[BUILD] 1176LN Rev D DIY

[Echo North]

Hi again.

first Thx for your reply Acoustix and college101!

Today I did the next round of troubleshooting...
but still no Signal at the Output, no VUreading at +4 and +8... hummig still there...

I've put an unbalanced signal straight to the PCB... no changes :-(


THEN:
I checked my Output transformer against the Specs. from Hairball:

My readings are:
brown->black: 47,6Ohm;
blue->red:48,8Ohm;
grey->violet: 252Ohm
This is when yellow and orange wire are connected
when they are not connected, my reading is:
blue->yellow: 26,6Ohm and
red->orange:22,3Ohm
i guess these are my 2 reading that make 48,8Ohm when the yellow and orange are connected;-)

So in the Hairball Datasheet http://hairballaudio.com/docs/5002/5002.pdf there is 600 Ohm between red and blue; brown and black and grey and violet.
My Measurements are far away from that.
So is my Outputtransformer not right/broken?

No.  You're measuring DC resistance with your meter.  The datasheet shows AC impedance.  When you hook up your meter and measure DCR you're just measuring the resistance in a length of wire.  Which is low like you're seeing.

 

[Echo North]

Next question: Do the main PCB needs ground connection where it is mounted on the rails?

No.

 

[pittsburgh]

Where are the test points for the power supply?

 

[acoustix]

Where are the test points for the power supply?

It's write on PCB

One Leg of the 1K1 res -> +30
One leg of the 1N4047A -> -10

 

[dbonin]

I'm about to start testing just the power suply voltages and I have a few noob questions.

Only the power suply section is on the main pcb.
The power trans is wired correctly and everything is grounded and the fuse is in place.
The secondaries are correctly wires to the main pcb.
The primaries are wired correctly to the power switch, but.....

The push button switch PCB is not on the switch - it's not clear just how much needs to be assembled to actually test the power supply.
Does the PCB need to be on the switch to test it?  I assume is does, but how much else needs to be assembled to test the power supply if you go thru the switch?

For the test, on the main board I'm grounding one of the board mounting holes to the chassis.

 

[Echo North]

You don't need to have the meter PCB assembled.  Just wire the IEC, power transformer, switch and get your safety ground connected.  All you need are the power supply components stuffed.  They are listed on the build guide on my site.  There is alos a silk screened box on the PCB indicating the power supply parts.

 

[dbonin]

Thanks Mike.

Ok, I checked that I'm getting 120 v to the switch, but the secondaries are still not showing any voltage. 

I pulled out the transformer just to check it in isolation but I wanted to get some feedback on if I'm checking this correctly.
Here is the transformer diagram - I understand connecting the two live and the two neutral for 120v mains.

I'm convused by the Avel site about the secondaries and the center tap.  This is how mnats says to wire the secondaries for the 0v center tap

Can someone please walk me through how to test this - perhaps I'm just not hooking my dmm to the correct wires?
What confuses me is the diagram of the secondaries - it says Blk 0v and  Ora ov.  I would have assumed I would have center tapped the two 0v wires (blk and ora) and left 30v on the other red and yel?

UPDATE:

To begin with, I had a blown fuse, uggg, so lets move on to what I did to check the transformer in isolation.

When I wired the primaries in parallel both the black and the yellow secondaries read 30 v.
If I wired the secondaries with the red and orage together (center tap??) the voltage read 60v. (series, so makes sense volts doubles)

"Just make absolutely sure you have tied the two "0V (centre tap)" ..."  so, on this transformer, the two 0V wires are blk and ora... or do I just ignore that and wire the "center two wires" according to the trans diagram (red/ora) as Brrnley's diagram would suggest?

 

[gemini86]

Make a probe with an old guitar cable, cut off one connector and solder a 100nF cap onto the end and plug it into a little guitar amp. use it to poke around your pcb until you find where the test tone disappears. Then go from there.

 

[mnats]

"Just make absolutely sure you have tied the two "0V (centre tap)" ..."  so, on this transformer, the two 0V wires are blk and ora... or do I just ignore that and wire the "center two wires" according to the trans diagram (red/ora) as Brrnley's diagram would suggest?

