JDS Labs C5/C5D (pg96) portable amp/amp+DAC
Aug 14, 2013 at 9:26 PM Post #1,276 of 3,417
Yeah the Konami code.
http://en.wikipedia.org/wiki/Konami_Code

Yeah you have to send it in to update the firmware to get finer volume controls......or you can do it yourself with external hardware/software. :D
Oh i know the code. Don't doubt that for a second. I have a nintendo thumb. Haha
 
Aug 14, 2013 at 9:27 PM Post #1,277 of 3,417
Quote:
 
Finer volume control?  Did I miss something?  How do you do that?  Don't tell me it's a simple firmware update.... ?

 
Start from this post, skipping to related posts...
 
http://www.head-fi.org/t/647838/jds-labs-c5-portable-amplifier-appreciation-discussion-thread-check-1st-post-for-review/1185#post_9665173
 
Aug 14, 2013 at 10:23 PM Post #1,280 of 3,417
As of today, volume control resolution is 200-400% finer:
https://github.com/jdslabs/C5_Firmware


Original firmware (v1.0.x) changed volume once every 55ms while pressing the volume control. So, holding the control for more than 1/20th of a second resulted in moving at least 2 volume steps. We noticed a few requests here for "more steps", and it took a while to realize that you guys weren't asking for more steps, but for better control of the large number of steps C5 already has. It turns out that the average finger motion results in a volume step change of 3-4dB; this motion should have changed volume by only 1dB. And thus, some of you thought C5 had too few steps. You really needed faster fingers, or better firmware.


Today's firmware release (v1.1.0) replaces C5's volume control logic. The amp now changes volume by exactly 1dB for every volume control touch shorter than 0.375 seconds. If you hold the volume control longer, it 
increases or decreases volume by 
1dB every 55 milliseconds. Much easier.
Yeah, i realized that flicking it faster helps, but it feels like it wouldn't be the best for the volume control switch in the long run. This is great.
 
Aug 15, 2013 at 3:47 PM Post #1,282 of 3,417
Sorry it took so long.  I've been working and very busy.  All my posts lately have been from my ipod, which ironically doesn't have any music on it now (using the fuze).  Did you check out the james horner song?  You could practically pick any of his music and music like it.

https://dl.dropboxusercontent.com/u/48137075/06%20The%20Wedding.mp3

If you turn that up to a good volume during the quieter parts such as 2:30 with no eq or gain, just full output of a fuze or ipod into the c5 and adjust the c5 volume you're o.k..  Now lower the source volume -10db to compensate for my average eq precut (I don't boost any frequency 10db, but for some reason the eq must be 'additive' in some way, because it clips with loud parts of songs unless i lower the precut to -10db.  This is the same on my computer eq.)

I just tested this on my duet and my fuze.  In both cases there is noise added when the precut is forcing the c5 to near max levels.  You will hear the volume sounds much more prominently and the noise floor increase.  It isn't a huge difference, but it's enough to lessen the enjoyment of the song for me on rare occasions.  This isn't the song.  This is additional noise.  I can literally turn the c5 up with my right hand while I drag the eq precut down 10db simultaneously and hear the noise grow.  Granted i'm using -10db precut.  But it's required if I want to use any eq.  :-o  The C5 is MORE THAN POWERFUL ENOUGH in almost all situations, except here and there when using a demanding phone with eq applied.  That's all.

I repeat... THE C5 IS AMAZING AND POWERFUL!!!! WOOO!  :)  End of story.  :p  I just wish it had a little more raw power for such situations.

Here's another horner song with the same results.
https://dl.dropboxusercontent.com/u/48137075/04%20The%20Portrait.wav

I've cut the main song out but left the intro and ending to make it sample length.  I've done absolutely nothing to the audio otherwise.  
You can compare it to the CD if you have it.  This is a direct lossless rip of the CD cut to sample length.

There are a few sections of the cast away credits by alan silvestri as well.

Listen to this.
https://dl.dropboxusercontent.com/u/48137075/castaway.wav

In this case, I've only removed the treble to hide all of the noise that was in the original recording.  This will hopefully make it easier to hear the added noise depending on your ears/phones.  If you do what i was saying and reduce gain by 10db via an eq app or just any old gain at the source.  If you turn that up it will start exhibiting noise and noticeable volume button sounds.  Remember, I'm using the er4s.  I'd never get a song to this volume with any other phone I own. :-o  Plus, just the fact that you need to "listen for it" and it's only in rare occasions, obviously means it isn't an issue per se.  Just me being particular.  But that's my right as an audiophile isn't it?  :wink:  haha

Maybe we just need to slap James Horner for his quiet recordings?  Ha.  But his soundtracks are amazing, and in order to keep the music consistently without reducing dynamics some songs have to be this quiet.  Otherwise, when they build up they wouldn't sound as good.  It's amazing how much one of his songs can change sometimes from barely audible to almost clipping. :p  But sometimes it isn't the raw volume, but rather a certain instrument or something.  I know orchestral music can be a challenge to master and mix, but his music is definitely beautiful and powerful, so I wouldn't change it and I'm glad he chose the mastering he did.  It just is a bit more demanding of amplifiers.  There's probably others if I can think of some.  They're usually far a few between when I'm shuffling through my music.  Some might be quieter at specific parts where the noise is more noticeable.  But again, rare.

