kevin gilmore

I have a receipt from the anodizer for accepting 16 heatsinks and 16 tops/bottoms and 16 fronts/backs So he will be paying for the missing stuff. Or he has to find the stuff. I really don't care. justin might have some more of the heatsink. Otherwise i have just enough heatsinks to match the fronts and backs. If justin does another batch of heatsink there will be plenty more. This time i will order extra. If people want me to ship what i have now, i can do that, the amp works fine without its bottom. That way you can start assembling now. All you need to do assembly is the fronts/backs,heatsinks and power supply bottom.

Found the four heatsinks in someone elses delivery... Can't find the 4 amp bottoms yet, so 4 more will be at the anodizer later today... You would think it would be simple enough to keep order A seperate from order B... Especially when they were different colors... And yes, all of my stuff is the same color.

Now i'm downright hostile. No amp bottoms... Will ship out 4 more bottoms and 4 more heatsinks today. Inu and Birgir parts will ship today.

Delivered by courier. I did get all 16 of the fronts/backs, so i have to trace down what the hell happened. Don't care about the tops and bottoms, i can make more. The heatsinks are a bigger problem. It is likely that they are sitting in another crate that got misplaced. Phonecalls in 1.5 hours. Just can't get good help these days. No one gives a shit.

Just great... One of the chassis is missing...

The 4 chassis are all back from anodizing... So 2 will ship today, and 2 will ship tomorrow. Justin wants to do another heatsink run. Which would mean that more T2's would be available. (yep lets prolong the pain and agony) So how many people would be interested in a second run of T2's ?

i'm going to verify that the hole size on the T2 will take an M8 but this is definitely what you want for the T2's

anodized parts will be delivered to me wednesday morning, so i will start shipping this batch wednesday/thursday (subject to size limits of vehicle, which should probably only be 3 of the four at once) Who wants the next batch which could be either 4 or 6 chassis. Voltron/Icarium, you can do one each for now... Makes things a bit easier.

Its just the pot. I don't even remember the impedance of the rk50 i put in. Actual input impedance of the amp not including the pot is 330k.

Good news, the batch of 4 just came back from polishing, and its better than before and just great. Should be at the anodizer by noon, then maybe another 10 days. That hammond case is going to be great for the KGSSHV... As long as its 13 x 16 on the inside

In about 6 weeks i can make another batch of stax jacks. Should be enough for everyone that wants them.

you should see the pictures of skylab's place. back yard 2 feet under water, basement many feet under water. Pictures posted over there somewhere. The records are absolutely cleanable. The sooner you get them into a bath tube with room temperature water, the better.

Well for example the fqpf3p50 seems to be out of stock at newark,digikey,mouser... So just because every single part is listed as a mouser part, it may do no good. ksc5042 has been discontinued, mouser is getting one more batch in, then that is done too. Exstata will have to change for the future anyway. thermal breakers are a real good idea on exstata's. Not a bad idea on a lot of other stuff too.

So a default exstata (pair of boards) is 30ma on the +300 line, and 36ma on the -300 line. (actual measured) If one of the two amp boards goes down for some reason, the regulators have to take 6 watts on the +300 line, and 7.1 watts on the -300 line. With the 4.7 C/W heatsink and forced air cooling, the temp of the heatsink is 122F on the +300 line, and 132F on the -300 line. Now if both boards are not connected, the heatsink reaches 172F, and on the -300 line about 192F. And of course with natural convection cooling, well the temp is way higher than that... You would need at least 4 times that much heatsink to prevent the thing from burning up...

The srmxh, srm212,srm313,srm-mk2 and srm323 all have exactly the same number of gain stages as the exstata. In fact my designs have the same number of gain stages too. The first stage, with the voltage translator, and the main VAS gain stage. Output stage is nothing but a current amplifier. Alex says the input fets do all the work. Alex is wrong, all the input fets do is buffer the input and subtract the feedback from the output. Voltage gain is no more than 5. Its the second stage that does all the amplification (voltage gain of 200 or more) and this is where non-linearities really end up going to the final sound. There is absolutely no reason the amplifier cannot be designed such that it can take anything in the range of 2 to 30 ma Idss. All you need is to replace a few resistors with a constant current supply. Just like stax does. One extra transistor, 2 extra resistors once you already have the constant current source for the Vas stage.

Here is the biggest problem i have with that power supply. Anything bad happens, and the load disappears and it goes nuclear. The heat sinks on the power supply are way to small. And absolutely no protection whatsoever. No place to put a fuse to blow if something happens to the load. The reason this is an issue is that people are already building and then quickly selling their exstata's and the build quality is awful. A unknowing customer gets the thing, and something happens, and flames shoot out of the power supply. The heatsinks need to be bigger, and thermal cutouts have to be added to the heatsinks to shut the thing down. And half the power going to the shunt devices needs to be taken up by power resistors bolted to the chassis. This is diy done wrong. If you really want a shunt supply, i came up with the schematics a couple of years ago. The current sources have shutdowns built into them, so if the load disappears the current into the shunt supply also disappears. If you use the right devices, it is only one extra opamp per rail. With any of the stax designs, standard cheap parts for the fets work fine as long as they are matched to each other. Plenty of range to zero the amp in after that.

you can always use 2sj74V's... in place of the j271's... then you don't have to match them. Trouble is the price. the srm323 uses 2sj74gr's (although bl's work too)

birgir just sent me this... http://gilmore.chem.northwestern.edu/exstata.bmp i guess that not having a car for 2 weeks forces a person to sit in front of a computer for way too long I assume a rational power supply that does not blow up is comming soon. Or just use the kgsshv supply turned down a bit. Should actually work fine at +/-450

this one looks like fun FOXNews.com - World's Strongest Beer Launches at $762 a Bottle

see our problem is this idiot agency called the fancy candy company who mandates that the output of those little toys is -88dbm. Pretty much useless these days. so its not that the devices are crappy, its that they don't put out enough power. Fortunately there is solutions, and the one like the sony actually does fit into the rf input line and switches itself in and out as necessary. I like my solution better. Its completely portable.

I forgot all about the protection circuit relays on the 717. Yep spritzer is right... What could be happening is that with the cover on, the temperature is going up (normal), and the output dc drift goes out of range and the protection circuit kicks in. So you have to rebalance the differential and set the offset to zero, for each channel.

That part is not so bad. When they give me 4 hours of machine time, i know what to do... I have each and every tool memorized as to position in the tool bin. The really bad part is dealing with the polisher and finisher. The polisher ended up with a huge job, and pushed my stuff off a week or two. So on the current batch i will be lucky to have the chassis finished by the end of next week. probably one more week. I'm sure justin has to deal with this in a massive way. The amp board (of which you need two) is going to be 8.25 x 6.25 The power supply board is going to be 9.3 x 7.7

i'm not going to make 2 runs of boards. will probably change this one to use the 1000 volt fet as the current source, then you can run it on +/-500. Tired of custom chassis work (except for myself) so i'm making this as easy as possible to build.

as soon as you take the cover off, it does not overheat... srm323a2 definitely has current limiting. Q13 (which you can't see the label) and Q14, Q17 (can't see the label) and Q18 set high enough to protect the transistors, but not to kick in otherwise. not the same kind of current limiting as most of the rest of the amps which are current sources.

if someone can build an exstata they will be able to build this... http://gilmore.chem.northwestern.edu/kgsshvhs.bmp slap it in any case you want. power supply this way will be next. perfect for pabbi1's wood boxes.