[BUILD] 1176LN Rev D DIY

[kosty]

Thank you Kazper !
I have rechecked the wiring and found that I soldered the wire from Pad 15 to the wrong leg of the output attenuator.
Furthermore there was a link between the shield and the wire from Pad 7 in the cable, which caused the ratio board to not function.

I've been thru calibration 1-3 now and everything is working great and sounds nice !
I will post some pics soon, after tidying up the wiring a bit.
Thanks again to everyone who helped me and made this project possible for me

 

[kosty]

Should I see a drop of 4 db on the meter when switching between +4 and +8 ?

I calibrated the devices several times and I can only see a difference of 3 db between the two modes.
I have double checked the resistor values on the meter board and they are correct (3.6k and 8.2k).

Any thoughts ?

 

[kazper]

http://mnats.net/1176_reva-d_hairball_wiring_power.html

This really covers any ones needs....

 

[kazper]

Should I see a drop of 4 db on the meter when switching between +4 and +8 ?

I calibrated the devices several times and I can only see a difference of 3 db between the two modes.
I have double checked the resistor values on the meter board and they are correct (3.6k and 8.2k).

Any thoughts ?

Check all related pars values in the switch mechanism...

What type of meter do you have?

So when you did the calibration procedure how close were  you when you started on setting up the controls.

 

[kosty]

http://mnats.net/1176_reva-d_hairball_wiring_power.html

This really covers any ones needs....

Thanks for the link but I already rechecked every step.

Should I see a drop of 4 db on the meter when switching between +4 and +8 ?

I calibrated the devices several times and I can only see a difference of 3 db between the two modes.
I have double checked the resistor values on the meter board and they are correct (3.6k and 8.2k).

Any thoughts ?

Check all related pars values in the switch mechanism...

What type of meter do you have?

So when you did the calibration procedure how close were  you when you started on setting up the controls.

They are only 2 resistors on the meter switch board. The only difference I can see between +4 and +8 setting is that +8 has a 8.2k resistor instead of the 3.6k for +4.

I have Hairballs HB-8037 meter.

I can't tell you how close I was, since R59 (Q-bias) pot was broken at the beginning and I had to replace it.
Instead of a 2K multiturn pot, I used a 1K. Could this be the problem ?

I redid the calibration at least 15 times.

Are you sure that the meter can show both settings (+4 and +8) at the same time ? Maybe it only works with either +4 or +8 depending on if you calibrated the meter for +4 or +8.

I really appreciate you help !

 

[monkey]

Hi

First post. Thanks to everyone for putting together such a vibrant community of DIY builders. I've searched and scanned for this and couldn't find anything, so my apologies if I missed it.

I'm just about finished with my Mnats/Hairball Rev D build with all standard Hairball BOM parts. I've got it passing audio and can perform the Q bias calibration step, but it's not compressing. When I switch in compression with the attack switch, nothing happens (no drop at all, etc.).

I've checked and rechecked the wiring, especially around the attack/release pots and ratio board, and to the various pads on the motherboard and everything seems right, but... nothin'. The switch measures as expected in both on and off. The meter bounces when flipping between ratios (which is what I remember from a real 1176).

Any thoughts?

Thanks!

-John

 

[tfletchii]

I think I blew the power transformer before i noticed a wiring mistake (that's what I get for working on this at odd hours i guess).
Where do I put the multimeter probes to test the DC current? Sorry I'm a newbie with a lot of beginners luck on my first few builds so I haven't done this before. Little nervous about shocking the poo out of myself.

thanks everyone, and thanks mnats for the new wiring guide for the hairball case. It is a great help

 

[mnats]

I think I blew the power transformer before i noticed a wiring mistake (that's what I get for working on this at odd hours i guess).
Where do I put the multimeter probes to test the DC current? Sorry I'm a newbie with a lot of beginners luck on my first few builds so I haven't done this before. Little nervous about shocking the poo out of myself.

thanks everyone, and thanks mnats for the new wiring guide for the hairball case. It is a great help

One of the reasons I've been reluctant to create such a wiring guide is that I have feared those who lack the knowledge and skills to properly wire the power circuit would ignore the prominent warnings I've placed on the page:

The AC power section of any DIY project is not something that can be taken lightly. Lethal current is involved and if you have no experience wiring circuits that use high voltage you should find someone who does to help you or leave this work to someone experienced in wiring high voltage circuits.

Laws and standards vary from country to country; familiarize yourself with local regulations concerning electrical wiring involving mains/wall power. If you have any doubts at all, seek out the assistance of a technician or repair person who can help you.

You could be held liable if a piece of equipment you miswired causes injury or death. Don't fuck around; this isn't the time to pretend you know what you're doing if you really don't.

Please don't give me a reason to pull it down. If you don't know where to measure DC current (did you mean voltage?) you should seek hands-on help with your project.

