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KOSS ESP-950 Thread - Page 33

post #481 of 1446
Quote:
Originally Posted by sorabji View Post

Doesn't bother me.  Lightweight and more likely to be comfortable.

You wear your amps ?

post #482 of 1446
Quote:
Originally Posted by BoogieWoogie View Post

You wear your amps ?


fanny pack ftw!

post #483 of 1446

Just FYI folks, I finally got ahold of the folks at headphones.com (took 3 days, not a good sign in the first place) and they indicated that they are no longer carrying the Koss ESP 950.  The guy had no reason, but mentioned possible quality control issues. 

 

I then chatted with Koss, who indicated that they had no QC issues with the 950s.  I also asked about their pricing policy, and whether they had recently raised the price or started enforcing the MSRP and they said no, that the MSRP had always been $999  and that they expected their dealers to sell at slightly lower than that and no higher.  No real effort to enforce any particular price (unlike some of the high-end headphone producers and other big electronics companies that are trying to force compliance with MSRPs).

 

They also told me that they work through distributors and had no list of authorized retail sellers, so there's no way to know whether any of these people advertising ESP 950s on the internet are legit... except when you look up the address cited on their website and it's an apartment complex or a gun shop, it's a pretty good indication that they aren't exactly on the up and up... (yup, that's what I found when I did some research on a few of them).

 

In any case, I think I'll just wait for the camel to tell me that Amazon's price has dropped before buying a set these headphones...wink.gif

post #484 of 1446
Quote:
Originally Posted by Mr.Sneis View Post


fanny pack ftw!

It actually comes with a bag for doing this...biggrin.gif

And I'd echo just leaving it stock unless you already have a STAX amp, and want the simplicity of using one amp for multiple 'stats. I think the 323 is the normal crowd pleaser for an upgrade though.
Quote:
Originally Posted by Gary in MD View Post

Just FYI folks, I finally got ahold of the folks at headphones.com (took 3 days, not a good sign in the first place) and they indicated that they are no longer carrying the Koss ESP 950.  The guy had no reason, but mentioned possible quality control issues. 

Sounds like sandbagging. But I've heard some real horror stories about headphones.com (NOT headphone.com (aka HeadRoom)).
Quote:
I then chatted with Koss, who indicated that they had no QC issues with the 950s.  I also asked about their pricing policy, and whether they had recently raised the price or started enforcing the MSRP and they said no, that the MSRP had always been $999  and that they expected their dealers to sell at slightly lower than that and no higher.  No real effort to enforce any particular price (unlike some of the high-end headphone producers and other big electronics companies that are trying to force compliance with MSRPs).

No, Koss doesn't have an enforced MAP. The pricing "increase" (it isn't an increase, they just aren't discounting them) is Amazon's logarithmic pricing. I know J&R used to sell them at one point (they no longer do), and $600-$750 was normal there as well. I have never seen them break $999 though (on the upside). At least in the US (apparently they run around $1300 NIB in Japan unless you go through Koss (but that's a recent occurrence)).

Quote:
They also told me that they work through distributors and had no list of authorized retail sellers, so there's no way to know whether any of these people advertising ESP 950s on the internet are legit... except when you look up the address cited on their website and it's an apartment complex or a gun shop, it's a pretty good indication that they aren't exactly on the up and up... (yup, that's what I found when I did some research on a few of them).

Yeah, this was my understanding too. Of course there are all sorts of small shops that may sell them and be perfectly legitimate, but you have no way of knowing this for certain. TMK there are no counterfeits though. So it's probably an all or nothing scenario (you either get the real item, in whatever condition, or you get nothing).

I have noticed though that in the last few years, a lot of places no longer carry the ESP/950 (I know that both J&R and Newegg used to stock them, and neither does currently, likely because they aren't huge sellers - same reason Amazon lets the price run so low - Amazon adjusts the prices to correlate with demand). So this basically means that Amazon and Koss are your only sources for them, and might also explain the price sticking right at MSRP (in other words, Amazon only has to compete with the manufacturer's direct sales, and the manufacturer will basically run retail pricing, so Amazon has no real competition).
Quote:
In any case, I think I'll just wait for the camel to tell me that Amazon's price has dropped before buying a set these headphones...wink.gif

Or the next Koss sale. smily_headphones1.gif
post #485 of 1446
Quote:
Originally Posted by obobskivich View Post


Or the next Koss sale. smily_headphones1.gif

 


Signed up for their e-mail list, for just that reason!  bigsmile_face.gif

post #486 of 1446
Thread Starter 
Quote:
Originally Posted by kevin gilmore View Post

The current sources for the output stage are solid state. The active gain element is a tube.

 

So the current flowing through the 2SJ79  supplies the cathode of the 6CA7 - the audio signal drives the 6CA7 grid.... and the output is taken off the plate. 

 

Sounds to me like the active element in the output stage is a tube, the "sound" of this stage would seem to me to be controlled by the operation of the 6CA7 along it's plate curve...   you know, typical tube character should be seen in any harmonics added by this stage, low in level though they may be....  so I'd call this a tube output stage, all things considered. The way the FET is being operated I wouldn't expect it to contribute anything solid-state-ish to the sound, seems to me that it would just be keeping the tube in the most linear portion of it's characteristic..... no?

post #487 of 1446
Thread Starter 
Quote:
Originally Posted by BoogieWoogie View Post

It has been reported that the esp950 doesn't sound much better with other amps than the stock one. 

