[A.Thorsen]

Quote:

Originally Posted by nierika Whoh...welcome back Justin!

Wow!

 

[darkninja67]

Quote:

Originally Posted by nierika Whoh...welcome back Justin!

Here Here. Nice to see him here.

 

[Asr]

I hope Justin posting is a sign that the 2006 AE-1 is nearly complete...

 

[Solude]

The HeadAmp Lite will drive anything you throw at it. The catch is you better be happy with your source because the Lite won't dress it up all pretty for you

 

[Svperstar]

Quote:

Originally Posted by grasshpr I'm not exactly sure what gain the gilmore lite is using but with at least a gain of 5 or so I can notice some noise from the output.

I'm sorry if I am misunderstanding you but are you saying there is noise in the signal due to the Gilmore lite? I completely disagree with you, I have tried different sources and different cans on my GL and have never noticed anything but the music, no noise at all.

 

[grasshpr]

Quote:

Originally Posted by Svperstar I'm sorry if I am misunderstanding you but are you saying there is noise in the signal due to the Gilmore lite? I completely disagree with you, I have tried different sources and different cans on my GL and have never noticed anything but the music, no noise at all.

I'm pretty sure that I'm making it clear that the noise is from the high gain amplifier (as no amplifier is perfect with respect to noise). All amps have some noise and to what degree depends on your hearing sensitivity and the types of cans you use (e.g., low impedance cans are typically very susceptable to amps that are typically built for high impedance phones, however, amps built for low impedance phones typically don't provide enough power to high impedance cans).

Keep in mind these are MY impressions of the Gilmore topology (NOT of the Gilmore lite since I don't own one). However these designs are almost identical and I was just putting my two cents in to help other discern my impressions of this TYPE of amp. If you don't notice them, more power to you! These are purely what I've noticed by testing with the rigs that I have. If you don't get any noise then that's great!

 

[Towert7]

Quote:

Originally Posted by grasshpr Keep in mind these are MY impressions of the Gilmore topology (NOT of the Gilmore lite since I don't own one).

With my headphones, my gilmore lite is extreamly quite. I can not hear any noise.

 

[Solude]

Never had noise on my Lite or Reference. Might have bad parts matching or assembly problem on your DIY amp.

 

[justin w.]

Quote:

Originally Posted by grasshpr I'm pretty sure that I'm making it clear that the noise is from the high gain amplifier (as no amplifier is perfect with respect to noise). All amps have some noise and to what degree depends on your hearing sensitivity and the types of cans you use (e.g., low impedance cans are typically very susceptable to amps that are typically built for high impedance phones, however, amps built for low impedance phones typically don't provide enough power to high impedance cans). Keep in mind these are MY impressions of the Gilmore topology (NOT of the Gilmore lite since I don't own one). However these designs are almost identical and I was just putting my two cents in to help other discern my impressions of this TYPE of amp. If you don't notice them, more power to you! These are purely what I've noticed by testing with the rigs that I have. If you don't get any noise then that's great!

I'm unaware of any headphone amp topology that has lower noise than the Gilmore design. It's a simple discrete circuit that uses pretty much the lowest noise transistors that are available.

I'm actually not able to accurately measure the noise level of the amp because it has a better signal-to-noise ratio than my test equipment (so the SNR spec on the website is underrated). However, I have found using ultra-sensitive IEMs to be the best real world test of an amp's noise level, and it sounds like your DIY amp is not an accurate representation of the Gilmore Lite.

 

[grasshpr]

It should be noted that I am not talking about high impedance cans as I presume that Towert and Solude are mentioning. And of course I am using moderate parts to stock my dynalo: Nichicon's, 1% metal can resistors hand matched, matched transistors, and also a dynahi PSU. I was however addressing that my e3c's do not sound great with this design because I do have some noise coming primarily through this amp at high gains. With my other phones, it is deadly quiet, e.g., HD600's and SR325's.

To address Justin's comments. I am in perfect agreement that this design has a very low SNR compared to other amps. It is however not without some limitations. Alot of people build dynalo's using a pretty high gain (default for dynalo's and of mine are gain of 11 which is pretty high for an amp). On a side note, number one reason why I have mine at a gain of 11 is to facilitate my high impedance cans. I am however still able to discern some noise at gains at around 5 with the e3c's. Very slight at that level though. I should apologize about making an erroneous statement that Gilmore topology would not work well with low impedance cans. With proper component choice, this shouldn't be a factor. Thanks for setting me straight Justin!

Also, as Justin indicated correctly, I am not making any definitive statements of the Gilmore lite since I don't own one myself. I was just posting some of my observations about my dynalo amp with respect to the e3c headphones.

 

[VR6ofpain]

I have a rega Planet going into my Gilmore Lite. If I pause the CD I can turn the lite up to full volume with my K601's without hearing a single bit of noise. This amp is incredibly quiet.

 

[justin w.]

Quote:

Originally Posted by grasshpr I am however still able to discern some noise at gains at around 5 with the e3c's. Very slight at that level though. I should apologize about making an erroneous statement that Gilmore topology would not work well with low impedance cans. With proper component choice, this shouldn't be a factor. Thanks for setting me straight Justin!

There's no need to run anything over unity gain (1x) for the E3C or similar phones. A SPL of 115dB is achieved with 0.16V of output and very low current. Considering even the weakest portable source probably has a line level output of 0.5V and home sources usually range from 1-3V, in the end you're going to be attenuating the signal considerably rather than amplifying it (so all you need is a volume control and a buffer for low output impedance). Any voltage amplification you do will just add unnecessary noise & amplify noise coming in.

 

[Solude]

Quote:

Originally Posted by justin w. Any voltage amplification you do will just add unnecessary noise & amplify noise coming in.

Which is why my Reference is set to unity gain for high impedance headphones. Thanks again for that Justin

Oh and by the way, the Dynalo design was made with low impedance in mind not high, that would be the Dynahi which err doubles as a speaker amp

 

[grasshpr]

Quote:

Originally Posted by justin w. There's no need to run anything over unity gain (1x) for the E3C or similar phones.

Your right about having unity gain. Actually e3c's don't benefit much from amps in general. In response to Solude, as for high impedance amps with unity gain, I doubt that alot of people would agree that having unity to suffice with phones like HD600/650 or DT880, etc. Not to say it is a bad thing to have unity gain amps, it just doesn't give you the voltage range that may want.

 

[Solude]

To be fair not a lot of people know enough about gain on headphones to have an opinion worth listening to

Lets put it this way. The Senn 650/AKG 701 put out 105dB@1V or about 90dB@250mV. Now since 90dB is hearing damage and sources put out 2V why would anyone need more than unity gain? Answer, if their source put out a weak output or the source material is recorded well below 0dB. Neither of which are concerns of mine.

Notches on a DACT for instance are 2dB in the usable range. A gain of 3x for instance will gain you 4 steps of increased volume while pushing your average listening notch down by 4. At unity gain my average listening step is 11 and on material recorded softly it can climb to 15. At that average level, its pretty loud and I regularily miss my wife talking to me. I still have another 9-13 steps to go before I cap out. Thats another 18dB or 6x gain from normal listening levels to cap. Think another 18dB on top of the 18dB already available is ever going to be needed