Wayne has previously measured these Silmics, and I have always trusted
his measurements, which put them on a par with Polypropylene for the
parameters of interest, specifically the resistance and distortion.
But since I am sitting in front of lots of expensive equipment, I made the
following test using my AP for performance in the kind of circuit I would
use them for, which is simply coupling.
I tested a 10 uF Silmic compared to a nice brand of PP driven by 600
ohms at 6 volts over a range of frequencies. The PP bottomed out at
0.04 ohms and the Silmic at 0.40 ohms
I then tested it for distortion when used as a coupling cap into 10 Kohm
at various audio frequencies with the same 6 volts. Whatever distortion
there was was below the system residual. Looking at the distortion
waveform with an averaging scope, nothing. With a spectrum analyzer,
only noise. I tested this with a bias voltage and not, no difference.
I further tested the Silmic under higher current conditions, 10 mA rms,
and they started to offer some distortion, bias dependent, which was
in the .002% range. The PP was better, but both were near the noise
residual of my setup.
You are of course free to find a better capacitor (or worse, if you like),
but I don't see a reason to stop using the Silmics.
This bottom dweller bought the boards, the sinks and all the components separately just a week ago. Then the kit comes out and I didn't really miss anything other than that bottom dweller price.
Sometimes, you just have to throw money at stuff until it either gives up or breaks you.
Where I would have saved a bit of time and money? If there was a current BOM in one spot. A sticky perhaps, with absolutely nothing else in it but those updates. Especially with regard to a specific min-max heat sink parameters.
Sometimes, you just have to throw money at stuff until it either gives up or breaks you.
Where I would have saved a bit of time and money? If there was a current BOM in one spot. A sticky perhaps, with absolutely nothing else in it but those updates. Especially with regard to a specific min-max heat sink parameters.
Was this the 25V version you tested. The very small one (4 x 10 mm)?
When I look back I made a measurement on a 22uF / 50V Silmic II which is physical larger and this one had much lower serial resistance. So maybe size matters here?
I did this measurement for a friend (picture attached). When he watched the results for the small 10uF/25V he suggested that I had got fake Silmics II.....but hopefully not so.....I measured some of the other (I got 10) with same result. I also tried to use different current for the measurement. But one thing is serial resistance another is distortion.
I need a digital scope which can perform FFT analysis so I can measure distortion. It will also require a very clean sinus generator......
Another thing that was a bit strange is that it only measure about 7 uF at 10k Hz but about 9 uF at 100 Hz. Maybe this is caused by the relative large serial resisstance I measued at 10 kHz.
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I have attached a link to the data sheet:
https://www.mouser.dk/ds/2/129/rfs_e-606.pdf
The 6.3 x 11 has higher mA rating than the 5 x 11 mA version........the 6.3 x 11 might also have lower ESR. But the 50V version could be better......
https://www.mouser.dk/ds/2/129/rfs_e-606.pdf
The 6.3 x 11 has higher mA rating than the 5 x 11 mA version........the 6.3 x 11 might also have lower ESR. But the 50V version could be better......
considering that ACA is having 10K-ish Rin , I wouldn't recommend any bufferless pot there , if one needs best possible results
In case of insisting on dumb pot , it can't be higher than 1K in value , so it is then up to sources (preceding pot) to have some cojones , able to drive it properly
2.7Ah is probably enough to feed some preamp stage , not amp working in Class A
besides , if you even think of doubling rail voltage , simply build amp which is made bigger from the start
conclusion ....... don't be so much of a cheapskate ......
if you look at pictures of M2 , DEF amp and some others , you'll see that Pa is clever chap ...... using smallest Silmics possible .... he also bought them in fridge box size quantity , so cheap that size became irrelevant ..... one toothpick price/piece
so , they simply ought to sound good
anyway , either believe fact that he's using them , further believe in his explanation how that's possible .... and use your brain power to think of some things more important for amps construction , than type of caps is ...
(and yes , silmic "issue" is nothing else than cluttering the thread)
I belive that the Silmics Pa has are good....but I may have got bad ones from DigiKey. I think it is good practice to test the components you get. I like to have some confidence in the components I put into the amp......and I don't have that for the 10uF (5 x 11 mm) Silmics I got. They must show better results at 10 kHz.
