[BUILD] 1176LN Rev D DIY

[TheWolfman]

Hi Mnats,

Thanks for getting back to me my man.

As I stated before all the voltages appear to be reading correctly and my transistors are definitely orientated correctly as I checked the data sheets for them.

It's late over here now in the UK but I will endeavor to open up my unit and re-check voltages etc as soon as I can.It took a considerable amount of time to put the video together...as you probably well know from your own forays into video production!

The unit it terms of compression seems to function exactly as expected and does indeed sound absolutely wonderful.I did notice however that the threshold/knee doesn't seem to respond quite like any 1176 I've used before in that you aren't able to 'push it' quite as far as I would expect.Compression seems to taper off after about  the '12' position on input.Could this be the nature of the input pot or that the level going into the compression circuit has too much resistance to be pushed fully?

Once again thanks for such a rapid response and I'll try to provide some more technical info a.s.a.p.

 

[mnats]

As I stated before all the voltages appear to be reading correctly and my transistors are definitely orientated correctly as I checked the data sheets for them.

The last post of yours I found mentioned that some of the voltages - including the ones associated with the metering circuit - were out. If this has since been corrected than the next thing to check in the case of intermittent operation is problems with solder joints and wiring as mentioned in the FAQ.

The part about transistor orientation was for another builder.

If the problem is not any of the things mentioned in the FAQ then I owe you a beer.

 

[TheWolfman]

Hi,

I just got around to taking the readings for the GR Meter section,as you can see the readings are actually way out!Now I guess it's a case of hunting the culprit down......

As I say one of the pads on the middle leg of one of the trims got lifted slightly when it was de-soldered as it had to be replaced.I was a bit taken aback by this as it was literally desoldered in less than a second!I've tested continuity though and it seems to work fine.

 

[TheWolfman]

@ Mnats,somehow I getting the feeling you won't be oweing me a beer!

 

[TheWolfman]

Any ideas anyone?

The Drain leg of Q11 is out by about 5V!

 

[berkleystudios]

can some one please help me with sourcing parts, all i need is the 920 ohm resister. my board is completely stuffed except for this and the parts from the hairball kit. what can i use in its place?

 

[germoju]

can some one please help me with sourcing parts, all i need is the 920 ohm resister. my board is completely stuffed except for this and the parts from the hairball kit. what can i use in its place?

Hi, you need this for R12 ? If you talk about R12, you need to use a 1,8k resister, not a 920.

 

[berkleystudios]

thank you!! i was trying to figure out why i had an extra 1,8k resister.

 

[Spadehead]

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.
[/quote]

Thanks for the help! I finally got my 1176 finished and calibrated and it worked perfectly first time!  ;D
Being patient (new for me) was definitely a struggle but sooooo worth it.....

One question for all you builders out there.....what are you all using to insulate the 240Ohm resistor for the meter lamp? I used a block of polystyrene which has since melted a tad and fallen off!......I can't seem to find any information on a good material to use. Does anyone have a link to a Mouser part or similar that I can buy online???

Best wishes to all and here's to my upcoming Rev A build!!

Ade

 

[sr1200]

How about just some shrink tubing and let it float on its leads... havent had an issue with mine yet.

 

[DigitalMetal]

Hi Everyone,
Im after a bit of help with my Rev D, its all done except when i try to do the calibration and adjust the QBias to reduce the reading from +1db to 0db as per the setup video, But when i turn the pot the meter needle goes up instead of down  ???

So my first thought is to check the orientation of components, does anyone have a close up photo of their board so i can check which way round my Vishay trimmers from mouser (i used the Hairball Audio Quick Cart from Mouser BOM) pots are mounted,
https://uk.mouser.com/QuickViewProdDetail.aspx?PartNum=72-T93YA-2K&KeepThis=true&TB_iframe=true&height=375&width=530&QuickView=true
Or point me to where in the build guide it mentions the orientation,  what it says here doesnt real help, am i supposed to just mount them a 90 degree clockwise turn in relation to the screen print?

Apologies if this topic had already been covered in this thread but i couldn't find it and this thread is HUUUGGGEE !

Thanks

Neil

 

[germoju]

hi guys,

I just finished my second 1176 but I got trouble with the 3th step of the calibration video...

INPUT 24
OUTPUT 24
ATTACK OFF
RELEASE 7
RATION 20:1
METER +4

I apply 1khz signal.
I ajust with OUPUT to get 0dB.

I turn ON compression with he tack pot and I see 20 dB drop.
Impossible to return to -10dB with my INPUT pot... I think I win 1 or 2 dB with INPUT max !

the INPUT pot is Bourns 600Ω T-Pad Attenuator http://hairballaudio.com/shop/product_info.php?cPath=27&products_id=65

Do you think it can be the problem ?

