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Everything posted by kevin gilmore
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KG Balanced Dynahi build discussion thread
kevin gilmore replied to Vortex's topic in Do It Yourself
pretty sure it was posted that340.zip -
That is a 30 amp nema connector.
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Stax mafia boards linked to in the stax mafia boards thread i highly recommend you doing a diy-t2 as your first amplifier. More than one person has done this. If you survive you will learn a lot less dangerous is the supersymmetry dynalo with the golden reference power supply then the current feedback amp balanced or single ended with the golden reference power supply more challenging is the uber2 amp
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i'm not sure that the burson like things are going to be good for servo opamps. from what I have seen all of these things are bipolar input and have significant input offset current. Plus they drift with temperature. A low offset jfet input slow opamp is what you want for a servo
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on the ksa5 the servo's are in the negative feedback loop. So they can influence the sound a little bit.
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the circlotron boards are 900V
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goldenreference low voltage power supply
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
same size board, up to 35mm caps, had to move the pass transistors, needs checking silicon carbide rectifiers 100mm x 109mm goldenreferencelargecap.zip -
that was for the alps quad pots as I remember
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goldenreference low voltage power supply
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
The Zener voltage minus 1.4V (darlington) plus about 1 V across the control transistor specifies the minimum output voltage. The zener guarantees enough start up voltage to power up the opamp so something like 8v with a 5v reference -
goldenreference low voltage power supply
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
The opamp needs to be able to run on what the output voltage is, and the zener plus 1.4V has to be less than the desired output voltage. -
Cp1117 optional part for doing controlled power up. For example tube circlotron. If you don't want it, do not populate the part.
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will fix the package in a minute. moved the resistor and diode to limit turn on charging current on the caps new picture and board file someone please check for errors
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which current limit circuit? on the singles board, to put the ac input on the front requires a size change
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I can certainly do a version with a ground plane. there is no ground on the 900v board, so it would be the entire top side and whatever clearance we decide. say .2 inches here it is without the keepout for the caps and .15 inch clearance
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and now for something completely different part 3
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
The 1k input is to prevent oscillations if you short the input to ground. The 20k is in parallel with the bipolar input stage. So the result is something on the order of 10k input impedance. Maybe a bit less. -
goldenreference low voltage power supply
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
way under a microvolt. pain in the ass to measure. -
that has to at least double the capacitance of the cable. probably more because the bias wire is no longer shielding the stator wires. stupid fucks.
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goldenreference low voltage power supply
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
works fine, more diode switching noise gets thru. Also requires more voltage differential as that current source eats up about 4v. -
[DT-HWT] electrostatic headphone tube Amplifier/Preamplifier
kevin gilmore replied to pham's topic in Do It Yourself
This is yet another attempt to make one amp that does both like the malvalve and RKV. You can optomize for one or the other but not both.- 47 replies
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although you certainly can (singlepower es1,es2...) when you apply high voltage with the tube cold, the cathode can strip. with the diy-T2 applying high voltage with the tubes cold does all sorts of bad to the input tube, putting +500 on the cathode with the filament grounded. soft start on an el34 seems like a waste of time, haven't seen anyone do that. On expensive DHT's, might be a good idea, might be a waste of time.
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Soft start is one thing, waiting 60 seconds to turn on the high voltage is something else and is a very good idea
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unbalanced/balanced to balanced tube input
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
so you add a volume control, then 4 of whatever flavor amps you like. -
the T2A round black thing is the fuse, you can check continuity. Looking for exact replacement now 24 volts 1.67 amps mounting holes 3.7 x 1.7 inches made in 2005, so its definitely time to replace this may or may not fit the mounting holes https://www.mouser.com/ProductDetail/Delta-Electronics/MDS-065APS24-BA/?qs=%2fha2pyFaduirkRCGmuVLPGG%2b%2b1Owb2DkcY1eufxPxz01f8scL9gSWw%3d%3d this seems the exact item but its end of life, so maybe buy 2 https://www.mouser.com/productdetail/murata-power-solutions/mvad040-24?qs=sGAEpiMZZMsPs3th5F8koHWdVLP2qW6GCxvvDr00QbM%3D