Sorry to crash the technical discussion. But plans to purchase the kit were foiled by the quick sell out AND I have a question(s).
The "new" ACA is no longer two physically seperate mono-blocks. Right? The mono blocks are now in one case. Correct?
So if, when in stock, I order 1 parts kit and 1 case (which assume is the complete kit for $278) I'll get everything I need to make this wonderful little stereo amplification system. Right?
PS: I'm hopeful of ordering this kit in April.
The "new" ACA is no longer two physically seperate mono-blocks. Right? The mono blocks are now in one case. Correct?
So if, when in stock, I order 1 parts kit and 1 case (which assume is the complete kit for $278) I'll get everything I need to make this wonderful little stereo amplification system. Right?
PS: I'm hopeful of ordering this kit in April.
you'll need not just a pot , you'll need buffer after it
buy ACA ,make it , then make B1 , any iteration of it
I already found the B1 on my own, but thanks anyway. What I réally want is an ACA with an integrated B1 (or something like it). Just one box, just one knob. I don't know if there's enough room in the chassis and of course such a kit would me more expensive, but it's what I would love to buy if it was available.
Don't let them fool you - Size always matters
I was testing part # RFS-35V100ME3#5, Origin Thailand. This has been
on my shelf for several years, and I understand from Wayne that new
production is from China. I asked him to see about testing the current
ones to confirm performance.
Could be another example of valuable old parts that I have a hoard of....
OTOH our tests could easily be apples and oranges, as I only have a
vague notion about your conditions. Certainly I can come up with
scenarios where the Silmics will behave badly.
Off topic:
Originally Posted by Zen Mod
you'll need not just a pot , you'll need buffer after it
buy ACA ,make it , then make B1 , any iteration of it
I already found the B1 on my own, but thanks anyway. What I réally want is an ACA with an integrated B1 (or something like it). Just one box, just one knob. I don't know if there's enough room in the chassis and of course such a kit would me more expensive, but it's what I would love to buy if it was available.
Mr Pass, is it possible?
Originally Posted by Zen Mod
you'll need not just a pot , you'll need buffer after it
buy ACA ,make it , then make B1 , any iteration of it
I already found the B1 on my own, but thanks anyway. What I réally want is an ACA with an integrated B1 (or something like it). Just one box, just one knob. I don't know if there's enough room in the chassis and of course such a kit would me more expensive, but it's what I would love to buy if it was available.
Mr Pass, is it possible?
Don't let them fool you - Size always matters
I was testing part # RFS-35V100ME3#5, Origin Thailand. This has been
on my shelf for several years, and I understand from Wayne that new
production is from China. I asked him to see about testing the current
ones to confirm performance.
Could be another example of valuable old parts that I have a hoard of....
OTOH our tests could easily be apples and oranges, as I only have a
vague notion about your conditions. Certainly I can come up with
scenarios where the Silmics will behave badly.
I use a Hioki 3522 LCR tester with Kelvin cables. I tested all 10 capacitors I have at 10 kHz. They all show the same figures.....more or less. Cs = 7 uF, D = 1, Ø = - 45 degree, Rs = 2.2 Ohm.
Then when I take my Jensen 10uF pure Alu foil capacitor it shows: Cs = 11 uF, D = 0.008, Ø = -89.5 degree, Rs = 12 mOhm.
I can change voltage, current etc...but no signigicant change when I does that.
At DigiKey manufacture says: Elna America .....is that the same as China?
....maybe in a few years....I get the ACA kit soon. There are included some 10uF Elna also. I will test them......and see....
I just observed that the 10uF Elna I have is this: # 604-1050-ND taken from the FirstWatt homepage in the article about the ACA. There is a part list with DigiKey numbers. So yours are 10 uF / 35V and the ones I have are 10 uF / 25 V. So it is not the same. Interesting what comes in the kit.......The 35V is this one: #604-1061-ND
My error. I tested the 25V part, but I pulled the number off a box on the
shelf of 35V parts. Next year when I have some more time I'll test those
too.
