you trying to get some money from youtube?
First of all, why should it matter? I don't recall asking you for any money, yet you are still welcome to freely watch all of my videos. UA-cam allows creators to post their videos at no charge. The ad revenue helps them to keep it this way. As for what I get from ad revenue (very little) and from Patreon, I return everything back to the channel to help fund all of the projects that I post. Everything else in funded personally by me. If you are asking about Patreon, I suggest you watch the video I released at the time the Patreon account went up. I hope that answers your question.