spritzer

The Dynalo is a pretty great preamp but just watch the gain.

I like bunnies...

Much better than any of his posts...ever!

Find me a cheap, broken set of 009's and I can check it out as I have a few sets of 007 drivers here.

They are lacking in the bass but that was on purpose. The Stax Pro series (so SR-X and 4070) all trade bass amount for depth and insight into the mix.

He's even worse than me in that regard so it is all good. The SR-X Mk3 Pro's are awesome though, truly one of the best headphones Stax have ever made. One of my goals now is to try and copy that design and improve it.

Sure blame me...

An excellent depiction of the struggle we face here too. Nobody dates here without checking islendingabok.is first. Literally "the book of Icelanders" and everybody is in it so you can enter a social ID number and see how this person is related to you. One just hopes all the info in there is accurate...

One word of warning, test all 601 pots as soon as you get them. My most recent batch was horrible and I had to throw away roughly half of the pots due to imbalance issues. So test before soldering them in.

The drivers have clearly been replaced so they are no longer 404LE's and worth a lot less too. You can see that the driver is encased in a housing which only came about with the x07 generation and the 404's never had that. Not a red ring on the driver, well then it has been replaced. I had the same thing happen to 4070's I bought and these x07 drivers (probably 507) sound terrible.

They are not SR-404LE's any longer. Those are probably SR-507 drivers so now they are pretty much horrible. Peaky treble with crappy bass? Yup, that's the joy of the 507's.

The specs will tell me very little about their requirements. Goes to show how useless they are but I'd start with the PureBipolar and work from there

I'd love to try the Focal phones but given how much I hate their speakers I'm not optimistic. Like so many other speaker manufacturers they just try way to hard to impress people and end up with a lackluster product. Still I really want to try the headphones.

It's one of my transformers and it is rated for 450VAC when loaded. It all measures just fine.

I would never run one of these with the cover on. The cover reaches 60+°C (so you can fry an egg on it) but the biggest problem is the PSU. The main power transformer will melt with enough hours on it.

It's their own layout but it is a S22.

Yup with a Sigma22 type PSU

Yeah and never discount the power of hype.

Yes but not to this set. I want a stock one for the collection (well stock-ish) but if I can find another cheap set then I'm all for a CNC chassis. Probably plywood like the HE90 if my new CNC likes it.

So I just got a recent ESP950 and I naturally could not resist taking a peek inside. Looks like they have finally updated the design of the amp a bit. New pot, new PSU board but the amplifier board is still dated 1990... There are also some clear signs of penny pinching going on. No name caps, non branded 3296 trimpots and that shitty as all hell volume pot. Bias is 600V off the main B+ line and through a 10M resistor. Next to is an "infinite" resistor which can clearly be replaced to trim the bias if they start to squeal. Not happy about the cap on the bias output but this is 1990 tech. The PSU is labeled 1317 so 2013 vintage so they are clearly still building them. It's quite funny that they didn't go to SMD for this as this is clearly a new layout. Gotta love Koss, hell they've made the same headphones for almost 50 years so why modernize. I left the amp alone except that dual section pot had to go. It can't track in stereo The headphones still look the same and were quickly modified to a SR-Gamma Pro cable. There is so much potential in those drivers but lost in the shitty as all hell housing. The earpads off ebay do help quite a bit but they should be angled to improve the soundstage.

I think the ratio is pretty much spot on... Given the number of headphones...yeah that is a lot of amps...

It can easily drive two sets at the same time but I agree, two output sockets are just a waste of everything.

Yup, those. They are well worth the low cost.

Happy Birthday my friend!!

One thing I've learned from 15 years on HF, it's very easy to sell something to the masses based on hype alone. Seen it too many times to count. Then the stuff just disappears from view... As for the ESP950, they really need to be modified to work best. The stock cable is gone and replaced with a Stax one (as the stock one is too short and I have a lot of Stax ones) and the damping in the back needs to be looked at. I'm also testing some ESP950 earpads off ebay. They are certainly a step up from the stock ones which are crappy as all hell.