 

[tfletchii]

Anybody in the Atlanta area feeling generous and want to offer me some help?

 

[alexilaiho]

hi,someone know please if its wrong to use a carnhill vtb9045 wired 1k2:300 for the input ? thanks.

 

[Fredyeah]

HI All,

I ordered a REV d from Hairball and selected the REV D pcb set from their site. I got everything, except the pcb for the input transformer. Did i need to order it seperatly? Where can I order one?

(It could also be that I misplaced it... since I have this stuff lying around for month now. Anyway, I need a new one. ?)

Thanks!

 

[monkey]

I'm just about finished with my Mnats/Hairball Rev D build with all standard Hairball BOM parts. I've got it passing audio and can perform the Q bias calibration step, but it's not compressing. When I switch in compression with the attack switch, nothing happens (no drop at all, etc.).

Alrighty, I'm all sorted.

I'm also an idiot: R9 is 560k, not 560. Note to other less experienced folks: if you have a part left over at the end, cross reference the value against the schematic. Duh.

My other issues were a couple slightly intermittent connections. They tested for continuity but I didn't find them until I started physically poking at everything. Duh.

So, my build works, sounds great and is everything I hoped it would be. Thanks Mako and Mike and the rest of the DIY community for making this project accessible to someone like me. I've learned a lot, and while I'm psyched to get back to making music for now, am mulling what my next build might be...

cheers!

-John

 

[kazper]

hi,someone know please if its wrong to use a carnhill vtb9045 wired 1k2:300 for the input ? thanks.

I'm thinking that would give you some problems...

specified Input trasformers is a 500R:200R

Check out http://www.audiomaintenance.com/downloads/carnhill_design_guide.pdf

VTB 2280
VTB 2281
VTB 9049
VTB 9057
VTB 9070

Are all possible options... but for the most part whats wrong with the EA part?

 

[kazper]

HI All,

I ordered a REV d from Hairball and selected the REV D pcb set from their site. I got everything, except the pcb for the input transformer. Did i need to order it seperatly? Where can I order one?

(It could also be that I misplaced it... since I have this stuff lying around for month now. Anyway, I need a new one. ?)

Thanks!

Ask mike... or look at his site.

 

[alexilaiho]

thanks a lot kazper for the help.nothing really wrong with EA they sound very good its just that i have one vtb9045 arround and i alway loved how canrhill sound.
so as you say there no harm to use a output for input? thanks again.

 

[kazper]

Shouldn't be a issue, I would try to do one that is set up as a 600R:200R ratio if there is one listed. Since it's placement is without an DC blocking cap, I'd go with something Gapped as well to cover you.

Let me know what you end up with and how it sounds...

 

[ShandonSound]

Hi,
To be honest it's probably way beyond my abilities but I'm having a go at building the Hairball kit with the help of the MNATS wiring pages. The guide shows a resistor being attached to the release pot. The Hairball BOM identifies components for the attack pot but, unless I'm mistaken, doesn't seem to identify this resistor. Can anyone tell me what the value of this resistor is please?

Sorry if this is a stupid question and thanks in advance.

Regards,

Steve

 

[monkey]

270k. (check the schematic... it really does have a lot of answers but you have to poke at it a bit)

 

[Delta Sigma]

Adjusting R86 using a selective voltmeter?

To adjust the distortion trimmer (R86 on mnats board and R16 in original) the UREI manual instructs adjusting for minimum THD. I do not have a spec analyser that goes low enough for audio (I have access to an Agilent that will only go down to 9k) and I'm not sure if I'll find software that will run on my Mac Pro I thought I could use a selective voltmeter (a Wandel & Goltermann SPM 34a with 3.1k bandwidth) to measure for a minimum level while the W&G's lower limit is set above 500Hz when adjusting R86.

My other option in injecting the 500Hz tone and using the spec analyser and adjust R86 for minimum amplitude on harmonics that are above 9kHz.

Any thoughts on whether either method will lead me astray?

 

[canidoit]

Adjusting R86 using a selective voltmeter?

To adjust the distortion trimmer (R86 on mnats board and R16 in original) the UREI manual instructs adjusting for minimum THD. I do not have a spec analyser that goes low enough for audio (I have access to an Agilent that will only go down to 9k) and I'm not sure if I'll find software that will run on my Mac Pro I thought I could use a selective voltmeter (a Wandel & Goltermann SPM 34a with 3.1k bandwidth) to measure for a minimum level while the W&G's lower limit is set above 500Hz when adjusting R86.

My other option in injecting the 500Hz tone and using the spec analyser and adjust R86 for minimum amplitude on harmonics that are above 9kHz.

Any thoughts on whether either method will lead me astray?

From what I recall, I had the same problem. I was advised to simply turn the trimmers and land it somewhere in the middle. I wouldn't mind callibrating it properly and see what the difference would be.