spritzer

Woot Al, team milled chassis FTW!!! I spent most of the day working on some stuff plus trying to convert FLAC's to ALAC's to cram on the iphone. Worked like a charm just in time for the drive to the summerhouse for a dinner with the family which I dread every year... Way too much drink with some people who shouldn't touch the stuff.

Yay for Todd!!!!!

That sucks Steve...

Yup, same design as the rest of the post 1994 Lambdas.

I do most of my countersinking with a hand held drill and just one bit for the standard 3-4mm screws I use.

It's a bit fiddly but I've never had any trouble with it. It's just a small tube with a cut in it so that it can compress held in place with friction. \

The forks are easy to replace so it shouldn't be a problem to get a new one from Stax.

10W shouldn't have any trouble fitting onto the board. There are also 180K/5W resistors on ebay but they aren't cheap...

Happy Birthday!!!

We have plenty of those.

The SR-007Mk2.5 that is? Without opening it up I can't be sure but the newer models have sealed ports and the earpads aren't quite as protruding as on the very first units.

As with so many crazy people, they are Icelandic...

I had 3 Mk2's and 3 A's, all of which were identical and had the same issues. All of them "fixed" and still with the original buyers. ...or reading my mind. Either way works for me... I usually try to scrape off as much glue as is possible with a razor blade and then try to lift off the rest with tape. All the chemical solutions I've tried still don't work better then a length of tape and there is zero chance of damaging the drivers.

Most of the non-US manufacturers wire the XLR's like that according to some standard which I'm forgetting at the moment.

Nahh, they are just releasing SR-303/404 Mk2's and have fixed the SR-007Mk2 to make it sound good again.

I prefer the SR-202 for this alone. It sounds more like a Lambda Nova then the 303/404

I've used nylon standoffs with either nylon screws or nuts and no issues what so ever.

SRM-T1 Let the crazy modding begin... Either that or Justine...

True dat!! I'm sure the ALO Rx would also have worked better since people are reporting great results with the HE-5/6 and K702...

Maker of the worst measuring headphones in existence?

About the sockets, take a look at these. You are absolutely right so simply finding some 2SK389's is well worth it or just bending the legs of a metal can LSK389. Yup, those are LED's and the RLED can be what ever you want it to be. It runs off the +15VDC line so a 1k5 resistor would work or something like the 3k3 which I use since I hate bright blue lights. Yup. No need for chassis mounted heatsinks either so any box large enough will do.

Well this isn't food per se, but rather industrial supplies.

Spent all day battling with the 3GS I bought from Mike, upgrading it to 3.1.2 and then jailbreaking/unlocking it. It works now but damn I don't like Apple one bit...

SRM-XH I've gotten a few PM's asking how to convert the small Stax amps to balanced operation and there really isn't much to it besides the issue of a 4 gang pot and finding inputs which fit the chassis. Now the SRM-XH I had used the green double layer PCB but some have a singe layer board and I haven't tested that as if yet. The whole point is to mimic the input as it is now and copy that to the other side of the 2SJ109. Here is how the input looked in my amp: Now I just ordered some 1/8W resistors and a cap and mounted this underneath the board using the holes which the 100R resistor used previously. I also replaced all the electrolytic caps in the amp with higher rated units and ran the amp at 14VDC and people quite liked it at CanJam even with it sitting next to the T2.

