MixBuzz1 Build/Support thread

[ilfungo]

I also double checked VCA and everything seems fine
It may be some mis-wiring between Attack and release?
if I unlink attack and release ratio from MAIN PCB
the compressor should sound anyway?
Thanks

 

[Igor]

Take the resistor equal to VCA unity gain (in case of 1x2181, it is 20k; in case of 4x2181, it is 5k), and put it
instead VCA between its input and output. You should have unity gain, phase reversed.
If there is a prob here, check sound path. If no prob, something is wrong with control circuit
(control voltage). Impatiently waiting for results. Curiosity!!!)

 

[ilfungo]

Thanks igor
I do not understand
like this?

 

[ilfungo]

Or like this?
In this case I must remove the VCA Board?

 

[baadc0de]

I would think the second option.

 

[ilfungo]

Thanks baadc0de
other measurements

no - that 1246

1  0v
2  0v
3  0v
4  -17.88v
5  +2.73v
6  +2.73v 
7  +17.90v
8  0v

with that 1246 inserted

1  0v
2  -17.88v
3  -17.88v
4  -17.88v
5  -12,83
6  -12,83
7  +17.83v
8  0v
???

 

[ilfungo]

Take the resistor equal to VCA unity gain (in case of 1x2181, it is 20k; in case of 4x2181, it is 5k), and put it
instead VCA between its input and output. You should have unity gain, phase reversed.
If there is a prob here, check sound path. If no prob, something is wrong with control circuit
(control voltage). Impatiently waiting for results. Curiosity!!!)

Hello Igor
If I do as you have suggested
I only have a continuous figs

"control circuit (control voltage)" is ?
Thanks

 

[ilfungo]

Sorry guys I'm going crazy

I double checked everything
all resistors (all values ​​are in place)
I double checked all the capacitors (polarity and right values​​).

Listening to loud I noticed that the front controls work.

It could be a problem on the 2 That 1246?

anyone of you  has the reference voltages on various points of the MAIN PCB?
Help
thanks

 

[evilcat]

evil: any news? I impatiently waiting about a week. Curiosity, aye!

Hi Igor!

I've disconnected pin1 of XLRs, it doesn't change anything (would have been to easy!!!).
I've measured 1.8R between pin1 and main board ground, no 0R. In fact, the case itself have a 1.8R resistance. When I measure it from any ground point (boards, XLRs, case) I have 1.8R. Is it normal ?
Thanks,

Ben

 

[ilfungo]

some improvement
I was able to run R channel (slightly distorted, but I think I have to adjust)
L channel  does not work but I saw that compresses and receive input.
I did as Igor said 5k between R6L and R4L
and it works.
the problem is on board 4xVCA?

last problem:
meter on the GR / out / in
GR = ok
OUT = OK
IN = comp bypass

Is this normal?

 

[baadc0de]

As Igor correctly identified, I swapped my 10pF feedback caps with 0.1uF power supply filter caps (well, they're both ceramic and same pitched and next to each other, so..)

Anyway, getting them out is difficult and I've already broken one and I have no more 10pF caps. But I do have 270pF (lowest caps I have) of same pitch. Will the circuit function badly with such feedback?

Am I correct this cuts off at 39kHz?

 

[Harpo]

Am I correct this cuts off at 39kHz?

Yes. Signal in C&B @39.3kHz will be -3dB down. Still -1dB down @20kHz. Not the end of the world. YMMV.

 

[ilfungo]

Mix Buzz finally works! ;D
my problems:
2 x that1246 broken
1 bad soldering

Thanks to all for help

 

[baadc0de]

CONGRATULATIONS!!

Mix Buzz finally works! ;D
my problems:
2 x that1246 broken
1 bad soldering

Thanks to all for help

 

[ilfungo]

Thanks  baadc0de!!!!!!!!!!!!!!!!!!!!!!!!!

 

[baadc0de]

Thanks for verifying

I guess I'll just wait and get some 10pF from a local store next week.

Am I correct this cuts off at 39kHz?

Yes. Signal in C&B @39.3kHz will be -3dB down. Still -1dB down @20kHz. Not the end of the world. YMMV.

 

[ilfungo]

I would like to use Stepped Switch to the mix.
What resistance should I use for every shot?
thanks


PS. CONTROL and FILTERS


"Check the voltages between TP1 and TP2 to ground, they should be 0.00 V,
adjust SC_SYM L/R trimpots."

Whre are TP1 and TP2?

 

[ilfungo]

???

 

[piano]

Stepped switch. OK. Me to on this. B10K - linear was supplied.

http://www.goldpt.com/prices.html

Goldpoint sells a dual 10K linear premade (that is what you need) for $150 or you can make your own for $108 plus --- and make it log. Although frankly, either log or lin is fine.

 

[piano]

Anyone know of a good tech in NH.

I need help on figuring out what happened on my Crush and Blend. I can not figure it out.