You didn't quote the complete sentence from my page; if you did, the meaning would be clear.

Please don't ignore the safety warnings regarding high voltage wiring from my page. These are not there to protect me but to protect you, the builder. It seems clear that many people have simply disregarded it and I've been very tempted to remove the information completely.

 

[dbonin]

You didn't quote the complete sentence from my page; if you did, the meaning would be clear.

Please don't ignore the safety warnings regarding high voltage wiring from my page. These are not there to protect me but to protect you, the builder. It seems clear that many people have simply disregarded it and I've been very tempted to remove the information completely.

I'm really trying to follow your  guide to a T and I'm definately not ignoring your warning!  That's why I'm here with questions.   I appreciate your help and the help of the community, make no mistake.

I just want to make sure I'm not inadvertantly getting it wrong - because to me it isn't yet clear.  It's not your instructions so much as it is the reference back to Burnley's split secondaries diagram that has me second guessing. 

"Refer again to Mark Burnley's transformer connections. Under the "Typical Output Configurations" we'll be using the "Split Secondary for +/- Power Supply"."
I was clear until I saw the diagram. In the actual diagram the secondaries appear to be simply tying the two "center" leads together - which, if you over layed my trans diagram, would correspond to red/ora.  But in my case, red is not 0V

"Identify the two "0V (centre tap)" wires coming from the power transformer secondary."  Your reference to "center" tap is what gives me pause - why not just say, "Identify the two "0V" wires coming from the power transformer secondary"?  I just want to be sure I'm not misreading some subtle instruction there.

So, ignoring the colors AND their relative center position in the diagram, and looking at MY tran secondaries (in the picture above), my two 0V wires are blk/ora.  But is that "center tap"?  Holy crap am I over analyzing?!!

 

[Echo North]

I think you're over analyzing the transformer label.  The 0V indication on the transformer label is simply indicating winding polarity.

You want to connect the secondary in series and then make the center (where you connect them in series) the ground reference.

I think you're having the same confusion as this post.  Read through the responses.
http://www.groupdiy.com/index.php?topic=20058.msg594943#msg594943

 

[dbonin]

I think you're over analyzing the transformer label.  The 0V indication on the transformer label is simply indicating winding polarity.

You want to connect the secondary in series and then make the center (where you connect them in series) the ground reference.

I think you're having the same confusion as this post.  Read through the responses.
http://www.groupdiy.com/index.php?topic=20058.msg594943#msg594943

Exactly the nudge I was looking for.  Thanks Mike.

 

[alexc]

My 1176 Rev D build - all worked as expected and calibrated up nicely.

Noise floor at unity gain with no GR was -73 dBu rms 20Hz to 20KHz on a calibrated RTA
Loop back noise floor for my Motu converters is -84 dBu.
This was with Input knob backed off some and Output knob adding some an no GR happening.

Sounds as expected for an MNats pcb and Altran/EA transformers - very, very pleasing.

Used the optional 'Depth' trim on the rotary ratio pcb - 1M lin pot.
Makes the whole 1176 much easier to control  .. um  'depth' or threshold without
messing up the gain structure - highly recommended  \

Added a led VU meter and relay bypass too. This one is intended to go after a 1081 pre/eq clone.


cheers

 

[Echo North]

Awesome!  ;D

 

[Edward]

I'm planning to add a relay or two for switching between two input transformers on my 1176 Rev D, but I can't figure out how to power up the relays... After searching Mouser for parts relays working on DC power seems the way to go. So my question is do I need to build a second power supply of the 30VAC to get for example 24VDC or is there a simpler way? Probably a stupid question but I'm trying hard to learn.

 

[acoustix]

Receiving Haiball package tomorrow and today my RevD Rocks !!!

so i have a question about Dist Trim.
Before i soldered it, i set it in a middle position (50R), but i don't know how set it.
With Smaart Live, i inject a 500Hz , can see little harmonics (maybe my poor sound card) but Dist Trim has no effect.

Anyone have an idéa ?

thx

My 1176 Rev D build - all worked as expected and calibrated up nicely.

Noise floor at unity gain with no GR was -73 dBu rms 20Hz to 20KHz on a calibrated RTA
Loop back noise floor for my Motu converters is -84 dBu.
This was with Input knob backed off some and Output knob adding some.

