spritzer

Most of our designs are finalized. There are some offshoots which are discarded but the general idea is finished and then either improved with a later version or put aside. Most have PCB's that go with them, either rough drafts or finished boards which is great when we revisit the designs.

Hand painted sinks... that would be a neat idea... Having some very mild hum issues in the amp so time for some trouble shooting. I'm guessing the input wiring from the pot to the PCB's as it's unshielded.

Yup, trackpads are a no, no for delicate PCB work.

There are quite a few that haven't been released....

Yeah, always better to do that. Though with a KGSSHV psu it is almost impossible to overload the input...

Can't go wrong with Antek. Dirt cheap and very well made.

Well the big brother of the mini KGSSHV I posted above is up and running. Huge sinks on this one so I could play with the current a bit. Running at almost 12mA now @+/-400V... Not happy with the quality of these boxes though so this one will be a one off. Managed to wash some of the anodizing off the heatsinks...

845's aren't a problem, the EML tubes Kevin used in the front end of that other amp are.... Around 4-5k$ in tubes alone. The Beast is a pretty neat design. The quality of the choke is crucial but it's nice to have CCS loaded front stages.

The last paragraph of that Stereophile test report says it all. In the circuits DHT's are mostly used (i.e. as old as the hills) they are simply painting a pretty picture that's not truly accurate. Similar in many ways to vinyl which has its issues and can't ever match the resolution of redbook but sounds "nice". The whole notion that tubes have a "sound" bothers me no end, just look at the BHSE distortion data Justin posted on HF. Here is the Beast. The quality is pretty crap as it's a huge schematic taken off a single page in a small book. Bonus points to anybody who sees why this one works but the WES fails so miserably? Kevin also has a design with a dozen DHT's but he hasn't even let me see it. Says I have to promise to build it before he does so....

The 3296 line would be a better fit in that spot. We never do the BOM's so no control over them...

They always used mylar until they switched to what I can only assume is PEEK. None of the other plastics really work for this role...

Even better.

My reply would have been: "DSD? That's so last year, now everybody is for retro red book. Aren't you keeping up?"

The thing with Woo is that the higher up in their lineup you go, the worse it gets. Something like a bog standard WA2 or a WA6 would be a pretty good choice for the money but nobody would go for them. Something like the WES is just fucked, they can't even get the bias and the ballast resistors for the bias right. This is crucial for something like the HE90 so I for one would never connect a HE90 into a WES. The risk is simply too great that the amp is slowly chewing up the 7k$ drivers...

Power supply technically doesn't work (look at all that rectifier tube rolling) and the amp circuit is terrible so not something I've ever recommend. For me it ticks most of the "fuck it, let's just make some money" boxes. 6SN7's driving 300B's is always going to suck but marrying it to cheap as dirt iron from China with a PSU which breaks all the rules for tube rectified PSU's just takes the cake. There are also small issues such as how the filaments are done (AC with a hum pot... in a headphone amp) and the Woo spirit of slapping on some upgraded parts that don't matter. Same can be said about the DNA amps, they are pretty much terrible and again, dirt cheap transformers and fucked filament supplies/PSU. I'm well aware how expensive iron is but opting for the cheapest off the shelf Edcor unit is just fucked. Alo Studio Six is also guilty of this as well as one of the worst tube amp designs I've ever seen.

Goes hand in hand with the two entities in the title...

Yeah, I'd like to know what the fuck they are smoking. Unless they are confusing warm and bright as all hell...

Exactly, everybody knows headphonia, 6moons, hifi+ and all the others are just garbage written by people who couldn't even buy a clue.

I'm sure there are some black SZ2's though I've never owned one. I prefer the silver and black which can be seen on all of my amps...

As I've been discussing this with Antonio, I've recently received a SZ2 Mk2 that is utterly mint. I assume they were just removed from the box in 2007 for a quick listen and then placed back as there wasn't a spec of dust on them. Stock they have that SZ2 sound and pretty terrible fit on the head. The earpads are way out there and the port wide open so everything is diffused with mad bass. Modified with Mk1 springs and a plugged port they sound awesome though. They have that ethereal feel of the Mk1 with bass that would make the LCD-2 jealous and the best soundstage there is. Me like... Yes and no... The SZ2 version was pretty much open at all times so they just breathed easily when lightly pressed towards the head. Force them and they will fart but the port is mostly open. The SZ3 OTOH is better executed so the port is mostly closed when they are placed on the head. They won't fart as much when placing them or removing them from the head but once settled they will far. Doesn't stop them from sounding horrid though... The mylar will last for a long, long time if properly cared for. It is isn't exposed to direct sunlight or driven hard enough for arc's to take place then it should be fine for the next 50 years on those SR-1's. What can perish is the resistive coating on the diaphragm as the old ones were carbon based so they can absorb moisture. Smoking near the sets will also kill them far quicker as any deposits on the diaphragm are not good. While something like the Quad speakers will require pretty frequent servicing that isn't true for Stax headphones for a number of reasons. First of all sunlight as that is the great killer for any ESL, second is the far higher voltage and lastly, pretty crap engineering on how the transducers are made on most sets. Take the Quad ESL57 for instance, drilled plates in a wooden frame with awful tolerances while the even the first Stax made just 4 years later looked like this: Stamped brass stators in a molded plastic shell. These have issues as does everything but the core design is still found in the SR-009...

Everything degrades with age but I have some Stax SR-1's here that work just fine and are ca. 50 years old. Not many dynamics last that long... Press the cups towards your head while wearing them.

I use red spirit (burning alcohol) with good results and the plastic is unharmed.

I would let the amp warm up to it's full running temp before adjusting but yeah, that's the procedure. Same as on the new KGSSHVk boards. There is also a jumper connection for the servo so you can simply engage it that way when you want.

Razor blade also works well

Goes to show just how fucking complex this PCB is. Also servo was added without enlarging the board... No space for connectors if the transformer was mounted to the back panel...