cclragnarok
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Posts posted by cclragnarok
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Is $1500 the price nowadays for an used stock KGSS? I'm not sure I have that much to spend at the moment.
I can afford to wait a little bit because I'll be kind of busy with family stuff for the next month or so.
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Duplicate post (sorry, but apparently I can't do anything right these days
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Sorry about turning this thread into a FS thread, and thanks for the interest. It looks like the amp is going to a better place (Iceland), and more capable hands.
Unfortunately, I no longer have an amp for my Omega II.
I guess it is time to go find myself something like an SRM-717 or KGSS.
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I was kind of half-joking because I was a bit frustrated, but I'm not going to take back my words.
I guess it is going to spritzer then?
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It could very well have been replaced at some point and with the wrong part. I think it's time to go resistor shopping.
I don't have the equipment for that though. I'm not really the DIY type.
\Actually, I'd rather switch to an SS unit at this point.
Anyone want a SRM-007t for cheap (say, $350)? I'll throw in 8 Toshiba 6FQ7 for $40 and a Lambda Pro for $300.
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lol, even Stax is running out of the dual parts
I guess so.
\The problem is the R13 resistor though. I think something happened that caused the discoloring on the circuit board, and R13, Q6, and Z1 had to be replaced. The outer shell of the new R13 resistor is now cracking and peeling off. It probably still works (considering the fact that the amp sounds fine), but it sure isn't pretty.
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While I am able to get the tvr1 adjustment down to less than 5V, I am wondering whether the left channel is a little messed up somehow. I think the previous owner of the amp also reported some difficulty with the biasing of the left channel, LED D3 not lighting up, etc.
I noticed that some parts (Q6 and R13) on the left channel look like they have been replaced with parts that look different from the original. R13 also looks like it has been charred/fried.
Here are some pics:
Here are some voltage readings (taken from the leg that is easier to access):
Left channel R13: -95V
Left channel Z1: 13V
Left channel Z2: -198V
Left channel R14: -290V
Right channel R13: -232V
Right channel Z1: -130V
Right channel Z2: -130V
Right channel R14: -230V
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The flash was probably from the fuse but the smoke is harder to pin down. Since you basically short circuited the transformer it could come from a number of components. If it works it works so no worries and listen to some tunes...
I'll do that when I finish burning in and biasing the tubes.
By the way, how much burn in do they need before the bias settles down?
You did put some insulation between the too... RIGHT??
its really going to damage something if it shorts again with
the capacitors charged up. Then you really will damage the
thing. Small sheet of fiberglass works great.
There is maybe 1.5mm of space between the pin and the fuse holder now. I haven't put in any insulation yet, but I will soon. I don't have any fiberglass though. Would electrical tape work?
Very few of the companies selling tubes actually match
section to section on an indivual tube. They just match
tube to tube. On the sr-007 it is very important for the
2 sections of each tube to be closely matches. The additional
adjustment for each section has a very small range.
I tried using the tubes with better-matching (according to the transconductance measurements given by the seller) sections first. I actually didn't have to adjust the section matching trimpots at all. All of them ended up within 0.1V before any adjustments.
For the right channel, I also haven't adjusted the tvr1 (matching tubes to each other). The value drifts a bit, but it never goes above 1v.
For the left channel, the tvr1 adjustment was actually quite off even before I swapped out the old EI tubes. I am trying to adjust tvr1, but it's really hard to get it right since the value swings wildly every time I move the trimpot even a little bit. It was even worse last night. I'd be making tiny adjustments to tvr1, and the multimeter reading would swing back and forth from ~100V to ~-100V.
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well if you fried the transformer, its over, or expensive, or both.
fix the fuse issue and turn it on, you will know soon.
Moving the transformer looked kind of complicated, so I bent the pin away using a plier. I just plugged in a new fuse, and everything seems to work (and sound) perfectly fine.
