[realmassy]

I tried even with no source.
 
One more thing I've noticed, the hum gets louder and louder.
I've wired the chassis to the steel structure of my sofa, so I've been able to listen touching the structure.
Left channel is now, after a few hours, very noisy, the right on the other hand is dead silent.
 
I'm now thinking the problem is in the headphones: I can 't hear any noise if I take them off and put my ears close to the amp.
Anyway, I think I'll send the system back to the seller, and he will have a look at it.
 
Too bad, as I really like it so far.

 

[livewire]

Bummer!
Sounds like a return is in order.

 

[milosz]

Quote:

I thought that too. Basically, more bass and less speed and extension. A muddy stax? lol
 
We'll see. I can't complain for the price. Still going to be a great headphone for $100 lol.
 

Muddy, well probably not.  I would say a tad darker, or a little warmer. Bass might even be a little tighter, less stretch to the diaphragm.
 
A little lower efficiency too.  Maybe a dB or two less SPL per volt.
 
Might actually be an interesting sound signature, the only Stax in the world that has it, too!  

 
 

 

[milosz]

Quote:

I tried even with no source.
 
One more thing I've noticed, the hum gets louder and louder.
I've wired the chassis to the steel structure of my sofa, so I've been able to listen touching the structure.
Left channel is now, after a few hours, very noisy, the right on the other hand is dead silent.
 
I'm now thinking the problem is in the headphones: I can 't hear any noise if I take them off and put my ears close to the amp.
Anyway, I think I'll send the system back to the seller, and he will have a look at it.
 
Too bad, as I really like it so far.

Not likely to be the headphones. Sounds like the amp to me.
 
Do you hear the hum even with NO SOURCE plugged in to the amp?  I.E., no input cable plugged in to the amp, you'd just be listening to the amp's rendition of "silence" since it has no signal going into it.  If you hear a hum in the headphones with NO input signal cable plugged into the amp, the problem is in the amp or it's power supply.
 

 

[K3cT]

I can't remember precisely what is bundled with the 2050 system but it must be the one that comes with a wallwart am I correct? Try using some other wallwart first. Make sure the voltage and polarity match. Digikey or Jameco should have a very complete inventory of what you need. 

 

[realmassy]

Thanks guys.
The seller is going to collect the system and send it to Stax: he even offered a refund but I want to keep it and get fixed.
I'll keep you posted!
Now back to iPod and ER4S...that's not quite the same

 

[Sim1]

Quote:

Anyone know about the stax 717 XLR plug polarity? Are they fit to US standard?

afair  SRM-717 had 1-ground, 2-cold and 3-hot, all new ampifiers have standard polarity 1-ground, 2-hot, 3-cold.
There should be picture on the rear panel describing the pins.
 

 

[Leonardo Drummond]

DaveBSC, KingLocal and arnaud, sorry about the delay! I'm travelling now and have little time to go on the internet!
 
Very interesting discussion! I agree with most of what's been said. The experience I had with tube rolling was rather revealing in that sense. I wasn't enjoying my K1000s anymore and thought about getting some new tubes for my Little Dot MKVI. When I got them running for the first time, I though that it was a large difference and was amazed with the results. In fact, for a few weeks, it got more head time than the O2s. However, when I got the old tubes back in so that I could AxB them, I was stunned to find out that the difference was not nearly as big as I was expecting. They were a bit less refined and had the mids pushed forward. That was it. But the "subjective" improvement was immense!
 
However, I have to say that I'm rather skeptical about some other things. Well, maybe not exactly skeptical, but, as (I think) visualguy, I find it hard to justify investing on something that I have to make an effort to find a difference or that I have to AxB to find them. If I don't find immediate differences, than to me it's usually not worth it. But then I guess this has more to do with my point of diminishing returns!

 

[KingLocal]

Quote:

DaveBSC, KingLocal and arnaud, sorry about the delay! I'm travelling now and have little time to go on the internet!
 
Very interesting discussion! I agree with most of what's been said. The experience I had with tube rolling was rather revealing in that sense. I wasn't enjoying my K1000s anymore and thought about getting some new tubes for my Little Dot MKVI. When I got them running for the first time, I though that it was a large difference and was amazed with the results. In fact, for a few weeks, it got more head time than the O2s. However, when I got the old tubes back in so that I could AxB them, I was stunned to find out that the difference was not nearly as big as I was expecting. They were a bit less refined and had the mids pushed forward. That was it. But the "subjective" improvement was immense!
 
However, I have to say that I'm rather skeptical about some other things. Well, maybe not exactly skeptical, but, as (I think) visualguy, I find it hard to justify investing on something that I have to make an effort to find a difference or that I have to AxB to find them. If I don't find immediate differences, than to me it's usually not worth it. But then I guess this has more to do with my point of diminishing returns!

