tag:blogger.com,1999:blog-6890046273025265768.post7470234165958523107..comments2024-03-18T03:10:30.572-07:00Comments on NwAvGuy: Cmoy With GainNwAvGuyhttp://www.blogger.com/profile/00309644608738074125noreply@blogger.comBlogger30125tag:blogger.com,1999:blog-6890046273025265768.post-43465750386342371072012-05-02T14:47:00.221-07:002012-05-02T14:47:00.221-07:00To add, I ended up with 47K at R1 and 22k at r2 an...To add, I ended up with 47K at R1 and 22k at r2 and r3 for about 4db gain and the offset averages 1mv per channel.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-66897863419173683942012-04-28T19:28:03.910-07:002012-04-28T19:28:03.910-07:00So, I got one of these to play with and used your ...So, I got one of these to play with and used your info to experiment a bit. I know there's debate on what can be heard but I used my ear and bits on hand to see what I could come up with. Damping factor and things like TIM can be audible even if not measured. For those that want to do the same please not that resistor positions were marked differently on mine, a fanmusic unit that was Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-31814584479710172682012-03-01T20:08:45.603-08:002012-03-01T20:08:45.603-08:00I believe the Clip+ uses, essentially, a virtual g...I believe the Clip+ uses, essentially, a virtual ground to avoid needing output capacitors (see my Virtual Ground article from last May). In something as small as the Clip+ space for the capacitors could be a serious concern. To get reasonably decent low frequency performance into 16 ohm headphones you need at least 470 uF caps which are physically fairly large.<br /><br />But, in general, using NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-88098245500298282762012-03-01T16:00:52.500-08:002012-03-01T16:00:52.500-08:00Would you know the reason behind the fact that few...Would you know the reason behind the fact that few portable players are direct-coupled? Is it due to the high degree of integration (everything audio in a single SigmaTel)? Is capacitor coupling any cheaper? That wouldn't make any sense since even the Clip+ is direct-coupled.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-79058625005908496592012-02-29T06:22:07.048-08:002012-02-29T06:22:07.048-08:00I see. I sorta anticipated this capacitor-coupled ...I see. I sorta anticipated this capacitor-coupled output thing.<br />I should go measure my MAX9722 (direct coupled, no caps) and see what comes out of it.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-64106586684023893512012-02-29T05:57:51.119-08:002012-02-29T05:57:51.119-08:00It sounds like your device may have capacitor coup...It sounds like your device may have capacitor coupled outputs. With only the load of the DMM (likely 1M--1 million ohms) there will be some DC "leakage" of the caps causing somewhat random readings. That's normal. The charge current of the caps also has an exponential asymptotic decay which means a high impedance load equates to a long time before it gets so close to zero your DMM NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-73013001791886146562012-02-28T17:05:08.218-08:002012-02-28T17:05:08.218-08:00Good news.
I tested again using this correct meth...Good news.<br /><br />I tested again using this correct method, with a headphone splitter and no music playing.<br />I am reading exactly 0.00 mV (always 200 mV scale). I even swapped the two sockets (on the splitter) to make sure things are working right. <br />I do indeed hear a faint hiss in my IEMs when plugged in so the output circuit is on. I have encountered devices that shut down their Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-17062082938479843222012-02-28T09:37:54.263-08:002012-02-28T09:37:54.263-08:00Anything over 20 mV may be cause for concern depen...Anything over 20 mV may be cause for concern depending on the headphones. But you have two issues that might be effecting your reading. First, yes the output should be loaded--you can use a "Y" splitter cable and plug headphones into the other jack or you can use a resistor in the 32 - 600 ohm range in parallel with the DMM. Second, no music should be playing. The DMM is likely to get NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-25598873926024586632012-02-28T03:09:28.399-08:002012-02-28T03:09:28.399-08:00I have a couple of questions regarding the DC offs...I have a couple of questions regarding the DC offset issue.<br /><br />I tried to measure the DC offset of one of my sources. What I did was to hook up a 3.5mm interconnect to the headphone jack. Then I took a multimeter, set it to DC 200mV and started playing music at the volume level which I listen to.<br /><br />I connected the black lead to the Ground and the red lead to the Left channel. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-88919185193837222592012-02-13T16:44:36.628-08:002012-02-13T16:44:36.628-08:00It's not a black and white thing in most cases...It's not a black and white thing in most cases, although the Asgard was way over the top and obviously a hazard (as confirmed by AKG and video of the driver being severely deformed). Towards the end of my O2 Details article I document the turn and turn off transients of the O2. In both cases they're no greater than what an iPod routinely puts out playing music. The turn on click is very NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-61221654414925923412012-02-13T14:29:19.037-08:002012-02-13T14:29:19.037-08:00You mention that with your eBay cmoy, "There’...You mention that with your eBay cmoy, "There’s a “pop” when you first turn it on that’s not that bad—especially with more typical headphones. There’s a softer click when you turn it off." After reading the back story to the Schiit Asgard being flagged as potentially dangerous to headphones during power-off, I've become someone concerned if other amps without a protection relay Joshnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-88765862115387454722011-12-18T08:10:40.906-08:002011-12-18T08:10:40.906-08:00@Daniel, the K701 needs 3.2 Vrms that's 4.5 vo...@Daniel, the K701 needs 3.2 Vrms that's 4.5 volts peak. At 62 ohms, that's 72 mA of peak current. The JDS designed amp can only manage about 20 mA of peak current because of the ground splitter used for the virtual ground.