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Old 13th September 2012, 06:30 PM   #1791
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Last night I switched the .47R source resistors out for a 1R resistor. I was wanting to see what effect it had on sound. To me, it killed some of the space and seperation from original attempt. I have been told before that these parts sound better with less source resistance. I will try .33R tonight ans see if stereo image and spaciousness improves. I agree with Ilquam, that the bass is surprising, although it reminds me of the AJ. The thing this amp foes well, IMO, is space and certain natural feel to voices. Lucinda Williams, Shawn Colvin, Patricia Barber sound wonderful.
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Can you play flac files? I want to send you a couple tracks.
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Old 13th September 2012, 06:38 PM   #1792
lhquam is offline lhquam  United States
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I made some measurements one of my Teaser-6 bias circuits using a variac to modify the AC line voltage. My measurements are the current through the source resistor and VGS vs. line voltage with zero voltage input to the channel.

The reduced numbers give:

delta_source_current / delta_line_voltage = 5.6mA/V

delta_VGS / delta_line_voltage = 0.67mV/V => 63.5dB
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File Type: jpg F6-VR-bias-vs-line-volts-sch.jpg (15.0 KB, 188 views)

Last edited by lhquam; 13th September 2012 at 06:43 PM.
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Old 13th September 2012, 06:41 PM   #1793
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How much of this AC fluctuation would you see with a big cap bank?
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Old 13th September 2012, 06:43 PM   #1794
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all of it , if fluctuation is slow enough

especially in case of brown out

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Old 13th September 2012, 06:45 PM   #1795
lhquam is offline lhquam  United States
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Cap bank will not help with very low frequency (cycles/minute) power line fluctuations. This is a DC stability issue.

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How much of this AC fluctuation would you see with a big cap bank?
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Old 13th September 2012, 06:50 PM   #1796
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90% of existing amps will have bias fluctuation while mains fluctuate

nature of the beast
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Old 13th September 2012, 06:53 PM   #1797
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Quote:
Originally Posted by lhquam View Post
Cap bank will not help with very low frequency (cycles/minute) power line fluctuations. This is a DC stability issue.
Sorry, I thought you were trying to draw a parallel with DC bias and AC fluctuations.
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Old 13th September 2012, 07:15 PM   #1798
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Quote:
Originally Posted by buzzforb View Post
Last night I switched the .47R source resistors out for a 1R resistor. I was wanting to see what effect it had on sound.
Just go straight to 0.1R if you have it
Or try 2 x 0.47 in parallel
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Old 13th September 2012, 07:21 PM   #1799
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Gonna move slowly down the plane and listen. Have resistors to try it all.
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Old 13th September 2012, 07:26 PM   #1800
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I don't even know why I'm in this thread????
Don't get me wrong though. I want to know how good a bias ref the TL is??? and how to optimize for that purpose
flg. Is the Avatar you show your living pet Jack Russell? I hope I named the right breed. He/she is handsome/pretty. This breed has a long life which is a blessing. My neighbor has one. It loves to chew on sticks. Smart dog. Takes in all the anti oxidants [vegetable extracts] it needs to live long!. I have a female Old English Sheepdog puppy named Bella. I'll figure out how to upload her picture as my new Avatar; if she behaves!
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