All things G1176 - the new "repost" thread.

[tubejay]

[quote author="jrmintz"]I'm confused about the power transformer - the parts list has a 12-0-12V transformer listed, unless I misread it, and the board calls for 24-0-24V. Which do you use in the 120V part of the world? Also, how many VA does it need to be rated for?

Thanks[/quote]

Anyone have an answer to this? I'm about to place my order with this part on it, and just happened to notice the same thing! Which should it be 24 or 12? Oh, and I'm 120v too.

Thanks,

Jay

 

[deanp920]

Jay, Seth:

jrmintz wrote:
I'm confused about the power transformer - the parts list has a 12-0-12V transformer listed, unless I misread it, and the board calls for 24-0-24V. Which do you use in the 120V part of the world? Also, how many VA does it need to be rated for?

Thanks


Anyone have an answer to this? I'm about to place my order with this part on it, and just happened to notice the same thing! Which should it be 24 or 12? Oh, and I'm 120v too.

Thanks,

Jay

Order: 24-0-24/500mA(24VA) This is on the 1176 parts list at the Gyraf site.

Dean

 

[jrmintz]

Thanks, Dean. I have a 24-0-24 toroid that's 350 mA per secondary. Is that likely to be big enough? I suppose I can ty it and see if the voltages are correct.

BTW, I know the source of my confusion. I downloaded a parts list somewhere that is the Gyraf list with part numbers from Mouser and Digi-Key added. Someone obviously did a lot of research, which I thank them for sharing, but the transformer on that list is a 12-0-12V part number, I think. So if anyone else has that parts list please be careful to double-check it.

 

[romeojesus]

ok status report!

after doing the cut jakob suggested, I was curious about
the improvement hitchhiker achieved with his
cutting spots.

so this morning I bridges the "JAKOB" cut
and did the "hitchhiker cut"

but accidentally I did not cut betwwen the 2&3 pin of the
output trannie , but between 3&4 (meaning: cut is one
pin closer to the edge than hitchhikers one)

result:

unit is DEAD QUIET......AND WORKING!!!

no hum at all, I cranked up my mixing board, its main volume fader
and my amplifier to the max....

no hum!!

it seems like humwise this thing turns out to be one of my quietest
units , just compared it with my bss dpr402

keep in mind that i don´ have the groundplane reinforcement...

i guess i can HIGHLY recommend that cut!



i am really happy now..thanks everybody
little sad though because the down side of the pcb looks
a little ugly, but who cares.....this thing is great...



christian

 

[orson whitfield]

So now we are all curious if you, Romeojesus, know how to post a pic too? :green: If so would you be so kind to post a pic of exactly where you made the accidental cut that rocks and rolls and gives No Hum! :thumb: :thumb: :thumb:

 

[gyraf]

Good work, Christian!

:thumb:

Could you make us a drawing of the cut point?

Jakob E.

 

[romeojesus]

dont know how to post pics
i´ll send a pic to gyraf


some statistics:

i am running unbalanced
all connections to input/output/attack/release pots via microphone cable
gustavs boards
no groundplane reinforcement
not cased yet

christian[/img]

 

[gyraf]

Here's Christian's edit suggestion:

Please let me know if this working for you also..!

Jakob E.

 

[xsmsx]

Hi there,

I just recognized the new PCB layout and I will try this solution as soon as I got some help for another problem. I built two units. One works fine, but the other doesn't. Maybe anyone has a solution idea for this:

The unit seems to work only in bypass. The meter switch seems to be out of order BUT the Release pot turns down the level when turned into the right direction. Also the unit seems to make much more level at the same Input and Output positions compared to the other unit.

Any suggestions anyone?

Thanks
Christoph

 

[gyraf]

Christoph,

- check for shorts.
- check for correct components (AND orientation!)
- check wireing
- compare DC and AC voltages between working and non-working units - specially in the sidechain/rectifier stages

Jakob E.

 

[hitchhiker]

good work Christian,

I think this ties the core and can of the transformer to the power supply
ground.

