JAT501 amplifier board assembly tips and first power up

[@iblesbosuok]

I've tried several types of transistors for LTP, VAS and buffer stage of JAT501, and here's the result. For CCS - LTP - current balance stage, *2SA1049* (PNP) and *2SC2459* (NPN) perform good. For CCS - VAS stage, *2SA1371* (PNP) and *2SC3468* (NPN) perform great. I reduced compensation capacitor down to 68pF. For buffer stage, *2SA965* (PNP) and *2SC2235* (NPN) perform well. These buffer transistors not necessarily need to fit on heatsink. Thermal stability still fine. Listening test with cheap full range speakers (two 8 inches $4 and 35 cents each) on various listeners (my neighbors, regular people). They said that your JAT501 sounds quiet natural. I recommend those types just as an alternative. Your JAT501 is a real sweet angel, sir. Thank you

[@antibrevity]

Thanks very much for your transistor tests as they could prove quite helpful to builders. I appreciate the listening tests, but they only mean that the amp doesn't have horrible problems; test results are undoubtedly more useful. You can't trust anything that people claim to hear, see, or smell, especially those that call themselves 'audiophiles' ;).

[@sw6188]

@@antibrevity As an electronics and radio engineer that has been repairing domestic and pro audio for 40+ years, I have heard a lot of absolute crap from these 'audiophools'. I've had them try to tell me that they can hear a difference between certain speaker cables and way too many other BS claims that I could list but it would take me an hour to compile them all!

[@MickeyMishra]

this comment here deserves a video all in itself because it's that in-depth I understand the basics of component Theory when it comes to the different transistor types but it would be fascinating to go into particular component selection in depth. building amplifiers is more of an art form and requires a high amount of technical expertise and Engineering at the same time. so it's like an amalgam of the two disciplines. and overall, it's just a swell and good time!

[@Kevin.L_]

As a former electronic technician I'm impressed with your work and dedication.

[@kirkhamandy]

lol, the video opens with "three years in the making" and here I am at the end of 2024 binge watch a playlist in two days everyone else had to spend years to get though! Cheers to everyone, it's been a really good and interesting series of videos to watch.

[@antibrevity]

Thanks for much, John! If anyone plans to build a full amplifier based on the JAT501, I'd love to see your build on youtube, even if you just did an unedited summary. I'd like to build this amp, but the power supply and chassis will invariably cost more than the amp itself. I look forward to John's remaining JAT501 videos as the final prototype performed very well.

[@marka1986]

I'd start by see if I could find a junk stereo that you could grab the transformer, bridge and it's your call whether you want to use the filter caps or not.

[@Dazzwidd]

@@marka1986 that's a good cost saving recycling initiative, excellent suggestion

[@diymaster1121]

Looks good. Definitely going to build one when its done.

[@CoquiAudio]

I also place values on the PCB too, and you did a great layout design 😊

[@beamer.electronics]

Congratulations from Devon UK John, I know how much effort something like this takes, and you're doing it for free. View all his videos folks - it's a superb learning experience and you will be seeing a lifetime's knowledge played out. All the best, Beamer.

[@marksinthedark2011]

Thank you so much for all your videos - love them!

[@CraftAero]

I appreciate that you show us how, but you also explain why.

[@marciojpcardoso]

I'm certain it will be a great little amp that will make many enthusiasts happy.

[@firuzpulatov7750]

Congratulations! I am very glad for you for reaching up to this stage.

[@EngineeringEssentials]

Happy to see the amplifier project becomes a final product. I am from India and it is hard to find quality components here. Once you make a amplifier kit, please give an option to buy PCB or Components or as a full kit. Thank you!

[@VIPINSAINI_20]

Brother, quality components available in India, You have to just pay extra for them and have to buy from someone trust worthy.

[@antibrevity]

John states that he will not be offering a kit for sale, but someone else could do such a thing if they felt there was a demand. If ordering boards from JLC PCB, it may be possible to find reasonable components from LCSC and they'd be included in the same package. Someone might be able to create a full order list with boards and BOM from such suppliers as I see Indian youtube channels using these services quite frequently.