So just to reiterate one more time:
C5 = AWESOME.  Awesome, powerful reference quality.
luisdent = Particular.  Picky, needy, demanding audiophile.
Rate of occurrence = very extremely low

:p

Ok so I just tried listening to 'the wedding' with the eq.
Fortunately/unfortunately,I don't have the problem!
Even with 10db precut,the volume was fine for me in low gain mode nowhere near maxed?-If I max the volume in the quiet part at -10db then I do hear noise,but at that volume,the loud part would be unbearable!
I'm still unsure that I understand.Why would you want to turn the volume up so high for a part of the song that is intended to be quiet??

Also, I know you don't use the iPod touch now, but did you ever try using the eq app called 'equalizer'?
I'm using that,and it has an auto normaliser built in. I've found that with a similar eq boost to yours the cut has never needed to be anywhere near 10db. For example on the wedding,the cut peaked at 1.6db.
I will have a listen to the other examples too ,perhaps they will be more demanding dynamically,but it's that 10db cut that is causing the issue,and luckily (for me)I haven't found that to be necessary!
 
Aug 15, 2013 at 4:22 PM Post #1,283 of 3,417
Ok so I just tried listening to 'the wedding' with the eq.
Fortunately/unfortunately,I don't have the problem!
Even with 10db precut,the volume was fine for me in low gain mode nowhere near maxed?-If I max the volume in the quiet part at -10db then I do hear noise,but at that volume,the loud part would be unbearable!
I'm still unsure that I understand.Why would you want to turn the volume up so high for a part of the song that is intended to be quiet??

Also, I know you don't use the iPod touch now, but did you ever try using the eq app called 'equalizer'?
I'm using that,and it has an auto normaliser built in. I've found that with a similar eq boost to yours the cut has never needed to be anywhere near 10db. For example on the wedding,the cut peaked at 1.6db.
I will have a listen to the other examples too ,perhaps they will be more demanding dynamically,but it's that 10db cut that is causing the issue,and luckily (for me)I haven't found that to be necessary!
I'm not listening to the quiet part loudly. I'm listening to it at what i consider realistic reference level. Low gain? I'm listening on HIGH gain! :-o

That sounds weird. I haven't used equilizer, but i've used denon eq, accudio, sansa rockbox eq and my apple au eq on the laptop. They all require a 10db cut minimum if i'm using around 8db at ine frequency and say 5db at another. It doesn't clip on every song if i don't precut the eq, but only where the music files are loud to begin with. So i need to leave it at -10db globally. As for equalizer, unfortunately/fortunately i have no desire to go back to my ipod for music in general... Maybe i'm more sensitive to noise to begin with? I know i can hear up to higher than normal frequencies and have zero hearing loss. Or maybe something else is going on.
 
Aug 15, 2013 at 4:51 PM Post #1,284 of 3,417
I just placed an order for this amp. I bought the E12 yesterday but this amp also looked interesting esp since it has a digital volume control. I'll probably end up picking one that I like better and sell the other off unless I want to use one for my itouch.
 
Aug 15, 2013 at 5:13 PM Post #1,285 of 3,417
Yes, it sounds like perhaps you are more sensitive to noise and have super good hearing,and in combination with high gain,pre cutting 10db and quiet music,have a recipe for disaster!
I do hear the noise when I max the volume on low gain,but that is way too loud for me!-(When the music goes loud again). I tried high gain,and that was indeed very noisy at max volume,but I dont think i could ever listen that loud.
I doubt you will now, but if you do ever get a chance to try out equalizer,It would be interesting to see if it helped with the noise/precut.
 
Aug 15, 2013 at 7:30 PM Post #1,286 of 3,417
Quote:
Yes, it sounds like perhaps you are more sensitive to noise and have super good hearing,and in combination with high gain,pre cutting 10db and quiet music,have a recipe for disaster!
I do hear the noise when I max the volume on low gain,but that is way too loud for me!-(When the music goes loud again). I tried high gain,and that was indeed very noisy at max volume,but I dont think i could ever listen that loud.
I doubt you will now, but if you do ever get a chance to try out equalizer,It would be interesting to see if it helped with the noise/precut.

 
Are you using the er4s?  Also, I definitely wouldn't call it a disaster.  It's just a very small amount of noise.  I just don't like noise :wink:
 
Aug 15, 2013 at 8:21 PM Post #1,287 of 3,417
I have the Klispch S4 IEM's and the Beyerdynamic T50p's.  I use my MBP and mostly my iPhone as my music source.  What would this amp get me?  Would I notice a significant improvement in sound quality when hooked up through this amp with either one of these headphones?  I'm new to amplifiers.
 
Also, would this be what's needed to drive something like the HD 650's?
 
Aug 15, 2013 at 10:17 PM Post #1,288 of 3,417
Quote:
I have the Klispch S4 IEM's and the Beyerdynamic T50p's.  I use my MBP and mostly my iPhone as my music source.  What would this amp get me?  Would I notice a significant improvement in sound quality when hooked up through this amp with either one of these headphones?  I'm new to amplifiers.
 
Also, would this be what's needed to drive something like the HD 650's?

 
It drives my hd600 no problem.  I think the hd650 is practically the same earphone in terms of power handling.
 
Aug 16, 2013 at 10:51 AM Post #1,290 of 3,417
I love the C5. Only problem is now I need a wall adapter. Has anyone bought one that worked well. Pretty sure the C5 battery is 14 volts. Thanks guys. 
 

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