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

[rainton]

rainton, I would love to see a photo of your front panel. Is it a custom panel, or did you buy the full hairball kit w/ bluestripe enclosure?

I bought the full kit with blue stripe enclosure but had it modified a little to make it look closer to the original 
Even though I know the original has no engraving but - anyway I like the look of it

 

[rainton]

here's a another on a little more close-up...

hope that helps

 

[Chrome Heart]

Looks good. Who engraved it?

 

[hymentoptera]

wow, rainton, that looks like a beast!

I'm thinking of doing pretty much the same thing, red LED, and some engraving, but I'll be using the standard hairball sourced meter. Hope mine comes out that good!

 

[rainton]

wow, rainton, that looks like a beast!

I'm thinking of doing pretty much the same thing, red LED, and some engraving, but I'll be using the standard hairball sourced meter. Hope mine comes out that good!

Thanks hymentoptera - I used the standard hairball meter to - I just modified it a little

Regarding the engraving below the VU-meter: I got the vector graphics from forum member "Phrazemaster" -
he did all the work designing it after the original and spent a lot of time to do so! Many thanks to Phrazemaster!!!
I'm sure he would send you the illustrator file if you ask for it
The engraving was done by frank at nrg here in Germany - he has a cnc machine and is very much into DIY himself.
He has been very helpful in the past with other projects, too!

 

[hymentoptera]

...
c27 is listed as a .012 uF capacitor but in my bill of materials I have a .01 uF 100Volt supplied and left over.  Apparently this is the cap for the Attack Potentiometer.  Will the .01uF work, or should I try and find a .012 uF?

...

bless, greg

[quote author=Echo North]Mouser didn't carry an appropriate .012uF cap so I subbed in the .01uF .

There should be no problem.

Mike[/quote]

[quote author=bieckmusic]Great, thanks so much.  Just want to make sure.....[/quote]

To anyone with a better understanding of the circuit than me;

I've got some 0.12uF .012uF NOS polypropylene caps I plan to put in my C27 positions on both of my Rev A units. What could I expect to be different? An immeasurably slower attack, perhaps?

I'm going for something authentic and using the rolled yellow film and mylar caps the original from the 1960's had in it, as well as carbon comps in the input and output amps. I'm also asking because I'm considering tweaking some things later and I don't quite understand how the attack and release pots affect the negative control voltage in the time domain.

Any insight into the effects (or lack thereof) between using 10nF vs 12nF on the attack, as well as other possible resistor values on either pot (besides 270k and 1k2), and their respective behaviors. Also curious if anyone else is using the yellow film caps (sometimes called "sprague lemon drops", although mine aren't all made by sprague, and include electrocube, wesco, and cornell dublier), and why you chose them, and how do they sound? Can anyone recommend that I *not* use them? Can anyone recommend that I not use 12nF for C27?

Thank in advance, fellas. Much respect for everyone here, especially mnats, ed, mike, and everyone who made this all possible

edit: typographical

 

[Harpo]

I've got some 0.12uF NOS polypropylene caps I plan to put in my C27 positions on both of my Rev A units. What could I expect to be different? An immeasurably slower attack, perhaps?

0.12uF = 120nF will not behave immeasurably different but much slower when compared to a 10nF timing cap. Maybe your 0.12uF is only a typo.

 

[sea_man]

Hi ! , I'm very happy with the unit.. sounds great! but I have an issue adjusting the gr view meter for my revision A 1176

I Tried moving the resistor R44 and nothing happen ( the r44 is placed correctly).. the view meter stays on the default position (-20) I adjusted the Q bias properly but definitely the GR Adjustment process is not working. the view meter isresponding to the signal the buttons +4, +8 but nothing happen when i select the GR

Any advice ?

Thanks !

 

[Echo North]

Hi ! , I'm very happy with the unit.. sounds great! but I have an issue adjusting the gr view meter for my revision A 1176

I Tried moving the resistor R44 and nothing happen ( the r44 is placed correctly).. the view meter stays on the default position (-20) I adjusted the Q bias properly but definitely the GR Adjustment process is not working. the view meter isresponding to the signal the buttons +4, +8 but nothing happen when i select the GR

Any advice ?

Thanks !

Did you check the DC voltages agains the schematic with voltages in that meter section?

Make sure you move the jumper when doing the measurement.

 

[hymentoptera]

I've got some 0.12uF NOS polypropylene caps I plan to put in my C27 positions on both of my Rev A units. What could I expect to be different? An immeasurably slower attack, perhaps?

0.12uF = 120nF will not behave immeasurably different but much slower when compared to a 10nF timing cap. Maybe your 0.12uF is only a typo.

Yes, thank you, that would be a typo. The value is .012uF, thanks for catching that.

