[BUILD] 1176LN Rev D DIY

[wimmy7986]

Really fun build!!  Thanks to everyone involved!

I just finished up one of these units, and I'm having a really weird problem.  It may have been covered earlier in this thread, or maybe its normal...  When I'm in 20:1 ratio and GR mode, my meter is calibrated and the needle hovers at 0 dB.  When I switch to the other ratios, the needle drifts to -1 dB at 12:1 and then drifts more at the other ratios.  Is this normal??  Everything sounds fine, but I wanted to see if anyone had any insight on this.  Thanks!

 

[sr1200]

it might swing a bit from ratio to ratio, let the unit get nice an hot before calibrating again if its really out of kilter. (leave it on for an hour or so).

 

[wimmy7986]

I had a hunch that might be why...  Last night I let it burn in for a good 4 hours, and when I came back and re-calibrated, it seems like it has gotten worse!  The weird thing is, I built to of these side by side, and the other unit is functioning properly.  Any thoughts?  Maybe bad meter?  Thanks

 

[Echo North]

I had a hunch that might be why...  Last night I let it burn in for a good 4 hours, and when I came back and re-calibrated, it seems like it has gotten worse!  The weird thing is, I built to of these side by side, and the other unit is functioning properly.  Any thoughts?  Maybe bad meter?  Thanks

Does the meter drift in +4 mode?

Most likely not the meter.  Check you wires that connect the meter to the XLR and make sure they are FAR away from the PCB.  Check you meter circuit voltages against the schematic with voltages. 

See if moving the meter wires changes anything.

Mike

 

[dbonin]

In case someone is getting confused by this... HANK is correct.  If, and ONLY if, you have the AVEL from Hairball (as MNATS says, this is only works for this particular AVEL xfmr) read this and take heed:
http://mnats.net/1176_reva-d_hairball_wiring_power_avel-lindberg.html

The placement of Peterl's wiring looks correct - as  a matter of fact, I have exactly the same wiring using the AVEL and my PS (and I have built many using that model) works perfectly.
Also, I have been working with Peter to bring his boards back to life and after transplanting them into my verified working rev d case for testing, they power up just fine.  (One does have the poping behavior when set to fast attack as he described in an earlier post... more on that in another post)....

Everyone is "new" in something different.
It's not a shame to ask.
Please hurry, because i need go to sleep (but don't kill yourself by voltage)

I hope that youre alive
I'm going to sleep.
If you measure different voltages, that you should have -  leave it for now, because you can damage something more.
Your problem is probably on a point where you conected secondary windings.

Your connection:

YELLOW (one side)
RED and ORANGE (center)
BLACK (other side)

Should be:

YELLOW (one side)
BLACK and ORANGE (center)
RED (other side)

I hope it will works now!

Goodnight

I don't think so. The transformer wiring seems correct to me...
Check the attachment if you're not sure.

 

[Bhudie]

Hey Guys,

I'm having some troubles with my build, and I was hoping someone could help me out.  I have put together one of the Hairball kits and it passes signal, but I have not been successfull in doing the 0 adjust calibration.  Every time I try to do it I can adjust R75 to get a reading of 0 volts across R74, but then when I try to zero the meter again, the reading goes back to 0.76V.  It seems that the two change proportionately to one another so I can never achieve the goal of zeroing them both...

Also, I've taken some measurements of my transistors, and most of them are off by a small amount in comparison to mnats schematic with typical voltages added, however the collectors of Q12 and Q13 in particular are way out.  Mnats schematic suggest that I should be getting 9.28V and 9.75V respectively on the collectors of Q12 and Q13, but I am getting 21.3V and 20.5V.

I'm using 2n5088s for this build, but it was my understanding that there weren't any changes that I needed to make for this, am I mistaken?

I have another build going that I'm using 2N3708s on, so my next efforts will be to finish that one and see if I can get it calibrated.  If successful then I'll use it to compare, but if anyone has any direction or ideas on how I should start troubleshooting this, they would be appreciated. 

Thanks,
Aaron

 

[Harpo]

I'm using 2n5088s ...

pinout EBC.....oops

I have another build going that I'm using 2N3708s ...

pinout ECB.

 

[andydiy]

Hi!


I would like to ask, after the 1176 completion of the test, the following diagram, the last should side sheets in the correct position?

