[BUILD] 1176LN Rev D DIY

[usekgb]

@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.

I haven't watched your video yet, so I can't comment on the oscillation, but I did have some weird things going on before I recalibrated.

What I mean by yanked is, I removed R44 from the circuit (I have one of the old boards with no jumpers).

 

[DigitalMetal]

Can anyone see anyhting obviously wrong with my board ?

http://campl.us/eSRZEV8lYpo

Im not getting anything on the meter now when trying to setup the Qbias after moving my trimmer pots to the same orientation as germoju's

I found this picture of someone elses which are totally round the other way (how i originally had them) which way round is correct?

Can anyone tell me if they are round the right way?
when building mine i could not find any info to tell me which way round they should be.
Also when installed, should the trimmers be wound fully clockwise, counter clockwise or centred ? i also couldnt find info for that.
Im getting 29.95 volts at the 30v test point on the psu output and -8.5 volts at the -10v test point are those figures ok ?
Thanks to anyone who can offer help!

 

[usekgb]

It doesn't matter which way they are facing.  You have installed them just fine.  If the qbias doesn't seem to be working when you turn the trimmer one way, try turning it the other way.  Also, make sure that R44 is out of the circuit before trying to adjust qbias.

Cheers,
Zach

 

[TheWolfman]

OK so it seems that I can't seem to get the voltage to change across R75 at all when adjusting the trim.It reads a constant of -3.70.This is with R44 out of circuit.

This seems like this could be the culprit no?

 

[usekgb]

OK so it seems that I can't seem to get the voltage to change across R75 at all when adjusting the trim.It reads a constant of -3.70.This is with R44 out of circuit.

This seems like this could be the culprit no?

That's really strange.  Did you set your meter back to 0 first?  Adjust the bias correctly?  Try turning the R75 the other way?  Do you mean get 0 volts across R74, not R75?

Cheers,
Zach

 

[a zombie]

Need some advice here,  I have 2 hairball rev D's that have been working great until recently.  One of them started putting out hum and crackling audio.  Opened it up and R32 was burnt.  I replaced it and it worked for a sec and then burnt.  I put another one in and it hasn't burn, but not the compressor makes synth like sounds, which seem to change pitch in with the meter position. 

They are both wired exactly the same, and are both rev D 2.2 boards.  I've rechecked the transformer wiring many times. 

Could it be the transformer?  How can I test this?  Could it be something further back in the chain??

 

[a zombie]

Oops, when I replaced the R32 the second time I soldered it accross the wrong points (I had to relocate it as the original holes were too burnt).  Now it is working fine, but I'm still confused why it burnt the first two times... what could cause this (it's not the way I wired the output transformer)

Just worried It's gonna keep frying...

 

[WhiteRhino]

Hey all,
Just received MNAT's blackface Rev D PCB boards today and I have a quick question before I begin I'm hoping someone can asnwer:
In the build guide at http://mnats.net/1176_revision_d.html near the bottom it mentions changes regarding versions.  My board is the Revision D Version 2.2 26.01.09, so I'm wondering if I have to adhere to the changes concerning version 2, Revision D Version 2 10.03.08 errata AND my Revision D 2.2 26.01.09, or just the latter of the 3.

Thanks,
Jeff

 

[germoju]

hi guys,

who can tell me how to test the 2N5457 ? How to see if it matched pair ?

 

[sr1200]

Need a meter that can read the HFE of the transistor.

 

[usekgb]

hi guys,

who can tell me how to test the 2N5457 ? How to see if it matched pair ?

http://www.groupdiy.com/index.php?topic=18834.0

 

[mrcase]

hey all!

I´m enjoying my Hairball 1176 for quite some time now. The only thing that bothers me or strikes me as not quite right is the input threshold. It feels like it starts compressing too soon, especially compared to a original unit. this is a pity because I can´t drive the circuit as hot without having too much compression. Any ideas or hints where to start looking at?

thanks as always
M

 

[germoju]

hi guys,

who can tell me how to test the 2N5457 ? How to see if it matched pair ?

http://www.groupdiy.com/index.php?topic=18834.0

Need a meter that can read the HFE of the transistor.

thanks guys

 

[s2udio]

2N5457 is a FET and you can't match these with a simple hfe test...

This is what is required.

http://www.axtsystems.com/index.php?option=com_content&view=article&id=46:1176lnfets&catid=34:1176ln&Itemid=62

 

[Matt C]

I just started building a 1176 RevD using the mnats board and the Hairball Audio kit. For those less experienced DIY-ers (like myself) who are not as comfortable with the mouser catalog yet, I wanted to add one very small detail about the build, since I wasn't able to find it while searching through these threads. 

The Mnats wiring page shows him using a terminal strip to connect the power transformer secondaries to the power supply section of the main PCB.  this part isn't included in the BOM provided by Hairball, but it is available from Mouser. here's the link:

http://www.mouser.com/ProductDetail/Molex/39100-0903/?qs=eHT%2fi514bK3J3K54wjBEBg%3d%3d

mouser part number 538-39100-0903
Molex Barrier Terminal Blocks
8.00MM 2scw ter stp

hope that helps someone.  I'm sure I will be back with a lot of questions.

 

[number2]

Well are you getting AC voltage at the PCB AC pads from the power transformer? What do you mean when you say you don't know what to do with VR1?

where do i put my probes on the power transformer to test this?

I re soldered and now have the correct DC voltage +30 and -10!!!!

 

[usekgb]

Put your negative prove on the center tap of the transformer secondary point on the main pcb.  This will be the 0V point.

 

[WhiteRhino]

Hey all question:
I'm stuffing the power supply right now, and my C23 is a 6.8uF 100 volt capacitor instead of 6.8uF 35v (On the B.O.M).  Should I order the exact part or does anyone know whether it would be okay to use a capacitor thats 65v (100-35...) over the Bill of Materials part.  Also my rectifiers were 1N4004 instead of 1N4003, but I scoured the forum and found out those are okay to use, however anyone confirming that would be great.

I appreciate the help I've looked for the answer before posting this but havent found anyone who has encountered the same capacitor issue I'm having.

Thanks!

 

[gtrmann]

In general, You can use a cap that has a greater breakdown voltage,  just don't change the value...  You can always go up in the breakdown voltage ,  do not ever go down in the breakdown voltage....    I just finished building two Hairball / Mnats rev D kits....  They sound nice..!!!!!

 

[WhiteRhino]

Great I appreciate the help man that definitely makes sense.