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Circuit error in Lite DAC-AH: Easy fix - Page 11

post #151 of 213
So ive been thinking.........
I feel like i want more bass from my dac. I have read that the value of the output caps determines the bass rolloff. How do i find out what freq. my 2.2uf caps are rolling off at? I want something that will let more bass come through.
post #152 of 213
Quote:
Originally Posted by pelayostyle
So ive been thinking.........
I feel like i want more bass from my dac. I have read that the value of the output caps determines the bass rolloff. How do i find out what freq. my 2.2uf caps are rolling off at? I want something that will let more bass come through.
Here's the link to the article on the topic.
http://www.ecp.cc/cap-notes.html

Though I'm not sure what the input impedance of LD II+ is.
post #153 of 213
Thread Starter 
Quote:
Originally Posted by pelayostyle
So ive been thinking.........
I feel like i want more bass from my dac. I have read that the value of the output caps determines the bass rolloff. How do i find out what freq. my 2.2uf caps are rolling off at? I want something that will let more bass come through.
Your 2.2uF caps are fine. Even when driving 10K resistance you should be getting an almost flat response down to 20Hz. I measured it. I tried adding 4.7uF Auricaps in parallel with my 2.2uF Auricaps just to make sure and couldn't hear a difference.
post #154 of 213
Quote:
Originally Posted by Kim Hardee
Your 2.2uF caps are fine. Even when driving 10K resistance you should be getting an almost flat response down to 20Hz. I measured it. I tried adding 4.7uF Auricaps in parallel with my 2.2uF Auricaps just to make sure and couldn't hear a difference.
Thats wierd. The mundorf caps sounded like they had more bass but less detail then the auricaps. Perhaps the added midrange clarity that the auricaps have masks the bass?

Kim, if youd like i can let you borrow the mundorf caps so you can see what im talking about. But give them back when your done
post #155 of 213
Quote:
Originally Posted by Kim Hardee
Your 2.2uF caps are fine. Even when driving 10K resistance you should be getting an almost flat response down to 20Hz. I measured it. I tried adding 4.7uF Auricaps in parallel with my 2.2uF Auricaps just to make sure and couldn't hear a difference.
Agreed. I'm no bass head, for the music I listen to, the 2uF Aerovox AFPS caps that replaced the stock electrolytic in mine provide plenty of bass. I did notice, however, there wasn't much bass immediately after the mod, and the highs and mids lacked the punch. So I decided to let it burn in for 40 hours or so, and after the burn-in the bass and clarity returns, and it's getting even better with more hours on it. HTH.
post #156 of 213
Hi Kim,
I'm finally happy with it. Please see new thread:
http://www6.head-fi.org/forums/showthread.php?t=208072
post #157 of 213
Thread Starter 
Quote:
Originally Posted by pelayostyle
Thats wierd. The mundorf caps sounded like they had more bass but less detail then the auricaps. Perhaps the added midrange clarity that the auricaps have masks the bass?

Kim, if youd like i can let you borrow the mundorf caps so you can see what im talking about. But give them back when your done
Thanks for the offer, but I think I already know what you're talking about. I tried a few PIO caps and initially it seemed like they had more bass, but over time it seemed to me that it was the more detailed and more forward midrange with the Auricaps in the bypass configuration that seemed to make the bass less prominent. I think the bass is still there, but the overall sound is more balanced, and probably more accurate. I think I'll just stick with the Auricaps. Thanks again.
post #158 of 213
hi kim, thank you for the great writeup on this thread. i just finished modding my dac a couple days ago. i used balckgate 4.7 uF N-series capacitors and kiwame 100k resistors for the bypass instead of auricaps/mundorf due to cost constraints, and i'm pretty happy with it.

i did notice a very lean bass at first time, but things just get better over time. before the passive mod, bass seemed a little bit bloated to my taste, but now everything is just nice and well balance. other mods that i did include running the chip @8V, replacing trimpot with bourns, 680 uF rubycon ZL for C28 & C37, 220 uF blackgate FK for C27, and 2200 uF Panasonic FC for C25 & C26.

i plannd to use a pair of blackgate for C28 & C37, but bass seemed too lean with 220 uF, when i replaced them with 680 uF the bass came back but not as bloated as running it active.

cheers for the tips folks.........
post #159 of 213
Is it possible to get a pdf copy or link for the Dac-Ah schematic?
Thanks
post #160 of 213
i notice that many of you have replaced the trimpot with a bourns model. what is the model number of the best part? it seems that there are a few over at digikey that might work...

thanks
post #161 of 213
Thread Starter 
Quote:
Originally Posted by shlomomofo View Post
i notice that many of you have replaced the trimpot with a bourns model. what is the model number of the best part? it seems that there are a few over at digikey that might work...

thanks
I'm not sure why you would want to replace the trimpot. I don't think it's critical to the sound quality. Does anyone have a different opinion?
post #162 of 213
i don't know if it makes any impact on sound, but definately there's less voltage drift on the DAC chip. with original trimpot i got around 0.5V variance with bourns trimpot it's around 0.1V variance. this is between the forst time i turned it on and after about 1hr playing.



ps: shlomomofo, i'll pm the part no. when i get home.


update: i think i use 3260/3266 series for bourns trimpot. not too sure, but it's a bit smaller than the original trimpot. looks like 3290 series etc works just fine too. it works really2 well.
post #163 of 213
Quote:
Originally Posted by revo_909 View Post
i don't know if it makes any impact on sound, but definately there's less voltage drift on the DAC chip. with original trimpot i got around 0.5V variance with bourns trimpot it's around 0.1V variance. this is between the forst time i turned it on and after about 1hr playing.
that's about what i figured... not in the signal path, but better trimpot equals more stable Vref. thought i may as well just replace it while i am changing the regulators and the I/V resistors. as for the part number, it looks like 3299W-1-102 will be ok. thanks.
post #164 of 213
Thread Starter 
Quote:
Originally Posted by revo_909 View Post
i don't know if it makes any impact on sound, but definately there's less voltage drift on the DAC chip. with original trimpot i got around 0.5V variance with bourns trimpot it's around 0.1V variance. this is between the forst time i turned it on and after about 1hr playing.
Thanks for the info. That's really interesting. I had assumed that the voltage drift was mainly due to the DACs heating up. You're describing about a 12% change in the resistance of the stock trimpot as it heats up, and almost no change in the DAC ouput current as they heat up. I agree that if a new trimpot can reduce the drift by a factor of 5 then it's well worth the change. I'd also be interested in the part number of your replacement trimpot. Maybe you could post it.
post #165 of 213
I wonder if any of you electronic gurus would consider upgrading my Lite Dac-AH with all/most of the goodies discussed here. If so PM me with what you would do and how much/long to do it. Thanks.
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