All things G1176 - the new "repost" thread.

[fauxjazz]

I'm a bit confused about the transformer wiring as the schematic on the datasheet (Farnell website) is different to the sticker on the actual unit. I'm guessing go with what is written on the transformer sticker ie:

Brown = Live
Blue = Neutral

Red and Orange tied together to form a center tap

Black and Yellow on the outer sides?

Thanks all.

 

[Whoops]

Go with the sticker on the transformer, that’s the diagram that counts.

For Center Tap the you should connect Red to Orange, yes

 

[fauxjazz]

Go with the sticker on the transformer, that’s the diagram that counts.

For Center Tap the you should connect Black to Orange, yes

Please forgive my ignorance, but if I am following the Mark Burnley's transformer wiring referenced from the MNATS description:


"Identify the two wires coming from the power transformer secondary that are closest to each other on the schematic. These are tied together to form the center tap. "

Is this not Red and Orange on my transformer, as pictured below?



Many thanks

 

[Whoops]

Sorry my mistake,
Red and Orange yes

I will edit my post

 

[fauxjazz]

Okay, have finished all the wiring except for the meter lamp. The compressor is working and all controls seem to function as expected! I'm looking to start q bias calibration and was wondering if anyone knows which connection I need to short to ground as per mnats first bias video on Youtube? My board is a Gyraf Rev 7 from pusherman.

Thanks all.

 

[fauxjazz]

Here is my effort, built and biased. Just waiting on a suitably sized 24v lamp for the meter. Unit seems very quiet with no discernable hum issues, even with the lid off. I did cut the ground trace as per Gyraf's advice on this thread. Sounding reassuringly familiar although I can't claim to have ever come into contact with a real one. Sounding particularly great on drum room mic and snare. Have yet to try it on vocals. Endless gratitude to Jakob and the members of this forum for making this project possible.

 

[raoul1983]

Hi All,
I just finished my build, the power rail was like it should be +30v and -10v. I think I've shorted something during calibration. The 220ohm resistor burned... Now I only get like over 60v and no -10(or anything there) I replaced the resistor and the voltage regulator, but stil got the same values.
Does anyone know what to do or what to replace?
cheers!

 

[sodastereo]

Comience separando la fuente de alimentación de la placa, de lo contrario podría quemar el circuito integrado y los transistores.
Una vez que separes la fuente, revísala y estabilízala a +30 -10v, seguro que esos reguladores están quemados.

 

[raoul1983]

o oh, I don't I only read English (or dutch) sorry..

 

[sodastereo]

Start by separating the power supply from the board, otherwise you may burn out the IC and transistors.
Once you separate the source, check it and stabilize it to +30 -10v, sure those regulators are burnt.
edit: the problem is when copying and pasting from google translate

 

[raoul1983]

I've already replaced the regulator, with the same result.

 

[sodastereo]

Hi All,
Now I only get like over 60v and no -10(or anything there)

you have 60v? in which part, the regulator will not support it of course, with which transformer does it feed? if it has 60v it should be around 42vac.
Your transformer should be approximately 21vac 21 x 1.4142= 30vdc .
Please provide more information:
-transformer voltages
-rectified voltages
-regulated voltages
-Is it with separate power supply? or integrated to the main board?

 

[calvinjosephalex]

Hey there guys!
Greetings. I'm planning to make a G1176, I don't think I'll be able to afford an output transformer right now, so would it be ok if I used a balancing circuit similar to AUDIOX balancing cards using NE5532 op amps instead of the Lundahll transformers?.

 

[sodastereo]

Good morning everyone, I have a question:
to the two xlr plugs add a plug plug in parallel, respectively tip, ring and ground connected, both input and output.
A friend connected the 1176 via an insert cable, to a console that has a place for the insert cable on each channel.
Now, he doesn't remember how the insert cable connection was, the problem is that he didn't get audio so he inverted the mono tips and got audio but of poor quality, and he gave it to me so I could check it. When I check it, I notice that the resistors r40 and r41 are burned, I replace them, I check everything, everything is ok, I connect it and everything works normally, what can cause those 2 resistors to burn?

 

[Whoops]

Hey there guys!
Greetings. I'm planning to make a G1176, I don't think I'll be able to afford an output transformer right now, so would it be ok if I used a balancing circuit similar to AUDIOX balancing cards using NE5532 op amps instead of the Lundahll transformers?.

The G1176 already has an option for IC balancing out in the Mnats pcb as for as I can remember.
Or it's just the input?

 

[calvinjosephalex]

The G1176 already has an option for IC balancing out in the Mnats pcb as for as I can remember.
Or it's just the input?

Ohh?
Is that so.. I think it's just the input. The input has an optional transformer choice. But i don't know if it's possible for the output?. And about the Mnats pcb where would I find the pcb?. Anyone have the required docs?

 

[Whoops]

Search in here and Google it,
You will find everything

 

[cprins]

Hello everyone,

Long time lurker, first time poster. I'm posting because I'm stuck on a build on a MNATS rev J board and hope that maybe someone may have some suggestions. The unit produces a crackling background noise which only disappears when the output know is 90-100% CW. At first I thought it was the pot itself, but this is not the case (swapped it for another brand new pot with the same results)... Capacitors C9 and C11 measure ok. Any suggestions as to the possible cause(s) would be very much appreciated!

 

[Whoops]

The unit produces a crackling background noise

Record a sound sample of the noise you're referring to.
Post it here

 

[cprins]

Hi Whoops,

Thanks for your reply. I've recorded three bits at unity gain with the output knob at three different positions:
- 50% (crackling noise audible);
- 75% (crackling noise further amplified); and
- 100% (no crackling noise, only hiss from the makeup stage).