[cat6man]

Quote:

Originally Posted by luvdunhill /img/forum/go_quote.gif Guys, I'll be doing one last run of sockets. In the beginning I had a restriction of one per person, and since then I've lifted that. I just have a lot going on and need to direct my free time elsewhere. Plus, this will use up the remaining material, and after this there would be a significant reinvestment in time to do anymore. I think I will have 10 or so left. PM me and we can go from there. Looks like people are enjoying them, which is a success in my book!

thanks..........also PM'd

cheers

 

[pabbi1]

Quote:

Originally Posted by sergery /img/forum/go_quote.gif gggrEAT success!!! I have finally secured a pair of stats to call my own. I need a little time to get used to them before I start making tall claims. Right away I will say that the sound is gorgeous, although I think I need to burn in the lesser used driver a bit to catch it up. Music is creepy, impactfull, precise but still beautiful and musical. more to come.

You, sir, are truly on the path to enlightenment. Impressions will absolutely be required in the proper thread. I am just glad Runeight was able to hear on of the (early proto) eXStatA with the he60 and OII. Seemed like he liked them...

Oh, and maybe some mercury vapor will add the final touch of magic dust...

 

[runeight]

I did get to do this. The amp/headphone combination was better than anything I've heard so far. The designer does get a perk from time to time.

 

[Emooze]

Quote:

Originally Posted by Keithpgdrb /img/forum/go_quote.gif would anyone be interested in a thread that featured pictures of the completed exstata builds? a pic thread really. It sounds like a nice idea to me, as we could use it as samples of how people case the amp. I know I'll need that. just an idea, let me know, and maybe I'll start collecting pics from people.

Went with the easy route and got a Nabu case. Nothing's even drilled yet. Though it's quite spacious.

Also you have my interest in a mercury rectifier supply.

 

[Lou Erickson]

Quote:

Originally Posted by luvdunhill /img/forum/go_quote.gif Guys, I'll be doing one last run of sockets. In the beginning I had a restriction of one per person, and since then I've lifted that. I just have a lot going on and need to direct my free time elsewhere. Plus, this will use up the remaining material, and after this there would be a significant reinvestment in time to do anymore. I think I will have 10 or so left. PM me and we can go from there. Looks like people are enjoying them, which is a success in my book!

My sockets just arrived yesterday and they sure are lovely things. I don't think you could go wrong with these.

 

[paxeaxe23]

Hi!

I'mhavingtrouble getting the QStax sockets here in Germany, can you send them here? I 'll obviously gulp hard and ignore how expensive the postage is. I'm lookng for a set (1 x 6pin and 1 x5 pins).

Hope you have some left and are happy to post to me here. I can pay paypal as soon as you let me know.

Thanks


Francis


Quote:

Originally Posted by luvdunhill /img/forum/go_quote.gif Guys, I'll be doing one last run of sockets. In the beginning I had a restriction of one per person, and since then I've lifted that. I just have a lot going on and need to direct my free time elsewhere. Plus, this will use up the remaining material, and after this there would be a significant reinvestment in time to do anymore. I think I will have 10 or so left. PM me and we can go from there. Looks like people are enjoying them, which is a success in my book!

 

[paxeaxe23]

sorry Guys, that was supposed to be a PM!

 

[Beefy]

Some of you may remember that I was having a 'crackling' issue in one of the drivers of my normal bias Lambda? Well as of today, the story gets really weird......

I bought a whole heap of parts to refurbish these phones, which I have been doing over the last couple of days. Hooked them back up to my Exstata after the recable today and they were unlistenable, with loud and intermittent buzzing and crackling. Now I've done lots of troubleshooting for this issue. Only one of the drivers is having problems. It isn't specific to one amp channel, because the problem goes with the affected driver when I switch the channel that the bad driver is hooked up to. Still there when a source isn't connected. Still there when I disconnect the power supply to luvdunhill's digital volume control. Doesn't seem to show up on my SRD7-SB, but I need to do more tests to confirm this tonight.

