kevin gilmore

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.

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.

Soft start is one thing, waiting 60 seconds to turn on the high voltage is something else and is a very good idea

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

has to be a $25 switcher in there. those things die all the time. Really easy to replace. pics and we should be able to find a replacement. there actually is a fuse on the power supply, looks like a resistor, and if its blown, likely the rest of it is toast, but I have been known to fix them if necessary.

you need transformers with higher output voltages. probably custom transformers.

updated the file. the caps are 25mm

Should be just fine

here is the version with the to220 sic diodes, someone really needs to check this goldenreference6drflipto220.zip

because soren is running the grlv supply at 4.5 amperes, here is a new version with the feedback resistor locations flipped so that the sense is not one inch away from the output connector. sense is now tied directly to the inner power supply connector. So the 20mv change in voltage due to current should be completely canceled out. for higher currents, best if the board is made with 3 oz copper. goldenreference6drflip.zip

He is anything but grumpy these days. Probably there are 2 reasons.

can't do 5V. best you can probably do is 12V and then you still have to change the reference to a 5V reference check C3 to make sure its not in backwards

check the values or r9 and r10, it looks like everything is working right if both input pins of the opamp are at -10v

BOM for the GRxx boards GR79.csv GR78.csv By the way, linear technology is now owned by analog devices, and you can buy these parts from mouser.

Looks close to the original dual board but bigger. I did not verify the wiring.

with the opa134 you are limited to 36v. you can certainly change that opamp to opa445 and then it would work up to higher voltages. going to check on the ratings of the transistors now edit: subject to the voltage ratings on the capacitors, so probably 35v

from Kerry, the gr78xx and gr79xx board files I want a few of each if there is going to be a group buy GR79xx.zip GR78xx-v1-2.zip

That should work also since it's normally closed could be used for startup and shutdown

yes but the opamps are wired regulated to ground so a opa134 is good for up to 36v output voltage

direct sunlight is definitely a bad thing

8.7 sp1 as of 1 month ago, but a lot of the stuff should be 8.4 or earlier try a standard gerber viewer. there should be no configuration or setup issues

All the newer gerber x2 stuff most likely. Can't make older gerber files with the new software

that340lsk.zip

I have always wanted a revox a700, but have absolutely no use for it. All it would be is a time sink to keep it working.