[svyr]

Iiiit's aliive. (the srm-1/mk2). 
 
I managed to desolder the old c008 cap and the 2 resistors (304/303) and solder on new ones... I've also adjusted the offset/bal to what seems to be +-1-3 depending on the amp's mood when it's been running for a couple of hours. Thank you for the help spritzer and kevin! 
It now works. Well, sorta

 . It's also pleasant to hear that it doesn't clip at high volume, or at least my ears clips first, unlike with the SRM-300. Although the sound is a bit less to my liking than the SRM-300 - more towards neutral instead of warmer mids/more bass.
 
There're 2 more problems: 
 
a) R is slightly quieter than L. At first I didn't notice it. But now it's noticeable and annoying. 
Aside from beating my head at the wall and then buying a new driver unit, is there anything I could to determine the cause/correct it (I guess playing a test tone and measuring output on both channels to whether it's my ears would be a good start, but not sure how)
 
b) There's a hum + quiet crackling at any volume. It's quite faint and only noticeable when there is no signal (the source is plugged in and on, just nothing's playing). Sounds kinda like a 1khz test tone overlayed by radio crackling when the station isn't quite right. Kinda reminds me of the hum I used to get on my laptop's built-in soundcard, where you can sort-of hear feeback from the ext hard drive reading things... O-ooooh it is that hum...Except on an ext DAC...(when I unplug the DAC from usb it disappears, when I scroll browser pages the hum tone changes...sounds a bit like a 56k modem at times

).
The hum is there on both SRM-300 and SRM-1/mk2, but I never actually noticed it on the SRM-300 (it seems I listened to it a bit quieter)
 
Any ideas? (maaaybe my dac isn't properly grounded... oh-s111)

 

[soundoholic]

 
Quote:

...
The O2 is also a lot more "natural," think a live jazz session (O2) versus produced pop (Lambda)
 
...  
P.S. I read that the older lambda signatures are some of the more detailed headphones in the lambda family due to there thinner diaphram, I am definately hearing lots of detail, though as with some of the other comments in the thread seems like different Lambdas have different sonic signatures, I believe though that the soundstage comment will always remain true. 
 

 

If I test two so different ES I prefer only one best recording (my test CD) and even comparison only of few characteristic bars. Two ES with the same shape I test blind. I don´t think you can test the natural sounding with electronic music. Pop, Rock - mostly, and partly jazz use today  advanced E-Instruments with specific colour what after all goes in the "washing machine" of mixer, equalizer, different soundprocessors and and. So you can say only very little how naturally an ES sounds. You can say more with recordings of acoustic instruments or voice if correctly recorded. That´s why I do prefer piano, classic orchester or voice if I test. As musician I have in my head the patterns of the music hall sound to compare with. That makes the difference. Everyone hears other way.
I have heard many many lambdas and sure they are different. IMO they have more soundstage to O2 but I found more details in 007. My 007A is built 2010 and I hate it! This O2 sounds not natural at all. I know the other O2 they are much better. Why? Because, as I thnk, the manufacture manipulate every year / two years the driver. Perhaps other diaphragm tension, perhaps the different glue, maybe too wide technology tolerance or something else, I don´t know. But I hear the difference very present. I use 717 or a DIY mod HighAmp with Accuphase classicals test CD at DP-500. Even though far from optimum the 404LE brings a lot more pleasure because of more naturality. The same to my lambda Signature with 1 micron diaphragm: Too bright for all of us but with very very true and detailed sound. It´s only my opinion!
 
@edstrelow
"One uncontroversial type breakin which is largely overlooked is flattening of the earpads with use  and I bet that changes the sonic signature."
 
Yes. It suits, the pads play important role in changing sonic signature, imo. But I don´t believe any other break-in exists.
 
How good will be the new 507?
 
 
 

 

[spritzer]

Any hum present in both amps is a source issue.  Try them with any other source you have (tv, ipod etc.) and see if the hum goes away.  As for balance issue and crackling, that is probably the volume control pot acting up.  You could try to clean it with something like Caig Deoxit or if that fails, replace it.  You won't be able to get a dual pot like that anywhere but a normal Alps RK27 will fit but you will need a new knob as well. 

 

[svyr]

Hmmm, the hum is there with both musilands, not there with cowon d2 mp3 player. Awesome... 
 
Irony:http://translate.google.com/translate?js=y&prev=_t&hl=en&ie=UTF-8&layout=1&eotf=1&u=http%3A%2F%2Fwww.musiland.com.cn%2Findex.php%2FProduct%2Fshow%2Fid%2F185%23&sl=auto&tl=en (point number 7).  
 
Heh, I tried over 2 different usb hubs and ports and using 3 different cables - still humming. What can I do to get rid of it/what could be causing it? 
Quote:

Any hum present in both amps is a source issue.  Try them with any other source you have (tv, ipod etc.) and see if the hum goes away.  As for balance issue and crackling, that is probably the volume control pot acting up.  You could try to clean it with something like Caig Deoxit or if that fails, replace it.  You won't be able to get a dual pot like that anywhere but a normal Alps RK27 will fit but you will need a new knob as well.  

 

[spritzer]

It's probably a groundloop with the computer.  The only real way of getting rid of it would be to use a optical connection from the computer to a DAC.  I don't recommend lifting the ground with cheater plugs...

 

[svyr]

COULD A MODERATOR PLEASE SEPARATE ALL OF MY/RESPONDER'S POSTS RELATING TO THE SRM1 troubleshooting into a thread in the DIY section? 
 
heh, it's a laptop, so pulling the power plug and running on battery works as well, but given that my battery lasts for an awesome 10 mins max...
 