Given the outcry for some documentation on how to build some of these ESP amps I think it is time for a thread on the subject. Now the plan is to post here a summary of the parts needed to build a KGSS amp using the boards from Headamp.com plus what ever build/mods of Stax amps come to mind. KGSS Now for some time people have claimed that the KGSS is somehow hard to build when it really couldn't be further from the truth. My first DIY amp was a KGSS with those horrible old PCB's using offboard heatsinks and caps but after blowing up a couple of boards and PSU's (I really didn't have a clue as to what I was doing) I had two working amps. Now the new boards make life a lot easier and they are pretty much self explainatory (as all the values are printed on the boards) but there are a few things that are good to keep in mind. Given the way the boards are made (i.e. with a full groundplanes and traces carrying very high voltage running right under the heatshinks) it is a very good idea to raise the boards a bit using plastic washers (or nylon or some other non conductive material) on the pins before soldering them in place. Doing this you aren't simply relying on the solder mask to be the insulatior as it really isn't a good idea. A second point would be to pick the correct LED's for the amp and PSU boards. You need LED's which have a nominal voltage drop of 1.7V. Mouser part# 859-LTL-307ELC is the one I use (also for the BH) but you can use other LED's but it will have an effect on the standing power of the amp and thus how much heat it gives off. With large enough heatsinks you could go crazy but lets not stray off the path. So lets start off with the PSU and here is a picture of the PSU board which shows all of the parts needed. Not shown is the transformer needed which has to be custom made. KG and I use SumR in Canada with great results and here are the specs (two 0-280V/140mA windings, one 36VCT/200ma) plus I'd go with a core band and two 0-117V primaries for international use. For the diode bridge in the LT supply (+/-15V) I use the RS402 unit as it fits and I've always used it with these boards. The small caps are 0.1uf/50V with a 5mm pitch such as these. 1N4007's are very common but you can also use UF4007's here. As for the transistors, the board offers two good choices for the first spot (and you only have to use one, the two spots are there just to offer a choice given the different pinout) but I use a third, cheaper option (at least when I bought my stash), the 2SA1831. It is alsmost identical to the 2SA1968 but has less voltage tolerance but that's not an issue here. It also goes in the spot marked for the 1968. As for the Mosfet, I use the IRFBC30 but there are other options. Both of these transistors should be easy to find but I get mine from bdent.com The caps for the bias supply are 0.1uf/1000V MKP with a 22.5mm pitch and the bias adjustment pot is the standard Bourns 3296W (straight line of pins on the bottom and with top mounted adjustment). For the bias resistor I use Xicon's which are rated at 500V but you could use a 1/2W unit which is rated at 700V. Anything between 4.7M and 5M is just fine for a Stax headphone. For Sennheiser's they need an additional 5M resistor but you can add that inline later on or find a 10M resistor at Mouser. To adjust the bias you must measure before the resistor so raising the bias resistor is a good idea so you can addatch a measuring probe to it. One should also know that not all multimeters are created equal and you need one with a real 10M input imedance to measure the bias accurately. The cheap VC99 appears to work ok for this but a Fluke is a good choice. For the rest of the parts they are all pretty easy to find. There are dozens and dozens of choices when it comes to terminal blocks so pick one which fits you budget. The mains PSU caps are all the standard size, I've used Nichicon and CDE which both fit well. The resistors are Vishay RN60D for the smaller ones which I'll cover in the next section. For the larger units I've never actually used 180K/5W but rather 100K/10W units I had here. Mostly due to me reading the board wrong but they have been fine for years of heavy use. AMP section Here is a picture of the amp board. The majority of the parts here are Vishay RN60D resistors which you can get from pretty much anywhere. Mouser is a good choice and there is a rather good way of buying all the values you need. Just do a search for 71-RN60D-F- and find the values you need from the drop down box and you are set. I always order resistors in multiples of 100 but you don't need so many here. The larger 3W resistors are also Vishay such as this one and this one. The 22pF caps on the board are 500V silver mica caps from CDE such as these. The heatsinks used in this amp are these and you also need something like this to insulate and mount the transistors. Trimpots are 3296W Bourns like the PSU. Now the only real problem here is the input transistor but as it often is, it's not a problem at all. The dual 2SK389 has been discontinued and the current LSK389 uses a very different package. The good part though is that you only need matched 2SK170's and the spot for them on the board has already been marked. You can buy these matched from AMB so it isn't a problem. Now lets say you have built the amp and then you need to adjust it. Like any of the SS amps you measure at the Stax terminals and there are two pots on the board, one for balance and one for offset. The one next to the 2SK389/2SK170 is the balance pot so put the probes between the + and - output and adjust for 0VDC. The pot towards the "back" of the board is the offse so put a probe between the + output and ground and adjuse for 0VDC. Simple really...