But just by chance I touched one of the Q11 heatsinks, and the buzzing suddenly stopped. Removed my fingers, it started again. I could hold my fingers on there for about a minute, before it started to progressively have no effect and the buzzing started again. And yes, before anybody asks, the heatsinks are properly grounded as per the Exstata website.

So What could possibly be going on? The amp seems to be going into some sort of oscillation, but only on the channel that this one particular driver is connected to. I wonder if whatever component is connected 'across' the stators at the cable connection is going bad? Could there be an intermittent short inside the driver? I've gone through this very logically, but it is confusing the crap out of me and I really don't want to effectively throw away the $1000+++ that I have invested in these phones and amp, so any and all suggestions are welcome......

 

[studeb]

so which Q11 do you touch, bad channel, either or other channel?
i would check your solder joints

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif Some of you may remember that I was having a 'crackling' issue in one of the drivers of my normal bias Lambda? Well as of today, the story gets really weird...... But just by chance I touched one of the Q11 heatsinks, and the buzzing suddenly stopped. Removed my fingers, it started again. I could hold my fingers on there for about a minute, before it started to progressively have no effect and the buzzing started again. And yes, before anybody asks, the heatsinks are properly grounded as per the Exstata website.......

 

[Beefy]

Quote:

Originally Posted by studeb /img/forum/go_quote.gif so which Q11 do you touch, bad channel, either or other channel? i would check your solder joints

Touching the heatsinks of either channel was 'fixing' it temporarily. But only the channel with the 'bad' driver connected ever has audible problems.

I'm stumped.

 

[runeight]

This is a though one. Do you have another pair of headphones? It would be helpful to know if any load causes this problem or if it is specific to the one set of headphones. Also, do you know if there is oscillation when no headphones are connected?

Do you have a scope available? If you can get to one it would be helpful to know what the oscillation looks like.

Try grounding the other heatsinks. Unlikely, but possible. Check the values of all components if you have the patience and do have one more look at the soldering, just in case.

Then, finally, try just putting 100pf caps across the outputs of each channel to see if the amp oscillates. You'll need 1200V units. And, of course, a scope.

 

[luvdunhill]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif Removed my fingers, it started again. I could hold my fingers on there for about a minute, before it started to progressively have no effect and the buzzing started again.

that's the strangest part in my opinion...

 

[Beefy]

Thanks for the reply

Unfortunately no other headphones, and no scope. But I am in a biomedical engineering department, so hopefully somebody will have a scope I can borrow. FWIW I just tested again a few minutes ago, and my results are completely repeatable. After things warm up, crackling and buzzing commences, touching any of the four Q11/Q12 heatsinks makes it go away.

Some random musings......

I haven't yet tested with just the bias connected, but not the stators to the amp. Might prove whether it is just the bias, or just 'half' the amp.

I was wondering whether I have a grounding issue that may be contributing as well, but I think everything is pretty well covered there. The grounds/shields from my incoming balanced connection connects to the input G terminals, SG on the amp boards and G from the power supply connect to a star ground, and the star ground is connected to IEC earth (and chassis) through a ground loop breaker consisting of a 10 ohm 5W resistor in parallel with a 0.1µF capacitor. I can try disconnecting the IEC and chassis from the star ground; I can try adding the vol control supply and the incoming signal ground to the star ground (although vol control ground is directly connected to incoming signal ground anyway).

I have some options to try with respect to the headphones...... I am told I can safely remove the components across the stators, which are apparently just protection diodes. I can also try with a lower bias, in case previous arcing has left carbon deposits on the membrane. I can remove the backing in case something is shorting inside the phones.

The amp chassis is still open, so perhaps a lack of shielding is contributing. My panels should arrive early next week.

....... and that's all I've got for now

 

[Beefy]

Quote:

Originally Posted by luvdunhill /img/forum/go_quote.gif that's the strangest part in my opinion...

I haven't yet tried to repeat the specific effect of the touching heatsinks losing effectiveness. Perhaps it is more a case of things getting worse as the amp heats up?

 

[runeight]

If there is any way you can attach another set of headphones that will really help. We need to have some kind of control in the testing. What we don't is: is it the headphones? is it the amp? or is it the combination? If we can eliminate any one of these ...