I'd agree.  Better, but not MUCH better.

 

I think my Stax SRM-T1 sounds better than the stock Koss K90.  Better, but not WAY better.  Somewhat better.  I also tried an SMR-1 MK II and that also sounded a little better than the E90, but not quite as 'refined' as the SRM-T1.  Considering what it is, the E90 is really quite a decent sounding amp.  I would guess that to get a MARKEDLY better sound on the ESP-950  you'd have to go to a BHSE, KGSSHV, or DIY-T2 amp, which is a pretty extravagant thing to do.

 

I already had the SRM-T1 when I bought the ESP-950's.

 

As with most high-end stuff, the last 15% of sonic improvement costs 80% of the money.   If you have the $$, go for it.  But I wouldn't tap my 401k or go on a ramen diet for a year just to get  ESP-950's to sound 10~15% better.

post #488 of 1446
Thread Starter 
post #489 of 1446
Quote:
Originally Posted by milosz View Post

 

As with most high-end stuff, the last 15% of sonic improvement costs 80% of the money.   If you have the $$, go for it.  But I wouldn't tap my 401k or go on a ramen diet for a year just to get  ESP-950's to sound 10~15% better.

I always enjoy your sense of humor beyersmile.png


Edited by Chodi - 9/30/12 at 1:48am
post #490 of 1446
Quote:
But I wouldn't tap my 401k or go on a ramen diet for a year just to get  ESP-950's to sound 10~15% better.

SHAME - This is NOT in the spirit of the Head-Fi ethos of "Sorry about your wallet"

Get with the program.............

 

Being poor keeps you humble, and ramen is good for your health.    Win/win all the way.

post #491 of 1446
Quote:
Originally Posted by wink View Post

SHAME - This is NOT in the spirit of the Head-Fi ethos of "Sorry about your wallet"
Get with the program.............

I lol'd.
Quote:
Being poor keeps you humble, and ramen is good for your health.    Win/win all the way.

Actually ramen has tons of salt, fat, and carbs, and lacks protein and vitamins/minerals. It is a very unhealthy thing to eat, especially as a primary nutritional source. redface.gif
post #492 of 1446
Quote:
Originally Posted by milosz View Post

 

So the current flowing through the 2SJ79  supplies the cathode of the 6CA7 - the audio signal drives the 6CA7 grid.... and the output is taken off the plate. 

 

 

The 2sj79 drives the cathode.  This is grounded grid drive. Way more linear than common cathode with input signal at the grid.

Output from the plate.

 

Grounded grid is used almost exclusively in large RF transmitters to keep the harmonics down to levels that a simple

one stage filter can remove.

post #493 of 1446
Thread Starter 
Quote:
Originally Posted by kevin gilmore View Post

 

The 2sj79 drives the cathode.  This is grounded grid drive. Way more linear than common cathode with input signal at the grid.

Output from the plate.

 

Grounded grid is used almost exclusively in large RF transmitters to keep the harmonics down to levels that a simple

one stage filter can remove.

Grounded grid,  OK, I know what that is from RF amplifiers. We used to build linear amplifiers for our CB's in the late 1960's using sweep tubes in grounded grid setups.  Those of course were not class A  but class C, one needed to use filters to get rid of all the harmonics above 27 MHz that they made.  Even then you usually came over nearby low-band VHF TV channels.... the filter would send the higher frequencies to ground meaning the chassis;  even a fairly decent earth ground can look like a fairly high impedance at 60 MHz, so the chassis and parts of the grounding system would radiate at those higher frequencies....  One's neighbor would hear "...breaker breaker 19, Informer do you copy....?"  while watching Mannix.

 

Anyway, OK, so the T2 is a grounded grid, and the 2SJ79 is actually supplying the driving signal to the output stage.  

 

This schematic is unlike any other amplifier I've ever looked at, and frankly I am only able to grasp some of what is going on in certain devices but the operation of the whole thing eludes me.... maybe somewhere in the other thread I can find a full discussion of the theory.  A bit daunting wading through all 148 pages of it, I read a few dozen and my eyes glazed over.....I'll have to have another go at it. 

post #494 of 1446

The T2 is deceptively simple at it's core.  The SRX circuit was clearly the inspiration as that's the best all tube electrostatic amp circuit I've ever seen.  Ultra stable, high gain so feedback isn't a problem and the cross coupled input stage is very clever indeed.  It's an all tube design so it has some major limitations.  It has an inherent DC-offset which needs to be countered with the PSU or a bias suppply, it's not fully DC coupled and resistors do not make for good current sources.  So they took that circuit and used SS parts to get rid of all the limitations they had to contend with in 1969.  Some of what they did is very, very clever... 

post #495 of 1446

My ESP-950's finally came in from headphones.com.

 

This is a very nice product, and it's too bad they don't get more due recognition. (due to audiopile hype-predjudice, imo)     They are much more neutral than my Stax Lambda Signatures and just as comfortable, perhaps more so.  The pads appear to breath a little better.

 

Going to order connectors so I can hook them up to my homebrew electrostatic amp that I built almost 25 years ago. +/-  750 volt supply with MOSFET buffers for each diff amp using 6SL7 and 6BL7 tubes.

 

Tried some minphase EQ as well.  Responds pretty well to it.  Better than the Stax, probably due to less high Q resonances @ high frequencies. (assuming purrin's plots are accurate)

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