spritzer

Here is a picture of the insides of the amp. I can't for the life of me remeber where I got it so if it steps on any toes, will the mods please remove it or I can just remove it from the 'shack. If the other stuff in this price range even approached to be half as well designed and executed as this then there could actually be some competition to speak of. I don't think that he uses Tango iron as they usually have a cutout at the bottom with terminals and not lead wires but it could simply be hidden from view by the PCB. The CCS is clearly off board. Btw. I approve of the Metcal soldering iron...

Do you want me to loan you Mj

Hey!! It hasn't even recuperated from the last crash... :'(

Don't forget that you can take the same design priciples and apply them to a 'stat amp too. All triodes with either direct or transformer coupling... yummy.

Congrats!! I plan to spend this Friday night stuffing four Blue Hawaii PCB's with parts. Mmmm PRP and Holco resistors...

The SR-007 pads should fit the SR-5...

Well KK did dig deep on some info on Peter's Balls which were a great read about where Quad could have gone and also there is some great info on how the ESL's came of age. I did enjoy it tremendously... 'nuff said.

Happy birthday!!

Looks great but where are the internal pics...?

DIY is certainly the way to go but you could pickup an old Sugden or something like that. You could also just put some resistors inline with the headphones from the NAD to lower the volume.

Will do. If this design doesn't pan out then we'll just have to start on a new one.

The ESP950 is a stunning headphone and you may want to look into changing the damping at a later stage but if your happy, then your happy.

The order I placed was for enough parts for two amps plus quite a bit of random ESP stuff/BH parts and the total was 250$+shipping. I bought a 280-0-280v/55mA R-core off ebay for 40$ and some 2SJ74's at 10$. The case I have (Galaxy or I find something nice and gut it) and quite a few of the parts needed (standoffs, RCA sockets, volume pot, IEC inlet, fuse holder, vector boards, stax sockets etc.) but they aren't expensive. This amp will be SE only though as I don't have a balanced source so that means I have more choice with pots. Odds are I'll go with a Noble here as usual. Yeah, that's never going to happen. The 717 is about 7-900$ used and a screaming deal at that so a 300$ amp will not beat it but it will be fun trying. That being said the target headphone is the Lambda range and a simple, affordable DIY amp that most can build is clearly a good thing for the community. That is will probably outperform the RSA A-10 is just a bonus...

I just placed an order for all the parts needed to build the Poor Man stat amp. Now we'll see if it is possible to build an amp for less then 300$...

No, not really. Sure both are forward but the 4070 is far more reserved and without all the sonic artifacts that the Jade has. The bass on the 4070 lacks bloom but it very detailed and tuneful which can't be said about the Jade. The upper midrange is more open on the Jade but that's just due to the closed nature of the 4070.

I'll see if I can make some time for that. I need to have my stash of Stax brochures at hand so I can't do it "while working" I'm sure our helpful Wikiphonia admin could add it to the side. The Stax cable is: + B - - B +

Just for your info I got the newest HFN this morning and there is a review of the Sony. I just glanced through it but they quite liked it and the measured performance is very good indeed.

There are + and - stators and they are identical or we would be seeing a lot of distortion. Like Dusty said it is all about absolute phase and I can hear the difference easily. I even made a cheater plug that reverses the phase on Stax headphone so that I can compare... Is that thing still flagged for lack of references? I really have to make good on my promise and write a few articles for Dmitriy's site...

Just as a reference for anybody else who might read this thread, with Stax cables the pinout is the following: Of the three wires which go to each ear, the wire with the line printed on it is +, the wire in the middle is the bias and the last one is -.

The soundstage on the SR-X Pro is much smaller and doesn't scale like the 007 so it is always on the small side.

The midrange on the SR-007 has this "stand out" feature but there is nothing unnatural about for me as it isn't a constant. It has more to do with how the small soundstage "interprets" a normal stereo image which places the key instruments in front of you and in the focal point. The treble on the 4070 is very good and certainly on par with the SR-X Pro. The 4070 is a closed headphone so you loose a bit of sparkle due to that but they are never harsh. Ruthlessly revealing, yes, but never harsh.

They are very different and the ESP10 drivers could even be something special in the right hands. They are heavily airdamped so no etch to worry about and work just fine off the Stax Pro bias. The ESP9 needs to TLC to sound ok but they will never even approach what Stax was doing at the time, let alone better it. Bypass all of the complicated Koss crap and open up the back of the drivers (there are PCB's directly on top of the drivers) plus some damping and they aren't half bad. It's much closet to the Pro version. The bass is quite similar and so is the slightly subdued midrange (compared to the SR-007).

I got your PM but I might just as well post it here. Electrostatic drivers make noises when something is wrong but the headphone drivers we use do not suffer from any bad effects due to the weather or the season like their speaker counterparts. The winters are pretty mild up here but I've never had any issues. The hum is then definitely not normal so the first thing to do it the check if it really is the headphone that is causing the problem. You didn't say what driver you were using so a tube slowly dieing could produce a hum sound or some other part of the system could be at fault. If the headphones are at fault then hum usually points to the bias leaking as some debris inside the driver will cause it to produce a static sound and even oscillate violently in very bad cases. This being an SR-Omega I would start off tightening the bolts on the back of the headphone. There are 5 hex bolts on the rear screen and of those two are fakes. bolts nr. 1,3 and 5 are used to secure the driver in place so tighten them but don't apply too much pressure. If that doesn't solve the problem then I would remove the earpads and secure the screws hidden underneath them. To remove the pads you have to loosen pins inside them with you fingernail. It's a sleeve that goes into the housing of the headphone and when the pin is inserted it expands. If none of this helps then it might be a problem with the bias connector on the drivers. The two stators are connected by soldered lead wires but the bias is connected by a mechanical connection which could go bad over the years. The cables inside the earcups could also have gone bad or the main cable but both are strong and not prone to fail. Now you could also have some dust inside the drivers so while you are working one them check the dust covers for any tears or holes. The best way to do so it to reflect light off the membrane as any non-reflective spots will be a sign that something is wrong. Your too cheap to use just about any plastic bag?

Then it's clear you need some Sigma pads in your life. PM me your address and I'll send them out on Monday. The 4070 headband could probably be arranged. I've never seen it listed though and since it is screwed into place (from the inside of the housing) Stax may not consider it "user replaceable" and thus not sell it.