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Old 21st July 2012, 07:55 AM   #2661
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I believe he's just very busy with life at the moment. He still answers emails, when he has a chance.
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Old 21st July 2012, 01:29 PM   #2662
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For R6, R12, R13, it calls for a 40.2k resistor. Could I run down to radio shack and use a 47k resistor instead? they are 5%ers, so potently, I can get one around 45k. Would this work?
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Old 22nd July 2012, 12:00 AM   #2663
br777 is offline br777  United States
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Click the image to open in full size.

is it possible to lower the gain further? using my custom IEM's and both the marked resistors clipped, i still get VERY little play in the volume knob until it is too loud. these are very sensitive IEM's.
thanks
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Old 22nd July 2012, 12:11 AM   #2664
jcx is offline jcx  United States
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very sensitive iem don't need amps - they need attenuation

my most recent answer to this at head-fi: How to make a fixed attenuator for headphones
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Old 22nd July 2012, 12:16 AM   #2665
br777 is offline br777  United States
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i am only using an amp in the first place b/c i am using the odac, and it requires an amp.. and im only using the odac to improve the signal, mainly ruducing noise, from my computer.

anyway, i'd prefer to be able to just clip more resistors if thats possible.

thanks, i'll look into your suggestions as well.
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Old 22nd July 2012, 01:39 AM   #2666
mikeaj is offline mikeaj  United States
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Clipping the resistors is to change the gain to unity (no gain). You can't really reduce it from that without some type of transformer or voltage divider circuit somewhere along the line. The simple hiss buster circuit linked would be one of those voltage dividers.

Just turn the volume down in software. You have an ODAC after all, with 24-bit playback. That's what it's for.
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Old 22nd July 2012, 02:22 AM   #2667
br777 is offline br777  United States
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fair enough.. forgot about the 24-bit thing.. thanks
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Old 22nd July 2012, 12:51 PM   #2668
Zigis is offline Zigis  Latvia
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br777, if even unity gain is too much for you, you can make divider on amp's input. Change R3,R7 to 10k - 30k, this make voltage divider with R14,R20.
Or simplest way to try - just connect 10K-30K resistors between ODAC output and amp input (instead wires)
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Old 23rd July 2012, 03:30 AM   #2669
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My amp was working for about a week, until last night it just stopped instantly. The light still works, just no output.


This is the measurements I get, with the pictures from the nwavguys's site.

o2 amp testing - Imgur

When I built it, it had a loud turn on pop, if that's any help.
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Old 23rd July 2012, 04:43 AM   #2670
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Quote:
Originally Posted by Hairymerkin View Post
My amp was working for about a week, until last night it just stopped instantly. The light still works, just no output.


This is the measurements I get, with the pictures from the nwavguys's site.

o2 amp testing - Imgur

When I built it, it had a loud turn on pop, if that's any help.
I had a hunch and charged the batteries and it works of those only. So does this point to a problem in the way the AC adapter charges the batteries?
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