It didn't explode....... YET (aka niges amp)

[Sligolad]

Stick my name on the Group Buy Nige....not having heard the amp but based on the feedback it is a no brainer for me.
Bought my first ever Li Po's a couple of week back so looks like I have started down the rabbit hole already.

Come on Tony....lets knock the dust off those Quads with some solid state muscle :-))

[tony]

Stick my name on the Group Buy Nige....not having heard the amp but based on the feedback it is a no brainer for me.
Bought my first ever Li Po's a couple of week back so looks like I have started down the rabbit hole already.

Come on Tony....lets knock the dust off those Quads with some solid state muscle :-))

Tempting having heard it, will have to get Nigel up for a meet to have a listen. It is the build that is the problem Pearse:)

[nige2000]

plan a is

short answer
going to design printed circuit boards to make assembly a breeze

long answer
the prototype build is quite laboursome
so i was thinking of designing something more simple,safe and just generally more foolproof

if there was enough interest to build say 3 or more amps

it would be certainly feasible to design and order two types of printed circuit boards
this would make the build far far far simpler to assemble
one to manage the voltage levels of the individual cells
and the other to incorporate the buffered jfet input and the lm3875s
it is possible to build two versions 0-33v (10 cells)and a 0-66v(20 cells) version from these same boards
i would not be in the least surprised if there was no audible difference between them due to the immense power of these lifep04 cells


incorporated into the design would be relays to insure that the cells never will discharge under any circumstance or mis-operation(basically the amp wont turn on until mains power is present)

each special order toroid would have ten secondaries which would feed into our linear voltage management pcb this will provide 0-33v
for 0-66v would require 2 toroids and 2 voltage management circuit boards

the amp isn't near as power hungry as i had built the prototype for so we can restrict the current from the regulators to a point where the regulators won't need to be heat sinked

the toroids and the batteries are the large cost and the hardest/slowest to obtain
total parts costs difficult to quantify until further investigation but would guess it would be wise to be prepared for between 500-800 euro
but as i keep getting reminded thats bugger all considering its been compared to amps costing several thousand

i can do the circuit board soldering if needs be
and help with assembly

[Fran]

+1 more for the group buy. I'd have a case already and give a hand on the soldering if needs be.

[tony]

Ok with three guru's on board I'm in as well.

Might try and meet up prior to going on holidays Nigel I would love to hear it as is on system and sure we are due a CA meet up! Just awaiting delivery of an industrial intona which I got from PuriteAudio in the UK.They had a sale. The wait for the alternative model seems to have dried up for the moment. Anyway with my battery set up adding any more odd bits will probably lead to melt down.

[nige2000]

Ok with three guru's on board I'm in as well.

Might try and meet up prior to going on holidays Nigel I would love to hear it as is on system and sure we are due a CA meet up! Just awaiting delivery of an industrial intona which I got from PuriteAudio in the UK.They had a sale. The wait for the alternative model seems to have dried up for the moment. Anyway with my battery set up adding any more odd bits will probably lead to melt down.

sound
im up for a meet whenever
would be good to hear it with your Quad collection
think this amp will make a great alternative to the jadis

probably give it a few days to make sure there's no others want to join the group buy
then we can organise an order for the transformers and the batteries coz that will take a few weeks
and in the meantime i can work on prototype pcbs and test suitable components
we can order the rest later as it will can delivered within a few days

transformers, voltage management boards, mono amp boards and batteries are needed by everybody
will post a list of optional part options later
ok we can order these type of parts together too to save a bit on postage
suggestions more than welcome

http://www.aliexpress.com/item/high-qua ... 86f57a3f1c
http://kacsa-audio.hu/webshop/home_audi ... 33rt.p.246
http://kacsa-audio.hu/webshop/home_audi ... 226s.p.225
http://www.aliexpress.com/item/Free-shi ... 21922.html
http://www.ebay.ie/itm/IEC320-C14-Inlet ... 35dc46430e


this enameled wire looks interesting for signal handling
http://wires.co.uk/acatalog/si_enam.html

[Diapason]

This amp, can it deliver into low impedances?

(I'm not getting sucked in. I'm not.)

[jkeny]

Nige
What charging current do you need for each battery cell?
I think you originally over-specced this - have you measured the max draw of the weakest cell?
I might have an alternative & cheaper suggestion for charging of cells?

[nige2000]

Nige
What charging current do you need for each battery cell?
I think you originally over-specced this - have you measured the max draw of the weakest cell?
I might have an alternative & cheaper suggestion for charging of cells?

i was working on about half an amp per cell and do a pcb all in smd to do ten rails of ac to linear 3.3v out

whats the idea

[jkeny]

Nige
What charging current do you need for each battery cell?
I think you originally over-specced this - have you measured the max draw of the weakest cell?
I might have an alternative & cheaper suggestion for charging of cells?

i was working on about half an amp per cell and do a pcb all in smd to do ten rails of ac to linear 3.3v out

whats the idea

You could use isolated converters to charge each cell - they're isolated so can be connected as needed without any issues
In Mouser a Meanwell regulated 3.3V 1.2A output isolated converter costs €10 & has built-in over voltage protection (so no chance of killing a battery with over-voltage), has remote control on/off so maybe this can replace relays (?), short-circuit protection

These could replace your toroids, rectifiers, caps & regulators & would be far safer dealing only with DC & not mains voltages.
Of course you would need a DC input (9V to 36V) to the converters so some external AC to DC supply PS needed but most have one of these already

The only concern might be ripple & noise on the output of the converter connected to the battery but the Meanwell above has a max of 75mV ripple @20MHz which the batteries can esaily absorb, AFAIK - I've tried a couple & they seem fine
http://www.mouser.com/ds/2/260/NSD05-S-spec-53378.pdf

There are other lower priced & lower current isolators - 500mA ones for €5 http://www.mouser.com/ds/2/632/DS_PC02S ... 349627.pdf

See what you think - it could substantially reduce the cost of the configuration & allow everything to be available off-the-shelf?