All things G1176 - the new "repost" thread.

[mfdu]

hi harry - sorry, spacecho. i have ole' yella up and running pretty much ok, and am getting big red fitted into a case today.
i'd be happy to meet up and compare - it'd be nice to turn this global into a local, you know? esp. since i missed the last melbourne engineers drinkies night . . . emailo me or sommat, ok?

ole yella and big red? well, i burnt out the lamps in both meters, so used an in series resistor and a couple of LED's - the colours reflect the name of each unit!

during my build, i tested resistors and capacitors, but didn't go around fitting sockets for semiconductors. i mean - i want character from my units - if the are a little "emotional" at times, then thats fine by me. ideally the two units i have built so far will have different characteristics. next pair of mono units i build will be using the lundahl trannie instead of OEP. but then, maybe i'll try a couple of joe meeks?

yes i had the tanty caps backwards. fixed now. doesn't seem like any damage done (on yella, at any rate - red is the one that i fried the bd135/bd136 trans) once both units are in cases then i'll begin properly testing and will post results. i think cannikan's magnifying glass would'a come in handy!!!

i dont have a publik access server, and thus cant post images. can anyone host a photo of my pair of finished units?? i'd like to show off. . .


c.

 

[Neeno]

Hi ppl !
I'm almost finished my first two 1176. I used mnats boards rev H.
After some problem solving (bad resistors and wiring) the unit seems to work properly...

I've done the calibration using the original 1176 manual from Gyraf (the guru) website... Finally GR works...

I've connected the compressor to a unbalanced soundcard, i use nuendo 3 so it's configured to work as an external FX.

The problem:
The signal on the input seems to be low, i have to turn the input pot to 12-18 to get compression (almost full CW) and the opposite on the output pot, the level seems too high... i can't turn it more then 48-36 (almost CCW) or i'll get a too hot signal on the output.

Any suggestion ???

P.S.: sorry for my bad english...

Neeeeeeeeeeeeeno

 

[cannikin]

Neeno,

Are using both input and output Transformers? just curious. I'm building version H of mnats pcbs and currently at the point of rewiring it ... I didn't do something right.

got any tips for wiring or something you learned that wasn't that obvious?

Anyway congratulations!! :green: :thumb: :sam:

 

[Neeno]

Hi cannikin !
Thank you ! :guinness:

I choosed to use only the ouput transformer (LL5402) and 5532 on input...

I've followed the wiring instructions provided by mnats because i've used interlocked pushbuttons...

Wiring is not so difficoult, take your time and read all the wiring instructions before you start, and don't forget to print a copy of the schematics on A3 sheet !!! :grin:

Neeeeeeno

 

[spacecho]

Hi all,

i have been reading through the posts as suggested, thanks Jakob, i was wondering, (might have missed a post) how much (VA) my power transformer needs to power 2 units in one box? i know that it needs to provide 500ma for one unit so 1amp for 2 units seems logical.. I can only seem to find torrodial transformers that come in a bigger size that is 3amps (80va) is this overkill, and will such a huge transformer create more inteference?

m.f.d.u,

where did u get your power transformer and 5Mohm and trimpots from?

thanks

 

[mfdu]

spacecho

my power transformer came from jaycar - just their 24V torroidal. i was worried it was way too powerful (3.2A) but all is good on the mono units now that i've got a resistor in on the VU lamp.

only place in melbourne i could find the 5Mohm pots is http://www.kalex.net.au/ . they're operating out of a private house in glen waverley. only $1.50 per item, so i drove over to avoid the $10 delivery. unfortunately i only got the items i need. shame i didn't get extras.

neeno - have you biased the unit properly yet? bias had an impact on output off the unit. . . may explain your difficulties? your english is fine, and hey - i only speak one language, so you must already rock harder than me!

i haven't been able to get an image to work, so check here for an image : http://home.alphalink.com.au/~mfdu/equipment.html

chris.

 

[Neeno]

Hi Chris !
Thanks a lot for your reply !

I've done the calibration procedure 2-3 times, but i always get the same behavior...

Input gain seems too low and output to hot...
IE, if i try to compress a vocal track i have to turn the input at least at 4 o'clock to start seeing gain reduction, and the ouput is too hot, i can't turn the output pot more than at 7 o'clock, because the output seems too high... but if i press the +4 for metering the VU level is low (around -10, -7 dB)

I have an old freq generator, i scoped the output to get a 1khz signal at 0dB (2.2Vpp, 0.775Vrms), i applied the signal to pin2 and gnd to pin 1 and i've done the bias procedure getting a gain reduction of 1dB on the output.

Is this right ?
Have I to apply the signal to pin 2 and pin 3 ?
Or maybe i have to put pin3 to gnd like in a unbalanced environment ?
Too many questions ? Sorry...

I've checked all the static DC voltages and they are correct (+-0.3V)...

Any suggestion ?

Neeeeeeeeeeeeeno

 

[gyraf]

Any suggestion ?

- Are you sure you have the "-A" version of the FET?

try changing it to a new one just in case..

 

[Neeno]

Hi Gyraf !
I'm using BF245A (Fairchild)
BC107B hfe > 230 (schematic ask for >250 on the gr amp but i've not found 107A so the hfe is a little bit lower)

Can you explain what's the right way to feed the signal into the units for the calibration process ?

I use to connect the gnd from the freq generator to pin1 and the signal to pin2 on the input xlr (do I have to tie the pin3 to gnd ?)

Thank you for your help !

Neeeeeeeeeeeno

 

[gyraf]

Yes, on balanced XLR inputs ALWAYS tie -in (pin3) to ground (pin1) when running unbalanced.

The BF245's can be very different - try with a different one.

Adjust Q-bias so there's only a little drop in output signal level (1dB), with unit in bypass.

Jakob E.

 

[Neeno]

Ok i'll try...
thank you for your suggestions guys !

 

[heybluez]

Howdy Party People,

After a million months I am ready to get back to my 1176. I have it working, at least it sounds like it is BUT my meter does work correctly. I have it jumping all over the place when I switch it. I moved to a push button switch so I figured that is the issue. I am looking through the board for wrong components and I cannot find any.

Question, what is the easiest way to see that the resistors are all ok....? Meaning when I switch I get the proper amount. At least this is what i think it is.

Thanks,
Michael

 

[heybluez]

would the meter be jumping if i have not calibrated the unit? I would not think so...but I dont know where to look.

thanks,
Michael

 

[FotisGR]

Just a question. Does someone has tried to hear any diference between BF245A vs 2n5457?

I have both of them, so what will be better?
Thank you

 

[gyraf]

No sonic difference that I could detect.

Use the ones that gives you the best tracking between actual GR and GR-meter when adjusted.

Jakob E.

 

[popedh]

Hello.
im just finnished an 1176 and have problems with the VU. it works perfect in GRmode, but not in output mode. I dont know if theres a rectifier in my meter. But should the gr mode work without it?

thanks / Isak

 

[gyraf]

As mentioned several times already, you will need a "real" VU-meter for the 1176 - that is, an AC meter with the right sensitivity: deflect to 0VU when +4dbU is input through a 3K6 resistor.

Jakob E.

 

[popedh]

Yes i know that i need a "real" VU. but this looks like a good one .. and the gr- reduction tracks well. in outpot mode theres no response at all;(/I

 

[popedh]

Hi. i have one more problem... there so low output. everything looks ok and it compress great.. but the output is only about -25db;(
please help me
/Isak

 

[gyraf]

..read this thread and check, check, and double check..