kevin gilmore

looking very nice reminds me of something but i can't remember what it is

i have a whole bunch of greenlee punches from .5 inch thru 3 inches The only way to go for chassis up to 3/16 inch thick i even bought a square one for doing the iec sockets. birgir can supply pictures of what happens when you try to use them on 10mm panels

if I have time I plan on looking into the screws issue on Monday.

the ksa1156 is a 400 volt device. The 270V zener across it prevents it from blowing up on turn on. You can leave the zener there for the 600v part

from pictures that have been posted elsewhere including bottom and top of the board, there is no protection on those caps. The manufacturer specifically states that if you put more than 2 in series (and Vinnie is putting 9 in series) you absolutely have to have 3V protection on each and every cap. Because somewhere past 3.1V the cap explodes. $500 in caps for absolutely nothing.

as always the devil is in the details, so lets look at this 24V cheapass switcher power supply brick supplies power to the caps. And probably fills the chassis with high frequency hash. 2 banks of caps, one charges, the other supplies power to the unit. Now is this +/-12V, or is this +24V single with the amplifiers capacitively coupled outputs. In either case, headphone output power is pretty limited. How far in voltage does the cap sink before it switches. So the amplifier and the rest of the stuff continuously see's the equivalent of triangle waves on top of the power supply. How often does it switch banks. How well isolated is that switching, and is it audible. What about the fact that all of this is to get rid of power supply noise, and ultracapacitors are electrochemical, and have way more noise than either lead-acid batteries, or well designed power supplies. A solution looking for a problem that can be made to not exist in far cheaper ways. but it does seem to be fairly well built.

The electrolytics may be one thing, but taking out the .01 caps that are absolutely as close to the circuit as possible, and hanging something on the end of at least 6 inches of wire is going to cause all sorts of problems. Don't even care if the caps are super trendy or not. plus the fact that the solder job is likely poor.

just wait till you turn 40

whats the total length, and the thread size. I assume m3? length of thread, and length of the head, and diameter of the head? should be easy to find a hex screw the same size, then slot it in a mill as far as the srm600 disaster, the green things replaced .1uf caps i think, 2 in the middle, and 3 along the outside edge. You can buy parts to put this back to original. And same thing with the doubled resistors that are the plate loads. (black things, 2 in series) Those caps are on the power supply lines, and would never change the sound in any way. another clueless idiot. This may have been done by duncan7 who is an utter and complete moron.

pictures of the screws you want please.

suggest you remove the current limit transistors, and absolutely the correct heatsinks which are about 3 times the dissipation of the ones you used. use thermal grease on the fqpf8n80c, mount directly to heatsink with metal screws.

i'm pretty sure the only difference is the position of the center mounting hole

I posted kgsshvampv15mini and kgssmvampv16mini

fqpf8n80c is an insulated part and goes directly on the heatsink and with a metal screw. power supply runs a lot hotter if the unregulated voltage is too high due to the transformer voltage.

seen a bunch of the ones on the left, every one tests as a darlington of about 30 volts if you got them from dalbani, or people associated with them, definitely fakes

if its for the kgst boards you want the machined ones also from parts connexion you just don't use the chassis strap

Sure looks like a 220V pin. 220V and 230V are the same thing.

unlike a lot of amps, the dynahi will work into a dead short if necessary but if you want, build and install the protector board

The failure mode is that the resistors open up, the outputs go to -350V, the resulting bias gets close to 900, and makes the headphones very unhappy.

yep

its supersymmetry, and the 5k resistors are part of the feedback. if you go with fets you can multiply both Rf and Ri by 10 to increase the input impedance. really does not matter for this. definitely does matter for the input impedance for the ubal to bal converter.

try doubling the values of the compensation caps

yep

in balanced mode the gain is Rf/Ri *2 you don't want to change the 5k input resistors, so change the feedback resistors. Unlikely the compensation cap needs to be changed

the pot by the led's is the input section offset pot. was thinking about a different board. you can probably get away with 18ma per output transistor.