JAT501 amplifier "hot rodded" for more power

[@KuntalGhosh]

I have been using the jat501 for almost a year now and amazing performance.

[@nathans7171]

It’s really awesome to see you sharing your knowledge on stuff like this. Not many people take the time or care to share knowledge about this dying art. Glad I’ve stumbled upon your channel keep up the great videos!

[@JohnAudioTech]

Glad to have you along!

[@argcargv]

Nice to see you get back to some of you JAT amplifier designs!

[@kurtzxcvb3481]

Congratulations I know the feeling

[@kdntool9369]

I decided to go the other direction, running +/-24VDC in class A mode. The performance is stellar!!!

[@peterlarkin762]

Must have great dynamics. Hope your heatsinks are up to it:)

[@VIPINSAINI_20]

any updates on your setup, how much bias I need to set to get the Class-A operation with same voltage as yours +/-24V DC

[@gamiwv]

I'm glad for you. I heard the bell from the notifications and I have interrupted my experiments to improve my little Chinese stereo amplifier with one (FAKE) TPA3116D2 - in reality it is the SC8673E or something similar (16-pin DIL). You have tested in the past a board like this. As I discovered the 4 bootstrap capacitors 1μF each (under the heatshink) are really crap ! Using good quality MUSE (Nichicon) capacitors 1μF/50V at that position + the capacitors that they drive the main chip, the amplifier is DEAD SILENT ! NO "hish" at all even with the speaker staked to my ear. Oh the Chineses with the crap smd cheap capacitors they are using just to save some pennies . As for the JAT-501 mods, if you make a new board try to consider if you please to mod a little the current mirror at the input and convert it to "MILLER CURRENT MIRROR". it is just one more thransistor .

[@andymouse]

Awesome, congrats on sale of your old house and a Happy new year.....cheers.

[@waynenickoleff9041]

Hey John nice to see you back at the bench! Happy New Year and congratulations on selling the house..Take care, Wayne

[@jakubczajka4275]

More and more high performance amplifiers these days are using proper, regulated power supplies, and soon the concept of "dynamic headroom" will only be remembered among some audio guys, dealing with obsolete technologies. Which they love.

[@peterlarkin762]

Aw man your so right, but also not really! I spent ages making beefy regulated supplies for solid state power amps. It's expensive, it's not easy to do at all and honestly they don't sound good (imo). Switching supplies are however viable options and used commercially but again they aren't fun to diy. Classic linear power supplies using a toroidal, a rectifier, and some filter caps are not becoming obsolete. The vast majority of amps use them. Further, quality linear supplies are incredibly noise and ripple free. I use complex low noise regulated supplies in opamp based preamps and sometimes input stages on amps. That's where they really shine.

[@jakubczajka4275]

Only for brief moment I was considering linear regulation, and I agree: It is difficult, big and expensive. But I will try SMPS.@@peterlarkin762

[@beamer.electronics]

Great to see another video, John. It could be an issue if your C6 is reduced too much - might leap into oscillation. All the best.

[@shawnhayden6674]

Blessings to you. Bravo.

[@jp-um2fr]

UK, Sorry - off-topic. I have a Samsui AU317 that needs re capping and I wanted a cheap fill in amp to tide me over. I bought Who Flung Dung AK 370 12V 20 + 20 W (RMS ?) that states 15 Ohms. My Tannoys are 15 Ohms. I was not expecting much for around £10 ($13) but. I know a little about amps but mainly valve. I built a Mullard 20 + 20W 15 Ohms (EL34's) and 2 x 3 valve pre amps many moons ago, which I still have. Back to the Who Flung Dung. In honesty, John, I was gobsmacked. I'm 77 and the old lugholes are fading now, but according to a test record I have, I'm still OK for 10K and a bit more with knob tweaking. If you like bass, old age is the best cure. If you should ever be in the mood, this little amp might make a good video.

[@HillsWorkbench]

I still miss Twin Lake a little but it sure is nice not having to maintain it. 2023 was F'd enough without that.

[@JohnAudioTech]

That house had the perfect layout to me. It just needed a proper garage. I hope to find a place similar to it in the future.

[@generalleigh7387]

Congratulations selling buddy. Peace to you in Jesus and wishing you well, I’ve not stopped by in a while.

[@soumikdas5857]

Hey john i think you should use a lot bigger filter bank around 15k microfarad on each rail side and a pi filter to stable the dc line voltage that would drop around 1.5 volt to 2 volt from one cycle to another on 110 watt load Ofc if the transformer is capable of handling 110 watt

[@amitghosh6966]

Nice video again

[@1pcfred]

Good to hear you sold your old house. One less thing.

[@Chor_Ultra_Pro_Max]

I would suggest you to use at least 2200uF capacitors at the dual rail supply. They can produce more punchy bass with less distortion.

[@argcargv]

The large capacitors would be on the power supply. The caps on the board is for local decoupling.

[@peterlarkin762]

The power decoupling caps on amp boards do make a bit of difference BUT when I've done this on amps they always get changed back to around 470uf. It's far more important to have a good supply with clean grounds and keep the cable to the amp short. As is the quality of the capacitors. My current diy lateral MOSFET amps use only 0.1uf poly caps on the board and they're the best amps I've tried.

[@gillanland]

John, you didn't clearly explain what "hot rodding" means!

[@JohnAudioTech]

It's a generic term for modifying something for more power. It comes from people who modified cars to make them faster, calling them hot rods.

[@markbrooks6979]

Congratulations on selling the house.

[@tarmovirves]

Algoritm

[@kurtsvids5529]

Congrats on selling your house!

[@b0xjoint]

I just went to the AISLER website to order the board and it says "One ore more drills violate the minimum distance to each other and have been removed from the board" Apparently the hole spacing in C4 is too close. Can you take a look?