mulveling

Happy birthday Tom, you're the OG h-fi high-roller!! You and Purk combined forces to get me incurably hooked to headphones, 2ch, and vinyl. Enjoy your day! I think you would also really enjoy the Stax 009, btw.

My newer pair (Feb 2015) was in fact slightly brighter compared to Purk's older pair (isn't yours 3 years now?). But I'm confident it's down to pad conditioning as there was quite a difference in firmness there. I'd be ecstatically happy with either pair. There is no newer more mellow version. They're all basically the same and sound great. Sent from my iPhone using Tapatalk

I have one of Tony's other KGST -- it runs quite cool and is about as trustworthy and robust as tube gear gets. But maybe don't turn it on/off 10 times a day because tubes -- but then if you're doing that I'd suggest you re-evaluate your life choices

I'm going to create a dup account so you can welcome me.

Can confirm everything Purk's said. The KGST has slightly sweeter mids, but the 450V/500V KGSShv implementations I've heard won't be far off that, and they've also got a wider soundstage, more solid bass, and play cleaner louder (I do listen loud at times). Though if your KGST is 400V (mine is 350V), then it may eat into those advantages considerably (though I have no way to confirm myself yet)? That's probably a really nice amp you've got yourself there.

I can tell that the guy on the computer is a huge dork, and has a very difficult time with women.

Well that's crappy. I'd immediately order a new pair on Price Japan and work out a deal with Spritzer that will make you both happy. I'd also consider telling ACCUTECH that PJ will be meeting my purchasing needs from now on (well probably not, but still I'd be pissed) -- after you get your old pair back for $100. Personally I wouldn't bother haggling with them, though perhaps it could bear fruit. Hope you find satisfaction soon; it's been a long time coming for you.

Thanks, interesting. Is it at all possible that the source (NAD M51 via XLR) could be pushing the extra DC into one channel at these times -- I could try to swap input channels (I realize many of my questions, probably this one, are going to be stupid)? If it still sounds like trimpot replacement time to you guys, I'll proceed with that. The problematic board uses Bourns 3299 (Costa Rica) which are slightly bigger than the L board's 3296 (Taiwan).

So the offset for both R and L kept creeping up and up and up as the amp warmed up for over 2 hours -- but otherwise it seems relatively stable and symmetric between the R and L. I adjusted them for full warmup conditions, then re-tweaked the balances and let them settle. This is a Prod Rev 0.2 board, so no offset servo. What's not so stable and symmetric is the R channel balance when driving higher signals. I can now pretty reliably reproduce the following: play music fairly loud (but not beyond listenable) on the SR-007, and about a minute or 2 in the distortion will appear (fairly abruptly, too) on the R channel. When I pause the input signal, remove headphones, and measure balance at this point, it can read up to 24V or so (!!), while the L channel is still in its reasonable range (under 2V). The R channel will start to drop back down to a reasonable value over the next few/several minutes as the signal is paused, but this seems to indicate a problem. It kind of seems like there's signal level at which the distortion/instability is triggered. I'm pushing 4-6dB more signal into the 007 vs. 009 and Lambda Pro for comparable volumes -- which I guess is why this has never occurred yet with Lambda Pros. And only once being stupid with the 009.

Thanks Spritzer -- 30 mins into warmup (not to adjust, just to check), and the balance and offset Voltages for both channels look fairly reasonable and stable (biggest number I saw was a touch over 5V for an offset and 3V for balance). I'll check again after 2 hours; maybe try to adjust them a bit closer to 0 if possible. I can eventually give trimpot replacement a shot if the noise proves problematic with continued use -- I read about how to adjust each of the 1K/2K before installation. Is there any potential danger to headphones from something like this, if the noisy part gets worse? I thought the only real danger to headphones was if the bias got way higher than 580V for some reason -- is that correct?

Cool, so if the R channel trimpots get replaced, then there's at least a chance it will resolve the issue? Also, is the KGSShv trimpot adjustment procedure anything at all like this: HeadAmp Blue Hawaii SE (BHSE) Electrostatic Amp Bias Adjustment

Is that the 1K trimpot labeled "Offset", and do you think the problem is that the adjustment is out of whack? Edit: Ah, VR="variable resistor"? I am not a DIY'er obviously, but I'd like to pick up bits where I can.

Any ideas what could be potential causes of intermittent noise & distortion on a 500V onboard KGSShv in a single channel? This unit uses boards from Lil Knight. The issue first reared its head with SR-009 a few weeks ago; I shut it down for the night, and then the amp continued playing clean until 2 days ago. It's a noticeable hash/grunge type distortion to the signal that has occurred while playing moderate-to-loud levels, and is readily apparent when I switch the source signal to mono to confirm the distortion's presence in the R channel. When I pause the source after this starts, there's a "rustling leaves" type noise floor in the R channel that sounds a lot like when a small-signal tube goes noisy/bad (this noise is very audible, but would be masked by the signal, so I believe it's 2 separate artifacts). The amp had been on for several hours each time it's occurred; the last 2 times it appeared very quickly after I switched from Lambda Pros at a moderate level to SR-007 at a higher level. I've verified with a rock-solid 400V offboard KGSShv that the issue is isolated to this 500V amp. Would love to know whether anyone else knows what this might be just from my meager description, though I realize that may not be possible. Hopefully more along the lines of "dance this jig" or "replace this part" rather than "rebuild the board". Possibly unrelated, the Alpha pot on this unit isn't very smooth and consistent on this unit, unlike the very smooth Alpha pot on the 400V amp. The damn thing sounds pretty amazing when clean, too -- almost on par with a BHSE.

Thanks for the birthday wishes, and hb to sherwood and grand enigma as well!! Thursday was not such a great time, between a work project and gf issues (all my fault, of course), but I had nice flanking days Wednesday and Saturday, so not too shabby overall.

I need to hear all that new gear! Last night I heard an Innovation Wood Compact on my old speakers & preamp; it was pretty friggin' sweet even with just an Ortofon $1200 Cadenza Red. Bass impact wasn't fully there, but I know that's typical for that combination of other gear.