Message Board

I think the 4.7k and 1.2k thing would be good. 1k output impedance is a little on the high side, but not anything to worry about I think in this case. If you want to be fussy, just be sure to put the pads at the speaker end rather than the control box end. Assuming the input impedance of the monitor...

Hi. I don't really know the specs on the 2control thing, but it sounds to me like its output impedance is 75 ohms, but that doesn't mean that it works best into 75 ohms, or that you need to match that. In general you want to make a bridging connection which means low impedance output into high imped...

I don't believe you have to take off the face. You might not even have to take off the back. The reel tables are attached to the reel motors by sleeves on the shafts with I think 2 set screws per table. In order to adjust the height you just loosen the set screws, move it in or out, and then tighten...

If you're going to making DC out of them, you could just use one transformer and make a voltage doubler. Ned

Hi, the latest Ive replaced all TL072, All transitors and the diodes Re-soldered every connection And guess what? Still noise Anymore ideas Thanks so much for all your help Paul Hi. So does this mean you haven't yet tried replacing the resistors in the mic preamp as Scum was suggesting? I really th...

It sounds like you've got something working, so probably you don't need any more input, but I thought I'd just mention a couple of things. Since you've got the shunt resistor you've probably already found out you need more than 23dB gain, probably something more like 30dB at least, I can't remember ...

I was actually just checking back over here to delete all of the messages I just wrote since it seemed like the only thing that might be of any relevance was the 232 ohm thing and you already had that. I still think you might want to still consider using 5K resistors, but probably not a big deal eit...

By the way, in a mixer like this, it's actually best to use TRS instead of XLR jacks. That way you can wire the jacks to switch so that the tip and ring connect when no jack is inserted. That keeps gain and impedance constant no matter how many inputs are being used. If you do it this way you could...

Whoops, look like while I was typing that big long POS you figured it out yourself.

Ned

Hi. I have a few comments: If your inputs to the mixer can drive 10K ohms then you're better off using 5K resistors than you would be using 10K resistors. For the same output impedance you'll get smaller attenuation -> smaller make-up gain -> lower noise. I didn't fully look at all the equations abo...

Here's a schematic for you: http://home.earthlink.net/~nwc4396/sunn_beta_lead_preamp1.jpg Download and save that, cause I'll probaby delete it off my ftp space in the next few days. This may not be the exact schematic that applies to your amp, though, as the 30K reverb pots shown here don't look lik...

It's hilarious to imply there's something intrinsically wrong with a 47uF cap. Soundcraft used a lot of them, yes, but they also used a shitload of 10K ohm resistors. What's the 3dB point of a 47uf cap loaded by a 10K resistor? It's about 0.3 Hz.

I'd say it's a pretty huge exagerration to imply that console designers regularly or even ever set single stage 3dB points at 20Hz. Those guys kind of knew about how those poles stack up, and you can almost always expect the individual stages to have 3dB points in the low single digits at the highes...

You could do it passively, but there are good reasons to use some active circuitry. Passive is going to increase source resistance and reduce overall level, both of which are going to tend to degrade your S/N. You're essentially going to be building two adjustable resistive pads, and they'll have th...

I'm pretty sure that's an amphenol connector based on the way the flange and the bayonet look. Yeah, just checked at digikey, and it might be PT02E-12-8P-ND. Hard to say for sure without any physical dimensions. check here: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PT02E-12-8P...