[BUILD] 1176 Rev A - Back to the beginning...

[jakearon]

If the 505-MKP20.015/100/5 part is reccomended, ill just go with that. I was just curious about that 10uf part.

 

[jakearon]

Also what part are people using as the jumper at r44 to calibrate the unit?

 

[hymentoptera]

Also what part are people using as the jumper at r44 to calibrate the unit?

There is a Molex header and a Kobiconn jumper in the Mouser cart that the vast majority of builders seems to be using. Is there a reason why you aren't using the Mouser cart link for this build?

 

[jakearon]

I used it but to be honest, a lot of parts came missing and had to put in yet another order with mouser which they didnt charge me for to get what they missed. going to pick up that cap you had recommended soon...

 

[hymentoptera]

Yeah I've had a few parts missing from them, and even some extras here and there. Over 2 Rev As and 2 Rev Fs, I think I'm about to place my 5th order, mostly due to changing my mind, or for needing extras for some things especially caps and resistors to sort through and mate up matched pairs, and also having used up parts in other projects, a friend's pair of Rev Gs, and some various repairs that gobbled up needed parts. I consider it all a crash-course in electronics

 

[obutcher]

Just having a bit of trouble calibrating my compressor. I'm up to calibrating the discrete meter circuit. In the video it says to place the probes across R74 and adjust R75 till the meter reads 0V, however no matter which way I turn the trim pot on R75 I'm getting a constant reading of 0.46V across R74. This is on the Rev A 1.2.5 board.

Everything else has been fine up until this point and the unit seems to pass signal cleanly. So close to finishing.

 

[Echo North]

Just having a bit of trouble calibrating my compressor. I'm up to calibrating the discrete meter circuit. In the video it says to place the probes across R74 and adjust R75 till the meter reads 0V, however no matter which way I turn the trim pot on R75 I'm getting a constant reading of 0.46V across R74. This is on the Rev A 1.2.5 board.

Everything else has been fine up until this point and the unit seems to pass signal cleanly. So close to finishing.

For the rev A you measure across TP10 and TP11 rather than R75.

Mike

 

[Curran]

Alright! 2nd rev A is finished and I thik I have the Qbias correct and the VU seems to be null adjusted BUT the final stage is a little goofy right now. getting the VU meter to move correctly. the needle seems to get "stuck" in spots on the VU. if I tap the meter it jumps around and sticks to another spot in the meter rage. when I switch the GR in and out the VU never returns to the correct spot. The reading of TP10 and TP11 is 0.0 eveb when i adjust the zero pot on the front. what am I looking fro here. or do I have a bad VU(I doubt this very much)

 

[Curran]

I also noticed that the VU needle does not go all the way down to -20 when I turn the unit off or do not feed signal through it

 

[Echo North]

Alright! 2nd rev A is finished and I thik I have the Qbias correct and the VU seems to be null adjusted BUT the final stage is a little goofy right now. getting the VU meter to move correctly. the needle seems to get "stuck" in spots on the VU. if I tap the meter it jumps around and sticks to another spot in the meter rage. when I switch the GR in and out the VU never returns to the correct spot. The reading of TP10 and TP11 is 0.0 eveb when i adjust the zero pot on the front. what am I looking fro here. or do I have a bad VU(I doubt this very much)

Loosen the mounting screws and see if that helps.

 

[Curran]

yeah that was the 1st thing I went for. I will dis mount the entire VU and remount it later today. If the unit is sounding "splatty" or overly distorted this would be bad "Q" bias adjustment correct? I am looking at this a little like a fuzz face pedal getting voltage starved. if I over do the "Q" Bias then it is getting to choked off at the trimmer and the compressor is to far into conduction. I also think i have a ground loop in here some where, but 1st things 1st METER

 

[Curran]

OK Loosened up the VU meter, but no luck. the needle still seems "sticky" it does not return to -20 when powered off (stops at -10) and gets stuck at no particular point in the needle path. If I tap the VU or bonk the chassis the needle will move and jump to another sticky spot.

 

[Echo North]

Send me an email (info at hairballaudio dot com) for a new meter.

CHeck all of your voltages against the MNATS schem w/ voltages and yes double check your Qbias.

 

[AusTex64]

My build is passing audio, input and output controls work. Was able to adjust q bias according to the video. When GR is chosen, meter does not go to zero. Have confirmed wired connections are correct and have continuity. Any ideas where to start?

Thank you.

 

[Echo North]

My build is passing audio, input and output controls work. Was able to adjust q bias according to the video. When GR is chosen, meter does not go to zero. Have confirmed wired connections are correct and have continuity. Any ideas where to start?

Thank you.

Pass a signal in +4 VU mode with GR off then on.  DO you get reduction?

Probably just an issue with the meter driver section.  But first confirm you are getting compression.

 

[ilikethesun]

Ya he will!  ;D

I think I have an email from you.  I'll get caught up on my email tonight and get it sorted for you.

Mike

New view meter arrived today ! And it works !!!! Thanks Mike So happy !!!

Can you just confirm how many Volt I have to mesure between Pin 1 and 2 of Input to get 0 dBu ? I searched a lot and fined a lot of infos but I see 2,4 v or 1,1 v or 2v.... I dont know... Do you ?

Thanks again !

 

[evilcat]

0 dBu = 0.775 V rms
usefull too : 0 Vu = +4 dBu = 1.228 V rms

 

[ilikethesun]

0 dBu = 0.775 V rms
usefull too : 0 Vu = +4 dBu = 1.228 V rms

Ok thanks !
1,228 V is the value on my DMM right ?

 

[Curran]

email sent Mr. Hairball! thanks for the help

 

[ilikethesun]

0 dBu = 0.775 V rms
usefull too : 0 Vu = +4 dBu = 1.228 V rms

I thinked about this but I dont understand...
What signal should I send to my INPUT ? 0dBu ? 0 Vu ? 0,775 V ? 1,228 V ?
If someone can help me please ?

I use the Signal Tool in my Daw : 1 khz and 0 dB correspond to 4,9 V between pin 2 & 3 of my INPUT.