[BUILD] 1176LN Rev D DIY

[Echo North]

Hi all,

I recently started my first Hairball 1176D build only to run into an early problem. I'm at the stage of testing the power rails and I seem to not be getting any power out of the transformer (Avel-Lindberg). After no readings at the 30v and -10v points on the pcb, I started working upstream. I tested the secondaries by probing between the red/orange pairing and the yellow, then black wires directly off the transformer by removing the wires from my terminal block (is this the correct way to measure secondaries?). No reading whatsoever. I then tested all combinations of the secondaries and still no reading.

I've verified that I'm getting 110v mains power (I'm in US) out of the meter switch to the brown/grey and blue/violet primary pairs. I've followed the Mnats AC wiring verbatim as far as I can tell, but I'd be grateful if anyone could please take a look at the following photos and let me know if you see any anomalies in my AC power circuit. Barring this, my next step would be to de-solder the primary pairs from the switch and wire them directly to the IEC terminals to more accurately test the transformer.

Many thanks!

Jason

I'd disconnect it and check each of the 4 windings to see if you have a broken winding.  Use the ohm setting on each winding, if you get an out of range reading you may have a bad transformer.

You should see AC on the secondaries.  DC at the rails.

 

[olafrec]

Ah, good idea.

Blue/Grey = 40.0 ohms
Violet/Brown = 40.5 ohms
Black/Red = 3.9 ohms
Orange/Yellow = 4.0 ohms

It looks like my transformer is fine, however, I did discover that the fuse in the IEC has no continuity. It doesn't appear blown but I can't get a reading via resistance or using a 9v, um, "light up" continuity tester.

Forgive my lack of electrical engineering skill (although I'm learning fast) but would this fuse not working potenially cause the problem I'm seeing?

Thanks Mike!

Jason

 

[germoju]

up
Who can help me with this please ?

hi everybody !

I got a distortion trouble on my new rev D.
I already builded 4x rev A, 4x rev F and 2x Rev D without "big" troubles....

But today I got a problem I never had...
All my Q values are correct voltage. In fact, it's the first time I'm so very close to the Mnats values
I'm 29,9 V and -9,7 V and Q1 to Q13 are fine.

I did the calibration 3 times but the sound is distorted a little bit... but too much ! I played with Dist Trim but nothin change....

I have a doubt about the 3th step when adjusting -10dB with Tracking adjustment. When it's good , I mean -10db with comp and 0 without comp, this trimmer is turned at the maximum... I never had this....

Do you think the INPUT transfo can be HS ?
Someone have an idea ?

 

[ln76d]

Any contraindications to use 300k potentiometer instead of 250k at the output?
I've measured CTS and they have 300K +/-0,5%.

 

[germoju]

hi everybody !

I got a distortion trouble on my new rev D.
I already builded 4x rev A, 4x rev F and 2x Rev D without "big" troubles....

But today I got a problem I never had...
All my Q values are correct voltage. In fact, it's the first time I'm so very close to the Mnats values
I'm 29,9 V and -9,7 V and Q1 to Q13 are fine.

I did the calibration 3 times but the sound is distorted a little bit... but too much ! I played with Dist Trim but nothin change....

I have a doubt about the 3th step when adjusting -10dB with Tracking adjustment. When it's good , I mean -10db with comp and 0 without comp, this trimmer is turned at the maximum... I never had this....

Do you think the INPUT transfo can be HS ?
Someone have an idea ?

EDIT :
I changed the 2K QBias Trimmer and I RE-calibrate it.  It's the same...
Something happened when playin with Traking Adj : It worked fine but suddenly the pin falled at -20dB and Traking adj doesn't work... When I turn off Comp, pin return to Zero and my Traking Adj works a little beat. At this moment, disortion STOP, but come back when Comp ON.

So now, I got no more distortion when comp is OFF (that's good), but distortion come back with comp and I can't finish the 3th step of calibration.

How have an idea please ?

 

[andydiy]

The following picture, Resistors direction is correct?

R44/R59/R75R86

Brand：Vishay

The R 71 should be configured to what?

