kevin gilmore

That is better than 1% accuracy which is all you should expect unless you get silly and hand match the parts.

Lets take a pure resistor. The voltage across the resistor and the current thru the resistor are in phase. There is actually no such thing as a perfect resistor, all resistors have some inductive component and some capacitive component.. So at higher frequencies the voltage and current are not in perfect phase. Lets take a pure capacitor. The voltage across the capacitor and the current thru the capacitor are 90 degrees out of phase. There is no such thing as a perfect capacitor as all capacitors also have some inductive and resistive component. Air does have a resistive component which also depends on the humidity. So the electrostatic transducer looses energy into the air because of the resistance, and the electrostatic transducer also looses energy as it transfers the energy to the air in the sound wave. So while electrostatic transducers are more efficient than dynamic transducers at producing a sound field, they still are only at most 10% efficient whereas dynamic transducers are at most 2% efficient. It still takes real power to make an electrostatic transducer create a sound field.

As i remember the dynahi is something in the 40 to 50 v/us range. I completely disagree with the analysis that says only a 2 v/us is required because i can deliberately slow down an amplifier and the sound changes dramatically. Changes in the way the feedback works which decreases the delay time also makes a big difference. The new balanced supersymmetry dynahi definitely sounds slightly different from the original and gives me the same feeling as listening to the T2.

I have listened to the lcd2's on my original dynahi, very Very good. Remember that balanced doubles the slew rate. Also the lower impedance input due to the super symmetry widens the frequency response a fair amount.

DIY of course. A commercial version done to the craftsmanship level of headamp would be well into the $20k range. Parts cost with the step attenuator will still be close to $4k.

First of all, some people that say that since electrostatics are capacitors and therefore the impedance is imaginary, there is no real power. This is absolutely wrong. In fact the real power to O2's can be in excess of 1 watt. All you have to do is put an amplifier on a scope, and then connect and disconnect headphones with test signals applied to prove that the amplifier is delivering real power. On some amplifiers when you connect one pair of headphones, the slew rate gets cut in half. Add another set of headphones and the slew rate slows down even more. This is real power, not imaginary power. The T2 has the largest voltage swing of any amplifier out there and has the most amount of power behind that voltage swing. Something like 20 watts per channel. The BHSE is second in this regard, less voltage swing, and slightly less power, something like 16 watts per channel. The added current source in the kgsshv and the toshiba output transistors make a big difference in both the slew rate, and distortion. Even at moderate volume levels, the difference between the kgss and kgsshv is significant. There will be a new version of the T2 with a solid state input stage. With output current sources based on the same toshiba transistor, you can now up the voltage rails to +/-600 volts. And push up the power to about 30 watts per channel. This will also increase the slew rate. Its not about how loud it goes, Its all about how well it handles the loud. Although i don't have lcd3's yet, with lcd2's, the new balanced and supersymmetry dynahi is lots of fun, lively and exiting. And its much more than the 120 volts peak to peak that this amplifier can produce that makes it sounds so good.

I was told to use the xicon resistors. I was not told why. Or i was told why, but did not understand. The spec on the prp resistors says 500 volts across the resistor. It says nothing about leakage from the resistor to ground or other parts of the circuit. They do leak about 150 nanoamps to ground at 500 volts. And probably moisture in the air makes a change in that number. For most stuff even including the kgsshv, this is not an issue. Properly adjusted, this amp is good for a 95 to 100db signal to noise ratio. Input tubes make a huge difference. Compared to the original which has oodles of hum from the unregulated power supplies there is a night and day difference. Its a tube amp, it is supposed to make some noise. Thermal noise from the output tubes is just the way it is. Kerrys solid state front end version should make less noise.

you should be fine without having to glue them together. Its more important on the dynamic amps where a little DC can cause major trouble. The lsk389 does have a bit less noise.

kerry is correct on all issues. The 500 version runs only a fraction hotter than the 450 volt version. Not an issue. I need to do some writeups for all the various different configurations. When i'm going to find the time for this, i have no idea.

