tag:blogger.com,1999:blog-6890046273025265768.post1824320715019029669..comments2021-06-20T06:15:54.386-07:00Comments on NwAvGuy: More Power?NwAvGuyhttp://www.blogger.com/profile/00309644608738074125noreply@blogger.comBlogger64125tag:blogger.com,1999:blog-6890046273025265768.post-81863990910548325202012-06-14T16:16:07.649-07:002012-06-14T16:16:07.649-07:00It's impossible to say without knowing the pow...It's impossible to say without knowing the power supply voltages supplying the NJM4580 if the DT880 would work. The Q701 will not be a good match as the 4580 can't supply enough current even if it can supply enough voltage. The volume control position isn't linear so you can't really predict anything from that.NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-44935750412362783702012-06-13T17:33:57.731-07:002012-06-13T17:33:57.731-07:00So, NwAvGuy, I've got an Auzentech Forte with ...So, NwAvGuy, I've got an Auzentech Forte with an NJM4580 op amp for the headphone amplifier (don't know if that is important). It's been difficult getting any solid answer on Head-Fi (where everyone has their own opinion or repeat what someone else said), so I'm wondering if you can tell me if this card can drive the beyer DT 880 (250 ohm) or AKG Q701 properly? Would I be right inAnonymoushttps://www.blogger.com/profile/07741823095432540281noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-15860713552218653882012-04-16T00:44:56.997-07:002012-04-16T00:44:56.997-07:00Hi, A simple xl based h/p power calculator can be ...Hi, A simple xl based h/p power calculator can be found over here www.apexhifi.com/specs.htmlSound Shuinoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-63213956159796866842012-04-15T19:52:43.101-07:002012-04-15T19:52:43.101-07:00The cheap Pro-ject Headbox, from what I know, does...The cheap Pro-ject Headbox, from what I know, does use a capacitor coupled output. Any headphone amp that runs on a single DC "wall" supply generally either uses capacitor coupled outputs, or a <a href="http://nwavguy.blogspot.com/2011/05/virtual-grounds-3-channel-amps.html" rel="nofollow">Virtual Ground</a>. Either can cause audible problems--especially with low impedance headphones. <NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-29865401150316987762012-04-15T19:22:30.319-07:002012-04-15T19:22:30.319-07:00I have a Pro-ject Headbox 2 which is problematic w...I have a Pro-ject Headbox 2 which is problematic with my AKG 702.<br />Why ? Very recessed from lower mid range down, easily bettered by<br />a Denon 1912 receiver head phone output, right next to it. A Pioneer<br />VSX 518 is also vastly better in bass and midrange. These are both supposedly resistor outputs, Denon going for opamps in the next model up.<br />These are reputed to be poor quality Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-40379224283203554232012-03-29T07:12:42.042-07:002012-03-29T07:12:42.042-07:00I didn't see NwAvGuy's answer at first, so...I didn't see NwAvGuy's answer at first, so I came up with this:<br />Sensitivity in dB/mW = dBV - (10 * log(1000 / Z))Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-29543165578445887692012-02-25T16:59:16.447-08:002012-02-25T16:59:16.447-08:00Geez, I didn't look carefully. Thanks for the ...Geez, I didn't look carefully. Thanks for the correction!<br />Was sorta thinking, wow not a K701 again!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-39589727311286754162012-02-25T16:39:50.460-08:002012-02-25T16:39:50.460-08:00The ER-4P is rated at 102 dB SPL at only 0.1 Vrms....The ER-4P is rated at 102 dB SPL at only 0.1 Vrms. That's 122 dB at 1V. So it's plenty efficient. A typical 0.5 Vrms portable will drive it to 116 dB which is above the 115 dB SPL target.NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-60794989039077095012012-02-25T14:06:08.918-08:002012-02-25T14:06:08.918-08:00Oh wow. Using your equation, the ER-4P has an effi...Oh wow. Using your equation, the ER-4P has an efficiency of a mere 86 dB/mW! With 27 ohms of impedance this has got to be a huge current-eater.<br /><br />...Might want to grab something with higher impedance and higher efficiency.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-84004198911919238772012-02-25T14:02:35.770-08:002012-02-25T14:02:35.770-08:00Very cool, thanks for the equation!Very cool, thanks for the equation!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-13420405890244673952012-02-25T07:11:17.152-08:002012-02-25T07:11:17.152-08:00The two are related by the impedance of the headph...The two are related by the impedance of the headphones. To convert from dB/mW to dB/V you add 20*LOG(1/SQRT(0.001*Z)). So for 32 ohm headphones (Z=32), that works out to adding about 15 dB. So if a pair of 32 ohm headphones are rated at 90 dB/mW they're 105 dB/V. To go the other way, you subtract the value you get from the above equation.<br /><br />The difference drops with increasing NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-54226259583396572752012-02-24T18:50:48.294-08:002012-02-24T18:50:48.294-08:00Hi there,
I know this has probably been asked alr...Hi there,<br /><br />I know this has probably been asked already, but is there a direct way to convert dB/V to dB/mW, in terms of headphone efficiency (sensitivity)?<br /><br />Thank you!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-9990319113799935632012-02-23T15:48:37.139-08:002012-02-23T15:48:37.139-08:00Nevermind... I just found out that most listeners ...Nevermind... I just found out that most listeners will set their average level at 69 dB in quiet environments, so my math was probably fine. Now I know I don't need 110 dB SPL!YTCrazyTieGuyhttps://www.blogger.com/profile/10184104554587419019noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-14520744315506945352012-02-21T11:00:05.634-08:002012-02-21T11:00:05.634-08:00Generally if it's not specified it's likel...Generally if it's not specified it's likely at 1 mW. As another guide, the 1V values are generally 10+ dB higher. The relationship between the two depends on the headphone's impedance.NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-51894886541999737582012-02-21T08:34:06.692-08:002012-02-21T08:34:06.692-08:00Hi, thanks for the great article.
