JAT501 amplifier tested on the Quant Asylum QA403 audio analyzer

[@bobisyouruncle1]

Great amplifier design. You may be proud of yourself for having designed an amplifier which is better than well known brands. Great stuff buddy.

[@gamiwv]

A truth Hi-End amplifier that costs A REASONABLE amount of money. EXCELLENT (and tested with a respectable instrument) John

[@krowwithakay]

Nice to see the OG circuit making a cameo :)

[@Roger_Gadd]

These distortion levels are as good as or better than my Icepower class D amp. Mental note: Add build pair of JAT501 amps to my to-do list 😊

[@Elecifun]

I really do like that QuantAsylum, it has many benefits compared to sound card with single voltage divider attenuation. Great video, cheers.

[@davidahmad6090]

Excellent John, very impressive, cheers. Very informative.

[@VIPINSAINI_20]

I'm happy to see such good results from the JAT501 and hope the JAT801 performs just as well. They're both great amps. Thanks for your Hardwork Sir John🥰🥰🥰

[@euroshopperbier1337]

excelent results john, looking good :)

[@iblesbosuok]

I'm still curious about what would happen if I added 2N5551 driven by Q3's collector together with Q9 to form a negative current mirror and change the circuit around Q6 and Q7 to form a positive current mirror. So both the current source and the current sink of the VAS stage are driven by the LTP stage.

[@sMAGTECH]

Thank you thank you very much.

[@opalescenthermit800]

Since you've designed the amp on KZbin and tested it to show it's capabilities, are you worried someone will copy your design and end up selling it on Aliexpress or similar website. Hopefully you patented the design or what ever you have to do to keep it yours. I realise you did it so people can create their own or buy the kit, but it's a little different if done by a third party on a commercial scale. Well done either way. I ended up buying a couple small wattage lm1875 amplifier boards from aliexpress based on your reviews of the chip back in the day and running them on custom made speakers. So your KZbin videos are greatly appreciate from someone who knows nothing about how these things work but just wants to enjoy their music without spending thousands of dollars.

[@lasskinn474]

what exactly would be the novel things to patent though?

[@JohnAudioTech]

The design is free and open to copy. This is a three stage amplifier w/ differential input design. There can be endless variations on the design. Hopefully anyone who copies it gives credit.

[@karllangeveld6449]

Good video, John, thanks a lot. The earth loop can really mess up the measurement, due to the return current of the load. You could use the input in differential mode. A few questions: Does the smaller miller cap increase the risk of oscillation? Maybe you already covered this in earlier videos. Also, did you have to alter anything with the +/-12V supply? I guess the bias current needs to be tweaked. Looking forward to future videos!

[@JohnAudioTech]

The miller capacitance value is a balance between performance and stability. The amp should be fine at 47p. No changes needed for low voltages.

[@andymouse]

Awesome !

[@HimanshuSharma-dm8ol]

Nice channel ❤

[@franklekwan5860]

Just curious what the results will be if you use the later builds in PCB instead of this perf-board build.

[@JohnAudioTech]

I tested it and the results were about the same.

[@xaviermontalban717]

Hi John, are you planning on selling these or the pcb's

[@snobilarkso9323]

Cool

[@woldemortxyz7996]

What sort of SNR does the JAT501 have at 1W? I plan to make one for compression drivers with 110dB sensitivity, so I need the highest SNR possible. Could it possibly be made better on this board? If so, how?

[@JohnAudioTech]

Looking at the noise on the FFT, it is below -120dB, though I'd have to do more careful measurements. Lowering the amplifiers gain to the usable minimum can reduce noise further, though you must check that you're still within stability margins. I find the noise present in recordings to be well above noise generated by most power amplifiers anyway.

[@woldemortxyz7996]

@@JohnAudioTech well the noise depends much on the speakers also. Like I said, mine are about 110dB sensitive and I sit quite close, this means the amp has to make 20dB less noise than normal amplifiers. I've found that even with amplifiers with a stated SNR of 118dB(probably at full output) , I still get a decent amount of noise with no signal. But I will try to make this jat501 amp and see if it would be good enough.

[@nice8230]

Hi john , I have made this circuit and its working good . Now I am planning to make an 800w @4ohm amplifier with 0.01% thd . I want to ask can I use the same input stage as jat501 in my 800w amplifier ,,, will it work properly ?

[@JohnAudioTech]

I'd have to analyze the circuit to be sure, but I think it would be okay.

[@nice8230]

@@JohnAudioTech can u suggest what I should change ? And can I have your mail ID to share the circuit with u and keep in touch with you ?

[@sarjanapenerbangan]

Mister ... please ... make 6j1 amplifier... palalel 2 tube...

[@antoniojoseandreomartinez9710]

👍♥️🫂

[@b0xjoint]

Any chance you will be working on the JAT-801 in the future?

[@JohnAudioTech]

I plan to.