jwzhan

Thank you. Sorry about the sucky photo. I had to turn of the light to see the LEDs... then the shutter speed slows down and my hand shakes.. I'm not quite sure about how to ground the XLRs, so I wasn't planning to ground them at all today. But the noise in the left channel made me suspect it was caused by no groudning, so I just chucked the white wire in the left XLR and ran it to the amp board's ground. It didn't resolve the issue though... The noise is there even without any input, so I flipped the left and right channel at the output. The noise stayed in the left driver, so it is most likely caused by the driver... Also, there is some noise coming from the IEC module... it sounds like AC line noise... I'm not quite sure what's causing it; I didn't even know that IEC is capable of producing audible noise...

basically done... it makes sound... ESP950 has some serious channel imbalance issue (which I know but didn't bother to do anything about it because energizer has separate volume control for each channel.) The left driver is also making some background noise, but I can't really tell if it's from the amp or the driver... Also... both drivers are occasionally squealing. Grounding still needs to be done properly. I'm going to get the ESP950 replaced and then worry about the rest... Also, for some reason the amp is blowing through 2A fuses like they aren't there, even with a thermistor. The 2A fuse can only somewhat survive with two thermistors wired in series... Now, I'm using a 3.15A fuse with 2 thermistors. Not such a sweet moment as I had hoped

left from bdent... right from MCM.... ehhhh......

I'm inclined to say not really. If you look at Justin's KGSS builds, you will see that the amp fits in a case slightly smaller than a 2U400 with plenty of room. For KGSSHV, the on-board heatsink version will barely fit in a 2U400 case, (Spritzer did it,) but things are way to close for my liking and I'd prefer it to be in a two case design. As for the off-board heatsink, you will need at least a 3U400 case. The cost of case+case work for both will be significantly higher than that of the the KGSS. Same goes for the effort and time. As for the building part, KGSSHV is a little bit more dangerous than KGSS, because some parts of the PSU run as high as 700VDC, but it shouldn't be more lethal than 400VDC... Overall, I'd say KGSS should be a easier and cheaper build. Why do you want to build KGSSHV instead of KGSS anyway? With lower voltage swing, KGSS has much more output current. According to Kevin, KGSS output current is 8.3mA while KGSSHV is 5.5mA. I'd be happy with either (but team over-kill won't be.) I don't see how it can, since it's only tapping off the positive rail for a very minute amoung of current, but I can be wrong.

Happy Birthday!

does anyone know if FETAudio is legit? They are based in HK. They are selling matched 170/74 at the same price as AMB (of course shipping is a lot higher for US.)

I bought 50 pairs of 2sj74 and 2sk170 from bdent. I got 11 matched quads within 0.2mA. I still have 28 of 2sj74s left. I'm wondering if anyone has extra 2sk170s with idss between 6.5mA and 7.8mA. I only need 10 matched quad sets. I'm going to sell the extra sets for $10/each shipped ConUS with postage (that's if I'm able to get those 170s for reasonable price.) Drop me a PM if you can help. Thanks.

It certainly works... but it's back-ordered for 10 weeks from the date of the order. I'd just get a bridge with higher current (KBU6M, KUB8M) instead of waiting for 10 weeks.

bdent has 2SC1815 and 2SC2705 in stock. as for the bridge, KBU4M is just out. You can probably replace it with ones with higher current.

just had the most horrible experience with Camexpert. Some how they decided that using an imperial tap for M3 is close enough. So, the screw got jammed when I tried to screw it in. It's partially my fault for not checking it before trying to screw the M3 screws in. I guess you really can't take anything for granted, even if the damn CAD file says clearly that they have to be M3. I decided to write them an email about it on Monday. Well, they have yet to reply me. I still remember how fast of a response I got when I was telling them I was placing an order. I decided to just go to a local machine shop. They are charging me $40 for the fix and re-sizing the holes. A little expensive consider that I had to drive 40min, but the owner of the shop was superb. I'll probably do all my future case works with him. I still can't understand how one can charge his customer $60 for twelve M3 holes and fail to check if M3 screws can actually go in before shipping them out. pure ridiculousness.

Congrats! What exactly did you change? Did you have to get a beefier transformer? IIRC your PSU was confirgured for 450V right?

I'm not matching them to the extreme.. 10% is good enough for me, although less will be better. There is a little "2005 AMB" water mark on the JEFT diagram.

ay understandable. I'm still interested in those 2sa1486 though. EDIT: just bought 50 of matched 2sk170BL+2sj74BL for $3.68 per pair from bdent... might be a price error? because they are selling 50 pieces of 2sk170BL for 0.99/each and 2sj74BL for $7.89/each no discount whatsoever. With 50 of each, I'v got to be able to have some matched quads. And I apparently bought out their 2SC3421.... I need 16, was going to buy 25 but they only have 14....

I'd be interested in 50pcs. Also, although not KGSSHV parts.. how about matched pairs/quads of 2sj74 and 2sk170? AMB has stopped selling them. @s_r Spares are always good. buy as much as you are comfortable with.

Is that price for one? I couldn't find description on quantity (probably somewhere very obvious.) bdent has them for $8.69/ea, so if this price is for one... it is a bit high..

damn that looks nasty must've been a pretty scary explosion if it took out that many traces... not commenting on anything else, but I think the jumpers could have been done better.. and if the diodes are in circuit, you are probably not measuring the diode, but measuring everything around them. I don't know how useful this is, I checked a few points on my kgsshv psu, in ohm test, the negative and the positive rail at the same component gave me near identical readings (just poked some random ones.)

^where I got mine. Shipping was fast for me, but the company is in the same state as I, so I don't know about other states. My amp boards are up (somewhat,) now I'm just waiting for the case to come back from Cam-Expert, which might take a week or two. At the first start-up, I think I saw some white somke from one amp board, but there weren't any during the second, third and many after (they are all very short though, around 1 mintues or so, because the only heatsink the transistors have are the angled aluminum bars.) Will do more extensive testing after the panels and heatsinks come back.

^nope

Front Panel Express is having a promotion in which an old customer introduces a new customer and both get 20% off on the next order. Once the new customer's order is shipped, a discount code will be sent to the old customer. I do not believe that there is an expiration date on the code (needs confirmation.) I'm going to be placing an order with FPE for the first time, so if anyone is doing panel work with FPE soon, PM me the customer reference code. If not, will some one still go request a reference code from FPE for me, so at least I can get the 20% off? Many thanks.

^I also used Yun's BOM. It is one of the most informative BOMs out there. The resistor ladder equation is fixed, so everything in there is correct and is laid out in its simplest form. Although I've said it many times, thank you Yun.

http://www.ebay.com/itm/Canon-EOS-5D-Mark-III-Digital-SLR-Camera-Body-22-3-Megapixels-USA-Warranty-/390468355036?forcev4exp=true Canon EOS 5D MK3 for $2750. $700 cheaper than the next cheapest. only if I have the money....

yep, that's the gist of it. It seems that the LT1021 was not completely fried(open). It somehow acted like a diode with a strange breakdown voltage value that prevented the frying of every component. I got lucky on this one. You are making me feel bad. Now here is the photo that I promised haven't gotten a chance to do a proper cleaning. Everything that happened is quite visible. This is a very educational experience.

shove anything under 40V DC into the input and see if the output is 10V... pinout is in the datasheet. In my case, I just used a 19V laptop power supply..