News: New speaker kit coming soon
May 26, 2017, 06:45:53 am

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The Electronic Bay.
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General Discussion / Where does one go to buy & sell used tubes?
« Last post by danderby on Today at 04:55:54 am »
I have a couple sets left over from my last build (Foreplay V2 - now sold) as well as my earlier excursions into tubeland (AR & Audible Illusions pre).  I would also like to do some tube rolling on my phono preamp (Jolida).  Is there somewhere anyone can recommend for buy/selling these kinds of tubes?  Thanks!
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Stereomour II / Re: Shunt Regulator with 45's?
« Last post by gstitt on Today at 03:58:38 am »
Jamie,

Great! I think the JJ should shine at that higher plate dissipation.

Greg
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Crack / Re: Choke specs for the Crack
« Last post by diynewbie on Today at 03:31:53 am »
Please correct if I have this wrong.  Still trying to figure this stuff out.

The -3dB roll off frequency is calculated by 1/(2*pi*R*C).

In this case, R is the impedance of the headphones in ohms and C is the effective capacitance of the last PS cap and the output cap in farads (not micro farads).

The effective capacitance of capacitors in series is calculated by 1/(1/C1 + 1/C2 +…).
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Crack / Re: Sudden Issues
« Last post by Mattrox217 on Today at 01:41:01 am »
hey fhon, sorry for the delay, I had to dig out my meter. Here's my measurements. All pretty regular...


1 - 82
2 - 185
3 - 0
4 - 185
5 - 82
6 - 0
7 - 112
8 - 0
9 - 112
10 - 0
11 - 0
12 - 0
13 - 185
14 - 0
15 - 205
20 - 0
21 - 225
A1 - 82
A2 - 0
A4 - 0
A5 - 0
A6 - 82
A7 - 0
A9 - 0
B1 - 82
B2 - 185
B3 - 112
B4 - 81
B5 - 185
B6 - 112
B7 - 0
B8 - 0

T21 seems a bit weird... Not sure if that should be worrisome?
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Speakers / Re: Speaker kit experiments
« Last post by Rocketman248 on Today at 12:34:15 am »
Nice and neat.  Lookin' good!
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Crack / Re: Crack volume control bypass?
« Last post by howzz1854 on Yesterday at 08:31:46 pm »
sorry to revive an old thread, but seeing that is a topic i am looking for clarity. i thought i'd share some of the findings.

here's what the guys at Head-fi have to say about digital volume control. i take NO credit at all.

response was by user Head Injury
https://www.head-fi.org/f/threads/volume-control-woes-its-too-loud-desktop-usb-schiit-bifrost-rca-bottlehead-crack-w-speedball-hd650.742594/

Quote
tl;dr Turn your computer volume down, you're fine.
 
Here's how digital volume control (like the one your computer uses) works:
 
Digital resolution is limited by the bit depth. As the volume increases or decreases, the digital signal has to round it to fit one of the values the bit depth can resolve, and this rounding creates noise (called "quantization noise"). The more bits, the smaller the volume steps and the less rounding, so less noise. It turns out that each bit lowers the noise floor by -6 dB. 16-bit signals have a quantization noise floor of -96 dB, and 24-bit signals have -144 dB.
 
The problem is, since this noise floor is determined by the bit depth, it will not go down when you turn the digital volume down, like the noise introduced by an amp will. So if you have a 16-bit file and turn the volume down by -10 dB (1/2 the volume), the peak signal that was 96 dB above the digital noise floor is now only 86 dB above it. The signal-to-noise ratio was reduced by -10 dB as well. This is why people recommend using the analog volume control.
 
This is made moot by the fact you're probably not listening much louder than 80 dB, and your room's ambient volume is likely around 30 to 50 dB, and you're probably not even getting 96 dB of signal-to-noise ratio from your gear anyway.
 
Plus, if you're using your DAC in 24-bit mode, you have 8 extra bits to use for volume control. Meaning you could lower the volume by 48 dB (that's about 1/28 the volume) in the digital realm without reaching the noise floor of the 16-bit file you're playing, or the noise floor of your equipment. Digital volume control will only matter if you're raising the noise floor above the rest of your noise, and you're not realistically going to do that.
 
So turn down your computer volume, you're fine.

sounds like if you're outputting digital in 24 bit mode, you have enough dynamic range room that allows you to turn down the digital volume all the way down to 1/28 of the total range before the noise floor / signal to noise start becoming an issue.

can anyone chime in on this? any sound engineer experts here?
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Stereomour II / Re: Shunt Regulator with 45's?
« Last post by Jamier on Yesterday at 05:38:02 pm »
Greg,

     Thanks for helping me understand this part of the SII circuit. I have been considering the JJ 2A3-40, and now,  considering PJ's modification list, I wonder if it would be at it's best if run at 60 mA and in combination with the EXO-003/TFA-2004. If That iron can be had, I'm gonna' find out.

Jamie
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Music / Re: If you like Soul, Jazz and Blues, this might be for you.
« Last post by 2wo on Yesterday at 05:07:27 pm »
There is always the classic "jazz at the. Pawnshop"...john
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Speakers / Re: Speaker kit experiments
« Last post by johnsonad on Yesterday at 01:08:12 pm »
Nice work!
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