yorkville 200KB line out level

[The Dude]

If we assume that this mic run, however long it is, works with a mic, then it should easily work with the amp. A mic's level (normal speaking/singing) would be much lower than 200mv. Doesn't make sense. They need to check the mic line with a mic and verify it is working correctly.

[guitardad]

If we assume that this mic run, however long it is, works with a mic, then it should easily work with the amp. A mic's level (normal speaking/singing) would be much lower than 200mv. Doesn't make sense. They need to check the mic line with a mic and verify it is working correctly.

That's what I told them. How can mics work, but this level be that much lower at the board using mic in. I think they are using a different line source as well.

[patlaw]

The length of the cable run in this case is not the problem.

[Chuck H]

There are so many possibilities for why they're having trouble amplifying. My first thought is that they're using a cheap mic with some sort of volume control on it. When the mic feeds back they turn it down. Then they can't get it loud enough.?. Or they're running through some other box before the amp that isn't adjusted correctly for the in/out levels. Loads of potential errors if the users aren't experienced. But since most other products have designs that account for this it might make the most sense to just make this one similar. You can't really argue the truth, as it relates, from one perspective with someone looking at it from another.

[J M Fahey]

There is ONE relatively common possibility for this riddle happening, I have seen it and made me chase ghosts before.

** The mixer, if cheap or very old, may be cheating too **

Some sport a nice XLR connector, but internally ground either pin 2 or pin 3, and use the other as a mic input.

Works if they cheated the same way as Yorkville but not otherwise.

I suggest, it will take 10/15 minutes tops, that you mod this output to true balanced, you have all the elements there, it just needs a little rewiring:



I am sure that the problem lies not in the Yorkville itself but to be *absolutely* certain :

a) do this simple Mod

b) IF needed, drill a small hole somewhere and add a 10k pot, wired as a variable resistor.
If you wish, just lift the right end of R228, add some twisted pair (one to its end, the other to the now empty PCB pad) towards the pot, add a drop of glue or silicone to R228 body to avoid leaving it floating.
This way, setting boost pot to 0 leaves everything "as original".

c) TESTb it by loading both XLR pins 2 and 3 with individual 1k resistors to ground, simulating an external load.
Just not to leave any stone unturned.

d) now it MUST work, and if not, let *them* worry, you are as clean as an angel.

e) to show them, grab the amp handle, walk up to the mixer and connect straight to it with a 6/12ft KNOWN GOOD cable. (or it will embarrass you).

[g1]

Agree with Juan about the mixer probably having "fake" balanced in with opposite pin hot compared to "fake" balanced out of amp.
This is the only logical way it could give proper level with a mic, but not from the xlr out.

An even quicker test of this theory would be a mic cable with pins 2 &3 wired reverse at one end.

[patlaw]

There is ONE relatively common possibility for this riddle happening, I have seen it and made me chase ghosts before.

** The mixer, if cheap or very old, may be cheating too **

If this is the problem, there's an easy fix. Get a 600 to 600 ohm transformer and insert it between the Line Out and mixer input. The phase will be reversed, but the audio will pass through. You can get 1:1 (isolation) transformers labeled as ground loop or hum isolators for reasonable prices.

[J M Fahey]

Look what the cat brought:

we were talking about Fake Balanced Inputs ... and this classic Yamaha EM150 drops on the discussion table.

Look at the Mic/Line input :



The Jack and XLR inputs are one and the same, joined by the jack leaf contact, and XLR pin 2 is same as jack tip; pin 3 is grounded at the preamp board ground (XLR pin1 goes to chassis ground) .

As-is it shoukld work with Yorkville fake out, but if the unknown mixer chose XLR 3 as hot we are out of luck.

Same with a Mic cable miswired with crossed 2 and 3 legs (or a miswired homemade or repaired snake, I have seen HORRORS many times) , it will work with a microphone which is truly floating but not with the mixer/combo connection.

Yes, adding a 600/600 ohm transformer will solve it, no doubt, but what I suggested takes only pulling 1 1/2 resistors and adding 4 or 6 inches of wire.

In any case, and given the bad Karma already accumulated, I suggest testing the combo near the mixer, trying with a couple cables if needed.

To further cheat, Yamaha wires an unnecessary 1k resistor in parallel only with the XLR input, so if you plug a guitar there it will kill its signal and you'll think "wow, it's a real low impedance Mic input!!!!" .... which it is not.

Naughty naughty Yamaha

[The Dude]

Ought to be illegal!

[J M Fahey]

It was very common during the late 70's and is still used today in some cheap box mixers.

I used it myself way back then, same as many respected names of the day, and still offer as an add on a passive XLR out, speaker out driven, which does provide for balanced signal, go figure, and will work with any of the active pins grounded or both floating or a true transformer balanced input .

No, I'm not publishing that one

And Fender uses their version of the fake out, even today, they call it something like "semi balanced XLR out"