 

[hymentoptera]

Concerning the current Mouser BOM for the Rev A;

-The 0.15uF "Orange Drop" capacitor is out of stock. You can use another 0.15uF film cap like a WIMA here. There is already a WIMA 0.15uF cap in the Rev A cart (MKP2D031501H00KC00). I've increased the QTY to 2 to reflect that change. If you want the Orange Drop, they are currently in stock at newark.com. Just search for part# 225P15491XD3.

Just a headsup... The BOM still shows only one .15uF WIMA. Two would still not be enough. The quantity will need to be 3 to satisfy C1, C2, and C8, unless the builder chooses to go another route, such and finding the orange drops at Newark, etc.

 

[Echo North]

Concerning the current Mouser BOM for the Rev A;

-The 0.15uF "Orange Drop" capacitor is out of stock. You can use another 0.15uF film cap like a WIMA here. There is already a WIMA 0.15uF cap in the Rev A cart (MKP2D031501H00KC00). I've increased the QTY to 2 to reflect that change. If you want the Orange Drop, they are currently in stock at newark.com. Just search for part# 225P15491XD3.

Just a headsup... The BOM still shows only one .15uF WIMA. Two would still not be enough. The quantity will need to be 3 to satisfy C1, C2, and C8, unless the builder chooses to go another route, such and finding the orange drops at Newark, etc.

Fixed! 

Thanks,

Mike

 

[Curran]

ok- hardware setup question. how should I signal chain this compressor into my studio? through the inserts on my console(Yamaha O2R96v2) OR just chain it after my VP25 into the 1176 into my console?

 

[Curran]

from the vp25 into the 1176 and WOW beautiful smoosh!!!!

 

[KSeaton]

Hi guys,

after some time trying to troubleshoot my 1176 thinking I had the problem narrowed down to the signal line amp (audio severely distorting) I caved and sent it to a tech (David Kulka @ studio electronics). He seems to have it sorted but wrote me this odd note about it. Does this seem right??? He suggested using a 10db pad before the unit.

DIY 1176 “Blue Stripe” Limiter. Audio is very distorted. Build quality appears good, hopefully this will not be a major repair.

Found intermittent short circuit in output wiring. Did complete calibration and check out.

Some notes about this unit:
The original blue stripe 1176 that this version is modeled after had 50 db of gain, 5 db more than the later versions. Because of this very high amount of gain, the input section must be operated with the Input control turned way down.
The Input pot in this unit seems to have less gradual tracking than a stock 1176. In other words, it has higher signal level with the Input control set to 9:00 than a stock unit. This, in addition to the high gain of the unit, means you have to be really careful not to turn the Input level up too far and overload the input preamp.

 

[Echo North]

Makes sense.

Basically the log curve of the tpads is a little different.  Obviously it's been working for people for a few years now, so the stock set up works well.  What David K is saying, is that a pad is a way to get a wider, less sensitive control back in the input pot/tpad.

Mike

 

[KSeaton]

Gotcha. Thanks Mike!

 

[baadc0de]

Guys... quick question, if anyone has an idea... at 20:1 and 12:1 the compressor works but is a bit too distorted. Sounding like 0.5% or more THD. But it compresses normally. Pressing 20:1 and 4:1 goes into "all buttons mode" and sounds like it, but THD feels like it *decreases* which is weird. At 8:1 and 4:1 there is no compression. Huh, what gives, any ideas on what to check, what could be a newbie mistake? Probably threshold is too high or something?

Built with hairballs switch PCBs, rev 1.25 main board I believe.

I'm thinking, maybe the threshold is set up too high at 8:1 and 4:1 .. how is the threshold calculated, what resistors are used to set this up? I should probably start experimenting there.

 

[evilcat]

You could minus the signal triggering the sidechain amp by putting a resistor in serie between pad 22 and the "GR off" switch. For the value you have to try, me I've put 200k. If I remember correctly it lowers the GR by 5-6 dB. I've put it on a SPDT switch to have standard setting and mod setting. Both work great.

Best,

Ben

 

[baadc0de]

Guys... quick question, if anyone has an idea... at 20:1 and 12:1 the compressor works but is a bit too distorted. Sounding like 0.5% or more THD. But it compresses normally. Pressing 20:1 and 4:1 goes into "all buttons mode" and sounds like it, but THD feels like it *decreases* which is weird. At 8:1 and 4:1 there is no compression. Huh, what gives, any ideas on what to check, what could be a newbie mistake? Probably threshold is too high or something?

Built with hairballs switch PCBs, rev 1.25 main board I believe.

I'm thinking, maybe the threshold is set up too high at 8:1 and 4:1 .. how is the threshold calculated, what resistors are used to set this up? I should probably start experimenting there.

Cold solder joint on the ratio switch board PCB, the one that links 12:1 and 8:1 ratios... god, so stupid!