Geofex hacked; de-lousing under way

[seedlings]

I finished my searching, deleting and repairing a couple of days ago, and had google re-crawl the site. Now not only me but the magic google bots think that geofex.com is clean.

Thank you.  100 times thank you.  (And not just for this ^ ).

CHAD

[rocket8810]

agreed, and thank god it's all good and clean now. i don't know where i would be in this hobby without you personally and your Geofex site, R.G.

[R.G.]

Guys, you're welcome. Effects have been a mania of mine for my entire adult life. Geofex is a bit of give back for the people who helped me.

[deadastronaut]

^

[Gus]

R.G.

I looked through the driver transformer rebuild.  I was thinking maybe you could do a 2x2 or 3x3 or 4x4 etc stacking instead of a I E gap for an easier lam rebuild

[R.G.]

I looked through the driver transformer rebuild.  I was thinking maybe you could do a 2x2 or 3x3 or 4x4 etc stacking instead of a I E gap for an easier lam rebuild

I would, but that makes it much, much harder to control the gap. The problem with that particular driver is that it's a single-ended design. It pulls DC through the primary equal to the maximum drive current in one direction at idle. And the core has to not saturate at twice that current so the opposite side can be driven. You're forced to air gap it, and probably to tinker with the gap to get the gap right. You're right that NxN stacking introduces more gap than 1x1, but I worry that any smallish number won't be a big enough gap. And the original was I-E stacked with a paper shim in the gap.

I think I have to finish the prototype and do some extended testing before I'll really know.

[Gus]

R.G. interesting thread from another forum about a Fender champ transformer that was not gapped

http://groupdiy.com/index.php?topic=50425.msg641523#msg641523

[R.G.]

Thanks for the reference. I was aware that the various stacking approaches varied the effective air gap, but I've never seen the curves before.

It's interesting that the smaller the transformer, the bigger the effect as a result of unintentional air gaps at the edges of laminations being fixed size and the magnetic path length being smaller in small laminations. I hadn't thought of that, but it makes sense once I see it.

I've always tended to go to Hanna's Curves for DC-excited inductors in spite of them being better for a bigger proportion of DC on top of AC flux, as in power supply inductors instead of audio transformers. Audio devices are always at the edge of the curves. 

I think I'm going to have to wind a bobbin, stack it, and run some pulse-inductance tests. I've always thought of pulse-inductance tests as the nearest thing to magic. They let you actually *see* the core edge over into saturation without there being a puff of smoke.