Amps N at Part 10 - Bringing it all together 

How very fortunate for all of us that those parts had to be sent out for powder coating

"We're not worthy! We're not worthy!" LOL Bravo Tony. Nobody knew it would end like this, and THAT is what makes this series great. 😎

Thanks for your kindness Sir XrayTonyB It was a long series, but it was interesting and educational, totally worth watching it, Your 🤗 Rant videos also very interesting, love to watch them.

Now that's how a kit amp should be built.

What absolutely fabulous series of videos! Thank you!

An excellent lesson for those interested in audio amplifiers. Thanks Tony!

Really enjoyed the series Tony, many thanks.

Wow! You really outdid yourself on this project. Appreciated your walk through on the schematic. I am alternately impressed and intimidated. Impressed by your knowledge and execution, and intimidated by how much your knowledge of how circuits work so far outstrips mine or those who taught what I know. I’ve only been introduced to the topics you cover in a community college education, supplemented by work experience in the industrial field. I’ve always been interested in electronics, even taught introductory courses on ‘Devices,’ but haven’t yet tried to build anything more complicated than an unregulated power supply. This has to change, for me. You’ve opened the door and motivated me to buy and build a kit amp or two. Maybe get around to finally fixing all the ‘American Five’ radios I’ve collected through the years -you’ve convinced me that is the only way I’ll be able to advance my education and learn what I need to know to do what I want to do. Thank you, Tony.

I'm again learnig a lot here, i love the way you take a simple amp design and explain the functions and (could be) improvements. Including theory and measurements. Good educational stuff! Tnx for sharing Tony. Looking forward to the fake/real tests!

Super-fine series, thanks so much. Lots of interesting and educational stuff to see and listen to. Have nice weekend.

Thanks Tony for taking the time & effort to do this series. I can't help thinking that the producers of this kit are looking with interest, & taking notes!

I always feel sorry for the dummy load some of them are quite intelligent 🤓 Great job Tony this has been a very entertaining series. Top Man...

Congratulations Tony for YOUR stereo power amplifier ! 26 W per channel is more than enough for home use, particularly with speakers like JBL or Klipsch. Distortion measures show that the quasi-complementary output layout is still up to date !

Very interesting, thanks Tony….Mate!!😊

Great work !....cheers.

Outstanding stuff, Tony! Thanks!

Loved that series, Tony, many thanks again.

Hi, WoW absolutely great series of videos, thank you for it, I didn't expect it to end with a complete rebuild and making another amp.. For one thing, I revived something that I had long forgotten, but I also learned something new, you make great videos and I always look forward to next. When I came across your channel I spent the whole weekend playing old videos 🤪 I didn't even sleep 😂 I'm really looking forward to finishing Spec4 Nice day 🙂 Tom

Thanks for sharing your knowledge, Tony. Excellent job once again! Cheers!

Amazing. Very well done it's quite an amp now!

Dear Tony, Thank you for these video's. Very entertaining and informative, keep up the good work !!

If I was an instructor of EET class I would have requested to use this series of your10 videos for pre qualifying students on amp technology. This was wonderful! Thanks so much!!

Usable with high sensitivity speakers. I can't hear nothing over 15.khz, so it will suit me if I didn't already have a good amp!

Nice circuit analysis, the final design is as good as a Class-A 20W amplifier.

You post amazing videos. THANKS ALOT for what you are doing.

Thank you very much X-ray Tony B. What do you know vs what you don't know? I've been watching this series from the first episode. I know enough about electronics to be dangerous. With the exception of a couple of concepts, here was nothing in this series I didn't already have a basic understanding of. Putting it all together, I want more. I've got a list of thigs to research, I will watch the series again and study more. I have a Pioneer SX-737 on my work bench. I bought it new from the US Navy Exchange at NB Subic in 1974. I really want to bring this back to life. I'm going to be going through this series again. This is the best!

