New spin on a old friend. 3Dss holllow core wind.

[6666]

Attachments all good now thanks.

[6666]

Hi godigit1, which front end design did you use to get such a high 1230 ohm damping resistor ?

[godigit1]

Hi godigit1, which front end design did you use to get such a high 1230 ohm damping resistor ?

Im using the rev d Mpp with a irf 840 fet pulse rate 3.333K the max I can get with current samples set up.
120us period 5 us to first sample.

Not sure where the ringing at turn off is coming from at first I thought it was the three op amp design but its else where. Its present in my older pictures to different extents. doesn't seem to effect anything performance wise that I can tell.

I thought damping resistor value was more dependent on the coil than the front end.?

I have other coils my damping resistor set up is maxed out on. I need to make a higher value damping resistor set (over 1700 ohms) up still to see where they are actually at.

[green]

Hi godigit, did you measure the inductance?
The 1k input resistor is in parallel with the damping resistor.

[godigit1]

Hi Green ,
I measured inductance at 270uh on the coil my meter is spotty but that's where I stabilize at the best.
Hadn't thought about the resistors in being in parallel. I thought they were in series.
Going to have to probe around a little.
Thanks

[6666]

Hi Godigit, would you mind just confirming that your MPP is standard 5532 preamp, or is it the modified one ?, because I have tried both - and + input preamps on my TRT,( target response tester) and for my 3dss 338 uH coil the damping resistor gives best wave form at about 460 Ohms, I cannot get any where near 1230 ohms ??

The pre amp with the + input works best for damper trimming, at least for me.

[godigit1]

Hi Godigit, would you mind just confirming that your MPP is standard 5532 preamp, or is it the modified one ?, because I have tried both - and + input preamps on my TRT,( target response tester) and for my 3dss 338 uH coil the damping resistor gives best wave form at about 460 Ohms, I cannot get any where near 1230 ohms ??

The pre amp with the + input works best for damper trimming, at least for me.

Hi 6666,
I'm still learning and thought the front end was up to the op amp .
This testing was done on the 3 op amp I set up from Teleno's thread.
I have been meaning to revisit this as I have some doubt's as to my damping.
All my old damping results were in the 400 to 680 ohm area for my coils and the window of damping was much tighter.

I have to do a video of what I'm talking about, I first hit a good Knee at a much lower resistance then can adjust my damping set up to just be slightly underdamped but I have a much wider range than before bringing me to question my results that's why I need to do a video see what you guys think.
Ill try to get to it soon and include the standard rev d op amp as well.

My damping resistor set up is a little different but im not sure that's it either, when replaced with a resistor the damping value works.
I got tired of blowing trimmer pots so I'm using a 5watt linear taper pot instead of the trimmer pot.