 

[germoju]

The following picture, Resistors direction is correct?

R44/R59/R75R86

Brand：Vishay

The R 71 should be configured to what?

yes that s good...
R71 connected to 2K potentiometer...

 

[andydiy]

Thank you!

I ask the following picture test 240 Mains Voltage configuration correct?

 

[germoju]

Thank you!

I ask the following picture test 240 Mains Voltage configuration correct?

Yes that's good

 

[andydiy]

Well thank you for your help!

Now I can pick 240 current electronic table to test it?

Can teach me properly test it?

Thank you!

I ask the following picture test 240 Mains Voltage configuration correct?

Yes that's good

 

[germoju]

Well thank you for your help!

Now I can pick 240 current electronic table to test it?

Can teach me properly test it?

not sure what you mean...

 

[andydiy]

Before Power Transformer installation, I would like to independent testing Power the Transformer.

How to test?

Thx!

Well thank you for your help!

Now I can pick 240 current electronic table to test it?

Can teach me properly test it?

not sure what you mean...

 

[germoju]

just plug it...

 

[ln76d]

Before Power Transformer installation, I would like to independent testing Power the Transformer.

How to test?

Thx!

Do You want to test power of transformer or transformer voltage or what?
Sorry, but i don't understand too

 

[olafrec]

Finished! 

After calibrating I tested using a Neumann TLM 49 through a Vintech 573. Sounds awesome! I've never heard "all buttons in" in person before. I love the fact that I can get that sound in my humble home studio now! Can't wait to try this unit on some drums. Other than trouble shooting an initial power supply problem that ended up being a bad IEC fuse, the build went very well.

I do have a question. There seems to be a lack of information on how to perform the distortion calibration. I've searched rather extensively to no avail other than the need to use specialized equpment. Is there a way I can perform this adjustment with my DAW and/or DMM?

Thanks to Hairball Audio and Mnats for putting together such well compiled kits, pcb's and documentation.

Cheers!

Jason

 

[mnats]

Finished! 

Congrats.

There seems to be a lack of information on how to perform the distortion calibration. I've searched rather extensively to no avail other than the need to use specialized equpment.

There's no lack of information - it's all covered in the original service manual.

Nor do you need any special equipment: Download and install RMAA or something similar. Put the 1176 in the audio loop. Adjust the pot until the distortion is at its minimum.

It's so simple I've managed to put off making a video for several years.

 

[Mr_tea]

Ok so I have my 1176 all working and am in the process of calibrating it. The first two steps (Q biasing and Null adjustment) have been simple enough. I've got the gain reduction meter adjustment but I can only get -6 VU. Even with the input control up the full way the maximum I can get is still -6VU. I've searched all over the net and cant figure out why this isn't working!! PLEASE HELP!

 

[ln76d]

Ok so I have my 1176 all working and am in the process of calibrating it. The first two steps (Q biasing and Null adjustment) have been simple enough. I've got the gain reduction meter adjustment but I can only get -6 VU. Even with the input control up the full way the maximum I can get is still -6VU. I've searched all over the net and cant figure out why this isn't working!! PLEASE HELP!

Maybe it's problem with VU meter?
Look at this topic, maybe it's similar problem:

http://www.groupdiy.com/index.php?topic=49473.msg626925#msg626925

 

[Trench Recordings]

Hey guys, building my first set of 1176s rev d. Mnats / Hairball.

Looks like I lifted a pad on the ratio board. The green wire, pin 4. Can I solder to the middle pin close to the pad on the 20 ratio switch ? Looks like the trace goes there.

Thanks,
Dave

 

[ln76d]

Hey guys, building my first set of 1176s rev d. Mnats / Hairball.

Looks like I lifted a pad on the ratio board. The green wire, pin 4. Can I solder to the middle pin close to the pad on the 20 ratio switch ? Looks like the trace goes there.

Thanks,
Dave

Hi Dave,

If You mean rotary version ratio board, just solder cable to the one of two central pins of rotary switch. This one where trace starts and goes to the "4".

Cheers!