Rant: what is it with high gain on amps these days?
Feb 20, 2008 at 6:03 AM Thread Starter Post #1 of 17


Headphoneus Supremus
Apr 12, 2004
I don't know about the rest of you but I'm getting sick and tired of the proliferation of high gain among amps these days! Does no one use IEMs or low-impedance headphones to design their amps anymore? What happened to the idea of being able to fine-tune volume on low-impedance headphones? I can count the number of lower-gain amps I've heard on one hand - EarMax Anniversary, Eddie Current EC/SS and Zana Deux, HeadAmp Gilmore Lite! Multi-way gain switches are certainly nice but more often than not, the low gain value is still too high! Xin's freaking-tiny SuperMicro IV, which you'd think he designed for IEMs, is practically unusable with my Klipsch IMAGE which tilts the scales at 50 Ohms even, I can't imagine what it would be like with even lesser-impedance IEMs.

It's frustrating & annoying, that's what it is, and I don't get why most amp designers do this. Low gain options should have a low gain value!

I frequently amp from my iAudio X5 too btw, I'm not always listening to my 2-2.5V CD players.
I also very frequently try to find the point where an amp coalesces the musical elements from the turn-on point on my K701 and HD650, which becomes harder to accomplish in high-gain scenarios.
Feb 20, 2008 at 6:19 AM Post #2 of 17
I have been pointing out the HissBuster thread and explaining that sometimes attenuation is technically a better approach than amplification - but the fanboy "you gotta try THIS amp" posts seem the rule


Originally Posted by jcx /img/forum/go_quote.gif
with the UM2 you actually need the opposite of an amp - a quality attenuator

iPODs put out ~ 1 Vrms peak, UM2 are 135 dB/V sensitivity, for low level listening you may be using ~ 70 dB SPL requiring over 60 dB attenuation - when you do this with soundcard or DAP you are then listening to the noise floor of the electronics and DAC

a resistor divider between the iPOD headphone out and the UM2 could help much more cheaply than an amp:


the really classy solution would be a step down transformer for the UM2 - but quality audio transformers would likely be >>$100/channel and bigger and heavier than the iPOD - particularly with the required sheilding to prevent chance encounters with magnets from saturating the high permability cores

extreme high end audiophiles sometimes use transformer attenuators/"passive preamps" - same principle but you'd need a custom from a knowlegable xfmr designer to tailor the design for the signal levels and headphone impedance (you should want << the 27 Ohms of the UM2's impedance on the xfmr output)


Originally Posted by jcx /img/forum/go_quote.gif
If you don't DIY you could still ask around for a cable/amp builder to make you a custom output attenuator - should be < $100 unless you insist on solid silver/naked Vishay...

I would modify the HissBuster thread's recommendation slightly:

~ 2.7 Ohms output Z should keep any possible modification of the UM2 frequency response < 1 dB, in fact many amps will have 10 Ohms (or more) series output R

by keeping the output R a little higher you can use a higer value attenuation R which decreases the load on the iPod's amp (lowering ampilfier distortion) and lowers the low frequency cutoff from the iPod's internal output Cap (more bass, less bass distortion)

for ~30 dB 82 : 2.7 Ohms would be my choice (some cheap metal film R are harder to find <10 Ohms, just parallel 4x 10 Ohms - should be close enough)

Low Ohm Resistor attenuators should be an easy solution for DAP or Desktop amp outputs

for line outs the transformer solution could work: a -20 dB xfmr would look like 10x impedance to the input for 320 Ohms with 32 Ohm iem

a good active electronic solution still needs a fairly low Ohm input attenuator step ahead of the (also unusually low R) volume pot to preserve S/N - then many unity gain amp/buffer circuits are possible
Feb 20, 2008 at 6:45 AM Post #3 of 17
I agree on the problem with so many amps having a high gain.

I've even found the RSA Tomahawk, being branded for IEMs to have too much gain for the UM2s. There's even a high-gain switch, but even when I'm listening to my Grado GS-1000s, I can get really loud volume on LOW gain at the 9-10o'lclock position.

I guess half the problem is the UM2s being so sensitive, but I would have hoped to turn the pot further so there's better channel balance.

I've tried using an attenuator, but that has degraded the sound (the Shure one with volume control. That was really horrible - I'd rather listen through a tin can!). I think Etymotic makes an attenuator (P to S adapter?), but I also find the use of an amp also provides benefits of soundstage and clarity that I think an attenuator does not. In otherwords, I'm not very impressed by the iPod headphone out (5G).
Feb 20, 2008 at 7:04 AM Post #4 of 17
i think one of the big problems is that iems and canalphones are made to be so sensitive. most daps cannot drive iems without big bass loss, so. if manufacturers would make iems to imp match ipod or other devices that have a better time driving 64ohm loads, and lower the sensitivity to 100db or so, i think it would be so much better. even 97 or 96 db would be great. then we would have no hiss, no bass roll off (or very little) and no reason to have to spend money on an extra amp or attenuator. ive seen too many posts forgiving the iem and canal phone manufacturers but not taking into account that they came after portable audio - just too bad the two will not meet in the middle.

it could be that they are in heavy cahoots with amp manufacturers who also make attenuators... shame it is.
Feb 20, 2008 at 9:22 AM Post #5 of 17
One abbreviation - DIY
If you're that unhappy with high gain on amps, have them custom built, build it yourself or modify it to lower its gain.

