Here's my 1176 rev A..
I hand built the case, so it looks a bit rough.


haven't test it out yet.. gonna test it tonight !
but my fellow friends how help built this unit told me that there's still a problem on the Q bias.

Wow! Your case looks great! I could never pull that off ;p

Here i've got the attack and release pots wired up. I went very very slowly so i didn't mess it up first time around. Better slow and right than quick an wrong.

Aaaaand skip a few steps of wiring... The mnats guide has it all in great detail. Here it is! Just about to fire it up for the first time!

So ive got the thing together, and am having some difficulty with calibrating. There are several resources that explain how to calibrate, but they all seem to differ. I could sure use some pointers.

Hi,

Best of luck with your build. It looks great. I build 5 rev ds that I love as much as any of my brand name hardware. Mike from Hairball gave me a great tip on the Group Diy rev d thread. The guys at Hairball are excellent. I think it around page 153 or 154 of that thread. Basically he helped me set the qbias using a multimeter at both the input and output. Other than that, one of the big things that I didn't understand is that sometimes it takes many, many turns to get the qbias to register on the meter. Once you get that qbias in its working range everything makes sense. Good luck!


Rich

Thanks a ton! I'm uploading a sound clip I just made to demonstrate the issue I'm having. I hope it is only caused by the internal trimmers' positions.

forgive me for asking, but you don't have a link do you?

I'd really like to give that a look but im afraid Im not savvy with the group diy website.

So I thre together this short audio clip testing out the unit and getting to the issue. PLEASE lend me a hand if you hear something that you can identify a problem with. Thanks!!

[BUILD] 1176LN Rev D DIY


This thread?

Uso this morning i find it is not turning on, and not flowing audio. Just a buzz.

Hi Again,

Yes this is the correct thread.The info you need for the qbias adjustment is on 163 of this post. Sorry I gave you the wrong page number.

Rich

Hi,

I listened to your clip. I really am not an electronics pro so please take any advise with a grain of salt but any weirdness I have had with the output knob that was similar to yours was due to not grounding the PCB board. You should do some research to make sure I am giving you the correct info, but I believe you need to ground the bottom of C25 to the chassis. Make sure it isn't the main ground that you ground it to. You should also be able to find this somewhere on that thread. On some of mine I had grounded it but found later that the connection wasn't as good as it should of been. Redoing that connection fixed it for me. Best of luck!

Rich

ONe more thing. These things need slow blow fuses. If it won't turn on it is probably your fuse. Sometimes mouser sends the quick blow ones. As soon as you get the correct fuses in there it becomes so much more stable and I can't tell you how many times during the build I thought it was wrecked forever when it was just the fuse.

Rich

Your two posts make me feel a LOT better. I'm in class now so I'll have to check which fuses I received. I opened up the bottom panel and found that the ground I have to the pcb had bare wire resting against and shorting the wire returning the signal from the output pot to the pcb. The ground I used is the one that was from the factory connected to the output transfo. I'll definitely re-check this connection after class.

I did check the fuse last night, and it seemed ok, not blown. But I may have just overlooked it.

On the fuse idea, I think you may be absolutely right- that the fuse is to blame. It was very strange that the unit stopped powering up at all, because it was only 20-30 minutes prior that I had it powered up and flowing audio. I left it on during that period, and at some point later looked down, and it was not on. I'm just crossing my fingers that I haven't fried anything. I never saw or heard any magic smoke escaping, so I think I'm safe.

One short cut i did choose to make during the build was with the 3708 transistors. I could not find an effective way to meaningfully measure the transistors' Hfe value. Is this a hugely important point?

I made it home, and we were both spot on. The fuse was blown, and my ground wire from C25 needed some help. It WAS the bare wire shorting on terminal 19 where the output knob outputs to the pcb. Furthermore, the electrical ground attached to the EA 5002 was not grounding to the enclosure, so with some countersinking and toothed washers, I'm in biddness, and probably ready finally to really calibrate the thing. I will definitely be getting some slow blow fuses very soon.

So is it done and working?

