All things G1176 - the new "repost" thread.

[JRE Productions]

I bought a lot of parts from www.apexjr.com He had the urei style knobs for 75 cents each, he has a rotary on/off switch for 79 cents each. He also has toroids for $17 but I found them from the manufacture cheaper with hardware. Any Steve at apexjr.com is a real nice guy, and the prices on some of this stuff like knobs are excellent. $0.75 for a skirted knob, and for the small ones too.

Almost done. Just waiting for the input/output iron.

 

[Esset]

Got one of my two 1176's to work yesterday!!! The distortion-problem were due to not having shielded pin3 on the XLRs and bad soldering at one point.

My Second unit is still not working and I really need some pointers on where to look next.
My voltages are to high on all the BC107 and BC560. (See list below)
The +30V and the -10V are fine, and the +30V "rail" along the board is all good.
The signal comes in fine and goes excellent through the IC-balanced inpout, into the BF245A out and in to Q2, where it disappears (due to the wrong voltages???)

Have checked, re-checked and tripple-checked and there are no loose wires, no shorts, no wrong placed polaritys.

Some resistor values are of a bit too. Took them away, measured the new one before I put it in place, perfectly fine, but when in place they change valu(!!!), the 15Kohm R53 is suddenly around 7Kohm, why?



Here are my f-ed up voltages
E B C
Q2 5,7 3,8 7
Q3 6,2 7 6,7
Q4 5,7 6,2 30
Q5 26 26 26
Q6 27 26 27
Q7 27,6 27,6 27
Q12 5 5,6 5,6
Q13 5 5,6 30
Q14 27 22 26
Q15 27 26,4 30

Just broken transistors that are screwing it up??

 

[erland]

Thanks Greg. What's considered high enough voltage for this project? over 24v?

Could someone let me know what hardware I need that's not included on the parts lists so I can order it and then get to the actual wiring? ie. torroid screw, XLR panel mount screws, IEC screws.

Are XLR panel mount screws 3/64th flat head?

Thanks a lot. I would really appreciate it.

 

[Nadege]

Hi,

I'm currently building a 1176 based on mnat's PCB but I cannot find the R50 on the board !!!!! It's said that this resistor is not in the gyraf version, OK, but where is it in the mnat's version?????

I'm also wondering what are the cap named c* for ?

And also if I have to place C16 (wich seems optional) into place. It's said in the BOM that C16 (33pF) is legacy item? (Don't understand because of my poor english) and that pin 89 is not connected on TL071 what I can see on the PCB

That's a lot of question, but I'm a bit confused especially that I'm new at DIY

Thanks for your help

:thumb:

 

[erland]

[quote author="Nadege"]Hi,

I'm currently building a 1176 based on mnat's PCB but I cannot find the R50 on the board !!!!! It's said that this resistor is not in the gyraf version, OK, but where is it in the mnat's version?????

I'm also wondering what are the cap named c* for ?

And also if I have to place C16 (wich seems optional) into place. It's said in the BOM that C16 (33pF) is legacy item? (Don't understand because of my poor english) and that pin 89 is not connected on TL071 what I can see on the PCB

That's a lot of question, but I'm a bit confused especially that I'm new at DIY

Thanks for your help

:thumb:[/quote]

Not so sure I'm the best one to answer this since I'm not a native English speaker, but "legacy" means something old, not in use. http://www.answers.com/legacy&r=67

All the markings with * for use when not using the optional input transformer.

Some more posts about R50: here and here

 

[Nadege]

Ok thanks for the answer

what are the value for the different c* capacitor, it's not mentionned in Mnat's BOM

 

[Esset]

[quote author="Esset"]My Second unit is still not working and I really need some pointers on where to look next.
My voltages are to high on all the BC107 and BC560. (See list below)
The +30V and the -10V are fine, and the +30V "rail" along the board is all good.
The signal comes in fine and goes excellent through the IC-balanced inpout, into the BF245A out and in to Q2, where it disappears (due to the wrong voltages???)

Have checked, re-checked and tripple-checked and there are no loose wires, no shorts, no wrong placed polaritys.

Some resistor values are of a bit too. Took them away, measured the new one before I put it in place, perfectly fine, but when in place they change valu(!!!), the 15Kohm R53 is suddenly around 7Kohm, why?