Thanks Tony! What an awesome series. You have helped me to understand amps much better. The baxandal circuit is a mod that I have done, but never understood the reason for it. When you get caught up on the other projects, could you do a similar series with preamps & tone controls and how they work?

46:30 - "Baxandall" I first encountered that name when reading about the tone controls in a Dynaco PAT-4 amp. It refers to tone-controls, when set at midpoint, provide flat response.

I feel kinda sad that this series is coming to an end! I have always wanted you to go over this circuit ever since you first put one together 6 years ago... This is far beyond anything I would have asked for! This series is amazing! You took something that someone might have seen on eBay or even purchased it and turned it into a lesson that I felt like each video was a cliff hanger, I just couldn't wait until the next episode! I have had Kicad sitting on my computer while apart from having a play with it, I haven't actually used it for anything constructive! I'm thinking about having a go at putting this amplifier circuit complete with the new modifications and having a whole new PCB board made, I already have a few of these kits so I have the components, I have a ton of TO3 3055's and the same heatsinks used in the final version... Possibly try and incorporate the soft start and the DC protection circuit on board..... Would be a great amplifier and look amazing at the same time! Hopefully you can find another amplifier or preamplifier or tone controls that you can go over like this series.... I know that I have seen things on eBay and Ali Express and wondered if they were any good or could they be fixed? As a viewer, a video is so much more interesting when it's about something that you have come across before.... No one else has done this to this extent.... That's why you are getting the comments from all of us that you are.... Thank you Tony so much for this.... Thank you!

Tony, your Bootyfab chassis gave me an idea - a fully point-to-point-wired solid state amp (lotsa terminal strips!)

Impressive bass from the mic

Thank you.

You could crank down that gain by lowering the value of the (33k) feedback resistors.

ROFL OMG i want that amp just to run my PC speakers would look so cool on my shelf :D

Tony Is a natural instructor Book List, How about give us a list of your favorite electronics books

As a very old USN Fire Control Technician (Radar) working on rebuilding an old stereo system this was a fantastic series. Forgot most of what I learned back in the day. You did a great job of explaining what you were doing. Hopefully the Sansui 7000Z Amp and M9 tape deck will end up sounding good as new. Got rid of my o-scope years ago. Can I get by with a newer less expensive digital handheld unit that I see on Amazon? If not, I can do all the labor intensive component replacement and take it in for fine tuning. I have a nice sounding Sansui 6060 but picked up the 7900Z as a non working unit pretty cheep to rebuild. Also 2 of the same tape decks. One working, one for repair. Too much time I my hands??? Thanks again for all you do.

And I always thought the VAS stage came after my 2nd child…

Okay, so most of your viewers are likely listening to their computer speakers. I normally listen on my 5.2 home theater system with Infinity speakers all around. Sounds good all the way down to 20Hz to above my frequency range, separation is the only issue with your microphone.

Thank you Tony for this entire series, and I have learned a great deal from it. How about a series on the topic of Dynaco solid-state gear using upgrades from Dan at Updatemydynaco, where you dive in, compare and dissect the new circuits/upgrades and compare to the original? Maybe an SCA-80?

You could put a pot in your bootstrap to make it adjustable in order to even out the clipping to be equal on the top and bottom of the output. I'd also like to see a 10khz square wave just for S&Gs! You could also put some small ceramic caps across all the bridge rectifier diodes to suppress any switching noise there to make your supply even quiter. Thanks for the series. It was great! Ok, one more question... Why not put a cap like C8 on Q10 on Q8 as well?

