The Stax thread (New)

[SquireC]

@eric65
 
Did you order your WEE from the USA or did you buy it in France? If so, where in France?
 

 

[milosz]

Quote:

I got an SRM1-MK2 Amp and it seems like the sound isn't near as loud as when it was new,
I think it's a problem with the Amp (not the headphones) b.c both my Sigma and Lambda Pros seem too low volume
what could be causing this problem?

Could be your hearing is getting progressively damaged....or just declining due to age.
 
Good idea to use a sound level meter and check the level you're listening at from time to time.
 
 

[size=medium] 85 dB greater than 8-hour listening will cause permanent hearing damage
85 - 90 dB 2-hour  listening will cause permanent hearing damage
90 - 100 dB 1 to 2-hour  listening will cause permanent hearing damage
100 - 110 between 2 and 15 minutes  listening will cause permanent hearing damage
110 - 120 less than 30 seconds  listening will cause permanent hearing damage
130 dB ANY EXPOSURE WILL RESULT IN PERMANENT HEARING LOSS
 
[/size]

[size=medium] From http://www.lowertheboom.org/trice/safedblevels.htm[/size]
[size=medium]  [/size]
[size=medium] You can download a reasonably accurate SPL meter app for iPhone / iPad / Android, and in fact you can even get a calibrated mic that plugs into your phone from Parts Express for about $18  http://www.parts-express.com/pe/showdetl.cfm?partnumber=390-810[/size]

 

[eric65]

Quote:

Hello.
I' m French.
Sorry for my poor English
It’s my first intervention in this thread.
Just to say i have 009 Stax headphone with tow amps: the SMR 727-II stax amp and, it is verry more orignaly the Audiovalve RKV Mark II amp directly coupled to has WooAudio Wee with the specialy adaptator  (for the jack to the HP enter of the Wee) (See the picture). 
The RKV is amp for electrodynamic headphone with 3 watts power outpur and n it is the most intersting, with 80 max RMS output volts.
With the WEE and the 1:25 at 1:50 ratio volts amplificator transformator, the voltage output of the WEE is to amplify to on 2000 at 4000 volts RMS! (Its enought too burn the headphone 

)
The most important with it's originaly association with RKV-WEE + 009 is i obtain has very very euphonious sound. The sound is no hard or shoulty in the hight-medium when your hear femal voice at hight level (NB : it is the situation with the 727 amp). The sound is very plaisant with good harmonics and also very good neutrality. It-is possibility that this amp is better sound that the all Stax amps (323S ; 727 and 007t2) for less money.
If you are interested you can see the french forum "HCFR" at  "Club des Heureux propriétaires de casque Stax"  for more picture and test.
(NB : you can use the google translation French to English il you are interested)

Thank to tolerate my very poor English.
 

 
 

 
 

 
 

 
 

 
 

 
 

 
 

 
 

 
Quote:

Eric, nice to see you over here! 
To summarize your post:
- you have obtained good results driving the sr009 using an audiovalve rkv driving a wee using a custom 1/4inch to bare wires adaptor cable
- you also own an srm-727 amp but found it shouty at higher volume levels with the sr009
- you've found the rkv-wee a much better fit for the 009 with much more euphonic sound and no deterioration with increased volume level
- you mention that the rkv can swing up to 80V so with the wee that has a step up ratio of 1:25 (you found through your own tests it was more like 1:50), there is sufficient voltage swing to damage the headphone (and at least much more headroom than the stax direct coupled amps in production)
- you surmise that the association rkv+wee might be a better fit for the 009 than any of the stax amps in production (and also better value consedering the stax prices in france)
 
arnaud

 
Quote SquireC
 
@eric65
 
Did you order your WEE from the USA or did you buy it in France? If so, where in France?
 
 
 
It is more complicated 

 
I bought the WEE, the RKV and the custom 1/4inch to bare wires adaptor cable, from a friend.
 
My friend bought the WEE in second-hand (300 dollars US i think) from a German audiophile.
 
This German audiophile had to buy the WEE directly from WooAudio in the United States.
 
Eric

 

[eric65]

Quote:

Could be your hearing is getting progressively damaged....or just declining due to age.
 
Good idea to use a sound level meter and check the level you're listening at from time to time.
 
 

[size=medium] 85 dB greater than 8-hour listening will cause permanent hearing damage
85 - 90 dB 2-hour  listening will cause permanent hearing damage
90 - 100 dB 1 to 2-hour  listening will cause permanent hearing damage
100 - 110 between 2 and 15 minutes  listening will cause permanent hearing damage
110 - 120 less than 30 seconds  listening will cause permanent hearing damage
130 dB ANY EXPOSURE WILL RESULT IN PERMANENT HEARING LOSS
 
[/size]

[size=medium] From http://www.lowertheboom.org/trice/safedblevels.htm[/size]
[size=medium]  [/size]
[size=medium] You can download a reasonably accurate SPL meter app for iPhone / iPad / Android, and in fact you can even get a calibrated mic that plugs into your phone from Parts Express for about $18  http://www.parts-express.com/pe/showdetl.cfm?partnumber=390-810[/size]

 
 
 
Be careful with the RKV/WEE for your ear .
 
 
The input impedance of the WEE (and therefore the output for any amplifier connected upstream of the WEE), input impedance of the WEE which is 100 Kilo-Ohms (I quote: "Input Impedance: 100 Kilo-Ohms"). The input impedance of the WEE, very high (100 Kilo-Ohms) operates all amplifiers connected to WEE voltage, and not amperage. I measured the input impedance of the RKV WEE with a frequency of 500 Hz sine signal with an input of 0.20 volts WEE giving a rating of 2 micro amp with 009 connected to the WEE listening level of about 83 dB SPL (within 2 dB) for an input signal 0.203 Volts to be precise, a calculated resistance R = U / I = 0.203/0. 000 002 = 101 500 Ohms or so about 100 Kilo-Ohms , corresponding well with the manufacturer's specifications for the input impedance of WEE.
 
