kevin gilmore

dan wants the male stax plugs, which are slightly more work. And printable with a $800 3D printer. any machine shop will happily make them for you out of teflon.

yes you can modify any of the power supplies to do that.

First 4 relays are opposite polarity from the second 4 on the max4820 boards. Yes all 4 of them in series, so 32 bits to write all relays.

not a fully balanced fully differential fully discrete one that i know of.

it is not illegal to own more than one amp. however it may damage the universe if one person owns more than 50 amplifiers (electrostatic,dynamic,speaker amps...) I think I am one amplifier away from that. And the ssdynalomini should put me over the top.

of course its hand solderable. you just have to find the right set of hands. preferably robotic.

fine, cram the new digital attenuator in there. should be enough room.

birgir has a large pile of the 10k alpha parts

my guess is that the amp is non linear at high gain with high impedance headphones. probably voltage clipping

i would not use the amphenol/wpi connectors i am also out of male connectors although hopefully in the next couple of weeks i will make a batch out of ebony (i predict lots of cracking) ask chinsettawong

Sure looks like 4 input wires and 2 output wires to the transformer, but what do I know. parallel dual single ended output stage sounds like push pull to me.

latest board

I read some of what you have written elsewhere, and its becoming clear you don't have any idea what you are talking about. The apex amplifier linked to above is a single ended amplifier, that is there is a single output tube driving an gapped output transformer that carries the full dc of the power supply. The rise time and fall time of the output signal is not the same. The eddie current tube amp pictured above is a push pull amplifier with 2 output tubes per channel. The output transformer is not gapped, and there is no dc in the transformer. The rise and fall time of the output signal is the same. In fact with both input and output transformers, that amplifier can be considered as fully balanced, and fully differential. Big difference in the kind of sounds that these amplifiers make. Now, since a couple have sent me emails about the black widow, here is my explanation of whats wrong with the picture above. Now maybe in the 2 box version the board had to be that size, and was obviously stuffed into a box of a specific size. But designing that way is stupid. In the single box there is all sorts of room to make the board bigger and do a much higher quality layout with better and bigger heatsinks, and having the left and right channels be absolutely identical. The worst offender of differences in left and right channel layout was the melos, but the liquid fire, liquid lightning and especially the liquid glass are in the running. The power supply board is obviously new, full ground plane on top, suitably sized heatsinks secured to the board etc, why use an amplifier from 2007. The stax mafia can (and probably should) do a much better layout with larger heatsinks, identical channels etc. There is absolutely nothing unique about the circuit design. If its going to be eye candy on the outside, it really needs to be eye candy on the inside if its going to command a premium price.

I would carefully check all the solder joints on the pzta parts I have been known to miss a couple

This is typical of all power amps with unregulated power rails. There is a solution (see uberamp2) which requires a lot more of a lot of stuff. You can mess with the filter settings in audio precision to make much of that appear to dissapear. Still 100db down is better than .01% thd, 3rd harmonic invisible, typical of bipolar outputs done that way. About the best you can do without feedback or lots and lots of current mirrors reducing distortions in circuits is not an easy thing, best to start with something decent to begin with.

You know that there IS a solution for that problem. But it's a slippery slope looking at the board now, its an astounding job. and its only 2 layers. infinitely better than the "professional" crap

There are other gerber viewers that work with the latest files. soon I will upgrade to the newest version that does the X2 version of Gerbers with full polygonal and contour support and that will probably make a mess with many of the viewers

want a pair of them real bad. (office/home)

Oh no the singlepower filament circuit very bad

for the high voltage 16 kohm 20 watt, you need a pair of them. for the low voltage 500 ohm 2 watt

yep that board and that power supply. what you want for the transformer is a real good torroid, or even better a R-core transformer although I used a Hammond transformer for my build because it was easy to source.

always check the power supply first. Into a set of resistors if possible.

The ksa5 is voltage limited, so for things like the he6, not enough oomph. And its single ended, although nothing prevents you from stacking 2 of them for balanced in which case its going to have serious amounts of power. ss dynahi is for all practical purposes way overkill for all modern in production headphones. Very nice on vintage electrovoice and jbl horn speakers. I did just pick up a pair of original "voice of the theater" set, if I bring them home i'm dead for sure. ss dynalo is what I listen to when I listen to dynamic headphones. as I only use the he6 now for testing. any of the audio-gd headphone amplifiers are better than that eddie current piece of crap in every single way, sound quality, build quality etc. And less than half the price. I hope the black widow is reliable because its stuffed with obsolete parts (although the layout for the thatcorp/Motorola front end is obviously there), repairing the thing is almost as bad as trying to repair a cavalli piece of trash. compare the picture above with this for $520 http://www.audio-gd.com/Pro/Headphoneamp/NFB1AMP/NFB1AMP9.JPG

would one more gain stage, and some output stage stability have killed them? Maybe $499 of course then it would be similar to a srxplus or half a megatron birgir can post the inside pictures, even with the crap case its still built better than any cavalli or ec I know of. and once you play with nagra gear including the stuff that is 30+ years old, nothing looks like nagra, nothing feels like nagra, nothing is built like nagra, even the rotary switches are different from everything else.

here you go its better than a lot of other eddie current stuff I have seen people that think that shunt regulated power supplies are better than really good linear supplies are wrong the input stage is very familiar really weak output stage with virtually no heatsinking painted really cheap steel chassis there are a number of ksa5 clone boards on ebay, some are mine and are obvious, but no one putting my board inside a chassis at the moment. if you have to buy one now on ebay, this one is complete, the power supply is not as strong as the original, but its cheap http://www.ebay.com/itm/Headphone-amplifier-Imitation-KRELL-ksa5-line-CPI-full-DC-amp-machine-ClassA-amp-/112050882595?hash=item1a16c0c823:g:61kAAOSwu4BVkJvH this one has my board but a different power supply http://www.ebay.com/itm/Finished-Kevin-Gilmore-KG-version-KSA5-headphone-amp-preamp-amplifier-HL-230-/142031703076?hash=item2111bfcc24:g:6GMAAOSwM4xXaLnE this one is my power supply with a different heatsink http://www.ebay.com/itm/Assembeled-Power-supply-board-for-KG-version-KSA5-headphone-amp-PSU-/322047929078?hash=item4afb8d6af6:g:-~UAAOSwoudW8MxP so you could buy the right board, and the right power supply, put it in your own chassis with a transformer for about $300 total...