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Bt schematic

Posted 22nd January 2012 at 04:59 PM by klewis
Updated 23rd January 2012 at 01:19 AM by klewis

http://www.diyaudio.com/forums/solid...lifier-86.html
Pavel's scheme http://www.diyaudio.com/forums/solid...ifier-103.html
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Old

Measuring Noise

Posted 19th January 2012 at 04:28 PM by klewis
Updated 19th January 2012 at 04:32 PM by klewis

For LED's - Christer's thread http://www.diyaudio.com/forums/parts...er-diodes.html
An interesting method of grading zeners for noise, that I have used for years, is to monitor the noise across the devices with a scope while using my HP bench supply to bias them. The noise spectrum changes quite dramatically as you come into breakdown and then drops to it's minimum at it's prefered current flow. I note the current and voltage after it has settled down. I choose the ones to use by voltage match and bias them accordingly.

One other trick, if you want to know how quiet your supply is, choose a suitible coupling cap and hook the output of it up to a line input on your preamp and listen to it. Try this with and without a load and during normal operation of the supply. A good supply is dead quiet. author: MikeBettinger
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Old

Improved current source

Posted 2nd January 2012 at 01:18 AM by klewis

http://www.diyaudio.com/forums/solid...urce-sink.html
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Old

Solid state relay

Posted 30th December 2011 at 11:55 PM by klewis
Updated 3rd January 2012 at 03:43 PM by klewis

Fets: http://www.diyaudio.com/forums/solid...relays-17.html

Pavel's Scheme http://www.diyaudio.com/forums/solid...ml#post2835407
Also see post #340, increase R1 to 100k and C3&4 to 47uf
recommendation for mosfets: #314
In general, you are seeking for a MOSFET with very high Vdsmax, very low Rdson and very high Idmax. Regarding Vdsmax, it must be higher than the sum of positive and negative supply rail voltage, and the output should be provided by clamping diodes connected to supply rails, reverse polarized. My tips are

Type Vdsmax Rdson Idmax
IRFB1227 200V 0.0197ohm 130A
IRFP90N20D 200V 0.023ohm 94A
IRF3710ZG 100V 0.018ohm 59A (too low Vdsmax to me)
IRFS59N10D 100V 0.025ohm 59A (too low Vdsmax to me)
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Old

Pass B1 buffer

Posted 26th December 2011 at 12:53 AM by klewis
Updated 26th December 2011 at 03:47 PM by klewis

Post #166 board layout
omron G6H2 12v relays
Motorized alps pot http://www.ebay.ie/itm/ws/eBayISAPI.dll?ViewItem&clk_rvr_id=300979180833&ite m=250467804650
Post #1062 for relays
Post 1031 cap tweak
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Swordfishy amp parts

Posted 18th July 2011 at 06:35 PM by klewis
Updated 30th November 2011 at 09:04 PM by klewis

latest schematic, parts list and pictures of boards: http://www.diyaudio.com/forums/aksa/...ml#post2702203 R4 1/2 W min

Build notes: http://www.diyaudio.com/forums/aksa/...ml#post2696859

18ga wire = 1.04 mm

bjt singleton input http://www.diyaudio.com/forums/solid...ml#post2723089

mikelm amp http://www.diyaudio.com/forums/solid...ml#post2724896

mikelm amp with buffer http://www.diyaudio.com/forums/solid...ml#post2746726

For 2sk1058/2SJ162 Amps lab 6 pieces total $45
Pacific Semi $8.48 2sk1058 $4.31 2SJ162

http://ampslab.com/trans_2sj162.htm

2SK170 GR Pacific Semi $1.10

http://www.pacificsemi.com/search.php?partno=2SK170GR...
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Old

For Paul

Posted 27th March 2011 at 04:18 PM by klewis

LME 49811 schematic is the one used for the tests with only the 30pf compensation in the circuit.
Attached Files
File Type: pdf cordell v6 t4 schematic.pdf (16.8 KB, 274 views)
File Type: pdf lme49811 v2 servo schematic.pdf (37.1 KB, 255 views)
File Type: pdf Allison V6a schematic.pdf (24.7 KB, 256 views)
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Old

On distortion by Bob C

Posted 25th March 2011 at 09:30 PM by klewis

I don't find it hard to believe that very low levels of certain kinds of distortion are detectable when at the same time virtually un-measurable differences between passive elements like cables and capacitors are widely believed to be audible.

THD-20 does not tell the whole story on amplifier behavior, but it has also been given a bad rap because single-number usage of THD-20 can obscure the real story. If you have THD-20 with a full-spectral analysis out to the 7th or 9th harmonic, it tells a lot more, but most THD analyzers start cutting off at 80 kHz. One should always take note of the waveshape of the THD-20 distortion residual as well. If it is rather sinusoidal, that is often not too bad. If it is spikey, that is potentially very bad.

CCIF 19+20KHz with full spectral analysis is much better because the IM products lie in-band.

At the same time, moderate levels of benign THD, like mostly 2nd and 3rd, may not bother anyone very much. This...
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Old

transistors for front end

Posted 24th December 2010 at 02:18 PM by klewis
Updated 31st October 2012 at 12:55 AM by klewis

This thread.
http://www.diyaudio.com/forums/solid...tp-choice.html

Sources:

http://www.utsource.net/index.aspx

http://www.taydaelectronics.com/servlet/StoreFront

Sadly the 2SC2240 and 2SA970 (npn, pnp) super-low-noise trannies in TO-92 packages no longer appear on Toshiba's Bipolar Transistors Product List, and have been designated NRND by Toshiba (Not Recommended for New Designs). [link] This means the factory is presumably still taking (large) orders, but they are destined for the dust-bin of history. FYI, last chance, B&D still has some inventory.

But, not to fear, Toshiba offers what appears to be the same (or better) die in SOT-23 packages, the 2SC3324 and 2SA1312. These are stocked by Mouser, and cost only 15 cents qty 100. Their datasheets are fairly complete, including two NF contour plots. The 1kHz plot shows the 3dB contour dropping 35 ohms at 1mA and below...
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Old

Software

Posted 29th November 2010 at 08:36 PM by klewis
Updated 5th January 2011 at 11:25 PM by klewis

Pcb software

Sprint-Layout

Audio analysis software;

Virtins MI http://www.virtins.com/
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