[preproman]

Quote:

We shall see when it gets here in a week or two. 

 The specs on it are quite impressive. 
 
I hope Birgir doesn't mind me posting his PM to me about the amp, but here goes:
 
"Full +/-500V IXYS specification with an oversized SumR transformer which is configured for 117V only.  This does mean it is dead silent  .... you can hardly tell the bloody thing is running...  

   ...... The case is the Italian steel case I used on my first HV back in the day so the front is aluminum but the rest is painted steel. "
 
Team Overkill strikes again. 

 
What pot did he install?

 

[negura]

Quote:

This is not the input power of the Wee that counts but the input voltage.
Stax headphones operate in voltage, not in amperage. The wattage does not mean anything.
The minimum specifications for the Wee wooaudio are at least 3 Watts on 8 ohms, which corresponds to a minimum input voltage of the Wee of about 5 volts.
V²= PR (P = 3 Watts ; R = 8 Ohms ; PR = 3*8=24 ; V = SQR 24 = 5 Volts)
 
There was therefore the margin with the output 80 volts max of the RKV.

 
It's been a while since my science classes, so may calculus below may not fare very well. Nevertheless according to the formula if we take the 80volts output and knowing the Impedance, could we not calcaulate the "power ouput" of the RKV accordingly based on an 80V voltage output into 8 ohms?
 
V = SQRT (PR) which is:
80 = SRQT (6400)
PR = 6400
P = 6400/8
Power = 800 Watts
 
That results into 800 Watts into 8 ohms. Something doesn't seem to add up... Where is the disconnect.

 

[Chris J]

It's been a while since my science classes, so may calculus below may not fare very well. Nevertheless according to the formula if we take the 80volts output and knowing the Impedance, could we not calcaulate the "power ouput" of the RKV accordingly based on an 80V voltage output into 8 ohms?

V = SQRT (PR) which is:
80 = SRQT (6400)
PR = 6400

P = 6400/8
Power = 800 Watts

That results into 800 Watts into 8 ohms. Something doesn't seem to add up... Where is the disconnect.

Never mind......! I screwed up, I mis-read the post! :rolleyes:

 

[negura]

Quote:

Looks like you have square root of 80 mixed up with 80 squared.

Square root of 80 is approx. 9!

 
The knowns here are the voltage, which is 80 volts and impedance 8 Ohms.
80^2 = 6400 (V²= PR). 6400 = PR = P x 8 (Ohms); P = 6400/8 = 800 Watts.
 
IF the calculation and formulas are correct the only way I can see the 80 volts happening with 3 watts power is in a different impedance. In other words those 80 Volts cannot be into 8 ohms with 3 Watts power. The reason I am going through this is that I am very interested to find what's required to drive the Wee/Stax well and what amplifier I need.
 
Also I am quite puzzled why Woo Audio is showing 3 Watts as minimal specs, if this is not very important, and no other criteria. I could actually ask them directly.

 

[SquireC]

Stax srd7SB Mk2 and Woo Wee can only 'pass on' the signal from the power amp (or speaker amp) that is driving them. The better the amp, ( and source) the better the sound. I think in an earlier post, someone was using one with a Cary tube amp - have to say that I'm not a fan of the Cary's. I think they are a bit ragged for a valve amp.
 
I find that the SRD7 is a transparent piece of kit - not to blame if the sound through the headphones fails to deliver 'magic'.
 
I have directly compared with a SRM T1 fed from the same system's pre amp and found the sound slightly warmer, but less detailed.
 
Perhaps to hit the heights you need a BHSE or KG, and perhaps in this 'test system' with such a headphone amp powering the headphones the sound would be a magnitude better - I don't know.
 
Just making the point that it's not just which cans you prefer, or what headphone amp or transformer you prefer - it's the whole system that delivers the sound. I sometimes wonder when people ask which are the best headphones, etc, to buy, that sometimes they may be adding high quality cans to a low quality system and - frankly - may be expecting miracles.
 

 

[arnaud]

The knowns here are the voltage, which is 80 volts and impedance 8 Ohms.
80^2 = 6400 (V²= PR). 6400 = PR = P x 8 (Ohms); P = 6400/8 = 800 Watts.


IF the calculation and formulas are correct the only way I can see the 80 volts happening with 3 watts power is in a different impedance. In other words those 80 Volts cannot be into 8 ohms with 3 Watts power. The reason I am going through this is that I am very interested to find what's required to drive the Wee/Stax well and what amplifier I need.