Are you reversing your transformer? If so, does it still work out that the can & core are wired to hole 3?

cheers,
Lance

 

[romeojesus]

no, my output transformer is not reversed
it´s 2:1 like the original hookup on www.gyraf.dk
and i am using the 5532 input

after playing around with it today I do not
feel the need for extra output gain

that jufgement is based on
the fact that my unit is not calibrated yet, due to the fact
that I am lacking a vu meter..

we´ll see...

christian

 

[hitchhiker]

hi Christian,

cool, thanks for the reply.I have not studied the recomended flip directions
of the output tranny but I would imagine they keep the core & can on
#3 pad.

I hooked up my can to the power supply side of the cut and I think there's still a hum way down there but too low to know if theres any difference from my original cut and wiring.

I'm using a different tranny so yours is the test that counts the most.

My hiss is plenty there . Did you use metal resitors or carbon?
I'm wondering if I'll get a noticable improvement if I order metal for my next units?

cheers,
Lance

 

[deanp920]

Seth,

I have a 24-0-24 toroid that's 350 mA per secondary. Is that likely to be big enough?

I measured the total current draw for one channel, including the sifam meter lamp, and it is ~200mA at the most.

Dean

 

[jrmintz]

Thanks, Dean. Much appreciated. It's almost ready to fire up - just need to get the chassis.

:sam:

 

[romeojesus]

hi hitchhiker..

i don´ really understand what you mean by "can"!!??


my unit has some hiss too (depending
on in/output pot setting), but i think thats the units
characteristic and it doesn´t bother me at all
the hum was way more annoying
(more hiss than my vca design based compressors)


i am using metal resistors, panasonic fc caps and wima polys throughout!

christian

 

[orson whitfield]

ABSOLUTELY EXCELLENT NEWS TO REPORT! :!: "Bye, Bye, hum. Bye, Bye, hummy hum. Hello si-i-lence. I think I'm gonna cry-hi".
The G1176 is almost completely quiet now. W- o- w ! ! :green: :sam: :guinness: :thumb: :grin: :razz:
Christian's (Romeojesus) cuts did the trick. I think I need to get rid of the jumpers between my two Xlr's to get rid of the very little hum thats present when the input volume is turned al the way CCW. But now it's really ok the way it is. I am very happy. [quote author="romeojesus"] my unit has some hiss too (depending
on in/output pot setting), but i think thats the units
characteristic and it doesn´t bother me at all
the hum was way more annoying
(more hiss than my vca design based compressors)[/quote] I totally agree! I am however going to build the next one without the modification to increase 12dB's. I am curious to see if I really need it and if this hiss decreases a bit but it really doesn't bother me at all. I remember at high settings my 1064 was hissy too. Thank you Romeojesus. Jakob, Dean, I can finally close the lid on this baby. You two are very helpful and generous with your time. I very much appreciate your help as well as Johnathan Hayward and Mark Burnley and many others. Thanks guys, you and this place rocks. :thumb:

 

[al_p]

what's the perfered method of powering 2 channels of G1176 in one box?

 

[deanp920]

al-p,

what's the perfered method of powering 2 channels of G1176 in one box?

Well, I used a single power transformer rated for 24-0-24V@1A that feeds two complete G1176 boards in parallel. This is easy and works great. The regulated PSU circuits on each board decouple the two channels very well. Even with the boards stacked atop one another with 1/2" of clearance the crosstalk is zero.


Dean

 

[romeojesus]

>"Bye, Bye, hum. Bye, Bye, hummy hum. Hello si-i-lence. I think I'm gonna cry-hi"

good to hear that this cut turned out to be helpful
on other peoples unit as well (orson)

and after building a ssl clone and g1176 it
also feels good to know that I contributed
something useful to this great forum (based
on hitchhiker idea and by accident)

>I think I'm gonna cry-hi
...that´s how I felt after noticing the hum was gone...

happy compressing...


christian