Annoyingly, while the hum goes away, the quiet crackling never goes away, but you said it may be a bad connection.
 
>I don't recommend lifting the ground with cheater plugs...
 
Why? Burn the usb port/controller|dac|myself?
 
Is there anything I could do to the usb side e.g. http://www.head-fi.org/forum/thread/131544/ground-lifting-a-usb-cable ?
 
Quote:

It's probably a groundloop with the computer.  The only real way of getting rid of it would be to use a optical connection from the computer to a DAC.  I don't recommend lifting the ground with cheater plugs...

 

[spritzer]

Most laptops aren't grounded in the traditional sense (there is no AC inside so no need for it) so a ground loop isn't the issue here. 

 

[svyr]

that makes me confused. So why does the hum go away when I switch to battery power (unplug the AC adapter)? (although, the crackling/pops still remain =(, but are less prominent ) 
Quote:

Most laptops aren't grounded in the traditional sense (there is no AC inside so no need for it) so a ground loop isn't the issue here. 

 

[spacemanspliff]

I am waiting on a pair of Nova Basics and a Spritzer modded SRD-7. Just thought of something. I am using a high end receiver to power the SRD-7. What should I set it to. Large speakers? Small? I suppose large so that I get full range sound correct?

 

[spritzer]

Quote:

that makes me confused. So why does the hum go away when I switch to battery power (unplug the AC adapter)? (although, the crackling/pops still remain =(, but are less prominent ) 

 

 
I missed that.  Very odd but there can be quite a few reasons for this.  Have you tried any of this with a different computer?  Given that the computer is old (10mn battery time would point to that) the caps may be toast inside it. 
 

 

[neoTT]

STAX New Product
SR-207 and SRM-252S
 
Earspeaker and Driver sets 
SRS-2170 (SR-207 and SRM-252S)
SRS-005S (SR-003 and SRM-252S)
 
http://blog.joshinweb.jp/ichinose/2010/09/stax.html (Japanese page)

 

[gilency]

interesting. Nothing in the English section yet. Still waiting to see what the new portable system is going to be like.

 

[jjinh]

@Vlad: Silly suggestion, but have you checked to make sure the two volume controls (L and R) are at the same level? Else for a quick fix you could just make R side a bit louder to equalise the volume. 
 
Quote:

STAX New Product
SR-207 and SRM-252S
 
Earspeaker and Driver sets 
SRS-2170 (SR-207 and SRM-252S)
SRS-005S (SR-003 and SRM-252S)
 
http://blog.joshinweb.jp/ichinose/2010/09/stax.html (Japanese page)

SR-207

 
Considering how much I like the SR-202s, I'm definitely getting a pair!

 

[svyr]

>@Vlad: Silly suggestion, but have you checked to make sure the two volume controls (L and R) are at the same level? Else for a quick fix you could just make R side a bit louder to equalise the volume. 
 
first thing i did. Unfortunately it's not that simple. R is the inside control and you have to hold L in place to turn it. It's very difficult to get it right this way. If Kevin or Birgir or someone else who knows how to, let me know how to measure per channel output, I can probably do a better job. 
 
 
>I missed that. Very odd but there can be quite a few reasons for this. Have you tried any of this with a different computer? Given that the computer is old (10mn battery time would point to that) the caps may be toast inside it. 
 
sorry, that was a bit confusing on my side. The crackling popping is still there with the mp3 player. So I guess we're back to the stuffed pot/and or singing transformer and or bad connection somewhere problem?
 
 
p.s. The crackling/popping is distinct from the problem I had with the SRM-300 and SRM-252. It is also not related to the grounding issues (although the grounding issue really is annoying). The crackling before was from the amp clipping and was loud/on high volumes.
Here's it's subtle and audible at any volume, with no source playing (gets more audible, the louder you turn it up. You can also hear it with music playing at low volumes). It also only happens on the SRM-1/mk2 and not on the SRM-300 (as does the bal issue).
 
p.s.s.:
 
 
mkay, 
here are the measurements (err, in the VdB mode AC, which is hopefully right. Laptop running on battery, so no annoying hum): 
 
 
FULL Knobs turn: (the readings drift, hence the range) 
no signal - 0-2v all.
@tone: sine wave, 0.5 amplitude 1khz:
R+ 279-281
R- 279-280
L+ 278-281
L - 279-282
I also tried 1.0 amplitude. and both channels all +- were at around 300V also with drift. 
I also tried vol knob at around 2 o'clock:  (little drift)
 
L+ 187.1, L- 187.0
R+ 187.7, R- 188.3
 
and 1'oclock:
All +- LR were dead set at 46.2V. no drift. 
 
So aside from the slight drift at the full vol turn, it seems I need to get my right ear checked for why it seems lower?
By the way, with the tones, it's a lot more noticeable that the transformer or something on the board near it occilated and produces the same tone

. It's very much audible at ful vol and 1 or 0.5 db. 
Now I'll try to bypass the vol ctrl to see if it's the cause for clipping.

 

[svyr]

>http://blog.joshinweb.jp/ichinose/2010/09/stax.html (Japanese page)
 
mmm, nice, and it also says 'SRM-252S amplifier is the gain increase.' (yay for google translate). 
 
The description for SR-207 sounds a bit like the 507 one (blabla new design, blablaba humidity and vibration reduced, blablaba

)
Heh, they should start selling the SR-207/202 separately...