On the power supply board, do not populate Q9,Q10,Q24,Q14,Q15,Q26 While it works great on the bench with dummy loads, when you try to power it up with a real amplifier, the current limit comes up so fast that those transistors pop. Likely need 1k ohm series base resistors on these, or the next size up in transistors, something in a to92-mod case. edit: andy/steve have a working balanced dynahi now, a few teething issues... Hopefully he will post the pictures he sent to me. second edit: only board from the group buy not tested now is the balanced dynafet board. (obviously the most complicated of the dynamics)

Those voltages are correct with those led's.

ujamerstand had his university make up some of my version of the stax jacks, maybe he is willing to sell a few. I have 3 of the 6 pin teflon versions that i make left, i'm not going to make any more jacks this year due to lack of time. You could always plug the center pin with an appropriate teflon rod if you wish. Someone needs to organize a group buy and find someone in china to make a large batch of them, with REAL teflon.

depends on which of the prp resistors and which wattage size. There is no spec between any wire and the closest possible physical ground. There actually can be up to 540 volts from the one end of the battery resistors to ground.

chinsettawong used the wrong led's the first time. Evidently that makes a huge difference too. The led's need to be 2.1V

So i finally had a few minutes to test the prp resistors last night and while you can put 350 volts across them, and they are stable, If you put them very close to the ground plane, they leak current thru the covering on the film. So the prp's probably work if you lift them off the board say .125 inch. But really there is nothing wrong with the xicon's.

You are not using it enough. Should be 6 or 7 times a week.

yep the voltmeter has gpib. unfortunately i don't have a pci express gpib board. (i'm not even sure that those things actually exist) Illegal uplinking to sattelites seems to be frowned upon these days. And dedicated microwave links seem to require a FCC permit. I would love a gigabit microwave link between my house and NWU. (without having to pay for the bandwidth)

so monday on the way home, this guy who i had bought those monster capacitors from was having another garage sale, and my eyes are keen on tektronix blue. So i bought these two pieces. $50 each As far as i can tell, brand new, never used with all the original stuff, including probes still in original packaging, original manual and warranty cards. http://gilmore.chem....du/dsc_2303.jpg I think i did pretty good. He had a bunch of microwave stuff too, not sure what i would do with all that stuff except cause trouble.

usa only... http://www.mouser.com/ProductDetail/Ixys/IXCP10M90S/?qs=sGAEpiMZZMuNY54QelN3z%2fGpmPBImucviXo%2flzMMtuQ%3d http://ixdev.ixys.com/DataSheet/98729.pdf

They are electrically isolated. But you still need some kind of thermal interface. So either the thermasil silicone impregnated things, or some thermal paste. Same thing with the 2sc4686a output transistors, and the 2sa1968ls current sources. the ixtp01n100d are NOT isolated, so they need the aluminum oxide washers.

notice to people doing the dynahi power supply boards. If you are using the lm4040, make sure you buy the 10 volt versions. Otherwise you end up with the biggest +/-15 volt around lt1021 definitely a better part, and not a lot more money if you buy from digikey.

I can't even tell you how pissed i'm getting at all the fake parts. And i've been recently bit by $200 in fake parts myself. None of the distributors stand by them either. Dalbani seems to be the worst of the bunch, complete thiefs.

Actually there is one spare pin in each of the power supply connectors. So there is room for the +5 volts. And the 12 volts for the attenuator can share one of the existing 12 volt power supply wires that go to the servo. Or add another connector to power the attenuator. Its a work in progress, need to find a space for the cpu.

silkscreen error on the dynahi power supply board. The resistor labeled as 40k for dual tracking should be 20k. schematic is correct.

The cell disruptor is not a joke. I have a 600 watt one. Nasty device. Reminds me of the dentist. In the future don't tap holes by hand without a jig that holds the tap absolutely straight. Then they don't crack off.