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AudioSector-chip amp kits, dacs, chassis

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Yesterday finished the intergrated amp from Peter.
It was more easy than assembling an Ikea closet.
The chassis is fitted with Peters premium 3875 kit as I was not satisfied with previous gain clones, they did not come close to my Aleph 30.

This amp is already in a different league. The sound is so clear and delicate already! It's still a bit raw with the only 5 hours of playing it performed, I expect that will fade away a bit.
The soundstage is huge. Good recordings get even better.
I am very happy with this amp.
I was also a bit concerned of leaving this amp turned on all time because both my previous normal 3875 as well as the 6DJ8 buffered chip amps produce quite some hiss all the time. Peter's amp is however dead silent when required.

The wiring is all pure silver, except for the supply, which is some wire we use at my work to calibrate automotive sensors.

Thank's Peter for making this excellent piece of equipment available for the 'poor' man!
 

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The value of 4.7uf was probably chosen for maximal frequency response for a reasonable input impedance (say 50K ohms- I don't know what input impedance Peter designed it for). So if you increase to 10 uf, you will lower the lower Hz cutoff. But it shouldn't make that much of a difference since 4.7uf is already a pretty big capacitor. The question is, what kind of 10uf capacitor are you going to use? Will it be at least as high quality as the Black Gate NX capacitor he recommends as the output capacitor? If it is, then fine, you probably will hear a *positive* difference. It needs to be a pretty high quality cap like oil, or teflon or a very pure metallized polypropylene (think SoniCap, SoniCap Teflon/Platinum, Cardas, VH audio OIMP or Teflon, Mundorf Silver in Oil/Gold.

To summarize, the quality of the capacitor will make more of a difference then the value in your case. I would stick with a higher quality cap, even 3 uf and you should have a great sounding dac. I own Peter Daniel's NOS dac and its absolutely delightful. FYI, the output impedance of the dac is about 2700 ohms in stock form.

I hope this helps. The equation to calculate the the -3dB point is simply Hertz = 1 / (2*pi*Rk*Ck). Rk in this case is 2700 ohms. Ck is in Farads, so remember to convert your microfarad value.

Anand.
 
I asked because we don't have a vendour for black gates here in sweden but I got an offer to buy the same brand and type but 10uF for a reasonable price. I think I need them since I used a very cheap cap that I had in my good-stuff-to-have-box.

I do have some pio of 10uF but those are atleast 4 times the size of the populated PCB :D
 
I choose BG N 4.7uF (not NX) for practical reasons: it's smaller than 10uF, it's slightly cheaper and it's also a bit faster, so in other words it plays a bit better in a DAC that same 10uF cap (but the difference is rather negligable).

I tried other good quality caps: MIT RTX, Jensen copper foil, Hovlands, Russian PIO, but I wouldn't choose any of them over BG N. For some reason, a combination of BG N in coupling and Rikens in I/V is very musical with slightly laid back character.

If I switch to teflon V-Caps, then Caddock TF020 would be a better choice for I/V resistors, but not with BG N.

10uF is not a problem at all.
 
Half snubberized=problems?

Peter,

I rebuilt my old kit to include two more LM4780 parallel non-snubberized boards.
My old kit consisted of three stereo LM4780 boards "snubberized". Now I am using the same power supply (snubberized) to power one stereo board and these two new parallel ones.
I am getting "thumps" when I power on and when I power off. (only coming from the speakers hooked up to the parallel boards)Although the sound isn't as loud when power on as power off.
Do I need to "snubberize" the two new parallel boards to eleviate this problem?

NOTE: The other two stereo boards have their own power supply, which are all snubberized. No thumps from them.
 
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