NSC's Full-range LM4651/52 PCB to the people

Hi All

I played around with the LM4651/52 chip-set own my own PCB some time ago. I did make it work in the end, put it was by no means easy and the PCB was almost "dead" by all the modification.

I would now like to play around with that chip-set again since I think it has a great potential.
To start on a fresh I would like to use the NSC full-range board (at least for now).

NSC have made the Gerber-file for this board public ( see http://www.national.com/appinfo/audio/0,1819,968,00.html) and I have found a place where they can make it in a good quality.

However as you most likley already know, having one or two high quality boards made for you is rather expensive.

I would therefor ask if there are any other audio DIY-people in the world that are interestet in this PCB. ??

I would estimate that it could be made and shipped anywhere in the world for around US$15 (max. US$20), if we are enough.

I don't want to turn this into a official group-buy. Just drop me a line if you would like the board for the indicated price.
I trust you, so if we do it, I will put up the money and ask you for the money before I ship the board to you.

It should be said that I can't help you with mounting the board /making the amplifier in any way and since this a class-D amp it should NOT be your first DIY-project.

Looking forward to hear from YOU !

Have fun



this was my original post hope it says summet bout percieved quality

completed mi LM4651 amp Post #13
Hey up folks, been a while since i was here sounding out info on this amp, but I done it, well the full range part *2 for stereo and left a space for the sub channel which I intend to build when money and time allows. It was for my HNC project at college, but obviously also for my personal use, and what can I say it is the most amazing system i've ever heard, except possibly the one in Glastonbury dance tent in 2000. The volume is pretty mental too (unbelievable for 60 watts). Other people who's been round and heard it, their jaw drops and there gutted bout buying there £1000's of consumer equipment.Iv'e tested it to death, but it won't die and this weekend its doing a small party so I'll get an idea of its sound outdoors.
So, I hope this is read by all those who slag it off, saying it won't work or will sound **** or is easy to blow up (this did happen to me when my probe touched the VCC and the pin next door by accident, but what do yer expect) and I can now afford to have a little gigle at their expense HA HA HA HA. Anyway national semiconductor wouldn't lie bout its specs was always my theory.
Anyroad, the two reasons i'm here is not to gloat, but firstly to say give me a couple or three weeks and i'll have gear to knock up your boards if yer interested ( NO SLIDING SCALE PRICING will be applied here ) i'll print the costing if yer want, can't say fairer than that. Also, does anybody know the legalities of producing units of this amplifier and others for sale cos I'm an engineer not a lawyer

and here is some photos of boards done using single side equipment, developed twice ;) , which, though perfect under operation will be better with the double sided equipment i'm buying this week and maybee i could plate em too.

Costs will be printed when i've worked em out, but rest assured costs + a small charge for my efforts, will be much less than the big companies who seem to discriminate against the little man.

Drilling would be the most time consuming activity therefore cost would be kept to absolute min if this wasd undertaken by the buyer, anyway here's the photo's

hope they upload ok


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Hi Spudspud

I don't want to be rude, but looking at your pictures I am not sure your boards quality-wise are up to the FR4-industial grade that I otherwise would buy.

Don't get me wrong. They will for sure work, I just prefer to spend the 5 & 10 US$ extra to get them in FR-4.

(what is all that extra solder doing on your boards)

Could you try to be more specific about the quality and possible price ??


those were prototypes, i said i'm getting my equipment to do em at home next week, but suit yerself.
would be intrested where you reckon you'll get these done so cheap and so good in small batches. When i priced em it worked out to above £50 per board + shipping so i made em myself

and the extra solder is to stop the boards peeling at high currents, but I was going to plate the whole board next time
Have only built the one but yer welcome to drop in

Be nice to meet somebody nearby what doesn't think i'm talking Dutch raving on bout amps 'n' electronics

and to have somebody elses opinion

Yes, I think we all know that feeling. It's not so far so I may try and get down there one day. Likewise I am always keen to have people visit here! ;)
on the busses

I'd be up for comming over to Burnham one of the days, but would be on the bus so will have to research times, we don't get many out here.
Would be well interested in hearing other high spec amps to get some idea of quality benchmarks in my head/ ears.
I did consult your site for some of my project research so feel somewhat onhoured by your reply :)
tis a good site and yer know what your talking about, which is refreshing, though not having been in the field that long myself I do somtimes struggle to keep up, but will do the HND next year and keep mi head down till i get to be good at what i want to do or go mad:confused:
Do you know the legalities of producing this and other amps to sell, i know i've got to be careful 'ere and for any info on which standards would be required.:confused:
Do you know the legalities of producing this and other amps to sell, i know i've got to be careful 'ere and for any info on which standards would be required.

Are you talking of making them commercially or just to sell the odd one to a friend? If the former, I'm not sure what the rules and regulations are. I guess if you want to sell them commercially there are all sorts of things like safety regulations to pass before you can do so legally.

I'd be up for comming over to Burnham one of the days, but would be on the bus so will have to research times, we don't get many out here.

I'm also without a car although I can borrow one!

I did consult your site for some of my project research

My honour! Just drop a line to the Minister for Education and ask them to give me a salary! :D
Hi All!

I'd like to try this amp, but these IC's are not available here (Hungary) (at least I didn't find). Could we trade? There are some cheap PCB manufacturers here. 4 pieces of 100*150mm FR-4 PCB with all coating and silkscreen layers costs 48 Euro. (42 Euro, if we don't need silkscreen, and 31 Euro without hole metallisation). But! I can't believe that it is impossible to make it on 60*50 mm! (My discrete 1 kW PWM amp is 140*95*36 mm, included heat sink.) At this size we could order 20 pcs, for 48 Euro. (No VAT, no bills.)

If somebody made a reduced board design, and could buy these IC's for me, I would ordered and send the PCBs!
to nuuk .... we'll get it together to meet up then.... do I post my address / phone number here or email it.

to paffi
how many do yer want, I'll have to find out postage to Hungry cost, but can't see a prob

them boards yer on about is the same as some matey reckoned he'd get for $15, inc shipped to anywhere and dissed the quality of mine..... :) least I know mine work and ain't got no issues with size.
aint a bad price like yer say, but i'm a stubbern person what likes to DIY
HI Spudspud

I was not asking about the quality of your bords to offend you. It is not just very clear form your prototypes (pictures) what quality level the final version is going to be in.

It would be spupid for you to make something that I might not wnat to buy and it would be stupid for me to wait for something I might not buy.

I would be more that happy to buy from you if the quality and price is right.

Have fun