Your pictures are worth $1,000,000 to me right now. I'm reading instructions on build but am not finding much about knob and button installation? (your first couple steps)

I'm glad some of your problems were solved. As far as the 3708s, I used those in all of mine. They were sent in the mouser parts from the Hairball site. If you plan on building more units it would be good to get a multimeter with a HFE tester. I believe that the most important thing is that they register above 250. Ideally you would match the ones that you are supposed to but the good news is that out of all of the ones that I received from mouser, only a couple ever tested lower than that. As long as it sounds good you are probably fine. Best of luck with your calibration!

Rich

Does this mean it really doesn't matter which holes you put them in?

That is done to allow for components of differing sizes to be used. It's just giving the option for builders to use their favourite capacitors, for example.

in addition, the caps that go in those spots are not polarized, as was mentioned earlier in the thread. So as long as one leg is in the strip of holes on the left, and one in the strip of holes on the right, it'll be good.

I noticed the pots do not sit flush due to a small piece of metal sticking out, did you just clip that off in order for them to sit flush through the case?

oh yeah sorry one more question, what equipment did you use for the q-bias part of the build?

I did clip off the little tabs. I'm not an electrical engineer by any stretch, but i cannot for the life of me think of a reason why those would be there. ;p

To generate a sine wave i used a function generator that i built (also from sparkfun). You're supposed to input .775 volts for the calibration according to the mnats video/documentation. My function generator could move in intervals of .1 volts, so i used .8. or .7v and adjusted more or less accordingly to set the q bias. I cant remember if i did .8 or .7 but you get what I'm saying yes?
I guess if you don't have a function generator or something else, you could always use a daw output and measure the voltage it is outputting and use it accordingly. Not sure if an interface will put out that kind of voltage but i guess its worth a shot.

One thing that was kind of annoying to me was the zero adjust pot. The larger nut that came with, doesn't go all the way on to the mounting screw part of the pot, so i cant actually mount it to the flange and faceplate until i find a new nut. Just a trip to the hardware store, but kind of a pain. First world problems i guess!

Awesome thank you, I'm starting to organize all the pieces and I noticed a pot came from my Mouser cart order but I was already given 4 pots with hair ball order, do you know which one I'm NOT suppose to use?

unfortunately I can't tell you what to or not to use, but each pot must be a specific value, so it will work itself out in the end when you actually start hooking things up. The hairball kit comes with all the pots for your front panel, and one more pot comes with the mouser BOM[edit: this pot is for the zero adjust]. <<also, there are inconsistencies between the various BOM from separate sources, and very close attention needs to be paid to comparing all of these and making sure you ended up with the right parts. To be more specific, the hairball link to the mouser shopping cart is not 100% accurate.

Great to know! I don't suppose you could save me some trouble and let me know what is not accurate. Also, if I have ordered from the Mouser cart link and the Hairball kit do I have every part I need or did you realize after you received your shipment and realized their were some inconsistencies did you have to order more?

Hope you don't mind my questions, your time is most appreciated!

Its ok! I have received so much help on this forum I'd be a turd to not help others.

I don't know what it was that motivated me to do so, but I did do all of the double & triple checking before I ordered from mouser. I think it may have been one of those rare occasions when attention deficit disorder kicks off and I actually was able to clearly think through the whole thing lol. As for what specifically was not right in the mouser cart, I have absolutely no idea at this point. what was a huge help for me was to use the input area per item in the mouser cart to add the BOM part number so that when it all showed up I was able to put all of the baggies from mouser in numerical order according to the BOM. Then I put them all into bags separating resistors, capacitors, static sensitive parts, and enclosure hardware/etc.

Thanks so much for all your time and help. We are in the wiring stage and are a bit confused on where the wires from the power transformer goes, the link on the mnats page shows a different transformer, you and I have the same one so whatever colors you have I have

The mnats wiring guide is correct. When i get home i'll crack mine open and try to post some close up photos of it wired up.

There is a link hidden somewhere in the mnats guide that is specific to the Power tranny we both have. The standard one from hairball i guess.