[@vloginml]

I have built this one with slightly altered PCB, the main power transistors and BD series are original from Digikey, except all are locally arranged generic parts in Bangalore local stores, but before assembling I did a basic verification of parameters of all transistors using a still it sounds great, better detail than my LM3886 IC amp

[@joohop]

Brilliant Work John Bless Up Fella

[@joshhyyym]

Really nice to see this coming together. I've been following this project for years :D

[@alanrutlidge4767]

Well done John. As usual you always impress and it's good to see the JAT501 power amplifier finally getting very close to a final design. Looking forward to you publishing the PCB gerbers as I'm keen to build a pair. Thanks again for all the development time and effort you have put into bringing this little beauty to a practical conclusion. :)

[@JuanHoya]

Great project, lots of thought and effort in this design. Piano music test sounds really nice.

[@handryraya2853]

Love it, love the progress up till now 👍👍👍

[@rickdodson5252]

Great work!!! I am definitely interested in this board. I hope you will be posting all the ratings and recommendations for the components. I plan to build 3 of these for a 3-way front stage setup using a DSP.

[@ArashPakzad]

Amazing! Well done! waiting to build a pair of these.

[@1959Berre]

I guess, somewhere out there, Snick is looking down, saying: "Well done, John".

[@ivovass195]

Great to see more progress on this project, well done. Definitely looking forward for the final performance results. Maybe consider including the power supply side schematic for reference for anyone looking to build a complete stereo unit like me. Thank you for all the hard work and not to forget props to the anonymous board design contributor

[@davidahmad6090]

Its all coming together, amazing stuff as usual. Chefs John.

[@landrec2]

Congrats man! Really nice work. Thanks for sharing with us!

[@jontallbacka9406]

Fantastic news :-D Well done! Looking forward to the final & getting my hands on this beast of an amplifier.

[@area46241]

I like it when will the kit be available?

[@natecontarino1748]

Snickers would be proud

[@tgirard123]

I am definitely interested in a kit.

[@34Kuro]

I am getting one of these for sure!

[@steveswan5714]

Nice work John 👍😊🏴󠁧󠁢󠁳󠁣󠁴󠁿

[@richarddolbec5379]

Hi John, great accomplishment.I will by it if it’s possible to ship it to your northern neighbour….. If you need a new challenge, a hifi riaa phono stage ampli could be cool. Great work again Thank Richard

[@gkcnalaka]

🔊🔊

[@KuntalGhosh]

my tda7498 board just blew up few minutes ago , the low side gets are all shorted , so i will build a JAT501 now!!

[@smeducare6858]

Keep it up...

[@marekwafel8651]

👍

[@bagus_nuryanto4595]

👍🏿👍🏿

[@largepimping]

You didn't once mention "supply chain," giving me hope that all the components on the board are available right now!

[@andybrown6981]

I would love to have a really nice sounding 9 volt so can make my own portable cabinet. Seymour Duncan 170 sounds great but needs AC voltage - What do you guys make of portable camping batteries and if they can run AC pedals - do they need pure sine wave?

[@RixtronixLAB]

Nice info, thanks for sharing :)

[@Spentelectrons]

Off topic but im curious about the perceived volume of a chip amp under different impedance. For example a LM1875 maxing safely at around +/-18v at 25w at 4ohms. But if you went with two of those same speakers in series you could easily push that to 30w at 8ohms. Only 15w per 4ohm speaker. But the kicker being that you are driving twice as much cone.

[@withoutl7980]

Wow very nice, I love your channel, respect man! Also, I've made a stereo amp with LM1875 for my project on college but I have troubles with understanding some concepts about analog amplifiers, for example when I see a schematic like one in your video I dont understand it completely. So in short what I would ask is, can any of you guys point me to a book or some literature where I could learn all these basics like the differential input, current mirror, voltage gain stage and all that so I could read these schematics and probably have that much understanding so I could design an amplifier myself. Thank you :)

[@williamcolvin3609]

Are you going to produce a Mono Board for use as a Guitar Amp Board?

