nige2000's amp - sitting on the edge of my seat

[jkeny]

Im pretty sure none of the 26650s ive bought are genuine a123 and ive bought quite a few from different sources so really the a123 data sheet cant really apply to them
i hear no differences in any of them and thats whats important
ive 100 cells now ordered so we shall know soon enough
tbh its not something i was worried about in the slightest

hmm now I wonder how they would perform with my tpa amp. a 19v lifepo pack and a matching smps charger?

You need some way to balance the charge going to each cell. Nige uses a 3.3V regulator powered from a separate rectifier & separate secondary winding on a custom made transformer (10 individual 6V? secondaries on a toroid)

[nige2000]

Im pretty sure none of the 26650s ive bought are genuine a123 and ive bought quite a few from different sources so really the a123 data sheet cant really apply to them
i hear no differences in any of them and thats whats important
ive 100 cells now ordered so we shall know soon enough
tbh its not something i was worried about in the slightest

yep, I agree - most of the LiFePO4 cells use nano-technology, whether A123 or another brand.

A 100 cells on order? Are you setting up shop?

just the gb and a few for myself

[jkeny]

Im pretty sure none of the 26650s ive bought are genuine a123 and ive bought quite a few from different sources so really the a123 data sheet cant really apply to them
i hear no differences in any of them and thats whats important
ive 100 cells now ordered so we shall know soon enough
tbh its not something i was worried about in the slightest

yep, I agree - most of the LiFePO4 cells use nano-technology, whether A123 or another brand.

A 100 cells on order? Are you setting up shop?

just the gb and a few for myself

Oh, sorry I didn't know the GB had gone ahead yet or I wouldn't have said anything about the AN8AH batteries.
I'm sure they will be perfect for the job at hand

[nige2000]

well as ive not heard any evidence of difference between different lifepo4 cells before
i really am not expecting any this time either

this is the data sheet for some of the last cells i got
specs seem to vary quite a bit between different manufacturers
http://cdn-reichelt.de/documents/datenb ... 0FP_DB.pdf

[rickmcinnis]

jkeny,

The noise of the typical SLA is well documented but there is something very different in the workings of the OPTIMA.

No comparison in the noise levels.

I have to say, depending on the gain chosen for the LM3875 I find it hard to believe supply noise, between OPTIMA and 26650, would be a factor. I used gain of 10, if my memory serves, and even with the PANASONICS I was not aware of the noise but I know my hearing skills are much better these days and those impressions are shallow now.

Peter Daniel, who got me interested in the LM3875, was a proponent of using simple AC supplies. I would think for a full range amp and direct radiators that would be good advice. I used them in limited frequency ranges. The low frequency pair from 100 to 500 - certainly not a brick wall at 100, of course. Peter said one would lose dynamics with a battery supply but with horns I did not detect this and these were not better than average batteries. Never bothered to try AC so I do not know the difference. They fulfilled my need at the time and must admit once something is working decently well I will leave it alone so I can have music on demand!

The chip has a pretty good PSRR.

Never one to discourage trying things so please do not take my comments the wrong way.

I have to say I was concerned those regulators and rectifiers would not be overly pleased with being in series, also, but I guess that has not shown itself to be a problem?

Who can figure out why that thing sounds as good as it does? Has to be close to class b in the outputs unless you add that resistor to force more current through it.

I remember the GAINCARD ads where they would talk about the path length as 2 or 3 inches (can't remember) when there is probably a mile of circuit length with the chip. An audio mystery.

[nige2000]

Peter Daniel, who got me interested in the LM3875, was a proponent of using simple AC supplies. I would think for a full range amp and direct radiators that would be good advice. I used them in limited frequency ranges. The low frequency pair from 100 to 500 - certainly not a brick wall at 100, of course. Peter said one would lose dynamics with a battery supply

loss of dynamics and a smoothing of the leading edges of the sound would be a signature sound of old sla batteries, lifepo4 is a completely different animal

The chip has a pretty good PSRR.
Never one to discourage trying things so please do not take my comments the wrong way.

well it does seem by times that i get told what can and cannot be done or done successfully,
to my mind these things can only be tested and heard, the working prototype is working and performing very well in very high end applications
data sheet cross examination is mostly speculation in audible terms

I have to say I was concerned those regulators and rectifiers would not be overly pleased with being in series, also, but I guess that has not shown itself to be a problem?

yea seems to be no problem

Who can figure out why that thing sounds as good as it does? Has to be close to class b in the outputs unless you add that resistor to force more current through it.

i reckon the supply is fast enough to cope with the dynamic load?

I remember the GAINCARD ads where they would talk about the path length as 2 or 3 inches (can't remember) when there is probably a mile of circuit length with the chip. An audio mystery.

yea im a less wire fan myself
long lengths of wire seem to lead to detail loss also helps alot when buying silver by the kilo