HELP ME!!!
Oct 29, 2003 at 2:24 PM Post #77 of 82

tangent

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Quote:

does that mean 40x louder than the input?


No, it means 40x more voltage than at the input. You can check it by putting on a test tone CD, measuring the voltage you get, and then measuring the voltage at the output of the amp at full volume. You'd really want to do this with an oscilloscope so you can see if it was clipping, though. Once it starts clipping, all bets are off.

40x the voltage in terms of volume depends on the headphones. It's simplest to think of it in terms of decibels: 20 * log(v1/v2). v1/v2 is 40 in this case, so it's increasing the voltage by 32dB. I must stress that this is not the same thing as 32dB in sound pressure level! That's an entirely different ball of wax, and it gets into the headphone driver performance.

Quote:

That is definetly not what is happening...is it possible that something else is attenuating the signal?


Yes, the crossfeed will take 6-10dB off. And of course the volume control is an attenuator, in front of the amp.

This is why it's simpler to think in terms of decibels: you can add them and subtract them instead of multiplying and dividing voltage levels. So, the total gain through the amp with the volume control at max should be 22 to 26dB. Reversing the function above, that's a voltage gain of at least 12x. If you don't see that much voltage gain through the amp with the tone test, either it's clipping at max or there's another attenuator in the system. What are R1 and R2?
 
Nov 3, 2003 at 9:10 AM Post #78 of 82

Zemo

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I really don't want to mess with this amp anymore, as I'm intending to return it. But I've sent Shutakagi over about 3 PMs in a period of over a week, and I still havn't heard a reply. What am I supposed to do?
 
Nov 5, 2003 at 6:28 AM Post #80 of 82

Zemo

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Apperently Shu is on vacation...

MisterX has kindly volunteered to help me out. I'd send my amp to him, and he'd use his knowledge and expertise to fix my amp. Sounds pretty good to me! But, the shipping cost is still there. Since I paid for a working amp, it would seem to reason that Shu should cover the shipping costs.

Well, I have been contacting him via PM (he decided to get on the internet while on vacation) and he says that he has a friend that could fix it as well. But he thinks I should cover shipping. These are the three options that I can come up with:

-Shu ships to michigan (where MisterX is)
-Shu ships to Canada (where his friend is)
-Shu gives a complete refund

Shu doesn't think this is fair, so I'm questioning its fairness myself. Opinions?
 

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