kevin gilmore

the 300v is made from the 500v with a resistor, or a separate supply. I don't remember about the current limit at the moment, will have to look that up later.

then you want a pair for balanced, one for each foot.

That's not the esl57 rig. That's the esl63 rig, and its in England, not Germany. the original esl63 panels were white plastic. the esl57 panels were gray with a wood outside.

That was the other possibility

looks like early joni mitchell

Love him or hate him or his products, certainly a major force in the industry http://web.mit.edu/newsoffice/2013/obit-amar-bose-0712.html

The penny & giles pots are great too. also rk50 pricing these days. The $5k JC parasound preamp uses a rk27. pretty sad. my 8 bit digital step attenuator seems more rational.

Paging Steve to the DIY T2 thread

the goldpoints are not enough steps, and are not 2 resistor shunts. same thing with the dact. that is if you want to be completely anal about it.

you can't get a ldr to track right. no matter how hard you try. even with multiple elements and extra feedback. plus the issues with low level non-linear behavior.

its not that those switchers are necessarily the wrong thing, i'll be that there is ultrasonic noise coming out of them that takes special equipment to see, its that the thing is enormously big for no reason. The original 2 box solution seems more rational. All the electrolytics likely get rid of any of the ultra high frequency noise. Now i'm certainly not one to pick on someone for excessive overkill but mine is going to look as close to the original just because I can. Complete with the rounded corners and the massively thick and machined front plate. Anodized two tone. The build job is still very nice, and the 4 pin headphone jack is what I intended.

seeing how they are built, if I had the time, I could design and build one that would never ever fail. Would have pure silver contacts et all. Would probably take 2 hours per section to assemble. Plus silly amounts of time to cast the silver pieces.

I spent over $4.5k with the rk50 pot. but its easier not to pay attention to those things. If I actually paid myself my standard consulting rates for labor, the price would be stupid.

well if you are doing balanced and the inputs are separated by a distance you might want to separate the grounds into left and right. that kind of thing.

I would eventually get the Krell Klone power supply and build an Off board balanced dynahi and crank the bias to 1.2 amps per Chanel And use those supplies for that.

I got one courtesy of hennyo and it took me about 2 hours to make it perfect. (not his fault) (balanced quad)

those are 150 watt switchers?? 24 volts at 6.5 amps ?? they are certainly running under their minimum power specs and are going to be too noisy at such low power... amp only pulls about 400 ma

they have assembly issues. if you take them apart and resolder all the resistors and then carefully adjust the wipers, they should last quite a while. they are shunt devices with only 2 resistors in the circuit at any time, and do sound good. they do however as default have a common ground, which you may wish to defeat.

most likely!

ebay is your friend for stuff like this. get a 100mhz scope to go with it. if you have a Tektronix power supply frame already, these are great http://www.ebay.com/itm/Tektronix-FG-502-Plug-In-Function-Generator-Rack-/111110966177?pt=LH_DefaultDomain_0&hash=item19debacba1 if you don't have the bias set right, its probably not going to sound right.

better change the opamp to something that can handle that like opa445.

don't know about T1, but sounds great on hd800 and lcd2. this amp does not have as much voltage swing as you might expect for something that runs on +/-21v.

it the source is true balanced with no ground reference then unbalanced output is not going to work with a high impedance pot as that is the only source of ground reference. This amplifier is a true differential amplifier in this mode.

are you using a se input or a balanced input? last time I checked, it was supposed to work all 4 ways.

fixed silkscreen http://gilmore.chem.northwestern.edu/ksa5psorig.zip