 

[Echo North]

The last photo is correct

 

[andydiy]

Thanks!

The last photo is correct

 

[Bhudie]

I'm using 2n5088s ...

pinout EBC.....oops

I have another build going that I'm using 2N3708s ...

pinout ECB.

Thanks Harpo,  but I know that the pinout is different and have used the alternate pads for the 2n5088s, so I'm not thinking that was my problem if that's what you are suggesting...  If it's something else,  could you elaborate?

Aaron

 

[Echo North]

Check your R values R79, R67, R74, R68-R73.

They do change on another but you should be able to get it to 0.

Did you match them for HFE?

Thanks,

Mike

 

[Bhudie]

Check your R values R79, R67, R74, R68-R73.

They do change on another but you should be able to get it to 0.

Did you match them for HFE?

Thanks,

Mike

I checked all values on the way in with my multimeter, and the codes are all correct for all of those resistors, but I guess I'll start pulling them up and rechecking if you think that's where my problem is...

I did also match the transistors for hfe, so I don't think it's that either.

Thanks,
Aaron

 

[Echo North]

Is your QBias set properly?

 

[Bhudie]

Yes,  I was successful at doing the QBias adjustment.

 

[jplebre]

did you jumper the pad/put the jumper back?
Not trying to be patronizing it did happen to me by mistake and took me almost an hour to realize.

 

[Bhudie]

AT LAST!!!!

No it wasn't the jumper... but it was almost as bad...  I am embarrassed to say that I did all of calibration step 2 and took my measurements with a 1K 0dBu sine wive at the input...  :-[  :-[

Thanks everyone for your patience and apologies for wasting your time.  I'm glad to say that my compressor works and sounds great!!  Now, on to the distortion calibration and then the next one.

-Aaron

 

[Echo North]

AT LAST!!!!

No it wasn't the jumper... but it was almost as bad...  I am embarrassed to say that I did all of calibration step 2 and took my measurements with a 1K 0dBu sine wive at the input...  :-[  :-[

Thanks everyone for your patience and apologies for wasting your time.  I'm glad to say that my compressor works and sounds great!!  Now, on to the distortion calibration and then the next one.

-Aaron

Cool!  Thanks for posting the solution.  The only time I feel like my time is wasted is when I help someone for days and they figure it out and disappear without posting the solution.

Mike

 

[jplebre]

AT LAST!!!!

No it wasn't the jumper... but it was almost as bad...  I am embarrassed to say that I did all of calibration step 2 and took my measurements with a 1K 0dBu sine wive at the input...  :-[  :-[

Thanks everyone for your patience and apologies for wasting your time.  I'm glad to say that my compressor works and sounds great!!  Now, on to the distortion calibration and then the next one.

-Aaron

Cool!  Thanks for posting the solution.  The only time I feel like my time is wasted is when I help someone for days and they figure it out and disappear without posting the solution.

Mike

my attack is still not working as it should. Seems to be "stuck" at about 7-6 and no matter how I spin it, nothing happens, but the unit is compressing as normal and release works with a wider range than our 1176  :

I just try not to get upset by it and unit still useable. Every now and then I spend an afternoon or an evening on it but so far nada.

Is it normal that the signal is present at the fet gate as well? seems like there is a negative feedback thing going on looking at the schemo

 

[Echo North]

AT LAST!!!!

No it wasn't the jumper... but it was almost as bad...  I am embarrassed to say that I did all of calibration step 2 and took my measurements with a 1K 0dBu sine wive at the input...  :-[  :-[

Thanks everyone for your patience and apologies for wasting your time.  I'm glad to say that my compressor works and sounds great!!  Now, on to the distortion calibration and then the next one.

-Aaron

Cool!  Thanks for posting the solution.  The only time I feel like my time is wasted is when I help someone for days and they figure it out and disappear without posting the solution.

Mike

my attack is still not working as it should. Seems to be "stuck" at about 7-6 and no matter how I spin it, nothing happens, but the unit is compressing as normal and release works with a wider range than our 1176  :

I just try not to get upset by it and unit still useable. Every now and then I spend an afternoon or an evening on it but so far nada.

Is it normal that the signal is present at the fet gate as well? seems like there is a negative feedback thing going on looking at the schemo

A DC representation of the signal yes.

The attack is VERY subtle IMO.