 
I blew an amp in one of my active PMC AML1s (weird b/c the amps and Xovers are by Bryston which have the rep for NEVER breaking...) and I substituted a much less ambitious (but good; my excellent PS Audio DAC w/ Bridge stayed in place) 2nd system for my main rig.  I was amazed at how close it was in quality... did I really need $20k in gear if the differences were so small?  But then when I got my AML1 back I was even *more* surprised at how much more I enjoyed listening to music again... in fact, I found I had fallen into the habit of just not listening much to my 2nd system except for background music.  That is what I mean by small yet profound differences.  
 
As much as I sympathize with Leonardo, that searching for differences seems self-defeating, it also points out how value can sometimes only be measured over time.  (Which is not to say that the differences between my main and 2nd systems were hard to discern--it was immediately apparent which was the superior system--but rather they importance of these differences only became clear over time.)
 
BTW, outside of component changes, in my experience, I have found the single biggest difference in sound quality to be found in power cords, one of the most aggressively attacked upgrades, not only from the you-can't-hear-the-difference crowd, but also from a number of electronics designers with whom I have spoken (vanity might have something to do with the latter: an amp designer I knew once revealingly said to me that saying a power cord/conditioner could improve his amps was a great insult because it was like saying he did not know how to design a proper power supply... I wanted to respond that that might well be the case and, apparently, he was not alone in this failing, but discretion being the better part of valor and all that...).

 

[Michgelsen]

It's weird that it's louder on one of the channels. Otherwise, I have encountered this hum problem with different Stax amps and headphones, and with my HE60 as well: a faint hum that would go away when I touched the chassis. I solved it easily by connecting the chassis to the radiator pipes with some wire. Hum gone! I should add that my system is not grounded via the electrical outlets. Now it's only grounded via the radiator, which is not the proper way to do it, as any electrician can tell you. However, the hum is gone.
 
 
Quote:

I tried even with no source.
 
One more thing I've noticed, the hum gets louder and louder.
I've wired the chassis to the steel structure of my sofa, so I've been able to listen touching the structure.
Left channel is now, after a few hours, very noisy, the right on the other hand is dead silent.
 
I'm now thinking the problem is in the headphones: I can 't hear any noise if I take them off and put my ears close to the amp.
Anyway, I think I'll send the system back to the seller, and he will have a look at it.
 
Too bad, as I really like it so far.

 

 

[realmassy]

 
Quote:

It's weird that it's louder on one of the channels. Otherwise, I have encountered this hum problem with different Stax amps and headphones, and with my HE60 as well: a faint hum that would go away when I touched the chassis. I solved it easily by connecting the chassis to the radiator pipes with some wire. Hum gone! I should add that my system is not grounded via the electrical outlets. Now it's only grounded via the radiator, which is not the proper way to do it, as any electrician can tell you. However, the hum is gone.
 

Michgelsen, you gave me the right idea!
I wired the chassis to the radiator, and the hum is gone!
Now, I'll get the amp fixed anyway (my wife is not happy about a green wire across the room) but at least I can listen during this weekend.
Right now listening to Dvorak Dumky Trio (Beaux Arts Trio)
Thanks!
 
 

 

[Michgelsen]

That's great to hear.
I don't know whether the amp can be fixed. Perhaps this problem is something that's part of its design. I suspect a lot of electrical equipment with metal enclosures suffers from this problem, but in this case an audible problem arises because the electrostatic headphones are so sensitive to this. I sometimes feel a very light tickling or vibrating in my fingertips when I move them over a metal enclosure of an apparatus. This does not happen when it's disconnected from the mains. I suspect a small voltage is applied to the enclosure when plugged in, in which case the tickling is caused by tiny electric shocks. Unfortunately I don't have enough knowledge to be sure, so this is speculation.

 

[realmassy]

Well, it makes sense to let them have a look anyway, and if it can't be fixed I'll try to ground the chassis properly to the rack. I tried that before but it didn't work.
Thing is...I can see myself upgrading the amp anyway in the future

But I'm amazed by the quality of this system: I tried many dynamic headphones and amp, I used to own a full balanced system with some HE5-LE... and it did sound very very well, but I was almost at the top for a dynamic rig. I can't believe the 2050 is the entry level!!

Its sound is probably technical inferior to that setup, less detail, less focus in instruments, but it has something special anyway...price aside!

 

[Michgelsen]

Maybe connecting the chassis to the rack didn't work because it's not a real ground. The heating system is, at least it is in my house. A new amp may show the same symptoms: my SRM-T1 and SRM-717 both did, though for some strange reason my 717 now doesn't hum anymore, even though it's no longer connected to the radiator...

 

[nick n]

Did a bit of searching couldn't locate any info and am wondering whether the Koss /e.9 energizer unit can be modded to accept Stax headphones. If so what if any benefit would one see.  I currently use an SRD-6 box with SR-5 's and my recently acquired SR-50 electrets.
 
 It's not really a priority project but since it came my way why not ask. 
If not I may simply pass it along to someone who needs one for dirt cheap.