Hi Tony! I know you have moved forward from this project but after viewing the video again I realised that this circuit is very similar to my project and I need help with something. I am working on an AKAI amplifier that had an STK463 in it but it got replaced with a module built with discrete components with TIP35C outputs and it is working ok. I made the DC Offset circuit that you made for this amp and it works great for it. But I want to make changes to the power supply once more, because the components on the module can handle it and I happened to find some toroidal transformers that fit perfectly in the case and also I have another module that I want to put in the amp for a dedicated subwoofer channel. The issue I am facing is that the original transformers are +-35V DC and the new ones are +-50V. The subwoofer amp can handle up to 90V so there is no problem there but the AKAI amp module biasing was made for 35V and maybe close to 40V but definitley not up to 50V. After viewing this video again I understood how the biasing is set in the module. If you google a datasheet for STK463 you will see the internal diagram of the chip, which is the exact circuit the module has. In the diagram they use two cascading transistors with collectors tied together (TR6 and TR8) for two base-emiter voltage drops and i'm guessing the ratio between R5 and R6 for the biasing. On my module the guy who built it chose 1K for R5 and 3.9K for R6 and with those values the amp works with +-35V. My question is, how should I go about adapting this to +-50V power supply and maybe add a bias adjustment? Can I increse R5 to 2K and put a 10K pot instead of R6? or it will be more involved? The circuit also has a boot strap 47uF capacitor, just as you showed in your project. It is pin 4 of the chip and the resitors are 3.3K and 1K, just like in the example that they give in the datasheet. I know this is alot to ask and I don't really expect you to spend the time and effort to search for all of this but I would really appreciate if you could give an answer. Thank you for all these videos and all the knowledge that you freely impart with us! I have learned so much from you! God bless!

that has been an amazing series. thanks much. 👍 one question, in some circuits, we have seen R14 is replaced by a transistor constant current source. in such cases, any bootstrap capacitor can be utilized, or is useful ?

Question: I see a 1Mohm in the complimentary CCS. What's the purpose of this resistor? I've done the CCS on a breadboard for now and the CCS is more constant and excellent fixed current without the 1Mohm resistor. The current drift depending on voltage with the resistor included is not mush, but still:)

I don't believe you need the pads under the output transistors. What's wrong with the collector voltage showing up on each heat-sink?

Great series, Tony! Very well done! Can you do the same with an Aliexpress tube amp?

I got nervous as it was almost beyond 10days since Pt9 and when did you release Pt10(??😂), but you really went all-in for this small amp! Excellent video with good mods there..😊 I've enjoyed it

Thanks Tony. This entire series has been very helpful and enlightening. I do believe that, now, I will be able to make some sense out of the books I've purchased on the subject. Question: Do you have a Github page to share your pcb gerbers?

I think R14 needs to be connected before R26

Can any one tell me what speaker protect module that is and where to buy one?

Excellent series. What you you recommend for a good design to work off of if someone like me wants to make an amp? And I don't have a mountain of $$. Plenty of free time to work with. I'm not looking for super powerful, but I would like to understand how to further chain on stages correctly to up the output. Enjoying all of your videos I have watched. Thanks.

Hi Tony Your videos are very scientific They are really enjoyable I have a question for you How much distortion can be detected by the human ear?

32:35 -can I implement this dc offset circuit in any voltage range. As l can see here is +- 25v has used I have an amplifier which is +-35 v rails and getting dc offset though the Ltp pair transistor are matched . So can I use it?

I Agree with Mr. Cordell . The knowledge is good the design was made because of lack of good matching of NPN/PNP pairs. It was later utilized because the bean counters loved it . And A worse design is the Single supply Quasi Amps (CCO) .

Im not worried about you being shocked as you are not real, just some pixels on a screen.

Just CRAK OPEN one of the 2N3055's and you will what I already know after buying MANY from different sellers - ALL FAKE!!!!!!!!!!!!!

Haha! I've been eyeing up Tony's Keithley THD multimeter for ages now and just googled the price, that Puppy is £6,600 new, so my down to earth image of XrayTonyB and his bench equipmenthas just evaporated

These videos are absolutely awesome !! Can someone tell me where I can find the Transformer 40 VAC 20-0-20 secondary with 5 Amps ??

Any chance someone can tell me where to get the small blue "Constant current PCB board" that was used in this Amp?