 "How WEE can it work with 0.2 volts if it needs 5 volts minimum ( by Jack Woo)? "
 Well, no problem with that, thanks to the volume knob RKV can be pushed to give a Output voltage up to 80 Volts and also thanks to the transformer WEE multiplying the input voltage by WEE one factor 50 ( 1:50 ) to be 50 times higher in the WEE Stax headphones.
 
 I give a few examples (based on the position of the volume knob potentiometer RKV) 
 
-  with an input signal of WEE of 0.2 Volts (RKV the volume knob in early stroke) (0.2 V x 50 = 10 V output WEE) WEE 009 provides the noise level of about 83 dB SPL (at 2 dB) 
-  with an input signal of the WEE 2 Volts (after further potentiometer volume RKV) (or V 2 x 50 = 100 V at the output of WEE), the WEE 009 provides a level SPL sound approximately 103 dB (at 2 dB)
- with an input signal of the WEE 5 Volts (pushing further the volume control on the RKV) (V or 5 x 50= 250 V at the output of WEE) WEE 009 provides the sound level SPL of about 111 dB (at 2 dB) 
- with an input signal of WEE 20 Volts (pushing again (much) further potentiometer volume RKV) (20 V x 50= 1000 V at the output of the WEE), the WEE 009 provides a noise level of around 123 dB SPL (at 2 dB) 
            - with an input signal of the WEE 80 Volts ( pushing up the volume knob of the RKV) (80 V x 50 = 4000 V output WEE) WEE 009 provides the sound level SPL of approximately 135 dB (at 2 dB)
Here, it suffices push a little further the volume knob of the RKV to have all the desired sound level , until they explode the eardrums (and helmet if you exceed the 009 maximum sound level not to exceed 118 dB in penalty grill head-phone ) 
 
Eric

 

[spritzer]

Anything above 1200Vp-p and the drivers are toast so keep that in mind. 
 
Quote:

Interesting way of powering those 009's from the HP/out jack of the RKV to the Wee. I've always wondered what the OTL RKV sounds like with other normal TOTL headphones. Last auction that ended was about 1400 euro's 4 years ago on ebay. I remember reading reviews praising on them back in 04.

 
The RKV design is quite bad to put it mildly so I'd take the reviews from back then with a few pounds of salt.  Some people tried to modify the RKV but there is no way to polish that particular circuit. 
 
Quote:

I got an SRM1-MK2 Amp and it seems like the sound isn't near as loud as when it was new,
I think it's a problem with the Amp (not the headphones) b.c both my Sigma and Lambda Pros seem too low volume
what could be causing this problem?

 
Bias supply has some fault?  It could just be outputting the B+ under certain fault conditions and that would lead to lower volume level. 

 

[eric65]

Quote:

Anything above 1200Vp-p and the drivers are toast so keep that in mind. 
 
 
The RKV design is quite bad to put it mildly so I'd take the reviews from back then with a few pounds of salt.  Some people tried to modify the RKV but there is no way to polish that particular circuit. 
 

 
 
“ The RKV design is quite bad ” 
 
 Perhaps, but the sound is very good, particulary with the 009 (with the WEE adaptator)
 Really good synergy and euphonique sound with the OTL RKV-WEE + 009 ; better sound than with the 727 amp without loss of definition, with more curvature and more bodies in the listening.
A great sound.
Delighted. 

 

[spritzer]

Well, high fidelity isn't for everybody. 

 

[cjfrbw]

A great amp for using Stax with transformer adaptors is one of the old VFET sony TA 4650  30watts/ch in good operating condition, usually a few C notes on bay, if you want all solid state.
 
Fatigue free listening, great detail, spacious, plenty of power for Stax with transformer adaptor, very close to a tube experience.
 
There is a power amp input/ preamp output to bypass the preamp if desired.
 
I really prefer transformer adaptor listening with an amp, I have modified two stax boxes with upgraded  transformers, one has new production Dyna Z565 at 1:31 and the other has old iron 25 watt Stancor A-3311 PP trannies at 1:50.
 
Both modified trannie boxes sound spectacular albeit ugly to look at.
 
I prefer 300b tubes, but found that they don't have enough power for my home repaired 507 Stax, they would clip on bass transients, so I switched to a vintage Luxman MQ68c push pull tube amp (30w/ch triode) or the Sony VFET, both amps sound great.
 
 I can still use 300b with traditional Lambda normal bias.  Pic is of butt ugly Stancor A-3311 modified SRD 5, it needs some beauty work and a box.
 
 
 

 

[arnaud]

Yes it could could a little better . Awesome nevertheless

 

[mwilson]

Completely off-topic, but this brought a smile to my face and made me think of spritzer. What a gorgeous place.
 
http://vimeo.com/63042888

 

[DefQon]

Loved that intro footage. Shame Iceland is so far, apparently they have goddess looking females inhabiting the country. Me like 

 

[dukeskd]

Quote:

Loved that intro footage. Shame Iceland is so far, apparently they have goddess looking females inhabiting the country. Me like 

Who are well over 6 feet

 

[DefQon]

Well I'm about exact 6 feet so no problem for me. If anything for that matter a step ladder would help.   (¬‿¬)

 

[milosz]

Some physics guys at UC-Berkeley have made an electrostatic driver with a graphene diaphragm. http://physicsworld.com/cws/article/news/2013/mar/29/graphene-loudspeaker-could-rival-commercial-speakers-and-earphones
 
Wonder if that will ever go anywhere.

 

[milosz]

Quote:

Well, high fidelity isn't for everybody. 

 
This made my day.