[BUILD] 1176 Rev A - Back to the beginning...

[phishman13]

Thanks so much Eddie!

Now that I read that thread, I am seeing that mine is acting very much like they described before the swap, so hopefully this is my answer!

 

[SaMpLeGoD]

Nice!!!!
Just swapp it and all will do great!!!!
Cheers,

Eddie

 

[benlindell]

So I did some measurements in protools of my Rev A Attack times. These are not very scientific but useful. It looks like there is a difference  between slow and fast, but compared to something like Bombfactory's 76 my Rev A's slow is the same as their fast. I would love to know how I can mod mine to have a bigger range of attack times. Do I just need a larger pot?

 

[stereokillah]

thank you phishman13 and SaMpLeGoD  i already did the zero + nul  the only  thing missing it was the last step adjust with the zero when the jumper is on normale place.

benlindell mine work well on attack and release but i ve tested it with a couple of batterie there is  so much difference fats and slow.

just one thing on 20 and 12 ratio when my input pot is one the first 1/4 i have a cut fats and intermitent.


( Edit after some test) it's caused by the fast attack and fats release)

 

[ilfungo]

Hi guys I tried this change on REV A and it seems to work well

"I made a stereo mnats rev f with the Hairball kit (matched fets, transformers etc..) Sounds fantastic! Just thought you all might like to know of a mod I (and probably many others...) came up with to get a better signal to noise ratio. It's quite simple.. I added a switch that puts a 100k resistor in series with the link between (22) on the pcb and the 'GR off' switch. This makes the threshold higher and allows more input before gain reduction. In situations like vocal tracking this allows for subtle compression without having to turn the input down and the output up - which adds noise. 100k gives about 4db less gain reduction."

 

[ilfungo]

My 2 rev A & 2 rev D
Thanks

 

[danjpiscina]

So I did some measurements in protools of my Rev A Attack times. These are not very scientific but useful. It looks like there is a difference  between slow and fast, but compared to something like Bombfactory's 76 my Rev A's slow is the same as their fast. I would love to know how I can mod mine to have a bigger range of attack times. Do I just need a larger pot?

this is interesting. the funny thing is that the BF76 actually sounds nothing like an 1176, so it's not a good comparison. but the nature of the 1176 is "fast" in general. that's just the sound of it. it's why they call it a "peak limiter".

 

[benlindell]

In my quest for some variation in the attack time I tried a simple mod, I increased the attack pot to 100k. Here's what it looks like now, this is 4 different samples starting CW moving CCW. I personally like having some variation in attack times.

 

[danjpiscina]

I personally like having some variation in attack times.

then don't build an 1176!

 

[regularjohn]

My 2 rev A & 2 rev D
Thanks

Hey those look great!

 

[stereokillah]

now i have clibrated it with your help thanx,
at time like phishman13 my ratio is the same on 4 and 20

phishman13 have swap the resistor does it change your ratio?

Thanx

 

[ilfungo]

My 2 rev A & 2 rev D
Thanks

Hey those look great!

thanks danjpiscina !!!!

 

[phishman13]

now i have clibrated it with your help thanx,
at time like phishman13 my ratio is the same on 4 and 20

phishman13 have swap the resistor does it change your ratio?

Thanx

Haven't done it yet.  I only have a stash of carbon comp resistors laying around, so if I have the values, I'll swap it out today and check back.  Let's hope I have em!

 

[phishman13]

Alright stereokillah,

swapped the 3 resistors.  It seems to work just like its supposed to!  Starting in the 4:1 selection, I listen to a couple tracks.  One is dry kick drum, other is dry snare drum, some dry vocals, etc.  The drum tracks are nice b/c each hit is a steady amplitude.  They come off of the AES Nashville Test Reference CD.  Anyway, as I listen, each progressive ratio position compresses more and more.  This leads me to believe that it is working how it should be.  4 DIFFERENT ratios!  And when I push in all the buttons, it kicks into what I believe to be the ALL buttons in mode (since i've never heard that in person before). 

Lets put it this way, if I walked into a studio and got down to business with this compressor, before the resistor swap, I wouldve thought it was broken or acting funny.  Now, I wouldn't question it as being DIY.  It responds visually and sonically like I feel a compressor should (and like the BF76 plug in that I'm most used to even though it is no comparison to the real thing anyway).

Now its still humming away, but I haven't tried to fix that yet.  I wanted to get it working normally.  So now I'm gonna fix the hum and put some real tracks through it that I know a little better and see what it can do.  And then i still have to mount those damn push buttons on purushas case.  I have an idea, but i think his backplate has a coating of some sort on it since JB weld wont stick to it.  I'll do some sanding and grinding and make it work.

CHANGE THOSE RESISTORS!!! You'll love it.  It's a way of life!

 

[gary o]

Couple a questions about this Rev A project....C7/8/9/10 Bom say 1n4004s schematic says 1n4003s boards says nothing Im guessing either will be ok.............

Bom shows a cap CX6  layout in PDF shows it on the board tooo but my board Rev A does have a place fro this....?

On the ratio board there is slot for trimmer (r opt1 thresh)....cant find it on bom ...is it optional ...i noticed on the solder side of the board a note say cut link to use trim....

Sorry for the questions I did read this whole thread first

Thankyou .......................Gary O.

 

[Rob Flinn]

1n4003 or 4004 will be fine

Cx is I think on the 1st revision of the board which you use if you are using it to make the mic pre rather than the compressor,  This is documented somewhere, possibly on Mnats website

 

[phishman13]

On the ratio board there is slot for trimmer (r opt1 thresh)....cant find it on bom ...is it optional ...i noticed on the solder side of the board a note say cut link to use trim....

Yeah I wondered what this was all about too. Is this simply a threshold control? So I could possibly raise it so I can feed more input signal into the compressor to over come some noise?  My rev a's input control is never very high so I'm not feeding much signal at all into it. I know I've seen some tweaks to fix this, haven't tried any yet, but just wondered if that is one way to do it.  Or really just what does that little thingy do? Ha.

 

[ethervalve]

i also wondered about that trimmer option... intriguing.

btw gary o, I learned the following from an Ampex list member: you can use 1n4007 diodes as 'universal' replacements for 1n4001, 1n4002, 1n4003 etc parts. The only difference is the maximum voltage they can handle (a higher final digit means a higher voltage rating). Once upon a time 1n4007s were quite a bit more expensive. nowadays there's barely a difference. If you're feeling extra flush you can stock up on the faster uf4007 and use them for as a 'deluxe' replacement for any 1n400x diode.

 

[gary o]

Thanks for the answers fellas.....ah yes the trimmer is prob as said for threashold....I added a 100k threashold pot to the front panel of my Rev J some time back...spose this is similar ...Im in paint by numbers mode at the moment but will switch to DIY and check on the schematic what this trimmer will do

Thanks once again

 

[muffy1975]

Hi message for Mike at Hairball,

got the new Avel but the secondary wiring side diagram on the actual transformer is not matching up ( I think ).

Usually on the secondary I wire the black and yellow together for the centre and take red and orange to the sides.

Is this still correct?

The primary side for 240v I wire the violet and grey together and take blue and brown to neutral and live respectively

Thanks in advance Mike.