Here are my f-ed up voltages
E B C
Q2 5,7 3,8 7
Q3 6,2 7 6,7
Q4 5,7 6,2 30
Q5 26 26 26
Q6 27 26 27
Q7 27,6 27,6 27
Q12 5 5,6 5,6
Q13 5 5,6 30
Q14 27 22 26
Q15 27 26,4 30

Just broken transistors that are screwing it up??[/quote]

ANy ideas/tips on where to look?

 

[mnats]

All the markings with * for use when not using the optional input transformer.

Not quite. Check the first item in my 1176 FAQ.

It's said that this resistor is not in the gyraf version, OK, but where is it in the mnat's version?????

Please remember that my boards are based on Jakob's original design. So most things that apply to the G1176 will also apply to my boards.

Took them away, measured the new one before I put it in place, perfectly fine, but when in place they change valu(!!!), the 15Kohm R53 is suddenly around 7Kohm, why?

When you put a component into the circuit, it will interact with other components. So if the resistor is in parallel with another resistance (even if it doesn't seem obvious) you will get a different reading.


You said your signal disappears around Q2 - sounds like you are getting very close to the problem! I'm not nearly as good as Jakob or some of the others who can troubleshoot from a distance but I think you might want to check your active devices. Got a transistor tester?

 

[Esset]

[quote author="mnats"][quote author="Esset"]Took them away, measured the new one before I put it in place, perfectly fine, but when in place they change valu(!!!), the 15Kohm R53 is suddenly around 7Kohm, why?[/quote]
When you put a component into the circuit, it will interact with other components. So if the resistor is in parallel with another resistance (even if it doesn't seem obvious) you will get a different reading.[/quote]
Yes, this dawned on me when I took a step back from the soldering iron.


[quote author="mnats"]
You said your signal disappears around Q2 - sounds like you are getting very close to the problem! I'm not nearly as good as Jakob or some of the others who can troubleshoot from a distance but I think you might want to check your active devices. Got a transistor tester?[/quote]

No transistor tester, am though about tot order some parts for other projects, will order som spare transistors aswell. Thanks for the help mnats and I hope somebody else has any ideas!

 

[erland]

[quote author="mnats"]

All the markings with * for use when not using the optional input transformer.

Not quite. Check the first item in my 1176 FAQ.
?[/quote]

Oops. Sorry.

 

[JRE Productions]

Both of my compressors are not working yet. UGH!

Compressor #1 Transformer input: Signal is distorted but it appears to compress. 30 and -10 voltages are right at the power section. The voltage on the TL071 seems suspect. 19v on the pos, and -9 on the neg V post. (actually both compressors measure the same on this pin).

Compessor #2 Electronic Balanced input: No signal going through. The signal seems to get cliped at the 5532 opamp. On my scope the signal become small and very square. The voltage seems posibly high on one side, and -9v on the other neg leg. Because its electronic input, I am guessing that the signal is not making it through the first stage.

What would cause the voltage to be low on opamps in both compressors?

Do I need to set up bias, before checkng voltages on the opamps?

HELP!

Joe

 

[JRE Productions]

Well seems no one is monitoring this page anymore......


I'll ask my question anyway. I have gotten the first of my compressors to pass audio and compress. It sounds pretty good. I HAVE NOT CALIBRATED IT YET. I do not know if that is part of my problem or not. In by-pass (Meter switch all the way counter clockwise) the unit has a ton of gain. I have to turn the output down. In GR or VU the unit has moderate gain. I mean enough to be louder than the original input level if I remove the compressor, but not over the top. But in the bypass mode, it gets really loud, and I have to adjust the output pot.

Question 1: Does the bypass mode still go through the amp?

Question 2: Under the higher ratio's the output pot seems to react differently. Meaning that it seems to have linear output in 4:1 mode, but in 20:1 mode it the center portion of the pot does not seem to make a difference. The begining and end portion of the rotaion makes the most significant gain. If this is make up gain, should it be linear no mater what ratio is selected?

Again, I have not calibrated the unit, and just left for LA for a few days. So I will have to calibrate next weekend.

Help?

Joe

 

[gyraf]

Hi Joe,

Yes, I still read this thread - but it seems that most problems has been covered already on the previous pages. To sum up:

- Check for shorts on the PCB.
- Check for wrong components, orientation, and interwireing.

This covers more than 99% of G1176-related problems.

Jakob E.

 

[JRE Productions]

Gyraf, At 57 plus pages, this post is difficult to find specific issues anymore. If you possible, please answer the two questions that are not related to parts/shorts ect. My units are now both functioning, but I have performance questions. I searched but did not find related topics.

