spritzer

I'm happy that I finally sent Kevin something he likes. Last time was a Liquid Lightning which he wasn't too happy with... Is the pot a real Alps unit or a fake? Can't tell from the pics...

Please don't compare anything here to HF. Here we can state our opinion, backed up by copious experience, and it is accepted as such. The LCD-3 isn't bad by any means but the model released three years ago is far from the current offering.

The shipping for the KGSS was just over 113$ for a 6.5Kg package. The transformer is a Talema unit so odds are that it has dual primaries. We are famous... http://item.taobao.com/item.htm?spm=a230r.1.14.72.YKuenw&id=37960660378 I say a new project with a new thread. Make it easy for them... Seriously, the only thing stopping us are those damn P-channel Jfets. Are any of the Fairchild parts usable?

Have a head banging birthday Justin!!

The KSA-5. Nobody had completely reverse engineered it until we did so. Speaking of which... http://www.ebay.com/itm/KRELL-ksa5-Class-A-8W-8W-amplifier-in-case-220V/271466031172?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222003%26algo%3DSIC.FIT%26ao%3D1%26asc%3D20131003132420%26meid%3D6872961694781196531%26pid%3D100005%26prg%3D20131003132420%26rk%3D1%26rkt%3D6%26sd%3D151276393019&rt=nc Not very subtle in their thieving...

I agree, the HD800 is simply better than any ortho I've ever heard. The Dynalo drives it perfectly and even better with some output resistance added. The Dynalo or a balanced one will drive the LCD-2 and 3 very well but a balanced Dynahi would be utter state of the art.

Stax really don't want to sell the sockets so not sure where this guy is getting them. They are genuine alright and the newest spec. First KGSS? I used Cart100.com but there are a lot of deputy services out there. Cart100 have been great on the two occasions I've used them, even reminded me that China is 230V so there might be a problem with that.

That's an issue with the bright nature of the phones, something which I know can be fixed without taking a sledgehammer to the top end. I'd have no reason to use the 009 if it mean making them less resolving... Just so it's clear, I've never felt the 009 offered any resolution bonus over a well fitted 007. It's even the opposite as the 007 just gets out of the bloody way and is in no way apparent.

I do like the build quality over all. Pretty nice parts and the correct ballast resistor for the phones. Even carbon comp like Stax still use. The transformer is 230V only so that is not good for US users. Still, easy enough to swap out. So the second Chinese copy this year, we must be doing something right.

Given how big a factor the output impedance is to the HD800 sound then that should be compensated for when comparing amps. Then again I'm a crazy purist... Sticking the HD800 on a WA5 is a bit like sticking the SR-009 on the Liquid Lightning, having a highly resolving transducer dumbed down by a highly colored amplifier. Didn't catch that SRD box. Do you have a link? Funny thing though, I recently found a box I'd put into storage years ago with a pile of SRD-7 transformers. No idea I had that so I'll have to find some use for them. Perhaps show Woo how the WEE should have been down with a regulated PSU and relay switching?

I just threw up a bit looking at that site... Anyway, the price difference is probably due to the weak Yen against the USD.

Poor or simply broken. Chewing up tubes might just be a design choice...

Happy Birthday!!!

Happy Birthday!!

The Chinese one is a KGSS, not a KGSSHV. It runs at +/-350V when a KGSSHV runs 400V or higher. Not the sole distinction though... Going by the pics the Chinese amp will need some mods to perform better than a nice little desktop unit.

The simplest answer is that the WES and BHSE have nothing in common, at all. Sure they both drive electrostatic phones and have similar tubes but it ends there, same with the Electra. The goal of both Woo and EC is to price their amps at the same level or higher to fool people to think they might be in the same class which they clearly aren't. Let's just view what a WES with all the upgrades and updates looks like: This is what 8000$ will buy you. Now for some impressions of the design, the PSU in this thing is the usual Woo joke. Utterly overloaded tube rectifiers which don't matter due to the bridge present. No regulation what so ever except for the circuit which powers the LED's and front end heaters. This power supply is very similar to what Stax do so why would anybody pay a premium for this? Now for the amp section, here is where it gets from bad to "we will kill your headphones". First off, a HE90 should never be used with a WES or a WEE. Never in a million years should the twain meet as both will destroy the phones. It's easy to see in the amp pic, see the small PCB next to the output sockets? Yeah, those aren't close to be the correct values though for Stax they are closer so not as big of a deal. So with actual amp the worst idea are those output chokes as there should be only two of them. Simply connecting them as a single push-pull unit doesn't work, they need to be on the same core. Inductors for Stax are bad idea though given the electrostatic load and its behaviour but a push-pull choke at least works. This doesn't which is why the amp sounds like shit, hell it sounds like it is broken. You can also clearly see that there are four isolated amp sections here with no adjustment so how can one phase know what the other one is doing? It can't so the natural drift found in all circuits is , quite literally, out of control. The amp should also be wired differently to use the benefits of matched triodes within the same envelope. The phase splitter is also an absolute dog and should never have been there. How come the ESX uses all the same tubes, far less components and doesn't need one? Other stuff such as series connected heaters for the EL34's are a problem. These are not computer/TV tubes and were never designed to be series connected. So the bottom line is this, it's an 8K$ amp that measures and sounds worse than a SRM-323S and has less power. Also worse components and build quality. My initial reaction to hearing a WES at CJ'10 was to ask Jack if it war broken. That sums it up nicely enough...