Also I am quite puzzled why Woo Audio is showing 3 Watts as minimal specs, if this is not very important, and no other criteria. I could actually ask them directly.

There may have been a misunderstanding. RKV is specified as 3W under 8Ohm load and max 80V output. It does not mean it can swing 80V into an 8Ohms without falling apart...

Actually, a google search returned 80V under 3-400 Ohm load which does correlate with the 3Wax output power.

Now the wee is 100kOhm input impedance, which implies the RKV can swing 80V without breaking a sweat under that charge, hence Eric's comment that you could potentially easily get to arcing using the wee as its transformer has at the very least a 25/1 ratio...

If forgot how Eric came up with 30 but, as I recall, he used the sensitivity info and SPL measurement. I believe spritzer thought it was more like 50, in any case much more than the ~10x ratio used by stax in the old days for the srd units. Maybe birgir could comment (although considering how highly he thinks of the rkv and wee in isolation, I can easily imagine the tone of his upcoming comment lol .

 

[negura]

Quote:

There may have been a misunderstanding. RKV is specified as 3W under 8Ohm load and max 80V output. It does not mean it can swing 80V into an 8Ohms without falling apart...

Actually, a google search returned 80V under 3-400 Ohm load which does correlate with the 3Wax output power.

Now the wee is 100kOhm input impedance, which implies the RKV can swing 80V without breaking a sweat under that charge, hence Eric's comment that you could potentially easily get to arcing using the wee as its transformer has at the very least a 25/1 ratio...

If forgot how Eric came up with 30 but, as I recall, he used the sensitivity info and SPL measurement. I believe spritzer thought it was more like 50, in any case much more than the ~10x ratio used by stax in the old days for the srd units. Maybe birgir could comment (although considering how highly he thinks of the rkv and wee in isolation, I can easily imagine the tone of his upcoming comment lol

.

 
I see. And regarding the Woo Wee "requirement" of 3 Watts or more. Does that provide sufficient information? Is there anything else to it or that we should know in terms of amplifier specifications to understand if a potential speaker/headphone amp will drive the Woo Wee optimally?

 

[eric65]

Hi

The input impédance of the wee is 100000 ohms not 8 ohm
No problem of load with the OTL RKV

Sorry for this short answer with my I Phone

Eric

PS thanks Arnaud

 

[autoteleology]

What do you think of the ELE DAC?

 
It's probably one of the best values in audio for the money I've ever heard. It's definitely not transparent and there are definitely audibly superior DACs out there, but for ten bucks, it's a massive value. It's a big eye-opener to how much you can get (especially DAC-wise) for just a little bit of cash.
 
Hearing the ELE DAC, and then hearing the PWD2 shortly afterwards, is probably why I believe what I do about DACs not being very important in the signal chain. If a ten dollar tiny box can get that close (relatively) to massive (and massively expensive) TOTL gear, it really makes you think.

 

[negura]

Editted: Still at my previous question.

 

[kevin gilmore]

I know what the specs say for the wee, but trust me they are not right.
The input impedance is something like 16 ohms. The output impedance
is something like 100k ohms. Very similar to the stax transformers.
Roughly same voltage gain.

 

[Golfnutz]

Quote:

We shall see when it gets here in a week or two. 

 The specs on it are quite impressive. 
 
I hope Birgir doesn't mind me posting his PM to me about the amp, but here goes:
 
"Full +/-500V IXYS specification with an oversized SumR transformer which is configured for 117V only.  This does mean it is dead silent  .... you can hardly tell the bloody thing is running...  

   ...... The case is the Italian steel case I used on my first HV back in the day so the front is aluminum but the rest is painted steel. "
 
Team Overkill strikes again. 

Birgir sent me an amp last year, took less than a week door to door. Maybe you'll have the same luck.

 

[autoteleology]

How do the bias voltage and the output voltage of an amplifier relate to each other?

 

[kevin gilmore]

The bias voltage depends on the distance between the diaphragm and the stators.
260V for early stax, 580v for current stax, 560v for he60, 500v for he90, 600v for esp950
 
output voltages of amplifiers ranges from +/-300 to +/-600 stator to ground.

 

[negura]

Quote:

I know what the specs say for the wee, but trust me they are not right.
The input impedance is something like 16 ohms. The output impedance
is something like 100k ohms. Very similar to the stax transformers.
Roughly same voltage gain.

 
Many thanks for the comments. Any advice or best guess to what one should look for one in amplifier specs to be a good match with the Wee? Or from anyone else that can answer.