 

[sr1200]

@germoju - crank the hell out of the input gain.  (like all the way up) then bring the output up to reach 0vu.  (when you engage the attack, bring the attack all the way up) if your meter goes BELOW the -10, adjust with the output pot, when disengaged you should then be above 0, now bring down the input pot to 0 and you should be close.

 

[germoju]

@germoju - crank the hell out of the input gain.  (like all the way up) then bring the output up to reach 0vu.  (when you engage the attack, bring the attack all the way up) if your meter goes BELOW the -10, adjust with the output pot, when disengaged you should then be above 0, now bring down the input pot to 0 and you should be close.

YEAH ! you saved my life again ! Second unit calibrated and ready !!
THAnKS !!!

 

[mnats]

But when i turn the pot the meter needle goes up instead of down  ???

What happens when you turn the pot the other way?

 

[usekgb]

I just finished getting two channels calibrated and squishing!  For whatever reason, I had a lot of trouble with channel two.  After checking all the voltages and pulling out whatever hair I have left, I finally just removed R44 and started the whole calibration procedure over again.  The second time around went really smooth.

Thanks to everyone who has contributed to this project.  I couldn't have done it without you!  Pics to follow in the next couple days.

Cheers,
Zach

 

[usekgb]

Hi,

I just got around to taking the readings for the GR Meter section,as you can see the readings are actually way out!Now I guess it's a case of hunting the culprit down......

As I say one of the pads on the middle leg of one of the trims got lifted slightly when it was de-soldered as it had to be replaced.I was a bit taken aback by this as it was literally desoldered in less than a second!I've tested continuity though and it seems to work fine.

I had the exact same problem as you, and was pulling my hair out trying to figure it out.  My voltages were almost exactly the same as yours.  I ended up yanking R44, doing the Q bias again, re-set the null adjust, and finally the meter calibration.  I must have screwed something up before and threw something out of alignment.  It works great now.  Just retrace your steps back to the beginning.

Cheers,
Zach

 

[germoju]

Hi Everyone,
Im after a bit of help with my Rev D, its all done except when i try to do the calibration and adjust the QBias to reduce the reading from +1db to 0db as per the setup video, But when i turn the pot the meter needle goes up instead of down  ???

So my first thought is to check the orientation of components, does anyone have a close up photo of their board so i can check which way round my Vishay trimmers from mouser (i used the Hairball Audio Quick Cart from Mouser BOM) pots are mounted,
https://uk.mouser.com/QuickViewProdDetail.aspx?PartNum=72-T93YA-2K&KeepThis=true&TB_iframe=true&height=375&width=530&QuickView=true
Or point me to where in the build guide it mentions the orientation,  what it says here doesnt real help, am i supposed to just mount them a 90 degree clockwise turn in relation to the screen print?

Apologies if this topic had already been covered in this thread but i couldn't find it and this thread is HUUUGGGEE !

Thanks

Neil

Did you try to turn on the other way ?
This thread is very long but you can find all what you need. It's good to read the 130 pages

 

[thefadedline]

Hi guys,

I've just started this build after it's been sat in my cupboard for 2 years, it's going well so far.  Just taking it slow and steady and making sure I follow both MNATS guide and the guide on Hairball Audio.  So far I've stuffed the power supply of the main PCB and I'm in the process of wiring it up so I can test it.

Anyway I had some pretty basic questions to begin with, mainly for the UK & European guys.

Where is a good place to buy 3-conductor wire?  I've checked Mouser for the Belden 8451 but the minimum length is 100ft and if possible I don't want to buy a 100ft roll when I'm only going to use approx. 30ft.  I was going to use Maplin's wire for the hook-up wire as I can buy it by the metre in multiple colours.  That is unless the wire quality is terrible so any opinions are appreciated.

Second question is this, Mouser made a few mistakes on my first order (one or two missing components and a broken XLR) so I'm going to have to place a second order and I wanted to use a Molex header and connector for the Ratio and Meter boards as visible in MNATS wiring guide. 

I don't suppose I could be cheeky and ask for a Mouser part no.  I've searched Mouser for a similar part but didn't want to commit to ordering one only to find out it's too big or too small. 

As my only experience is with point-to-point tube amp building I've never dealt with Molex connectors.

I understand these are quite basic questions but I've searched the thread and couldn't seem to find an answer.

 

[TheWolfman]

@Zach

You had the same problem?very interesting!

Did you also have the same oscilation problem as I demonstrated in this video I made?:

http://www.youtube.com/watch?v=ifbG5rmt56A

What exactly do yo mean you 'yanked' R44?!You replaced it?

Thanks for spotting this by the way and posting.