livewire

Adios muthafuka! I was walking by the TV set in one of our hospital's waiting rooms. Had to do a doubletake, couldn't believe my eyes. I want to see his rotten corpse...

@ Craig Sawyers - Thanks for the explanation, I need to study current mirror theory. @ KG - Thanks again for your continued efforts, cant wait to see it.

That's good to hear, so I guess the design of the battery circuit is a sound one. Please remember that I initiated the trouble both times. (blew it up) I suspect that rille's woes were from HV shorting to the heatsink, but i'm guessing here. This battery sub-circuit is shrouded in mystery to me. It seems that after things "went sideways" I could not get the battery circuits to function properly no matter what I did. I got tired of shooting in the dark. Then I saw the (zener) light. I know they are probably noisier and may not regulate down to the last nanoamp, but should be good enough. You have used them in most of your previous psu's. Without knowing the inner workings of the battery circuit I have a gut feeling concern about the 2SC3381 sand and the two 100 ohm resistors sitting right on the -450 volt rail. They do seem like a weak link and fried on me both times I shorted things out upstream. I'm just a tech, not a design engineer. I dont have an understanding of exotic circuits such as current tunnels. It would be nice to have a "blow by blow" on how this battery circuit functions. That is one of the things that I appreciated while reading about your stat amp designs in your HeadWize site. Though not detailed, the sub-circuits were explained in a way that a novice could grasp or at least research further. Anyhow, blah-blah-blah. Please excuse my moaning. I am really happy to have a functioning stat amp even if it was a little over my head to build. There will not be a T2 in my future. Next thing for me is to learn what I need to test the audio output on the KGSSHV for quality. I may take it to a lab, cause I have no idea what is needed to test audio that has a 900 volt swing.

Yo Yo Yo DAWG!

I got the first one. "He farts higher than his ass". The second one is still confusing to me.

KGSSHV at the San Diego HF Meet last Saturday. Check out what's plugged into it. We were standing off to the right side auditioning the O2 Mk1. It was a big deal for me, I've never heard (ex)flagships before.

No, nothing exists that shows test point voltages. If you read back about seven pages, you will see that I asked similar questions and had similar findings. When this happened to me, I also found the 100ohm resistors in the battery sub-circuit to be fried as well as the 2SC3381 sand. Since I wasnt having any luck with understanding how the battery outputs work, that coupled with the negative rail still bad and the positive rail working but not regulating under load, I gave up and went to a simpler iteration of the power supply circuit sans battery, using a zener string instead. FWIW, I started researching older psu designs on KG's HeadWize site, then tripped across his earlier psu design in this thread. It all made perfect sense to me now. This I could understand and implement. Worked fine for me. I would like to revert to the battery regulator design, but wont for now until those questions are answered regarding it's function and input/output voltage test points. So long story short, I left the crippled battery circuits in place and cut some traces to disable current flow through them and soldered in the zener strings(3ea@150V-5W) as shown in the schematics below. kgsshvps2.pdf

Thanks for the compliments guys. I just wanted a clean "econo-build", nothing fancy to help keep the price down. Kerry, you're right about the "start saving". I heard an O2 Mk1 (I believe n3rdling's) through the KGSSHV at the meet last weekend. All I can say is WOW!!! His Blue Hawaii with the original Omegas trumped that experience. I AM IN AWE! Now where am I gonna find $11K for a BHSE and a SR-009? Aint gonna happen soon unless I were to win the lottery. Think I'll stay content with what I got. It does sound nice.

Ha-Ha!!! That thought actually crossed my mind. Section the cover in the middle with a piano hinge running front to back. Have some gas shocks to hold it in the up position.

Buttoned up, ready for the meet tomorrow.

What knife?

One thing I forgot to mention is that the KGSSHV having balanced inputs makes a big difference in the quality of sound texture and minute detail retreival compared to the single ended stock amps. I guess also having a good balanced source helps here too.

Thanks, I'm a stat n00b so I dont have much in the way of comparisons to other stat amps. All I've heard is what I own. The Stax SR-202 & SRM-252II amp, also the Koss ESP-950 system. Compared to any dynamic headphone setup in general, stats rule. No real comparison IMHO. Here again, I'm a "mid-fi" guy so take what i say with a grain (or truckload) of salt, I have not heard any of the real high end dynamic stuff. (but want to, someday) Actually the KGSSHV's performance is a bit of a let down for me due to the fact it is a mismatch with the Stax SR-202s. It tends to overdrive them at higher volume levels.(@SPL>95dB) Distortion sets in and no decent improvement in bass response. The Stax Basic headset works great with the puny SRM-252II amp it came with, a match made in heaven. The sound is as good as it is with the KGSSHV but limited to a SPL of ~95dB. So I guess the Basic Stax setup is matched well, just not head shakers or bass thumpers. The Koss ESP-950 on the other hand..... Wow! These cans can handle all the power the KGSSHV throws at them. For a stat there is gobs of butt stompin bass and they can produce insane amounts of volume without distorting. They sound fine with the little plastic box amp they came with, but with these cans the KGSSHV makes a marked difference, although on the extreme end of things. I dont know if I can (or really want to) take those SPL levels for very long. The overall sound of the KGSSHV is very neutral, no coloration, no perceived noise at all at any volume setting. It suits me fine, just what I was looking for in a DIY stat amp project. I have found that with the quad DACT attenuator I just installed, the highs are sharper. There was a slight "upper veil" with the RK27 pot. The log taper is different to what I am used to, there is more finite adjustment to the middle range. Just as well, I dont need to have my head blasted off with the volume maxing at 12 o'clock therefore having the upper half of the range unusable.

Will be showing the KGSSHV at a local HF meet next Saturday. We have reserved a meeting room at a hotel in downtown San Diego with a private patio overlooking the beach. A sponsor will be picking up the hotel tab, forty or so expected to be in attendance. I'm wiring in a 50K DACT that I recently picked up from Justin. Curious to see the improvement over the existing quad RK27. Also gonna do some surgery on the bias circuits. Just picked up a Koss ESP-950 and want to do 610 volt bias instead of the existing low voltage Stax bias which I will prolly never use. Finished "big box" pics to follow. The theme will be "Back To The Future". Ha-ha, it kind of looks like a piece of lab equipment designed by a mad professor.

Looks like "Dark Side Of The Moon" treated with Miracle Grow laced with LSD.

Someday I'll prolly do a rewire. These are brand new, I dont want to jack with the warranty yet. I know the E90 is a POS, when I mentioned "big box" I was referring to my KGSSHV.

I have yet to experience them. Just listened to two songs on the included amp. Gonna wire up an adapter for the "big box".

Sorry, fixed it.

New toy for the KGSSHV.

And overheating isnt an issue. All is well ventilated and runs cool.

I dont know about the ERS paper treatment but I do prefer the Hello Kitty drapes! At the risk of being heckled like poor Ed, I do notice the same thing with my Stax setup when left on for prolonged periods. (although never any background noise whatsoever) Good to know that I'm not the only "nutcase" around here.

Road rage?

Indeedely!

My eyes hurt just looking at it and trying to translate the two-sided-ness. The original design had a nice symmetry to it. I really like how the collective around here helps morph KG's designs into advanced things of wonder. Brainstorming works!