[wheelbuilder_25]

I did a search and didn't see anything definitive, I hope someone else finds this helpful. If everyone knew this already, just ignore it, I can be a little slow.

I ordered a pair of RF-603 II, and a YN-560 IV to use with my new to me k20, as my older auto-thyristor flashes had trigger voltages in the mid-200s. I was able to find that the 603 II had a safe trigger input of up to 300V, and thought I'd meter their output with my old flashes mounted to the radio trigger. I get 3 volts. The thyristor flash works just fine mounted to the trigger in the camera's hotshoe. Sort of handy (even if it looks awkward) for reasonably quick flash work. Cheaper than buying just the safe-sync as well, unless you had a voltage over the 300 limit on the RF-603 II.

I did a search and didn't see anything definitive, I hope someone else finds this helpful. If everyone knew this already, just ignore it, I can be a little slow.

I ordered a pair of RF-603 II, and a YN-560 IV to use with my new to me k20, as my older auto-thyristor flashes had trigger voltages in the mid-200s. I was able to find that the 603 II had a safe trigger input of up to 300V, and thought I'd meter their output with my old flashes mounted to the radio trigger. I get 3 volts. The thyristor flash works just fine mounted to the trigger in the camera's hotshoe. Sort of handy (even if it looks awkward) for reasonably quick flash work. Cheaper than buying just the safe-sync as well, unless you had a voltage over the 300 limit on the RF-603 II.

The RF-603 II N (Nikon) version, which works on Pentax hot shoes, passes the firing signal through to its hot shoe. I've used an RF-603 II N in the hot shoe for my Yongnou 560 III's and stacked an old PT-04 (Cowboy Studio) to fire my Alien Bees. Works with the Buff Cyber Commander too. It allowed me to keep a couple of lighting setups intact during a long studio session without continually swapping out triggers, .

Since 560 III's have receivers built-in, a pair of 603II's gives me redundancy. When using just the 560 III's, I use the 560-TX to control zoom & power, great for head shot sessions. If it dies, I have the 603II's and manual adjustment. All AA batteries too, flash and triggers, so I don't have to keep up with two kinds of batteries like the PT-04 Triggers & Receivers.

But since I accumulated a bag of the PT-04s, they do come in handy. Have used them for years, just keep the batteries fresh.

[wheelbuilder_25]

To be more specific, I was using the RF-603 II C version when I was checking the voltage.

To be more specific, I was using the RF-603 II C version when I was checking the voltage.

They are the same except for the pin layout on the foot. Could not get the Canon version to work on a K5 or K5IIs. Use the Nikon version often without any fuss. To me, it looks like the pins on the Canon version don't line up to the Pentax hot shoe contacts.

[rawr]

Cactus v6 works as a safe-sync too.

[reh321]

Cactus v6 works as a safe-sync too.

Its not blown away by 100+ volt triggering on a flash?

[rawr]

Its not blown away by 100+ volt triggering on a flash?

No. Safe-sync is in the Cactus v6 by design. It's certainly a useful feature.
One of the reasons I got a Cactus v6 was to use my old Metz 45 CT1, which has a very high trigger voltage (about 200V, if I remember my voltage test correctly), with my K-3. Now the Metz works a treat with the K-3, without frying the camera.