THAT1570/5171 DIP Adapter

[mediatechnology]

Gotcha... that could damage mics and phantom powered external gear expecting the 6.8k

Definitely not good...

JR

Yep. Very loud. A lot like hot-patching the input.

[JR.]

Ok no worse than normal... to outside world.

JR

[promixe]

you could move the phantom resistors over to the XLR in fig 2 also, while it is not usual to leave unused inputs floating, Over time the caps will discharge to 0v due to internal leakage.

Yes, but you see, the main reason for the double phantom resistors in figure 2 was that the caps do NOT discharge while the phantom is on, because I want to switch between the transformer and transformerless "seamlessly". I don't want to recharge C5 and C6 upon switching back from "transformer path" because there will be a significant DC offset and at high preamp gains that will not be pleasant to hear. It would take over a second to settle, which doesn't allow for smooth A/B-ing of both paths by the end-user. Therefore figure #1 is "better" in this sense, because it allows me to switch rapidly between the two paths and DC offset is minimal, comparing to fig.2.

[mediatechnology]

Take a quick look at this article:

http://www.waynekirkwood.com/Images/pdf ... itters.pdf

What you're doing is similar to a split.

Do re-draw RE6B when you get the chance. Pins 5 and 7 aren't right.

Wouldn't you want the pad ahead of the transformer and C5/C6? Or is the point to overdrive the transformer?

Why not put the transformer on the "dry" (right-hand) side of the capacitors and then do a transformer bypass? When "in transformer mode" C5/C6 are in series with the primary. (C5/C6 could also be bypassed.) That solves the loading problems and should help your phantom wet-switching issues.