MixBuzz1 Build/Support thread

[piano]

Does the switch get placed this way?

 

[piano]

C1, C44, C8, 8 pin inline chip sockets (do I have to order them -did not come with kit) and 20K questions in picture.

 

[piano]

C29L, C29R, CP11 Questions??? These are the parts I have left.

 

[piano]

C40, C42 Questions as in Picture:

 

[piano]

C41, C43 Questions as in Picture:

 

[piano]

CM5, CM6 Questions as in Picture:

 

[piano]

Molex question. I used all the Molex supplied. What do I use to hook up wires to the front panel?

 

[culteousness1]

On the MixBuzz500 the silkprint marked the placement of the circles on the switches.
I don't think Igor changed it. So you can orientate the switches on that.

 

[mata_haze]

Hello Everybody,
my unit is nearly finished I only have one problem and I hope someone who has finished the unit could give me some read-out.
unit passes audio,makeup works but no compression.
I have checked the Threshold pot is wired properly (I get a swing of + and - 12V at the wiper) and the RAtio and attack-release pots are ok.

I have carried out the following measurements:
on IC3 on both PIN 8 and PIN 14 I have the following: (DC)

RATIO          Voltage Swing
1.5                                3 - 17 mV
2                              203 - 216 mV
4                          no swing 156 mV (fixed)
6                              361 - 362 mV             
8                              380 - 381 mV
10                            391 - 392 mV

on the same Chip (Ic3) I have a swing of 5 to 150 mV on PIN 1 and 7. (DC)

I am trying to figure out were my mistake lies I can see that the DC voltage runs all the way from the wiper of the threshold pot to PIN 1 and PIN 7 of IC3 and then it gets "messy" on PIN 8 and 14, also no DC after the diodes D6L and D6R.
also the makeup works fine so IC5B it's ok.
I am using IGOR's mod to implement a continuos pot for attack and release, so I am not using the stepped lorlin.

any help (and/or measurements from working units) will be VERY much appreciated!

Best,
Mattia.

Sfter further investigations I have found out that the sidechain signal stops before hitting the detector.
I can trace the a sinewave (1V RMS) up until the left side (looking at schematics) of R14L and R14R and then it disappears.

by checking TP1 and TP2 I found out there is no sinewave there either.
I am assuming the VCA works in a "current fashion" rather than voltage and then IC1A and IC5A then convert the current into voltage again hence the TP1 and TP2 afterwards.

can anyone comment on this?

I am not sure what the " - CONTROL " and " + CONTROL" means on pins 5 and 7 of the VCA, are they not just supply +-15 VDC? or should I expect some signal there too?

EDIT: I have +15 VDC on pin 7 and -15VDC on the 5k1 resistor attached to pin5. there is -2.85 Vcc on pin 5 of the VCA.

Best,
Mattia

Further investigations lead me to test the sidechain signal with different ratios and the following pictures are taken from PIN 8 of IC3C (so between the last step of the sinewave rectifier and the 1N4148 Diode).
each picture has been taken with 1VRMS input.and the RATIO is as follows:
1.5,2,4,6,8,10


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Uploaded with ImageShack.us



any idea?

Best,
Mattia.

 

[tekno808]

Hi,

With the LED Meter kit i received Q1&Q2 2N4403 !! it's referenced also in the LED Meter BOM as a equivalent for the 2N3904 !!

This is not wright !!! The 2N4403 is a PNP transistor and the 2N3904 is a NPN !
The 2N3904 is the wright one ! if you put the 2N4403 you got full meter readout even without the ic4 CD4016 !
If you already installed ic4 with the 2N4403 then ic4 is dead !!

Danny.

 

[Purup]

Hi Piano,

Does the switch get placed this way?

The switch can only be placed in two different ways, because of the two pins in the middle. It does not matter which way of these two you select.

About the molex connectors in the front panel PCBs: Solder the wires directly into the PCB and only connect molex to the other end. Of course you can choose to or buy some molex connectors to the front panel PCB if you prefer this solution.

About the 8 pin socket: If you wanna be able to change the op-amp, get a socket and install it (in case the op-amp breaks down). I think that would be a good idea for you.

About all the capacitor questions: For ceramic capacitors the first two numbers indicates the two significant figures and the last number is the multiplier in pico farad. E.g. 334 means 330000 pF = 330 nF, and 220 means 22 pF.
For the polyester caps: u47 means 0.47uF, u1 means 0.1 uF = 100nF. The number after the letter is the the voltage, e.g. u1k100 is a 100nF 100V capacitor. Check the part list / kit lists to see where the different capacitors goes to when you have identified their value.

Install all 20kohm resistors in replacement-board if your are using four 2181.

Hope this helps you.

 

[Winetree]

I'd like to try out the sound of the DBX 202C and The Sound Path Upgrade in the Mixbuzz.
I'll use MilMax sockets and pins to interchange them. Are there any board changes involved
to stop this from being a swap and play.
Anybody know the sound diffences between the two?

 

[funball2]

hi all mixbuzz makers,

no bang , smoke , firework , voltage oke but...

relay is 300 ohm , get little warm , do i need to change r33 on powersupply ?
also 7812 on psu gets about 90 celcius ....

soundwise

if i use ne5534 in IC4 i have distortion , with no compression

change ne5534 to opa604 ,distortion is gone ...

when i dial in threshold and go over 5db compression distortion starts heavy

so seems the 2181 x4 makes that distortion ...

strange things help!!!

cheers

funball

 

[AW_music]

Hi,

Igor, where are you disappeared ?  ??? ???
We need your help and support,
we need to finish Mixbuzz ,  ;D ;D !

So please, take a break .....
.....and come here with us !! 

 

[pacemaker]

Hi guys !
might be a dumb question but while measuring voltages on the IC's
i noticed i have 15v at pin 1 and 8 of IC4L and IC4R
but i can't find them on the schematics,
is that normal ?
regards,
Francois

 

[piano]

Does anyone have a .dxf or .fpd (Front Panel Designer) file for the Mixbuzz?

I need to do a panel in Front Panel Designer.

Thanks!

 

[pacemaker]

ok all others voltages were fine,
so i fired up the unit,
unfortunatly it's not passing audio,
after searching a lot, tracing signal etc..
i found that the attack control is cutting signal,
when it's not plugged on the mainboard,
i got some signal through the audio path
and gain is working.
But when plugging the attack control back,
signal dissapear,
i've checked my wiring and resistors values, eevrything is fine,
any leads for me ?

 

[piano]

Bump. Igor is still taking people's money for orders --- so he is here. : )


Does anyone have a .dxf or .fpd (Front Panel Designer) file for the Mixbuzz? No, I do not have Corral.

Thanks!

 

[tekno808]

Igor,

Finished my MixBuzz (see pic) everyhthing is working just have problems with meter calibration, i dont realy understand what you mean in meter calibration 1). Check the offset....

Is it normal that leds -22db lights up with no signal after calibration, with in/out switch position ?

Danny.

 

[pacemaker]

Hurrah !
I found the problem,
D3 was in the wrong direction , oooops
now everything is ok,
let's continue calibration !