spritzer

Yeah and even so you may load the voltage divider and/or the doubler so no way to get a good result. An offset/balance drift of less than 5V is nothing to worry about.

The GES is a lovely amp but I would second Ari's recommendation for the ESX. Simply a better circuit and easier to build. Here is my old one: http://i.imgur.com/qzdT4ws.jpg Forgot how colorful it was. Here is my balanced GES: http://i.imgur.com/8ZDDx.jpg http://i.imgur.com/4n24s.jpg It's very cramped as the box is tiny and I wouldn't recommend doing that. Going ever smaller leads to more and more complicated solutions. Then there is the option of combining the two circuits... http://i.imgur.com/oGWCd02.jpg ESX front end with GES style output stage.

Dust is a problem at 700VDC but I bet this is just a tube issue. I would change the caps though...

No problem posting it here but the basics are simple enough. Do a diode test on all the transistors to sort out obvious shorts and then compare the voltages between the channels. It is a very nice headphone, lacking in most areas but it just sounds right despite the shortcomings. I really have to get that really old one I found shipped here as it might be a 150V version... The BH is already set to 230V so it's all good.

A few things to try, are all the LED's in the circuit lit and have you swapped the tubes or replaced them? How is the offset/balance?

For me it's all about research. Not nearly enough data on this stuff so I buy nearly all I can find.

I just bid on it out of obligation as I already have two sets, one identical to that one. Well mine is clean (hell pristine) and charges in less than a second.

Those odd 3675's could be real as I've encountered some odd markings. One didn't look anything like the bulk stuff we bought but tests just the same... I didn't order this particular unit but it's something to consider. While we are discussing transformers, I'm talking to SumR now to see if we can get rid of the buzz issues I and some others have had.

I'd be happy to.bring them along. One driver buzzes enough to annoy me so they need to be fixed at some point... Seems people liked the SR-1 Milos had at the LA meet. We inadvertently got into a bidding war over that one...

Is there no direct ground connection from the sockets to the pot? Conduction in those boxes is shit unless you take special measures to get good contacts all over the place. First thing I'd try... I've used one Toroidy transformer and it worked well enough but who in their right mind puts 10cm leads on transformers?

LNS drivers in a HE90 shell sounds very nice indeed...

Payment sent.

Twisting or braiding AC disrupts the magnetic field so it's a good idea. With DC it's not crucial and could even be a bad idea (capacitance)

Indeed....

I'm with Doug that simply adding series resistance to transformer coupled amps is not a good idea but with directly coupled amps it works just fine. I do think the HD800 first and foremost needs a very stable amp, one that isn't swayed by the odd load. Take something like the SPL Phonitor, arguably wire with gain but really just a crappy opamp circuit and it sounds horrible with the 800. Thin, bright, edgy etc. and adding 32 ohm to it (it's output impedance is 9 ohm) didn't make it right. Better but not as good as the Dynalo or Dynahi with the same 43ohm. OTL amps have their own issues too. In the HDVD800 I think I can make out 22R in series with the SE outputs and 10R in series with each leg of the XLR. I wonder what output chips they used though... Couple of things I like about the L-2, the glow is all but impossible to see and there is no tuberolling.

It is a bit ironic that the most revealing dynamic headphone ever made needs that... I'm with Ari though that wire with gain is not a good thing for the 800's at least not fully stock.

Interested about the transformer too as I'm looking at other options. The Asia suppliers usually fail to be cheap once I impose strict tolerances and specs such as low max heat rise. They usually underspec the cores and use silly small wires to keep the cost down. I did contact Talema as they are so close to me in Ireland but haven't heard back.

Don't get me started on front panel today. My laser guy decided go cheap and only placed the color film on the spots that were going to be marked. It's pretty much silkscreen by laser but then he has to submerge it in a solution to clean it all off. That solution oxidized the panels but only where there was nothing to cover them so hello patchy panels. Time to find somebody else to do this... As for the volume knob guide pin, just cut it off. No need for it if you can secure the pot properly.

http://soundnews.ro/2013/07/18/sennheiser-hdvd800-review/ Internal pics and it is quite dire indeed. Chipamps underneath the big sink and hello output resistors which means the 43ohm was intentional.

I'd go for it. The 207 is just lovely if a shade bright but nothing like the Pro's.

The B22 would be a pretty terrible match for the HD800 in the first place. It's certainly not fully neutral with a tendency towards brightness which is not a good match. I do get somebody liking the Rudistor as the cap coupled output and quite frankly, horrific circuit design would fix some of the HD800's issues. Now this is doing it with a nuke than a tactical strike but the end result could be pleasing. People sure like the Luxman amps with the HD800 and the circuits have some similarities, including the cap coupling.

The comparison is against a Rudistor... I'd think severe brain trauma could be a factor here.

They really need to have the correct bias voltage, +500V and 10M. It just so happens you have a nicely regulated +500V in there already. Just take a line from there with a small 10nf bypass cap and a 10M resistor to the Fischer socket. One thing to note, the HE90 should never see more than 1000Vp-p at any time which the HV will easily pass even with a 2V source.

Looks good. I was going to finish 3 HV's over the weekend but my laser shop fucked up 2 out of the 3 front panels...

No but the Squarewave would be a good alternative.