I wasn't looking directly at the amp when the shorting happened. Now that I thought about it a little, the little flash probably just came from the fuse. I wonder where the smoke came from though. Maybe the insulation on the wires.
Anyway, thanks a lot for the help.
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well if you fried the transformer, its over, or expensive, or both.
fix the fuse issue and turn it on, you will know soon.
Thanks for the suggestion. I will go buy a replacement fuse and try it out.
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fuse now shorting against one of the transformer pins.
needs to be fixed. Transformer needs to be loosened up and
moved a bit, and some kind of insulation between the fuse holder
and the transformer.
Thanks a lot for the quick reply.
I understand that the shorting problem definitely needs to be fixed before using the amp again. Considering that smoke was coming out of the unit, do you think some other parts might need to be replaced?
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Uh oh.... I think I have much bigger problems now than the tubes not biasing properly. :'(
I opened up the 007t today to swap the tubes out. Before I actually did anything, I saw that one side of the fuse holder was bent, and wasn't actually clamping down the fuse. There was still contact though, so the amp was working before.
I figured that it would be better if the fuse was actually clamped down on both ends, so I used a piece of floss, and restored the fuse holder to the shape that it was supposed to be. Obviously I didn't notice it at this point, but this also caused that side of the fuse holder to touch one of the pins on the power transformer.
I plugged the power cord back in and switched on the 007t. Right away, I saw a few small flashes, and a bunch of smoke (which kind of smelled like solder) started coming out of the power supply section, around where the big capacitors are. I switched the 007t off and unplugged the power cord, but I guess the damage has been done.
The fuse also blew. I'm not sure when it did, but it probably wasn't fast enough.
Here are some pictures I just took after all this happened:
What do you guys think (how bad is the damage, what parts need to be replaced, etc)?
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Congrats!! There is no need for a matched quad of tubes but matched pairs will make your life much easier as biasing Stax amps is a bitch!!! I need to get me a Trends UD-10 for the computer one of these days...
Thanks for the info.
I bought 8 tubes, and had the seller give me the tube tester readings of each of them. I think the numbers are transconductance values, which isn't ideal, but I guess it's better than nothing. Hopefully, I'll be able to group them into 4 pairs, but I am a bit worried about the sections not being well matched on some of the tubes.
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I just received my Omega II yesterday.
Unfortunately, I don't have enough money for a KGBH or even a KGSS, so I'll be driving it with an SRM-007t for now. I bought some Toshiba tubes for the amp, but they aren't matched pairs. I hope I won't have too much trouble biasing the amp after I put in the new tubes.
The current chain of components:
foobar + asio4all -> Trends UD-10 -> CIAudio VDA-2 + VAC-1 -> VRX-1 -> SRM-007t -> Omega II
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Nope. Amplifier is fully balanced output. Single ended input, or balanced input
does not matter.
Thanks for the answer. This makes a lot more sense. I was just wondering since the description of the 007t says that it has "no transformer or inverting amplifier in the signal path."
To answer my other question, I tested the inputs using a multimeter yesterday, and it looks like the RCA input does work as an SE loop out for the XLR input.
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With the amp set to RCA the - side of the amp is grounded.
So the output also becomes single ended, with the maximum output voltage halved?
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This is kind of a random question, but does anyone know how the XLR/RCA input on the SRM-007t works?
If I switch the input to XLR, and feed the amp balanced (+, -, and gnd) signal, would the RCA input work as a single ended (+ and gnd) loop out? I've actually tried this, and it seems to work. I hope I'm not somehow shorting the L and R - signals together when I do this.
Also, I am assuming that the amp is simply "fully balanced" (+ and - are separately amplified with respect to gnd) when the input is switched to XLR. What happens when the input is switched to RCA?
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yup, that looks more like it. WCF? I'm assuming something-cathode-follower?
I think that means "white cathode follower," but I don't know much about amp design, so I have no idea how that is different from a regular cathode follower.
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Wuss!!!
