MixBuzz1 Build/Support thread

Hi Guys,


while setting the ratios following Igor's instructions I got satisfying readings on the RATIO=10 setting and adjusted trimpot a little bit to get to the -8db that was needed.
However in the the second stage with Ratio=2 I got a reading that was 4.5 db lower than what the description suggests.

Any ideas what could have caused this?

Hi guys, finally building two of these. This is a tough build! A few questions so far.

Igor shipped R49 at 499K. The bom says R49 470K. Is this ok ?

Is 1N4002 ok for DP5, DP6, DP7, DP8 ? BOM says 1N4004 to 1N4007

Also how closely matched do the 20K resistors have to be on the quad 2181 vcas? The all measured 20.3K or so. One out of the bunch was 19.6k

Thanks,
Dave

hello together!

i startet right now and in the in the moment i try to get a overview. most seem clear, but i am a bit confused about attack/release right now. is it a 6 position switch in version 2.5? the boom say still it´s  poti. would be great to know before i order...

thanx and greetz from germany!

use lorlin switches for attack & release. I used CK101X12

my gr meter is still bonker.
I have no positive voltage for the meter. swapped opamps. if I turn the offset meter far enough I get a inversed GR meter reading.
seems like I hit a wall. what else could it be? is the gr voltage only positive after IC202A? I swapped this IC, btw.
it must be something simple, everything else is working just fine...
yours desperate
mrcase

mrcase said:

if I turn the offset meter far enough I get a inversed GR meter reading.

Click to expand...

yepp. Just like an 1176.
No compression showing 0dB (with no signal at input, adjust trimmer GR_OFSL so the LEDs up to the 0dB LED show up).
When compressing, less LEDs show up to reflect the amount of gain reduction.

is the gr voltage only positive after IC202A?

Click to expand...

Positive after IC202A with no audio signal present and less positive when GR takes place.

aaahhrrgggh.
so it is supposed to work like that?  so essentially you only have the first LED bars showing GR?
at least on my frontpanel 0db is on the 1st led of the second bar. or could I just go from the very right LED to have a more detailed GR meter?

thanks for clearingthat up harpo!

The moment is finally there... I finished my mixbuzz.
There are still some small trimpots to adjust but everything seems to work without smoke, cracks and humms.
After some testing it seems to be a very delicate piece of gear.
Thanks to Igor (I wish you all the best with your health) and everyone else sharing their thoughts and experiences on the build.
Cheers!

Hey guys,

Ratio board... 4  x 3m9  MF 2% OR CAN BE CARBON, 5%  R.11, R.12, R.15, R.16

Igor shipped 4 x 3m3... is this ok ?

Just finished my Mixbuzz1,sounds ace!!  8),here's a pic

Wow that's some messy wiring  Congrats Chris

I hope to get mine up in a few days

Can someone explain how to wire up the 23 stepped switches with resistors? Looks like i have three switches for  Mix(C&B), Makeup and Threhold and a whole bunch of 499r resistors  :-\

The lorlin switches for Attack, Rel, Ratio and SC Filter seem pretty straight forward into thier pcb board

I am testing the power supply with a toroidal 18 volt pri and 18 volt sec transformer.
http://docs-europe.electrocomponents.com/webdocs/0028/0900766b800284c0.pdf

I connected the Red wire to ~18.1 the Black and Yellow to CT and the Orange one to ~18.2

When I measure the voltages I came with the following results (inlcuded in the attachment).

I am wondering if I did it correct and go further without blowing things up

Cheers,

M.

MrBlomski said:

I am testing the power supply with a toroidal 18 volt pri and 18 volt sec transformer.
http://docs-europe.electrocomponents.com/webdocs/0028/0900766b800284c0.pdf
I connected the Red wire to ~18.1 the Black and Yellow to CT and the Orange one to ~18.2

Click to expand...

Correct.

When I measure the voltages I came with the following results (inlcuded in the attachment).
I am wondering if I did it correct and go further without blowing things up

Click to expand...

A little mind bending, but your +/-18V rails are low and your -15V rail is high. The +12V and +15V rail are within vregs parts tolerances.
Maybe use some croco-clips to connect temporary about 1K resistors for 15mA or 18mA between AGND and the +18, -18 and -15V DC output connections to get the vregs  min.current drawn with disconnected mixbuzz circuit. The above -20V probably will drop to the wanted -15V with this little load connected. The 5K trimmers adjust the wanted +18V and -18VDC rail voltages.

Thanks Harpo,

I did use a 1K resistor and trimmed the voltage to 18.03VDC + aswel as - after that I checked the -15VDC rail and it reads 15.10VDC, eureka!

Next is cables and drilling holes

Cheers,

M.

Hi,
I'm french and I want to find pcb Mixbuzz 1. Is there anybody know where can I order one ?
Merci beaucoup.
Slegg

slegg said:

Hi,
I'm french and I want to find pcb Mixbuzz 1. Is there anybody know where can I order one ?
Merci beaucoup.
Slegg

Click to expand...

ramshackle recording just started selling them

Thanks whiskey...
I did it. But I want to build a Mixbuzz 1.
I'm not sure they sell this model because they have the serie 500.
I'll ask them...
Regards

Hi.

MixBuzz 1 is the same design as mixbuzz500, but rearranged to fit in a 1U rack

We only sell the 500 series version.

You could rack it in a 2U rack/half rack using rackit!

I've got my MixBuzz 90% complete but I am stuck with meter calibration. When I switch to GR all the LED's light up and don't move.
I have a changing voltage at pin 3 of IC202 when I move the threshold knob and the compressor applies gain reduction to the 1V RMS test tone at the input. But at pin 1, the output, I just get a steady 11.9V. How can I have a steady voltage at the output with a changing voltage at the input?
This stays the same when I remove IC204 from the board, so that voltage isn't coming from the meter board on the front or anything.
Anyone have a similar problem?
I also have the issue others have, where a signal at the right input shows up on both meters at the same time. I'll try to fix that one next....