I was wondering...Hi, thanks for the great article.<br /><br />I was wondering, if it's not specified weather a headphone's sensitivity is for 1 mW or 1 volt, is it safe to assume it's one of the two? or could it be for some other amount of power or voltage?<br /><br />ThanksYTCrazyTieGuyhttps://www.blogger.com/profile/10184104554587419019noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-84691111885660340892011-12-25T15:12:58.046-08:002011-12-25T15:12:58.046-08:00Does anyone have a link to the formula for calcula...Does anyone have a link to the formula for calculating the perceptual change in loudness, for a given change in SPL? So far, the best I've found is the table here: http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm but that's just in 3dB increments. \Greg.SullivanGnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-29511569273600486082011-12-24T12:46:43.692-08:002011-12-24T12:46:43.692-08:00Of course, the SPL I am experiencing when playing ...Of course, the SPL I am experiencing when playing piano depends on the frequencies present at the time. So, there was no point in consulting the frequency response graph to determine the SPL that happened to conincide with the sine wave test signal I used. The purpose of the test signal is simply to determine the maximum voltage that the amp is capable of, when loaded with the headphones. <br /><SullivanGnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-44994018307958424582011-12-01T03:38:51.480-08:002011-12-01T03:38:51.480-08:00(minor correction to last - the K601 sensitivity i...(minor correction to last - the K601 sensitivity is actually 101dB/V)SullivanGnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-35011863513735863312011-12-01T03:36:54.656-08:002011-12-01T03:36:54.656-08:00Great article. I am indeed running into the peak p...Great article. I am indeed running into the peak power problem with my V-Can amp driving AKG K601 headphones. I first noticed the problem when playing a software piano, live. I sometimes experience clipping at the "attacks" of the piano. (the moment the hammers strike the strings). If my calculations are correct, the V-Can is clipping at about 113dB SPL. (3.2V RMS into 120 ohms, SullivanGnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-65381914136915231562011-10-30T12:33:28.935-07:002011-10-30T12:33:28.935-07:00When looking for an inexpensive amp to drive K701s...When looking for an inexpensive amp to drive K701s, the E9 would definitely be fairly high on my list. That, or maybe the Pro-Ject Head-Box II (I don't think these are available outside Europe - it's a single-supply '2068 + BD139/140 AB buffer design running on +15V with a somewhat highish gain and output impedance, but nice build quality, costs a little less than the E9 here).<br /><Stephanhttp://stephan.win31.de/noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-88198691209623030062011-10-30T08:58:42.264-07:002011-10-30T08:58:42.264-07:00If the E10 is like the E11 (they use the same outp...If the E10 is like the E11 (they use the same output op amp) it won't have enough power for the K701. The E11 can only manage around 2 Vrms or less into the K701 and the distortion is relatively high. Just like the Mini3 it's based on, the E11 doesn't do well with lower impedance headphones that need much over 0.5 volts. I'm not sure if the E10 will be much better but I'll be NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-78460329384140812102011-10-30T03:28:06.480-07:002011-10-30T03:28:06.480-07:00Ah, the O2. I would gladly get this if it is avail...Ah, the O2. I would gladly get this if it is available in the market without the diy stuff. I hope it goes into production in the future. <br /><br />But for now, I am thinking of pairing e10+e9 for the k701. Would this make some improvement over e9 alone or e10 would do better due to its lower ouput impedance? I have no idea if e10 theoretically has enough power to drive the k701s as everyone Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-44963576838423094022011-10-29T15:23:42.400-07:002011-10-29T15:23:42.400-07:00@anon, I think the E9 is marginal for the K701 bec...@anon, I think the E9 is marginal for the K701 because of the 1/8th rule and I'm also not impressed with the low frequency distortion. You could certainly do worse than the E9, but you can also do better for around the same price--i.e. the O2.NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-57998117122019464562011-10-29T09:43:21.126-07:002011-10-29T09:43:21.126-07:00Hi NwAvGuy,
I have read your extensive review on ...Hi NwAvGuy,<br /><br />I have read your extensive review on the E9. I would like to know if it would be a good match for the AKG K701.<br /><br />The input impedance is 62Ohms and sensitivity is<br />105dB SPL/V. Based on the 1/8 rule you discussed, does it mean this pair would not work?<br /><br />Of course there are other variables like you stated above, but I am not really sure how this pair Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-88388693622398506762011-10-25T08:48:35.542-07:002011-10-25T08:48:35.542-07:00@hlin599, The sensitivity and impedance are not co...@hlin599, The sensitivity and impedance are not constant. Ideally it's measured with broadband pink noise which takes into account what you mention. Otherwise, you have to do the best you can with whatever data you have.<br /><br />If you want to be conservative, and know the maximum impedance, you can use that value for calculating required power. But be sure to use the minimum or nominal NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.com