Sounds as expected for an MNats pcb and Altran/EA transformers - very, very pleasing.

Used the optional 'Depth' trim on the rotary ratio pcb - 1M lin pot.
Makes the whole 1176 much easier to control  .. um  'depth' or threshold without
messing up the gain structure - highly recommended  \

Added a led VU meter and relay bypass too. This one is intended to go after a 1081 pre/eq clone.


cheers

La grande classe !

It's a  true Do It Yourself !

 

[alexc]

Cheers

With the question regarding relay switching of inputs - the simplest way would be be
use the pcb onboard +24V rail. Plenty of juice available from the 7824 regulator for
a couple of relays using around 10-20mA for each coil or so depending on the coil spec.

However, I find that tapping the onboard rail with a wire going to seperate pcb for the
relays almost always degrades the noise floor a dB or several.

So - I recommend trying first off the main pcb and if that doesn't add appreciable noise, then fine. Otherwise, add a separate regulated relay supply. For a coil, a simple cap/zener would be fine.

In my case, I generally add a few things requiring additional supply rail(s) at the same time,
so it is worth the effort of adding extra regulated rails and just leave the main pcb alone.

I find it saves me a couple of dB of noise floor - which you probably won't notice unless you
use a soundcard real time analyser application. Which I highly recommend as part of the last
stages of a build - optimise the noise floor by checking it with rta as you do your final wire/toroid
and in some cases, signal transformer placement.

Also, with regard to distortion trim - I've never seen or heard any effect of this trimmer!

 

[phantomas]

I built a couple of 1176s with extra switching using 9V relays off the -10V rail (Mouser no 653-G5V-2-H1-DC9). The relay coils don't really care about polarity, just turn the suppression diode the right way to avoid unnecessary troubleshooting. I used mnats separate PSUs, so I don't know if it's a problem borrowing some milliamps from the onboard PSU.

Tomas

 

[Edward]

Thank you for your input, Alexc and Tomas.

I now feel I know enough to get the relay switching working, i only need to orders the parts.


By the way, great work on your version of the 1176 Alexc. Looks awsome!


/E.

 

[Edward]

Hi guys! I am new here and in the middle of my build of what i believe to be one of the best compressors ever the 1176! I freakin love these bad boys! I will be around here alot more in future as there's so much info. Ive never built any electronic units before except really small LED testers back in high school but im enjoying this build so much that i plan on building many more sttudio pre-amps, comps ect.

Anyway, enough with introductions. I have almost completely stuffed my board but have run into 4 problems so far.....

Problem 1:

R4 - Pc board says 270R - Is that simply a 270 Ohms resistor? Same as at R41 on the board?

Problem 2:

Mouser sent me 20 (Twenty) 2N3708 semi bi-polar small with my BOM....... Am i missing something cuz i only see 2N5457, 2N3707, 2N3391 spots on my board....... are the 2N3708 that mouser sent perhaps substitutes for the boards marked 2N3707 spots? If so why did mouser send 20 cuz theres only 7 of those marked positions? (apologies if this is a stupid question but i prefer to make 100 percent sure of my build.)

Problem 3: (Related to problem 2) Just need some confirmation of what "think" i know LOL 

The matched pair of 2N5457 FET that come with the hairball kit go into the two spots of the same name right? (yeah yeah lol) rather safe than sorry..... Are there any other spots where there should be matched pairs?

Problem 4:

How do I know what is the correct way to insert the trimmer resistors from Mouser? How do I know which side is the screw side? Does it matter?

THANKS IN ADVANCE GUYS I WILL REALLY APPRECIATE YOUR ADVICE AND HELP. Looking forward to this unit.

Well, I found that using 2N3708 made it easier finding ones that had a HPF value over 250. I think they are basically the same only the 2N3708 is a high gain version. You should probably read http://mnats.net/1176_revision_d.html very carefully. You will find answers to many of your questions reading that.

About the trimmers i suggest checking out Hairball Audios website, there is a compressor build guide which shows you exactly how to place those trimmers.

Hope that helps, and good luck with your 1176. It truly is a nice unit!