[BUILD] 1176LN Rev D DIY

[Echo North]

ph-  good to hear someone else is running into this.  My units are the pushbutton and not the rotary.  Can anyone else confirm that moving up in amperage is an ok thing?  Is the heart of the problem coming from a switch issue?

Just to check, Im switching just one side of the iec supply.  So the neutral wires of the transformer go directly to the neutral iec, then the high gets fused, then to the switch, then to the transformer.  Is this right?  

Is anyone else blowing fuses with the hairball push switches?

I have blown a few 250mA slow-blow's but it's very rare for me.  Maybe the rotary is taming the inrush current a little but I can't see how.  I've measured inrush to be over 500mA on 1176's.  You could move up a little on the fuse like pH.  I wouldn't go above 500mA slow-blow.

 

[wkbdgeorge]

Cool, great info!  thanks, i will try moving up to 375 ish. 

 

[TomWaterman]

Hey sorry no thoughts on your issue Echo,

Apologies for blasting this up without a full check of the thread...on a mobile here, no net at home so 70+ pages sucks on a phone!

Just building up my rev ds with mikes kit and chassis.

A few issues so far. Any tips?

1. No matter where I locate the main pcb on the mounting bars inside, the ea5002 output tx wires are too short to make the board, is this an error with my part?

2. How do you get the 600ohm t-pad fastened to the faceplate without stopping the shaft from  rotating with the nut grip? There isn't much wiggle room to bring the nut behind the panel up easily, any tips?

3. Also has anybody tried shortening the bourns metal shaft on the output pot so that in and out knobs sit as flush as each other and if so any tips?

Thanks and sorry if this has been covered but finding it hard to browse!

-T

 

[sahib]

Not specifically for this project but;

1. Just extend the wires.

2. I am not sure if we are talking about the same thing but use a locking washer at the back of the panel. This will stop the attenuator rotating when you fasten the nut from front. Also use a normal washer on the front side so that the nut does not scrape the faceplate.

The other option is that if the attenuator has a stopping lug, then drill a hole on the faceplate so that the lug mates with it and locks the attenuator.

3. I am asuming the shaft is short and needs just a touch of shortening. Just hold it using long nose pliers and grind it on your table grinder, if you have one.

If it is a bit longer (even a few milimeters) grip it on the corner of the jaws of your bench vice at 45 degrees angle and saw the excess off. This is dificult to explain but I hope you get what I mean. Imagine if the two corners of the vice form the two sides of a triangle at right angle, the shaft forms the hypotenuse. I know it is quite awkward but sometimes you have to do dances like that.

 

[Echo North]

Yes I extend the wires too.

For the output I just use another nut between the pot and the rear of the panel a spacer.

If you have the old attenuator with the spit bushing, tightening will cause the pot to stiffen.  You need to tighten it just enough.  The new attenuators do not have the split bushing.

Thanks,

Mike

 

[TomWaterman]

Perfect thank you gents.

Was going to extend the wires just wondered if my part was as it should be...the extension is kinda fugly but will hide with in a bundle with some shrink!

Great idea on extra nut, why didn't I think of that lol?

I'm having a real hard time getting the t-pad to stay in place with the split busing so I'm going to order some new ones and keep the old ones for prototyping.

Thanks dudes!

 

[jandoste]

No hum, no noise,

I got them I tried to fine the problem today but I couldn't fine ! any idea?
Thanks

I'm still here Any idea ?  the Output has noise and hum ? I am trying with pro tools HD 96 i/o!.
Thanks

bump?

 

[BrodieSound]

Hi,
As this is my first post hello to all! By way of introduction I'm a freelance engineer/recordist living in Norfolk in the UK. I recently built a Hamptone kit and got the DIY bug but I'm sadly lacking in knowledge and experience so I'm hoping some of you will be will be kind enough to help me along.
Anyway decided to have a go at this project and have ordered a kit from Hairball and placed my order for PCB components from Mouser. Sadly Mouser have a really long lead time on a few of the resistors so I have been trying to source alternatives. Whilst it's fairly straight forward to match the obvious specs (metal film, tolerance, value etc.) some specifications are given on one site and not on the other and that type of thing, and my understanding is so rudimentary I don't feel confident that I have found suitable alternatives. I'd be very grateful if somebody could have a look at the digikey alternatives listed below (it's only three items) and advise me if they are suitable? Apologies if these are really stupid questions, but I'm here to learn so any help would very sincerely appreciated.