[@ford1546]

a tip. bend your legs and screw everything to the heatsink first and then solder all the transistors it is not better to use metal stand off that does not change shape when they get hot

[@mrmax1467]

Hi JAT, I would love to buy this amp from you, if you have any more of them. Thanks

[@montynorth3009]

How does it sound compared to your favourite I/C chip amps, because that is what really matters. Hopefully as good if not better.

[@ligius3]

It should sound better as it has lower overall distortion. Unless distortion somehow 'warms' the sound and 'opens the stage'.

[@johnsonlam]

Will DIY Audio help to make it a kit?

[@yarindam]

First, Thank you John! I am starting to build this. Boards are coming, speakers came today. Collecting parts now. I have a question. Do you suggest two isolated heat sinks for each channel or can I use just one and mount the PCBs side by side?

[@JohnAudioTech]

Thanks for watching! You can use one HS if you want. Just be sure each transistor that is mounted is isolated.

[@yarindam]

@@JohnAudioTech Thank you

[@rickdodson5252]

Ok John, it has been six days and still nothing is available. How many days do you need? I can't be the only one who is impatient...lol. I am ready to drop some lettuce on this project. Take your time but hurry up!!! 😆

[@jameshoverson7686]

John I would definitely buy one of these if you sold them. Do you have any plans to sell these?

[@JohnAudioTech]

I'll provide the files for having the boards made and bill of material after testing.

[@jameshoverson7686]

@@JohnAudioTech sounds awesome. I’m not good with the soldering iron. So you’re saying I would be able to have this assembled and sent as a finished product?

[@JohnAudioTech]

@@jameshoverson7686 No, the board would be made and you would have to order the components. I don't have the time to assemble and test boards but I might have that done by someone at some point.

[@ford1546]

if you want the amplifier tested against many hifi amplifiers like kenwood nad technics sony fischer denon to find out if it has good sound then I have the opportunity to do so

[@chrisredfield5278]

Can i buy gerber from patreon ?

[@JohnAudioTech]

They will be offered free of charge.

[@chrisredfield5278]

@@JohnAudioTech Thank you sir

[@bagus_nuryanto4595]

pdf sir😂🙏

[@Mandrag0ras]

I'm wondering, how many seconds of copyrighted music do they allow you to play without giving you any trouble?

[@JohnAudioTech]

Not sure of a fixed time (perhaps 15 sec), but a copyright holder can claim and take revenue for even 3 seconds.

[@ford1546]

you should not mount the amplifier this way! the card can get very hot and it shortens the life of capacitors and solder points are weakened over time. L12 class-ab from from ebay is a good amplifier that is mounted in this way. naim nap 250 clone is no good amplifier if sound quality means a lot. it has 2 transistors measuring just over 100 watts

[@JohnAudioTech]

The heatsink should be sized so that it doesn't exceed 60C. The only significant form of heat transfer would be radiation and at 60 Deg C would be very small, so this concern is unfounded.

[@ford1546]

@@JohnAudioTech Many times when flat screen TVs break down there are many times capacitor problems that are often caused by heat. Why did you not go for 100 watts and 50v-0-50v By the way good amplifier you have built.

[@Centar1964]

I was screaming "no no no" at the layout of that board until you showed the other board...I'd like to see that one populated and run... 50 - 100 watt class AB amps seem to be an already overdone design exercise especially since ESP Audio released their perfected 60/100 watt design years ago...hard to top that. I take it your doing this just for fun.

[@mikebond6328]

He explains in the video that this will be a diy kit and fun is what it’s all about.

[@argcargv]

If you look through John's videos you can track his entire design process. If you want to understand the design of the kit you are building then this would be the kit for you.

[@Blowncaraudio]

Im not sure i like your tone! 🤣🤣🤣

[@Centar1964]

@@Blowncaraudio Ditto... ;-)

[@Centar1964]

@@mikebond6328 That is what I figured.