I've been zapped plenty of times and you can barely feel it. But you weren't using headphones that can vaporize dust particles.
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The bias isn't high enough nor the charge strong enough to do anything like that. Even electrostatic speakers can't as can be seen with the ML panels.
If an electrostatic headphone is powerful enough to do that, I'm not sure I want it on my head.
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I don't think it's SPDIF, I see at least 2 optical connections
Maybe the input clock and DAC clock are separated using some sort of a buffer, and the second optical is used for feedback rate control? Then it wouldn't matter whether or not TOSLINK is used to transfer the data.
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I value the midrange more than anything else in my systems, and anything with an offensively colored midrange is right out. Every headphone I've ever liked has shared one quality - a somewhat forward, lush, fluid, but very clear midrange (i.e. SR-003, K340, ES2, HD650 balanced, HE90). I like a warmish midrange coloration that comes from a slightly boosted lower midrange, but I can't stand a thin, brittle coloration that comes from a boosted upper midrange or a recessed lower midrange. That's why the SR-404 doesn't cut it for me.
P.S. hope this is all coherent. I'm smashed off my face.
It all makes sense. Like I said, I think we are hearing (mostly) the same thing, we just have different preferences on what we like to hear.
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I have to side with Deepak on this. I think the SR-404 is crap in most systems. Heck, I've lived with one for over a year. I don't think that it's crap universally, and it did sound pretty good off the McAlister amp (much more punchy and focused), but that midrange coloration simply destroys their tone, and the somewhat diffuse and unfocused imaging doesn't help either. It has some very strong points (detail, nice deep bass and a very airy, articulate treble, wide-open soundstage with a great sense of air, and of course electrostatic speed), but they don't offset the whole sonic picture. Ultimately, the K340 off a cheap old tube amp sounded better, very similar in most respects but much more focused with a much better midrange, and that's a $400 in total system. Compared to an SR-404 off a SRM-007t or a McAlister... you draw your own conclusions.
I miss the planar sound quite a bit, and I'm hoping the SR-007 will be one heck of a lot better (or whatever 'stat I decide to go with).
I never had any comfort issues though. I think it's one of the most comfortable headphones I've ever worn. The only comfort issues are that it gets hot after a long listening session, and that the inner foam tends to make your ears itch. Still, it's better than the vice-like grip of the HD650, which somehow still doesn't prevent the headphones from sliding around and needing adjustment every few minutes.
I'm tempted to get an SR-Lambda to play around with. I already have the Dareds to drive it.
I actually (mostly) agree with your description of the SR-404 sound, except I think the flaws are subtle enough that the SR-404 is still a very good headphone overall.
In comparison to the SR-404, every high end AT I've tried (W5000, AD2000, L3000) was more colored in the midrange IMO. I also thought that the Qualia had a more offensive tone than the SR-404. That said, I think I might be able to get used to the sound signature of these headphones as well if I get longer listening sessions with them.
\Oh well. All I'm saying is that every headphone has its flaws (though some have fewer flaws than the others). Different people choose to tolerate different flaws, and some people might even like a headphone more because of its flaws. I personally find the sound of the SR-404 very good overall.
I should probably shut up now considering the fact that I might sell my SR-404 soon.
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Hmm?! What shape is your head? j/k! Even though I haven't had much experience with the K1000 (heard it at two meets), it is already one of my favourite headphones:D Still, I wouldn't sell my electrostats for a pair.
I'm glad to hear that, since we seem to have similar tastes.
My current plan is to try the esp-950 or save money for the Omega II. I'm not sure which one is the better idea, so I guess I'll just wait for a good deal on either of them.
As for my head, it's just too big, and my forehead is too wide.
).
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I've been zapped plenty of times and you can barely feel it. 
The Headcase Stax thread
in Headphones
Posted
Hmm.... I guess I'll try to find a SRM-717 or SRM-727 for now. Then when the new flood of Headamp KG** hits the market, maybe the price of the older units will drop a bit.