<br /><br />So, in summary, the JDS amp is a poor match for the K701s. Putting in a high current op amp like the 4556 won't help because the current output is NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-22367889637298569852011-12-18T03:59:42.276-08:002011-12-18T03:59:42.276-08:00Hi, It's Daniel again. Got another question fo...Hi, It's Daniel again. Got another question for you. I got a JDS Labs Cmoy PCB Laying around, would it be worthwhile to complete it and mate it with my AKG701's til I get my hands on a ODAC-combo or something similiar?<br /><br />Any ideas on what OPamps to use for it? 4556?Danielnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-44228375951838336892011-10-19T08:09:46.216-07:002011-10-19T08:09:46.216-07:00I've seen several RA1 clones that use a differ...I've seen several RA1 clones that use a different op amp, and/or use a single battery with a rail splitter. Neither can be expected to work very well as the 4556 stands alone among all dual DIP8 op amps for driving low impedance loads. Any op amp "upgrades" are really "downgrades".<br /><br />The power management circuit in the O2 immediately shuts the amp down with littleNwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-22921766311691041652011-10-19T03:44:12.667-07:002011-10-19T03:44:12.667-07:00FWIW, a few years ago I bought an RA1 clone on eba...FWIW, a few years ago I bought an RA1 clone on ebay. I sold it on head-fi after 2 weeks.<br />From a purely subjective stand point: it did mate well with my Grado SR-80, didn't move the Senn HD580 properly. While the sound was not bad at all, I felt my portable pimeta was better.<br />I am not sure how close that clone was to the actual RA1 circuit though (didn't occur to me to check). Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-65521038279969994762011-10-11T20:56:15.697-07:002011-10-11T20:56:15.697-07:00Just was told the RA1 cmoy "clones" are ...Just was told the RA1 cmoy "clones" are 8-12ohms output impedance. Surprisingly high. Definitely not a true RA1 clone if it's got a split rail and isn't near zero ohm. Too bad, as this one you found on ebay seems very rare. It's probably closer to the Grado than the ones that say RA1 on them on ebay.Reticulinoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-69282268413167666722011-07-14T15:41:13.262-07:002011-07-14T15:41:13.262-07:00I will be reporting more on DIY designs soon. Havi...I will be reporting more on DIY designs soon. Having separate channels is questionable as most of these designs are limited in other ways (like the rail splitter on the Nico). In a properly designed amp separate channels can have some measurable advantages. But eBay amps are rarely properly designed.<br /><br />A lot of the headphone amps and DACs being sold on eBay are all about buzzwords, NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-47139029799696272392011-07-14T15:14:33.555-07:002011-07-14T15:14:33.555-07:00ok, discard the Neco SoundLab, but i have seen ver...ok, discard the Neco SoundLab, but i have seen very good reviews...<br /><br />which is the best design for headphone amplifier <br />DIY? Cmoy with channel separate?<br /><br />thanks..Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-62518424945494672532011-07-14T11:05:22.282-07:002011-07-14T11:05:22.282-07:00The Neco Soundlab V2 is a single battery design an...The Neco Soundlab V2 is a single battery design and uses the TLE2426 rail splitter which is only rated for 20 mA of current. That's only 10 mA per channel and LOTS of headphones need much more than 10 mA even some common ones like the Denon AH-D2000s. So for anything but very efficient high impedance ( > 250 ohms) headphones, the Neco Soundlab is a poor choice.<br /><br />The TLE2426 will NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-62043037102082226582011-07-14T10:40:14.672-07:002011-07-14T10:40:14.672-07:00NwAvGuy, what is your opinion on neco soundlab v2,...NwAvGuy, what is your opinion on neco soundlab v2, similar to cmoy, but power supply and the channels audio separate..<br /><br />thanks, you're the bestAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-27877456987575657402011-07-09T16:26:33.043-07:002011-07-09T16:26:33.043-07:00"given more or less the same ingredients--sor..."given more or less the same ingredients--sort of a battle of the Chefs"<br /><br />So who's "Iron Chef: Silicon" and does that count as an oxymoron?maverickroninnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-35607320631328569302011-07-08T11:38:58.278-07:002011-07-08T11:38:58.278-07:00To Gonzalo, I have my doubts about RMAA's cros...To Gonzalo, I have my doubts about RMAA's crosstalk measurements in general. But, if the tests you link were really loaded with the UE TripleFi headphones, the iBasso does at least seem to have a very low output impedance (which is good). According to those tests, the Nano 6G does roll off at high frequencies in a potentially audible way due to its higher output impedance.<br /><br />The NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-80914739140000351832011-07-08T05:50:07.737-07:002011-07-08T05:50:07.737-07:00As just a fan of the most accurate sound i can get...As just a fan of the most accurate sound i can get into my multidriver UM3x iem i'm kind of a fan of the iBasso T3 as a way of getting a ruler flat response into the transducer without degrading other aspects like THD or crosstalk. What i did not know till this day was that flaws of the 3ch concept may render not so good crosstalk figures.<br /><br />Here you can check an RMAA on an iPod NanoGonzalohttps://www.blogger.com/profile/05606205794364659817noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-20479821637877779772011-07-07T15:44:10.352-07:002011-07-07T15:44:10.352-07:00Thanks for the follow up. Its too bad you cant buy...Thanks for the follow up. Its too bad you cant buy this exact amp on ebay any more as it would be a great cheap way to drive high z phones. I would easily take one over a mini3.<br /><br />As an engineer I agree with your 3 channel design view. I can see it where you have no other choice but to claim it's superior to a conventional ground is pure audiophile BS. The 3 ch fanbois should get D Wilsonnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-22748843276483383892011-07-07T01:53:49.679-07:002011-07-07T01:53:49.679-07:00Ups, did not know anything about the 3ch architect...Ups, did not know anything about the 3ch architecture.Going by the numbers the iBasso T3 seems to measure quite well but obviously i'm referring to a few RMAA's. Subjectively i'd say it's competent and clean for multidriver iems.Gonzalohttps://www.blogger.com/profile/05606205794364659817noreply@blogger.com