DY20 (150W) power supply on 100W tube?

Any reason not to use an DY20 instead of DY13 for a 100W (EFR F4) tube?

Max current on DY13 is 28ma (although it was over 30ma when I first tested/adjusted it) and 40KV.
Max current on DY20 is 35ma and 50KV.

Max sustained current on EFR F4 is 28ma. It feels like the DY13 is being maxed out, and I’m not a fan of that. Can the DY20 be tuned down enough so 100% is 28ma? Is the higher voltage going to cause any harm to the tube?

I’m also thinking that the 1ms rise time (“to 90% power”) might make the DY20 a little more responsive than DY13.

One way to find out is to install the HY20 and see if you’re able to calibrate the trim pot down far enough to drive the tube at 28mA when provided 100% power on the layer.

Yeah, I was hoping somebody might have already done that. :slight_smile: The 2nd question is on the 40K vs 50K output voltage. I’m looking for the EFR specs/limtis.

40K and 50K are starting / strike voltages required to initiate the laser beam. The operating voltage thereafter drops. Your F4 Tube calls for 24KV starting voltage.

The laser PSU is designed to provide voltage to the tube in proportion to the tube current.

Good reference material here:
https://www.repairfaq.org/sam/laserco2.htm

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So this is more a case of “normal” current limiting maxiums. The PSU is current limited, not voltage, so it’s as long as the PSU has at least enough starting voltage, and limits to the max current. And, in this case, that the DY20 can be tuned down to 28ma.

I’m seeing some DY20 paired with Reci 100W/130W for sale, as well as “also works with…” with one seller.

So, it will probably work. However, I also just recently noticed that it’s about 2" longer and almost 2" wider so it would require more mods.