-
Posts
7,145 -
Joined
-
Last visited
-
Days Won
21
Content Type
Profiles
Forums
Events
Everything posted by kevin gilmore
-
and now for something completely different part 3
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
1 amp at 30 volts times 2 power supplies is the same as 1 amp at 60v same total power -
no idea, evidently lots of stax mafia stuff on taobao. The one guy took my power supply layout, copied it 100% then added stuff and changed the form factor and holes...
-
that is the ss dynalo balanced version with the mpsw transistors. which you are going to have a hard time finding. this is not the original unbalanced dynalo.
-
A 4 pin plug does not mean it's balanced the liquid Crimson is not balanced
-
the only one with a lifetime warranty was the liquid carbon version 1. https://item.taobao.com/item.htm?spm=2013.1.20141003.7.4edb00b7muYKyQ&scm=1007.10011.70203.100200300000001&id=560442101039&pvid=d455e4ef-3a60-417c-9653-9dc0aea4d782 this guy will repair your piece of shit for you, the shipping both ways is going to be more than a liquid carbon is actually worth. my offer to ONE and only ONE person, send me your liquid crimson (the only one I don't have schematics of) and I will fix it for free. (plus parts and shipping) options can include turning the output stage into bipolar.
-
like this, one side, replace r7,r8 with 10k pot electroopamp.PDF
-
that cannot work with the + inputs of the opamps grounded.
-
and now for something completely different part 3
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
quite a bit more power and heat and bigger power supply etc -
the second schematic is not going to work, there is nothing to keep the output at +300, the left side of R4 needs to go to some negative value and AGAIN, the dn2540 will BLOW UP when the voltage across it hits 400v use a bsp125 in the to220 package if you want a 600v power supply but much better is a c2m1000 and a 900v power supply
-
the massdrop is a liquid carbon. not a liquid gold. lower voltage power supplies, less heat, less power etc a correctly built liquid gold is at least 50 watts of heat. but hey its cheap
-
the 2 channel pot to do balanced is the same crap eddie current uses. it can be made to work, but causes all sorts of problems. All 4 wires are with respect to ground so not what you think. Also you need a reverse log pot for it to work right, and no one makes those. electrostat, dn2540 goes boom at anything over 400v. and its a depletion mode part, so not a great idea. what you are doing is a hev70 copy, look at the original for better ideas. also the opamps driving the mosfets have the feedback wrong.
-
and now for something completely different part 3
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
its always better to match parts, less work for the servo -
those JJ tubes have only 1 hole in the plate per side, the originals have 3 holes and a different configuration of the plate, more square than rectangular. my T2 is still using the same tubes as when I demo'd it at CJ010. I recently did a 100 to 120V conversion on a real T2 for someone on HF. It has the original tubes, 22 years old. (pictures can be supplied if anyone has a real T2 and wants to convert voltages, better than $250 in shipping both ways) The gold aero's are labeled 6dj8
-
so on the input tubes the input tube has a plate voltage of roughly +75 volts and a cathode voltage of -3 volts the cascade tube has a plate voltage that would be a max of 250v, but its a current source, and is typically +200V and a cathode voltage of +75 volts and the maximum voltage swing is about 15v so both tubes well within specifications closer look at the original pictures and the original tubes are el34G they look absolutely identical to the Richardson tubes currently made in china which are labeled as 6ca7
-
The real original has el34 with the Richardson electronics National Logo made in USSR about 1994 the 6dj8's were gold aero
-
lots of floating filaments
-
although a lot more parts, and not all tubes, the T2 battery appropriately adjusted for voltage to replace the loss across the 0a2. of course you could just use a 1uf cap across the gas tubes
-
ssdynahi has a lower input impedance and would be fully balanced.
-
r19 in parallel with r20 is the gain resistor
-
KG Balanced Dynahi build discussion thread
kevin gilmore replied to Vortex's topic in Do It Yourself
that definitely works, but the price is a bit goofy. probably what happens when you spend 10 years trying to make better parts only to make parts identical to the originals -
KG Balanced Dynahi build discussion thread
kevin gilmore replied to Vortex's topic in Do It Yourself
lh0033 is a diamond buffer, and is VERY obsolete. I have a couple of originals somewhere. -
and now for something completely different part 3
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
That was a jpg picture, the schematic above is the latest -
and now for something completely different part 3
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
that is the correct schematic with q27 and q28 replaced with surface mount on the back of the board -
lg.zip note: phase splitter not included you need 4 for balanced
-
so after thinking about it a while, something is wrong with the hv delay circuit which turned on with the tubes cold. this has to be fixed first. when the tubes are cold, the output voltage is going to go to +500v, and thru the 100k feedback resistor is going to put 500v on the cathode of the input tube. With the filament of the input tube grounded, there is 500v cathode to filament. Guaranteed to cause a light show and permanently trash the input tubes.