[BUILD] 1176LN Rev D DIY

[number2]

I PUT THAT GROUND BUT STILL NOTHING

MY DIODES ARE ALL GOOD
RESISTORS ALL GOOD
CAPS ARE CHARGING

DON'T KNOW WHAT TO DO WITH VR1

 

[MatthisD]

Well are you getting AC voltage at the PCB AC pads from the power transformer? What do you mean when you say you don't know what to do with VR1?

 

[usekgb]

germoju  Only guessing but thoroughly check your output transformer wiring. If you used screw terminals it will cover up the color legend on the board. So use the layout pic.

John

hi guys
shame on me... Yesterday I re-builded all my input wires... nothin'changed... my solders are good...
I found the problem : my patch OR my jacks !!!
When the 1176 is directly plug to my sound card the sound is great
So my "new" problem is not a 1176 problem !! YOuuuuuhhhouuuuUUUUuu !
Thanks again guys

It sounds like you are getting phase cancellation somewhere along the way.  Do you have a way to invert the polarity of your 1176?

 

[sr1200]

Thats easy, just reverse the +/- leads on the output or input of the compressor...

 

[usekgb]

I have a couple XLR cables that have reverse polarity.  I use those from time to time when a phase button is not available. 

 

[bspro]

Put your AC meter on the output XLR (pin 2 and 3).  Feed a large signal into the input and increase the input in GR mode.  See if the voltage drops.  That would show your GR is working and it's a meter calibration issue.

If it does not drop, I would suspect the things in my previous post.

Hi Guys, still trying to slowly solve my build issues...just to remind where I'm at...hairball enclosure, version 2.2 mnats board.  I was not seeing a change in metering when shorting pad 22 to ground.

I've been trying every test I can find on the board.  Checked for continuity from green on ratio board to pad 22...good.  From black on ratio board to green, no...good.  Checked all of the voltage readings from MNats pdf in the GR Amp section and they all check out properly.  But, when I try what Echo North has suggested previously (as quoted), the voltage does not drop!  As I increase the input, the voltage coming from the output xlr on pin 2 and 3 does not drop, it increases.  However, when I increased the signal of the input from my DAW (using ProTools, was set at -17.7db with a 1 kHz signal for .775), all the sudden the meter comes alive when I short pad 22.  Are one or more of my trimmers just way off so that the metering just isn't picking up whats going on?  Or do I have a deeper issue?

 

[Echo North]

I may had worded that poorly.  Increasing the input will increase the signal, but should also increase how much it's over the compression threshold.  With the input at about 2-3 o'clock you should be getting compression.  So with the input that high and the output at 12 o'clock, with GR off (black connected to 22) you should see a high signal at the output.  Then switch GR on (green connected to 22) and you should get a good drop at the output.

With 22 shorted to ground (black) your meter should not move in with the GR pushbutton in. It should rest at 0. If it's moving you may have green and black reversed.

Mike

 

[TheWolfman]

Hi,

After having to take a break from the final stages of my project for a little while,due to not only going a little mad but also actually recording some music rather than mucking around my multimeter I have found a curious anomaly with my build.

When the output control is rotated all the way counter clockwise the unit outputs a repetative beating tone that sounds like a kick drum and the meter bounces full scale to reflect this.

The VU meter lamp actually dulls ever so slightly with each oscillation aswell indicating that when this happens the unit is drawing excessive power.

Any ideas anyone?

 

[minor_glitch]

If anyone is looking for some inspiration to get their 1176 finished, I posted a bunch of photos of my finished rev d mnats/hairball build on my website: http://paulmantiniaudio.blogspot.ca/2012/03/and-so-we-continue-our-journey.html
Enjoy!

 

[acoustix]

Cool website and nice clones  8)

 

[Echo North]

If anyone is looking for some inspiration to get their 1176 finished, I posted a bunch of photos of my finished rev d mnats/hairball build on my website: http://paulmantiniaudio.blogspot.ca/2012/03/and-so-we-continue-our-journey.html
Enjoy!

Nice!  You should have received some silver mounting screws in your hardware bag for the bluestripe frontpanel.  Unless of course you like the black ones, which kind of look cool.

 

[minor_glitch]

Nice!  You should have received some silver mounting screws in your hardware bag for the bluestripe frontpanel.  Unless of course you like the black ones, which kind of look cool.

I kind of like the black screws, but now you've got me wondering what I did with those silver ones!  ???

 

[Echo North]

I dig the black ones.  The silver are #6-32 (like the black of course).  Pretty common.

If you need some send me an email.

 

[minor_glitch]

I dig the black ones.  The silver are #6-32 (like the black of course).  Pretty common.

If you need some send me an email.

Now worries. I'm sure I have a stash of 6-32 pan heads lying around here somewhere if I feel the urge to swap them out. Thanks though!

 

[ilfungo]

hello
I can use Lundahl 1539 and 1540 in this circuit?
how?
thanks

 

[Echo North]

hello
I can use Lundahl 1539 and 1540 in this circuit?
how?
thanks

The 1549 should work as the input but the 1539 output doesn't have the required tertiary feedback winding.

 

[Spadehead]

Hi all,

This is my first post here and may I first of all say how wonderful this community is. I have been patiently working my way through my first Rev D build (as well as the last 129 pages!) and this resource as well as the mnats and Hairball sites have been essential and have helped no end. Thanks to everyone involved!

Now to my issue!

I have nearly stuffed the PCB and only have 4 spaces to fill: Q7, Q8, Q9 & Q10.

I received the 20 2N3708 transistors with the original BOM and none of these met the requirement of over 250 HFE. Has anyone managed to receive any that do?

I made up another order of 40 units and none of these made it above 205.......? I am just using a bog-standard DMM to measure these, is there a better way??

Luckily I added 40 2N5088 units to the same order as I read that someone here had had success with these and they all read 450+ so I am looking to swap these out on the PCB.

Question 1: what difference if any will using these instead of the 3708s make?

Question 2: The legs on these transistors appear to be orientated differently. The 3708s go (L-R curved edge towards the front) BCE whereas the 5088s are CBE. Do I need to insert them in the PCB in a different way or do I orientate them with the curved side

just like the PCB?

Best wishes

Ade

 

[Spadehead]

Bump

 

[TheWolfman]

Good evening.

So after beginning to gain an understanding of what it must have been like in the unfortunate days of leprosy I have decided to put a little video together of the issue with my 1176.Hopefully this might explain my problem a little better:

http://youtu.be/ifbG5rmt56A

Hopefully someone might be kind enough to take a look and maybe point me in the right direction as I am now completely baffled and somewhat frustrated.

Once again any help at all would be highly appreciated.

 

[mnats]

@TheWolfman. I read this earlier:

Question 1: what difference if any will using these instead of the 3708s make?

If you use the 2N5088 transistors the beta will be above 250 and the circuit will operate correctly.

Question 2: The legs on these transistors appear to be orientated differently. The 3708s go (L-R curved edge towards the front) BCE whereas the 5088s are CBE. Do I need to insert them in the PCB in a different way or do I orientate them with the curved side just like the PCB?

This is covered on my Rev D page. You could also look at the schematic, data sheet for the transistor and the PCB overlay on my site if the explanation on the page isn't clear.