R40, R49
Mouser Part # 271-2.4K-RC
link: http://gb.mouser.com/ProductDetail/Xicon/271-24K-RC/?qs=sGAEpiMZZMu61qfTUdNhG%2f79vAMFdCTImJrjFhOQbHY%3d

Digikey Part #  P2.40KCACT-ND
Link: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P2.40KCACT-ND&itemSeq=89431156&uq=634170003724306603&cshift_ck=null&client_id=5042


R47
Mouser Part # 271-44.2K-RC
link: http://gb.mouser.com/ProductDetail/Xicon/271-442K-RC/?qs=sGAEpiMZZMu61qfTUdNhG4Pa1JDA%2fQTwSBLQb2uy9fg%3d

Digikey Part # 44.2XBK-ND
link http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=44.2XBK-ND&itemSeq=89431041&uq=634170003724306603&cshift_ck=null&client_id=5042


R65
Mouser Part # 291-3.9M-RC
link: http://gb.mouser.com/ProductDetail/Xicon/291-39M-RC/?qs=sGAEpiMZZMu61qfTUdNhGyuukJyd7cSjt4s8LbOoMPc%3d

Digikey Part # 3.9MQBK-ND
link: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=3.9MQBK-ND&itemSeq=89431321&uq=634170003724306603&cshift_ck=null&client_id=5042

Best regards,
Steve

 

[dmp]

They look the same to me - the important specs are the same, first two: metal film, 1/4watt, 1% tolerance.
The last are both carbon film, 5%.
For that resistor, 3.9Meg, I used a metal film. Available at Mouser 594-5043DMM900J

 

[ofarrellaudio]

Hello everyone.  I've been slowly working on a Hairball Rev D (push button with the GR off switch on the attack pot) over the past few months and (after burning out R32 the first time I fired it up due to following Skyler's diagram for the output transformer instead of the markings on the board like an idiot) I finally have it up and running without any fire or horrible humming.  The unit is passing audio and seems to be pretty quiet.  Reading this forum has been incredibly helpful.  This is my first build of anything.  I did put together a couple of those starter kits from radio shack just to get some practice soldering PCB's before I jumped in and trashed this one by accident, but that doesn't really count.  Huge thanks to Mike, Mnats, and everyone else here.  I was going through the calibration process tonight and I ran into a snag.  I seemingly got through the q bias and null adjust ok, but have run into a snag with the gain reduction meter tracking calibration. 

I'm using a cable tester that has a 1k signal generator built into it as my 1k tone.  I'm running that through a mic pre and then into the 1176 so that I can be sure (using the vu on the mic pre) that the signal I am sending is 0 db. 

My problem is this...

I switch the meter to GR mode and zero the meter with no problem.  Then I switch the meter to +4 and the ratio to 20:1 and put the in and out at 12 O'Clock just like in the video.  I switch off the GR on the attack pot, apply the 0 db 1k tone, and adjust the output till the VU comes back to 0.  Then...  when I switch the GR on with the attack knob instead of the meter dropping it pegs hard right! 

In the process of writing this I think I may have thought of a solution, but please humor me with your insights anyway.  Is it possible that this is happening because I wired the switch on the attack pot backwards and when I have the switch "off" to adjust the output to 0 it is actually compressing and then when I switch the GR "on" I'm actually turning the GR off and that is causing the meter to peg hard right because I'm then metering the uncompressed signal?  This seems the most logical answer to me.  Thanks in advance for your thoughts.

P.S.  I also wired the red from the output tranny (EA50002) to the hot (pin 2) on the XLR output and blue to cold (pin 3) on the XLR output as per Skyler's diagram, but after doing some reading tonight it appears that those are supposed to be swapped.  Is this correct?  The unit is passing audio and not humming, but I'll swap them if I'm wrong.  Thanks again.

-Reggie

 

[BrodieSound]

They look the same to me - the important specs are the same, first two: metal film, 1/4watt, 1% tolerance.
The last are both carbon film, 5%.
For that resistor, 3.9Meg, I used a metal film. Available at Mouser 594-5043DMM900J

Thanks for that, I appreciate you taking the time to look at it for me.

S.

 

[ofarrellaudio]

OK...

I figured out my attack pot switch wiring by verifying things with a continuity check.  I don't know why I didn't think of this in the first place.  I suppose this is what happens when you try to work on wiring your 1176 at 4am.  This is my first build so I'm still learning from my bonehead mistakes.  I also finally got my head around the schematic enough to realize that red is cold and blue is hot on the output tranny.  I got my unit calibrated as far as I can tell.  I had some confusion about the level of the 1k signal so I just checked the incoming signal with a multimeter to verify that the signal was actually coming in at .775v.  This is not equivalent to 0db on my ADL600's VU meter.  I tried to do the distortion adjustment using the scope plug-in in Cubase 4, but turning the pot didn't seem to change what I was seeing at all.  Any tips on adjusting THD?  Also, I noticed that when I turned on gain reduction and measured a drop about 7.5 db on the meters in Cubase (using as steady 1k tone to test this) the 1176 was only showing 5 db of gain reduction on the VU.  Is this normal?  I'm also measuring about 28 volts across AC1 and CT on the mainboard and about 29 volts across AC2 and CT.  Thanks for your thoughts.

Reggie ???

