CrackBerry9000
100+ Head-Fier
- Joined
- Oct 26, 2009
- Posts
- 129
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- 11
That is too cool.
Originally Posted by Pricklely Peete /img/forum/go_quote.gif netsky3 I can't help but think your source may be part of the problem WRT sound stage issues (either in setup or the actual software hardware combination used). I'm not familiar with the Cowon device but the X-FI card from a notebook without a decent outboard DAC between the amp and the transport can really mess things up (no matter what you do with the amp mod wise). What OS are using ? If it's XP see of if you can upgrade to Win7 since it's audio layer is way way better than the old NT4/5 kernel/HAL interface. That being said if you have a CDP or DVDP use it with your amp to see if the amp can be better tuned to a standard 2.0V line level source output level. The trim pots if set too high (with the source line level set too low) can cause all kinds of problems (distortion etc) not only that if you lower the level at the computer source (depending on O/S and SC driver) you actually truncate the bit depth of the file rather than attenuate the gain. It's a shortcoming of computer based transports with some hardware configs. That is why I suggest you calibrate the trim pots to a 2.0V line level standard (for a CDP/DVDP) and then transfer the amp to your comp source to see if the problems persist or have been solved. It's best to have the computer set at 100% and adjust the input trimmers on the amp. If the computer output is too hot (well above 2.5V) the input stage of the amp may be clipping causing distortion. The only way to tell if that is the case is to measure the signal level coming from your source using a meter. It's also possible that the cheap trim pots have been damaged by excessive heating when being installed. It doesn't take much to mess them up since they are very cheap parts. That likelihood is rather remote however although not out of the realm of possibility. Another possible issue is adjusting the trim pots too far in one direction...they sometimes crap out (stick at that setting) from being adjusted too far ...only very small increments should be used. If you have a test tone (say 1Khz) and a SPL meter you can match the L/R levels fairly accurately. Err on the side of caution with the levels. I agree with the S-Man slow down and take a look at your entire system chain to make sure it's setup optimally for your hardware config/source etc...you may find you have overlooked something (then again maybe not) but it's worth checking it all out anyway while you wait for the amp to mature in it's current revision. Simplify your system chain down to it's bare essential components and work up from there and worry about the parts quality of the amp later. Peete. |
Originally Posted by netsky3 /img/forum/go_quote.gif Actually the only source that i have is my pc with the x-fi as output where i connect directly my Akg (i'm waiting for my dac arrives from canada) and where i use also the amp between pc and cans Maybe next week end i can use the amp with a CDP as source but i don't think that is the problem because the headphones on the x-fi sounds well. The only things a little damaged are 2-3 holes where are soldered the caps 7-8 (but still working) and the jack for the output (that will be soon changed with a new piece) Desolder everything and re-do the amp will be a solution?? Thanks again for your patience |
Originally Posted by Pricklely Peete /img/forum/go_quote.gif Sit tight until the DAC arrives is my advice for now. The difference in SQ from your current source to an outboard DAC will likely surprise you by a quite a fair margin. No use in doing anything until it arrives. Peete. |
Originally Posted by calico88 /img/forum/go_quote.gif Sennsay, are you saying that this board can just use Opa627.. just drop in ? I have mine but I thought is not working at all. how is the sound compare to 2134 for Headphone Amplifier ? you have not tried that as a headphone amp ? Cal |
Originally Posted by sennsay /img/forum/go_quote.gif Okay, play time Bearing in mind that all this is with the stock resistors and poly box caps on the first board. |
Originally Posted by studeb /img/forum/go_quote.gif Sensay, Are you changing the supply V for the opamps? With the L4949 there, wont it stay at 5V? |
Originally Posted by netsky3 /img/forum/go_quote.gif Today I have used my amp with a CDP as source and after a long burn in with a psu at 15V the sound is a little better but i don't like the bass, the drums on Echoes sounds with less punch, soft and behind the others instruments than without the amp and usinge the cans on the CDP Sennsay do you can compare this Song with and without the amp? Maybe with 18V can be a little better? |