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Dang, ol 'madman' Muntz would have loved this one!

You hid your frustration with the amp design flaws so well Tony!! 😂

The THD is so high because it is sad it doesn't have a larger volume knob.

This thing is the overengineering/underperforming poster child -- definitely not competitive with its counterparts from other Japanese makers, not to mention a huge PITA to service.

Looks painful to work on for sure.... about like rearranging furniture with the little toe.

Mental note… Never buy or work in one of those!

Your Peak component tester comes from Buxton in North Derbyshire, England, UK. They are based in an area known as The Peak District - hence the name. I live about 90 minutes drive away from them. 🙂

At first glance this amp looks like to be a real deal but 🥴

I have seen speaker relay contacts cause distortion even when not visible in the waveform. A quick thump on the relay while monitoring the distortion will expose this.

I don't get what the JFETS in the power supply were for. Surplus parts or to do with 90 degree shift?

yes over engineered like the "cube" you mentioned amps like that may sound really good brand new but as they age they suffer from all the complications that were added and difficulty of getting something that complicated into a box that will fit on a shelf in an ordinary house, making it almost impossible to work on. I fear we they are doing similar a thing now with the use of surface mounted devices space is no longer the constraint it once was so bring on the overly clever overly processed. seems like the idea of keeping it simple has been forgotten. thanks for working on the thing and talking about it as you go along working. So long as the camera is not swinging all over the place it is OK you are clearly not faking it, it is all good!

Why so high THD at high vol ,is it not strange ? . Can you explain tony its not because jfet are replaced with resistors ? Again i remind to upload service manual where any body can download , from hifi only few already registered guys can download those may not have this amp.

Excellent Series on this amp. I work on a lot of vintage audio and really enjoy your videos. ( I'm even a subscriber LOL ) But honestly , on this unit , I would have given it back to my customer as needing too much work. And your right , I would not put that much work and time and money into an amp like this. Keep up the Great Work Buddy !

Great work on this beast. I totally agree with you that this integrated amp was way overengineered. And in my years of servicing audio equipment, when something is way overengineered, serviceability is an afterthought. I feel that the overengineering was to produce a product with good specs on paper, but leaves the integrated amp to sound clinical.

Totally impressed.. super beautiful. I am about to recreate a case myself and the attention to detail is where it's at. You nailed it :- ) !!

A+++++ for effort. Thank you, Tony. For the reserve cap system... Remember how you taught us that you want to keep the voltage rating on a replacement cap to be within a reasonable range of the original, in order that the cap be formed correctly to operate correctly? I wonder if the reserve system is intended to have the caps operating within their best voltage region, in order to achieve the best ripple rejection? I only have a hobbyist knowledge base, so I could be off base. <grin> And, I probably did not explain it so well. I hope you got my meaning. Cheers.

these are the most under rated amps out their if you have a nec dual power supply amp its a keeper cant wait for part 2 of your show I have an nec ava 505 80 watts per ch bought it back in the mid 80s its fantastic sound use it for movies not music have other hi end amps but this is analog as it should be i truly love its sound

I'd get a Sony ZV-1 camera. They are inexpensive (~$700) and can record in 4K. Hard to beat for the money. DJI makes some interesting cameras that are very small.

Wow!! I gotta get someone to do that to mine (powder coat).

I am suprised they used so many J-FETs to drop the voltage. I wondered if putting in a 7815 voltage regulator for the +15V and 7915 for the -15V supply would have worked well.

I see nothing wrong with a triangle signal, in fact, one can even consider this a better option. The triangle wave will "retrace" the curve, which will eliminate a high frequency inevitable with a sawtooth wave. Retracing could even have the advantage of showing an average of two of the same trace, which is desirable.

One hour seventeen minutes twenty two seconds and not a single camera rant. Who are you and what have you done with our Tony?! 😉

Question: Are the resistors replacing the constant current source? if so, how can passives do that?

I think that's a great call Tony, with its 'Out there 70s design because the transistor was a new fangled thing and let's give the marketing guys something to get their teeth into approach to say 'That's it not worth any more time and money" is the right thing....cheers.

At 52.58 top left by ccs jfets bulging electrolytic cap.

I've got a 1948, Zenith model 7H820 (7E01 chassis) with the original Armstrong FM band, current FM band and AM. I'm guessing, after watching these two vids, it won't be an easy restoration. Any advice? Thanks.

Oh boy, what a horrible, complex design in the power supply circuits! I say like Buck Owens' title in one of his songs : "Please don't play A 11"...

Love this long stream of consciousness format Tony! Seriously. Constantly on pins and needles what might happen next!

Great description well explained ! maybe NEC had a 'shit-ton' of those JFETS lying around, I mean 22 on one board !!? lol Talk about over engineered 15v power supply.....cheers.

Holllyweird is responsible for the way your camera functions. They're responsible for the 10 minute length of recording time. Well, them + the feds...

Thanks a lot Tony for those videos. Vor many years this NEC Amplifier was on my wishlist, but also the prices on the aftermarket and his rarity blocked these wish until today. And now you blown all the positive attractivity away. 😂 The Design is freaky and as you declared it over designed. The only positive point on the amplifier, which alived, is the optical design. I like it. Kind regards from Germany Marcel

A good tell that this design wasn't so great is that nobody latched onto it and either did it themselves or made a variant of it. I wonder if they didn't start out with good intentions and in the end realized that it wasn't any better (and in fact worse), but they were already invested in this unique design. It only having a 1-year availability is another tell. Honestly, I didn't even know that NEC got into the HiFi market like that. Did the power LED/lamp end up working? I don't think your video ever show it lit (could have been the camera angle. Thank you for your pain on this.

"Rube" and "Murphy" were both Optomistic. Next stop for this brick would be next to the "Pyramid", wherever you packed it away. Otherwise good learning stimulation, thanks Tony.

How do you ascertain the the diodes match exactly? If you get the transistors in wrong are they going to smoke?

I prefer a warmer amp to like a Nad

NEC A-11E was sold from 1984-1985 and retailed for $799. (Source: Orion Audio Bluebook 1997) Consider a Denon PMA-500V integrated 80wpc amp 87-88 retailed for $370, and a Pioneer A-77X integrated 95wpc amp 85-89 production run with three transformer multi-supply retailed for $500

That is a amp from hell !!!!

Wow. What a mess. Just say no to NEC...

Bought mine 25 years ago and they just split at the foam. Well worth it

thank you tony cant wait for part 2

The SK104’s would have probably worked fine as replacements if those two 12v zeners were simply replaced with 15v zeners

Such an inefficient design. 🫤

service manual is on hifiengine

Thanks for the amazing amplifier analysis Tony! For oddball amplifier designs, I'll stick to my Luxman Lv-105.

43:00 I'm sure you know this Tony, I would use tiny buck converter to lower the voltage without wasting too much power. You may add a voltage regulator if required.

Well.. at least it's really heavy. Nice job on this one Tony.

For Our Tony resistance is futile.....

what a piece of crap!

54:00 sounds like a wish almost! 😂 I can understand and my hat is off to you for seeing this one through.

I don't want one, but looked on e-bay out of curiosity, no 11's but a few 10's there asking real money. Hope the early model had a better design and layout.