 

[Alistair]

Hey all,

Bought my kit a few weeks ago and have spent the last 3 weeks reading this thread- have finally got everything wired up but I've hit a few snags.  I have searched and searched this thread, so many many apologies if this has been covered before.
I'm using the Hairball pushbutton kit, Mnats boards and wired for 240v.

I'm passing a signal through with no problems, and I have to say just having those transformers there makes things sound fat!  But I can't actually get the compression to engage.  I've got it wired for off on the attack switch, but I can't hear any difference whatsoever between on and off, and between any of the ratio settings. I've checked all the wiring, and it all seems to be pretty spot on- are there other things that I should be checking?

Also, my VU meter is working and shows output volume etc- but it tends to get stuck.  Eg., it's sitting at 20, and then a loud signal will hit it and when the loud signal is over it will 're-zero' to around 80.  The only way I can get it to go back to 0-20 is to bang the unit on top of the meter.  I'm not sure if this is in any way related to the lack of compression.  It also quite often will just get stuck either far left or far right- and I've got to turn it off and wait 5 minutes for it to start moving again.

Thanks in advance!

 

[Stagefright13]

Well the meter is connected directly to the output xlr. So maybe you have a cold solder joint there? Or on the meter board?

John

 

[Alistair]

Thanks for the reply John- I've had a bit of fiddling around and it seems the compression IS working, it's just very very subtle.  The only time I can really notice it is when I've got it set to slam.  I wonder if this is because I'm actually feeding it a very quiet signal because the VU meter is off.

Assuming the compression is ok and just needs calibration- any ideas on why the VU meter is sticking?  It now sits on around 95 even when turned off.   Occasionally if the output is turned up it will bash rhythmically on the right hand side aswell.  I've checked and re-soldered all connections on the meter board, XLR jacks and both connections into the VU meter (and lamp!).
Is it possible the VU meter itself is faulty?  I'm sure it's much more likely I'm faulty, but I'm a bit lost.
EDIT- The problem with electronics is sometimes you miss the most obvious thing.  :  The "fault" with the meter was entirely mechanical, and due to me overtightening the screws to attach the meter.  Due to the design of the mounting, over tightening put too much pressure on the sides of the meter, causing it to stick.  Loosened the screws, and everything is ok.  The only 'strange' phenomena is that if the Output knob is full CW or CCW the meter shoots all the way to the right.  Hopefully calibration will fix that...
At least my wiring was ok (even if my eyes obviously aren't!)  

Thanks!

 

[benlindell]

Just gave mine a quick fire up before heading out. getting 25VAC on the AC terminals just fine, Getting +30V, but on the -10V Test point I only get -5, any ideas?

 

[Stagefright13]

-5 is wrong. It should be up around 9.5, 9.7, 10.2 etc. You have triple checked the caps are installed with the correct polarity? That's a bad rail. Do you feel any hot components? Besides the 3055 or reg? Check the diode orientation too.

And I would wear safety glasses. Just in case. Ya never know. Can ya show a closeup pic? Maybe someone will see something.

John

 

[bdubya]

Ben L

As one Ben to another:   ;D  

Take a look at CR6, CR9, CR10, R81, R82, C24, and C26, visually checking for the correct orientation and values against the schematic and touch up the solder joints for all of them.  If all appears to be well, but you're still getting -5, then get in there and find the faulty part and replace it, or, if you have the parts handy, replace them all.  That's all the components that might affect the negative rail in the PSU, so it's the parts, the soldering, or, possibly, a messed up trace, but you'd probably be able to tell on your visual check if that's the case as well.  Hope that's of some help.  Cheers!

Ben W

 

[benlindell]

Thanks for the help guys, ended up being C26, replaced it and we're up and running.

Quick Pic: http://blog.benlindell.com/?p=280

 

[Josiah]

Hello everyone,

I have a quick question. I ordered a Rev D BOM from Mouser and I noticed that they are out of a few components. Lucky for me I have a majority of the backordered parts on hand, but I do not have the (C1) 1uF WIMA capacitor. I have noticed that some people use a Spraure Orange Drop capacitor in that location. I was able to find a 1uF Sprauge that works in the Rev A unit, can I use this as a replacement? The voltage is higher at 100V vs the WIMA 63V.

Here is the link to the parts in question:

http://www.mouser.com/Search/ProductDetail.aspx?R=MKS2-1.0/63/5virtualkey50520000virtualkey505-MKS21.0/63/5

http://www.mouser.com/Search/ProductDetail.aspx?R=225P10591YD3virtualkey61320000virtualkey75-225P100V1.0

In addition I do have a Rev D unit with Sprauge capacitors assembled by Jason at ISM Studios. I noticed that the capacitor has a part number listed, but I am unable to find that exact match when searching online. The part number is: SBE225P100V 105K. Does anyone know where to find this?


Thank you for the help...



Regards,
Josiah