I can understand why a lot of IEM/earphone/canalphone manufacturers will make their products with low impedance and very sensitive - it's so that you don't need an amp to get high listening levels from portable DAPs.

I can also understand why some portable amps are made to have reasonably high gain for IEMs (about 5x is average, no?). It's because some DAPs have much lower strength signals than others. An iPod line out has a 1V signal strenth, a lot of other DAPs have half of that or less. If you're using an iPod with an "average gain" amp and IEMs sure, it might be pretty loud, but if you use some other small DAP, you might get very different results.

Home amps - No reason to have insane gain, really none that I can think of; unless of course you MUST. Tube and tube hybrid amps have a set gain because of the tubes used - more than 10x for Millet and SOHA. Lowering the gain means putting resistors inline on the output and this degrades the sound quality. When I built my SOHA with a gain of over 10x, I still skipped the output resistors and just used lower volume with Grados, it sounds better than higher volume settings and even the best resistors I found (at that point I tried Kiwame, PRP, Holco, Riken and Allan-Bradley). No resistor on the output sounds better than any "high quality" resistor.

For home-based solid state amps, I don't see a really good reason why gain can't be set to something reasonable. I have a PPAv2 with a gain of 6x which drives everything I have very well off the iPod and AlienDAC. I don't see a reason to have higher gain. Perhaps some really inefficient AKG?

I guess this all comes down to trying to suit all headphones off the same amp. Make sure to handle the hardest to drive headphones while keeping a low noise floor on efficient headphones means a great amp. If an amp acheives that, who cares that you only use the first 25% of the volume control with your efficient headphones!
Feb 20, 2008 at 1:02 PM Post #7 of 17

Originally Posted by jellojoe /img/forum/go_quote.gif
I thought one was suppose to use a voltage divider instead of a resistor to effective lower the volume without degrading the sound quality.

Totally true, but a lot of amps don't do it. It still doesn't really lower the volume "without degrading the sound quality" since signal still goes through the extra pair of resistors, and it would be better to use the feedback loop resistor values to adjust gain, but it does make a difference for the better vs inline resistors (I think it's the same idea, but it doesn't add extra parts to the circuit).
Feb 20, 2008 at 1:48 PM Post #8 of 17
Because, everybody wants a "drive everything" amp, rather than just as you said, specialized on a specific area. It's the way everything is today, all in one's good at everything, but not GREAT at anything.
Feb 20, 2008 at 1:53 PM Post #9 of 17
My Etymotic ER6s require more than half the volume my iPod is capable of to get to good listening levels. They must be insensitive brutes for ear canal phones. Sound pretty good, though.

Feb 20, 2008 at 2:00 PM Post #10 of 17

Originally Posted by oicdn /img/forum/go_quote.gif
Because, everybody wants a "drive everything" amp, rather than just as you said, specialized on a specific area. It's the way everything is today, all in one's good at everything, but not GREAT at anything.

Beat me to the punch,and hit the nail on the head ! That fast food mentaltity at work.
Feb 20, 2008 at 2:09 PM Post #11 of 17
Great rant. I was just thinking about this the other day.

My tube amps, even with gain switches, are still set too high for my Grados. I can't get anywhere near the center of the volume control. I'm usually around 9 o'clock, with zero being at 7 o'clock.
Feb 20, 2008 at 2:13 PM Post #12 of 17
My Graham Slee Voyager matches my Grados pretty well - my volume tends to move between 11 o'clock and 1 o'clock depending on the music and my mood.
I have a new lower gain edition though...
Feb 20, 2008 at 3:16 PM Post #13 of 17
the ety also as they are less sensitive with an imp of 48 have less bass-roll of from portables. sensitive low imp phones still make no sense. even from my sony which has nothing the output of my ipod or d2, the volume is far too loud. only the sony however has push pull output to properly or near properly drive the iems i have (atrio, formerly um2).

in order to not get bass rolloff with portable dap and iem you need an amp. it is not a good pairing. i think the idea is that still iems are thought of as musician tools and they are always put up to a battery powered wireless amp. the musician will need none nor can use the same amount of detail with all the noise around her so if a little bass-roll off occurs it is not detremental. but some of those wireless amps are very good and can drive even um2 very well.

iem manufacturers should make dap iems with daps in mind. i understand the argument about voltage and power but i have never used more than 6/20 on my sony which has a relatively low output compared to the ipod. for my d2, never went above 14/50 and that was only experimental days when i felt dangerous. the ipod is about the same 1/4 of volume.

a little extra volume is worth not having bass-roll off. really
Feb 20, 2008 at 3:32 PM Post #14 of 17

Originally Posted by oicdn /img/forum/go_quote.gif
Because, everybody wants a "drive everything" amp, rather than just as you said, specialized on a specific area. It's the way everything is today, all in one's good at everything, but not GREAT at anything.

Couple that thought with a vendor's desire to sell something to the whole market vs. something that appeals to a fraction of it. More potential customers = more potential profit. I don't see anything particularly wrong with that though.

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