The Stax Thread III

[duncan1]

I dont know if Canada has "gone Metric" so in old UK measure its 3/16s-of an inch- looks like 5 MM in metric.

 

[SBranson]

Thanks very much!  I have quite a bit of 3/16"SS rod for knife handle work.  We are metric in Canada, officially...  I am not however.

 

[duncan1]

Same here--SBRANSON neither am I.

 

[davidsh]

My sig's does definitely seem to have a more dry sound after messing with the pads, with less bass bloom... Still dunno if it just is me...

 

[NoPants]

Has stax published any information regarding the capacitance/inductance of their ribbon cables? There was some link I remember reading way back when about how normal wires are disastrous because of their low inductance? I could be wrong though. I'm trying to leverage some parts I have lying around for recabling, as stupid as that might sound.
 
Also, does the material for the cable housing/strain relief matter? It seems like something that could be 3D-printed and then covered in another material, etc. etc.

 

[kevin gilmore]

pretty sure the capacitance of a sr007/009 cable between adjacent wires
is 30pf for the standard length and is 3000 nanohenrys.
remember that the bias wire is always between the two stators.

 

[jcx]

I don't think homebrew ES headphone cable is the best idea...
Quote:

milli amps can kill, higher V (> ~ 200 V) punches thru your outer dead skin cells which give some insulation when dry, when wet you don't even have that much insulation
 
as little as 50 mA passing thru your chest can kill - not that anyone would think to do it while getting shocked but you would theoretically be better ripping the phones off your head with one hand (the right) rather than grabbing each cup with each hand
 
smaller body mass women, children are more sensitive to electrical shock
 
[ES] headphone amplifiers have potentially lethal high V and stored charge, current from the line xfmr to kill - don't remove covers, poke around inside if you don't know what you're doing (even with power off the capacitors can retain or even recover some charge after shorting them from their dielectric absorbtion)
 
at the amp outputs there are normally several current limiting mechanisms - the amps are often Class A biased with 5-10 mA which often means they are current limited by that amount on at least one polarity
 
Gilmore's project amps have series R on each output that is large enough to keep external current below lethal levels for short times, less than a second - takes less current for longer durations
 
and the headphone construction itself should meet "double/reinforced insulation" standards - again opening, modding your ESL headphones should only be attempted by someone knowledgeable of the construction requirements and mechanically competent enough to not break/disable during (dis/re)assembly and meet/exceed the standards with any mod
 
after market cable for ESL headphones are a bad idea because of the insulation construction, special impedance requirements
 
so well designed ESL headphone amps shouldn't provide (instantly) lethal current at the output if working properly internally, but can give unpleasant shocks causing strong muscle contractions - people get hurt from falls, hitting things due to the muscle contractions - you could probably figure out how to kill yourself with ESL amp output, its a problem with "foolproof" design - fools are incredibly ingenious
 
(relatively) safe design, construction, properly working ESL amps combined with undamaged, well insulated ESL headphones, worn while you are dry, in dry conditions are "safe enough" - since nothing is ever absolutely safe - the headphone's insulation can give a layer of safety if the amp fails in unsafe way and vice versa - but both need to be safe individually
 

 

[ultimanium]

I've got a friend who has a pair or electrets. The srd-4 box for them has been modified for a TRS plug, and their current amp cannot power it.
Is their a relatively cheap amp headphone amp that would be good for these?
Cutting off the TRS plug and hooking it into a speaker amp would be a pain.

 

[milosz]

Quote:

I've got a friend who has a pair or electrets. The srd-4 box for them has been modified for a TRS plug, and their current amp cannot power it.
Is their a relatively cheap amp headphone amp that would be good for these?
Cutting off the TRS plug and hooking it into a speaker amp would be a pain.

Get a TRS jack and put a set of wires on it to connect to speaker terminals of a regular amp or receiver. Plug the TRS plug into that jack....  No low-cost headphone amp is going to have enough power to drive those.

 

[3X0]

Thanks for the tip on the PS1 screws spritzer. I replaced 7 of the crappy HE60 screws with the robust PS1 screws last night and now I'm not worried they'll strip every time I have at them. The heads are a little larger so the pads don't snap on as easily but I'm fine with the compromise.
 
Of concern though, I mentioned one of my o-rings definitely snapped. When I removed the left earcup to take a look the driver lifted off of the grommet with the earcup. I wasn't able to secure the snapped o-ring back into place and even with the left earcup fully re-assembled and screwed down, the left driver rattles a bit off the grommet and into the back of the earcup when handling the headphones.
 
I'm not really concerned with the sonic consequences of the lack of o-rings as I will not be using the HE60 until I obtain replacements, but I am concerned if uncharged stators are prone to damage by repeated minor physical shock such as rattling between the rubber inner grommet and outer hard plastic.
 
The final concern is that the last screw is unbelievably stripped. I was rather unsuccessful with the JB Weld so I purchased a screw extractor set off Amazon and am hoping for the best. Failing that, I might just have to try and carefully dremel a slot into the head. Have not been able to access the right earcup yet to due this setback.

 

[spritzer]

Easy fix to a snapped o-ring, take some crazy glue and just glue it together again.  Works like a charm until some other part of it snaps... 
 
I wouldn't worry about the drivers as they are all fiber reinforced plastic and quite strong. 

 

[Oingo Boingo]

[size=medium]After few years of headphones’ hobby it has turned down (or up)) mostly e-stats for me.  SR-Omega, HE90, 009 and 007 are now the core team.  As a side comment: the R10 bass light go as “dynamic phones with the great e-stat mids” for me (kind of)).  After few tries to find the best amp for e-stats it has ended up in DIY.  The idea was very modest and simple: to put together the best e-stat amp out there))  I was lucky enough to get a very experienced engineer/designer on my side.  Dmitry (the Man) has designed numerous pieces of audio equipment including amps for e-stats, but this time he needed to get back to his lab for a while…  The design is Dmitry’s know-how, but it’s based on classic pre-WW2 designs, sure taking into account the specifics of e-stats.  Three prototypes have been made and tested.  The designs of T2, HEV90, KGBH, WES and few other e-stat amps have been reviewed.  The current tubes include Philips Miniwatt AL4 (Telefunken AL4 as a second set), RCA JAN 5692 red base and CV1264 rectifier (in PU).  All the 4 e-stat phones have benefited a lot.  The original SR-Omegas and HE90 are my favorites, followed by 009. 007mk2 are the most amp-hungry, a lion to feed and roar, became a major basshead attraction))  To cut a long story short few pics are attached: [/size]
 

 

 

 

 

 

 

 

 

 

 

 

 

 

[n3rdling]

Very nice collection

 
Did the headband on your SR-Omega snap?  It looks kinda weird from the side.

 

[davidsh]

Ohh god, that is amazing!! What is your source?

 

[arnaud]