Same size IRC as the dual fet we put on the KGSSHV board. Almost impossible to solder...

The choice of RCA's on each cup is just bizzare but those earpads do interest me.

Yup, the WES is a clusterfuck and the Coriolan/Egmont also. Let's not go into the ES-1/ES-2 again...

Some good news as we can all expect some more measurements of electrostatic headphones. Kevin and I weren't happy with the lack of a good amp for Tyll to measure on so being a bit loopy we decided to build one for him and donate to the cause. It fell to me to build it and it had to be something special, with some unique features but also a known standard. A souped up KGSS felt like the best choice as it's a well known design and probably the most popular high end Stax amp out there. Justin built a pile of them, it's been a popular DIY project, I'vv and the Stax SRM-717 is pretty much a KGSS so an easy reference point. I've also built a dozen or so of them so plenty of parts in stock. Here it is sitting on top of it's younger sibling. It is clear that this isn't a bog standard KGSS since Tyll as a reviewer needs flexibility. All the outputs are driven off the same amp section but the three major bias voltages are taken care off via their dedicated sockets. The bias supplies are all either generated by fully regulated power supplies or derived via a voltage divider off a fully regulated line. Now the fourth output is a bit special as it is a small variable DC supply driving an EMCO DC-DC converter and goes up to 1kV. There are jacks on the side to plug in multimeter probes and the pot to adjust it. The ballast resistor can also easily be swapped out for any value required by what ever unit is up for testing. I'll ship it with a 4M7 unit rated to 2000V which works just fine for most sets. The LED's for power indication are mounted underneath the chassis to make the front a bit cleaner. I looked into transparent feet but found nothing that I liked. So here are the guts. The PSU is a design derived from the KGSSHV but simplified and limited to single 500V caps. I run it at +/-415V which is about as high as that Edcor transformer will give me. On the KGSS amp board the 2SA1156's are replaced with 2SA1486's and it uses 2SC4686A's as output/gain devices. I had to back the current off a bit as the sinks were reaching 95°C at the stock KGSS setup but even at 8.5mA it is a very powerful amplifier. Vanishingly low output capacitance and no protection resistors means a very linear output. I left the 5k1 output resistors off as they might interfere with a non Stax based design. Other than that it is a pretty standard fair for my builds, XLR inputs and loopouts, quad Alpha pot which is easy enough to bypass by simply maxing it out. The AC input also features a voltage selector which made hooking up three transformers a bit easier. Needless to say this amp sounds awesome and has no problem driving even the tricky SR-007A (SZ2) to perfection. Tyll is happy and and so are we. The "God amp". Who comes up with this shit as it is a pretty lackluster piece of engineering. Same with the Electra which nobody cares about any more. How come nobody can build an all tube electrostatic amp properly?

I've never built a 500V offboard amp so only dealt with isolated packages but zero issues here. I do bend the leads so that they enter the PCB holes at a straight 90° angle so no chance of shorts. This is not fun with the super tiny board...

There is no way to run a stock 323 at 400V without building a new PSU and fitting a new transformer. It isn't regulated so there is no headroom, the B+/B- is just what comes out of the rectifier. Here is a SRM-323A schematic I found somewhere. It's a bit clearer than our own: Very simple circuit and quite clear where the LL was stolen from. The output devices are 800V units so good for +/-400V but any higher you'd have to start swapping out parts. When I look at this, it would be interesting to design a PCB for this as it's so bloody simple to build. It would require matched J74's which is a problem, at least for now. Ramp up the current, swap out the gain stage CCS for a 10M90 solution and it's a cracker of an amp. Far better than either the Exstata or the LL. Edit: The 717 is a slightly modified KGSS but the 727 is a bit different. It can be modified to become a KGSSHV though which is what Tony did. Still limited to +/-350V though.

This certainly isn't BH levels of heat which does make it more user friendly. The "normal" board is still on for production, just finishing up one other design to save on shipping.

Happy Birthday Purk

Happy Birthday Shelly!!!