Question 1: Does the bypass mode still go through the amp section, or just the output transformer?

Question 2: Under the higher ratio's the output pot seems to react differently. Meaning that it seems to have linear output in 4:1 mode, but in 20:1 mode, the center portion of the pot does not seem to make a difference. The begining and end portion of the rotaion makes the most significant gain changes. If this is make up gain, should it be linear no mater what ratio is selected?

Thanks for any help.

 

[gyraf]

[quote author="JRE Productions"]
Question 1: Does the bypass mode still go through the amp section, or just the output transformer? [/quote]

Take a look at the schematic: the only thing the bypass switch does, is take out the sidechain signal, i.e. disable gainreduction. No change in audio signal path.

[quote author="JRE Productions"]
Question 2: Under the higher ratio's the output pot seems to react differently. Meaning that it seems to have linear output in 4:1 mode, but in 20:1 mode, the center portion of the pot does not seem to make a difference. The begining and end portion of the rotaion makes the most significant gain changes. If this is make up gain, should it be linear no mater what ratio is selected? [/quote]

Output pot should react the same no matter what ratio. But input pot will behave like you describe at high ratios, because it'll push into gain reduction (holding steady level) untill you run out of FET attenuation at the other side of 40dB GR, at which point the ratio in effect reduces.

Jakob E.

 

[Guest]

[quote author="JRE Productions"]
Gyraf, At 57 plus pages, this post is difficult to find specific issues anymore. If you possible, please answer the two questions that are not related to parts/shorts ect.
Thanks for any help.[/quote]
That's a bit harsh on Jakob mate

 

[JRE Productions]

Jacob, I did not mean anything to sound harsh. I read and reread all 57 pages, and used the search function and still can not seem to find what I needed. It almost would have been better to have seperate topics for each trouble. Easier to search.

Thanks for the help.

 

[imo]

It is a bit overwhelming, and i have been unbelievably frustrated at times with projects i was working on, largely due to my lack of knowledge and consequential lack of understanding about problems i ran into, but the whole forum is done as a BIG favor to those of us who are trying to learn about, and build electronics. I have found this to be an enormous asset in understanding and building the gear that all seems to point back ultimately to Jacob's site and willingness to share design ideas and information. It takes a lot of time to compile all of this information, and i am really impressed that he, as well as so many others volunteer this. I guess this is what impresses me about the community, all of the people that give and help those of us that have little to offer in return, and i want to thank everyone in being so helpful. I would keep in mind that this is all done without any type of return other than a thanks so we all owe quite a bit of that.
Not trying to be too preachy, i just have seen Jacob already answer the same question so many times, a couple were my boneheaded queries, and i want to make sure to keep those channels open as they have been really great so far
Ian

 

[JRE Productions]

Well both units are up and running. I really like both of them (1 with input iron, one without). They sound wonderfull. I have a full compliment of compressors in the studio and these sound as good as any.

One of them I am having troubles with the tracking pot. Seems it only moves the meter 1 db or so either way. Even when I change the zero control a little each way. When I have 6db of gain reduction, I can only get the meter to about -10db. I will have to check a few more resistors around the trim pot.

Observations:

The release pot seems to really effect the output too.
The attack pot seems to really affect the threshold too.
The tracking (even on the working one) seems to not be all that great. I find its best to just use my ears.
A little goes a long way with the compression.
The compression is quite smooth, but can really slam too.

Thanks for all the help with my lack electrical knowledge.

Joe

 

[gyraf]

[quote author="JRE Productions"]Well both units are up and running. I really like both of them (1 with input iron, one without). They sound wonderfull. I have a full compliment of compressors in the studio and these sound as good as any.[/quote]

:grin: :thumb:

[quote author="JRE Productions"]
One of them I am having troubles with the tracking pot. Seems it only moves the meter 1 db or so either way. Even when I change the zero control a little each way. When I have 6db of gain reduction, I can only get the meter to about -10db. I will have to check a few more resistors around the trim pot.[/quote]

This may be because of unmatched FET's. Try changing the meter driver FET 'till you get useable meter tracking (this is why sockets for the FET's are a great idea)


[quote author="JRE Productions"]
The release pot seems to really effect the output too.
The attack pot seems to really affect the threshold too.[/quote]

It should, as different timing will rectify different amounts of audio AC.

[quote author="JRE Productions"]
The tracking (even on the working one) seems to not be all that great. I find its best to just use my ears.
[/quote]

For better tracking, you may experiment with changing audio attenuator FET's.

Jakob E.