Pro Audio Design Forum

I believe I've shared this before but in my experience the noise contribution from leakage in the electrolytics are variable between brand/series of capacitors. I encountered one while at peavey that was so bad we had to black ball it for that application. My understanding from talking to the engine...

We have a smoking gun, for my concerns about DC coupling every mic in the world.

Problems reported with TLM 103

http://www.prodigy-pro.com/diy/index.ph ... #msg407094

JR

I agree with John that tricks are best performed elsewhere. ;) Alright then, I shall resist. LOL John, I remember you mentioned that bootstrapping trick once, and I stored it away in my noggin for possible later use. I'm more of a cookbook guy than a textbook guy, but examples of stuff like that ar...

Yup.. I once had to locate a mic trim pot about 18" away from a circuit in a console (back in the '70s) for ergonomic reasons. The C in the shielded cable was enough to destabilize the circuits. I ended up driving the shield of the cable with a CM output signal I derived to keep it happy.

JR.

Nah.. electrolytic capacitors don't do well at low impedances, and in that circuit node the cap is dealing with ohms or at best tens of ohms.. DC couple and HPF elsewhere...

Unfortunately you don't want to wrap anything like this variable HPF around a mic preamp due to input impedances...

JR

We would never go off topic here Yes, where are the moderators?... What do you think about adapting the sliding 'wow filter' hpf into a preamp? Seems like it might make for a sort of rumble filter... The sliding HPF might make some sense in a compressor, so when it is commanding a bunch of boost it...

The diode(s) in that circuit mainly create a threshold at roughly 10x a diode drop.. (because of the resistor divider 2k/20k). above about 5-6V p-p it just looks like a 20k feedback resistor added in parallel with the rest of the negative feedback. Below that p-p voltage it is just part of the DC fe...

You already know how I feel about coupling caps (the best cap is no cap).

I need to digest this.. right now I'm a little too scattered.. to wrap my head around this.

JR

If you are talking about that diode break where above a P-P voltage another feedback path becomes active, that will was done to sound better that hard clipping, and IIRC with the 570- series gain cells the could get nasty if they are overdriven. So it was a lesser evil decision ands only expected to...

The cost of tooling IM has come down quite a bit thanks to our Chinese friends... While I expect it could be another zero added to my last version. The size of the package and complexity will make a difference. I will need to get up to speed in 3d cad since I want to take my best shot at a design, a...