Beefy

Happy birthday!

Who did you get an Exstata board from?

Vague memory...... wasn't Kevin Gilmore looking for something like this?

Grawk suggested I take a dump on the stairs of Mellon Arena when I was in Pittsburgh, so I just think he really isn't a Penguins fan

What a cracker of a game! As a complete novice to hockey, it seems that Miller did such a great job, but just couldn't hold the pressure from the Canadians for the whole match. I predict big celebrations in Nova Scotia, this being Crosby's home province

I'll have you know, our Winter Olympics prowess is unmatched! Australia's first Winter Olympics gold came in 2002 courtesy of a guy called Steve Bradbury in the short track speed skating. He barely scraped through into the final, and was trailing the whole race until the last corner...... the first three places all tripped over each other, allowing him to sail to 'victory'.

Just put some nachos in the oven and have beer cold, all ready for the US v Canada hockey

Awesome. I love how everything is just so damn easy in this hobby * I just progressively dropped the bias on my Exstata from 230 to 140V while listening carefully. The lower the bias, the more intermittent and quieter the crackling, until it seems to disappear somewhere between 150-170V. It comes back as the bias hits 180-190V. I am 100% sure that I am measuring correctly before the ballast resistor (the Exstata has a test point here for this purpose), and 99% sure that my meter isn't bogging down the voltage in the first fraction of a second. And surely if was just that the bias was actually much higher than I am measuring, the crackling noise would be in both drivers - or at the very least, in both stators on the same driver. I'm not ready to call it yet because the symptoms have been intermittent...... but have I found my problem? At the higher bias, I am getting a short or arcing from the bias to the rear stator, and the Exstata holds the bias well enough that it just keeps on happening. If the bias on the SRD7-SB is indeed that easy to bog down, the slightest short is enough to constantly keep the bias down, thus I don't hear the crackling.

Well the reason I ask is that the highest I can measure from the bias pins out of the SRD7-SB is 60V relative to the outputs, which then slowly drops. It seems very low to me, even considering any effect of the voltage sagging through the multimeter. And the reason I am measuring this is that the 'crackling' problem I am having with my Exstata and Lambdas doesn't happen on the SRD7-SB. But I'm quite sure it isn't the amplifier, because the crackling only ever happens when the bias is up and the rear stator on one particular driver is connected to the amp. I have recabled, removed the diodes, get no apparent continuity between this stator and the bias wire, but still it crackles away when connected. My idea was that perhaps the bias on the SRD7-SB is much lower than the Exstata. At the higher bias, something is shorting or arcing. I will drop the bias on the Exstata to its minimum and see if this helps, and consider cracking open the SRD7-SB to get a better assessment of the bias voltage.

Quick question...... what is the easiest way to measure/check the bias voltage being produced by an SRD7-SB? Can I measure from bias to one of the outputs with no music playing, then calculate the actual voltage assuming a 5M ballast resistor in series and 10M multimeter input impedance?

He's a witch! Burn him!

Fet-tastic is a great name for that amp.

Sure, but you're spending what I assume is big dollars on custom caps for what may or may not be flawed data. And if you weren't really happy with the idea of these whizzbang caps, you wouldn't have posted a picture of them in this thread. Unless you do the tests, you are lying to us and to yourself. Same shit, different shovel. You wouldn't need to swap it back and forward several times, but just once. And you would have to make 100% sure that the listener never knew what you had done.

You fail at audiophile

Yep to all of that. The BIG one to do at the design stage is to do experiments where you also try and disprove your hypothesis. Confirmation bias is a bitch, but do the negative tests in the first place and people can't challenge you. My suggested test would be to swap the caps between the two units. See if the 'preferred' listening follows the caps or remains with the rest of the amp.

Put me in the 'or not' camp.

Forgive my skepticism, but what benefit could possibly be gained from custom caps in a fully DC-coupled amplifier?

From everything I have ever read and learned, the step down transformer will make sweet bugger all difference. Any manufacturer or distributor who says otherwise is using FUD to extract more money from you. Perhaps think of it as an extra layer of galvanic isolation

Yep, from American Psycho. TRY GETTING A RESERVATION AT DORSIA NOW YOU FUCKING STUPID BASTARD!

Sweeeeeet. They are certainly a lot prettier than the HD800 IMHO. Really keen to see what you think after an extended listen!

Thanks mate, some options to try Regarding the bias setting and measurement, it is set at 230V with a VC99 which does not seem to sag, even after several seconds; I will try with the bias lower and see if that helps. In addition to carbon deposits or bad diodes, I suppose something might also be shorting through the mineral wool at the back? I will do some testing with the back case removed, but I would have thought the dielectric strength and resistivity of that stuff would be very high. I would blame the amp, but the problem seems to only show up with this 'bad' driver. It all just makes no damn sense......

Alright, I'll duplicate the post I made in the Exstata thread on Head-Fi to give a bit more context to why I am asking the above question...... 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 be present on my T-amp SRD7-SB combo, 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 wtf 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...... [EDIT] Ah, just missed the diode post. Don't know if it makes my problem any clearer or not?

Quick question...... what is soldered 'across' the stators of a Lambda normal bias at the cable connection? Is it anything that could go bad over time?

Corsair value select is usually a good cheap option that is widely available. Use the configuratorororororor. Crucial has a good reputation as well, but they screwed me a few years back with RMA shipping charges on an incompatible module so I tend to avoid them. *thumbs up* I've used Kasperksy Internet Security on my own system for a few years now, and really like it over every other solution I've encountered on other people's computers.

You joined up almost 2 years ago, and only just making your first post? The ultimate lurker!