All things G1176 - the new "repost" thread.

[glide 1]

[quote author="gswan"]There should be no problem doing this. I am assuming you are using a single 50VA toroid and connecting it to two 1176 modules with onboard regulators. I don't think you'll have any crosstalk problems through the AC power rails doing this. Two 1176 modules draw less than 50VA so your power budget should be ample.[/quote]

Yes both boards have on board regulators. Thanks for the quick reply.

I have another question. I've got these Denon VU's that i will be using and i think the lamps are rated at 12V and rev J boards put out 24V.

I'm thinking that i may have to use the mnats power supply to power the VU lamps after all. Is this possible still using 1 toroid?

 

[gswan]

Wire the two 12V lamps in series, which can work from a 24V rail.

 

[gswan]

BTW, are these real VU meters with internal rectifiers? The 1176 expects VU meters with internal rectifiers so if you don't have these you may need to add a germanium diode in series with each meter.

 

[glide 1]

gswan,

yes i believe they are i but still have to check them with 3.6k resistor.

I visited your website, helped me a lot. Thank you much

 

[Even]

[quote author="Even"]Just finished a 1176 today - mnats REV J - oep in Lundahl out - all woking fine but getting a little hum.
I didnt have a 2x24 Power transformer at home , but a 2x18 1.3VA.
So connected it and getting the 10V and instead of the 30V about 26.9V.
Can it be that the hum is caused by that????
I tried all grounding possibilities but getting the same hum with or without grounding.
Rechecked everything - looks all fine to me[/quote]

Ok, exchanged the transformer from 2x18 to 2x25.
The piece is deadly quit now!!!!!!!!!!!! Yesssssss!!!!
No hum at all anymore...so 2x18 for mnats isnt working fine...
Cheers

 

[glide 1]

quick question.

Can anyone recommend a replacement IC for the TL071 (IC1) on the mnats J board?

 

[kenrinc]

Dual 1176 power transformer info was in this post:

http://www.groupdiy.com/index.php?topic=22073&highlight=

50va is way more than enough. 30va is perfect.

Ken-

 

[gswan]

[quote author="glide 1"]quick question.

Can anyone recommend a replacement IC for the TL071 (IC1) on the mnats J board?[/quote]

LF351

 

[glide 1]

gswan & kenrinc thank you

 

[Even]

Silly question about stereo interconnct mnats rev j:
As far as i understand i just need to wire (with switch) "stereo interconnect" ?
If its that simple , is it possible to connect two mono units (i built two mono g1176´s) with a - for example - jack cable?

 

[dissonantstring]

hi even,
i don't see why not (though someone with more knowledge may say differently). just wire the stereo interconnect pad to the tip of a TS jack on each unit. don't even need a SPST switch. plugging in the cable to both units will be your switch. i would keep the cable run as short as possible though. one caveat...a stereo interconnect jack on the back makes it kind of difficult to have dual/stereo switching if the units are racked.
test before drilling any holes in your chassis for the jacks. :wink:
i added the dual/stereo switch on my 2-G1176 and it works pretty well (with all FETs matched) from what little testing I've done so far.
regards,
grant

 

[guitarguy12387]

Hey guys,

Back with a quick troubleshooting question. I got the first unit up and running great, but my second one passes no audio. So i started by double checking all my wiring/connections. All looked good. So i started taking a signal gen and working my way backward from the output jack. My question is: how to i tell if the output transformer is working properly? My signal passes until i reach the transformer. applying signal to pins 1-5 of the lundahl output transformer produces no deflection of the VU meter.

Does this mean the o/p tranny is faulty, or is there an error in my test methods?

Thanks for the help.

 

[adoucette]

Stumped!!

I set my 1176 project aside for awhile, closed it up, racked it and forgot about it. I get it out and open it up to start working on it again and now for some reason its not working.. When I left it, it was powering up and working, but there were grounding issues and hum,, now I turn it on and nothing seems to be powering up. Aside from the lamps not turning on, but my heat sink on my voltage regulator is cold to the touch, which makes me think that maybe something happened to the voltage regulator.. is it possible something happened to it when its racked up safely?

Doesnt make sense does it?

Thanks
Andre

 

[adoucette]

anyone?

 

[Echo North]

Check out the last few posts in the Rev D thread. Sometimes posting pictures can help out a lot.

A good close up of the PCB and wiring can help people rule out and basic component or wiring issues.

Are you getting any voltage at the power supply check points? Is your fuse blown?

Try working your way back from the -10/+30 points...then to the power transformer header pins...then to the transformer. That should help narrow down the issue and rule out or confirm a faulty regulator.

Mike

 

[Guest]

Hi.

I started building 1176 on summer vacation, and after all the pieces found their places I have had more or less problems. Some of the problems has been solved, but currently I totally stuck, and I would really appreciate if someone could help me a bit..

I am not able to calibrate the compressor. Calibrating stops on the first step, adjusting the Q bias. Instructions says that the VU meter should drop 1 VU, but I'm able to drop only half of it.

Just measured the voltages for nth time and the results looks like below:

Q B C E
2 0,9 1,8 0,6
3 1,8 11,9 1,2
4 11,9 29,6 11,5
5 4,3 27,7 4,5
6 27,7 14,6 28,4
7 28,4 14,6 29
8 14,6 29,6 14,0
9 13,3 0 13,9
12 3 11 2,5
13 11 29,6 10,6
14 1,8 22,6 1,4
15 22,6 29,6 0,3

Comparing my voltages to reference voltages (e.g. http://www.axtsystems.com/index.php?view=article&catid=34%3A1176ln&id=57%3A1176lnproblems&option=com_content&Itemid=62) all other voltages seems to be allright except Q12-Q5.

I have gone through the resistors for several times, as well as other components and soldering faults etc... ; of course there might be somthing wrong in my vision, but... I have also read this thread for a while without finding a similar case.

I had a problem with toroid transformer that blew the fuse once in a while when switching the power on or off, I ordered new toroid and the fuse blowing issue was solved. Is it possible that the misfunctional toroid might have blown something on the pcb that my eyes just can't see?

And one more thing.. the -10V voltage on my pcb is -8.8V, is it too low?

I would really, really appreciate if someone here could help me to get this machine work... So, any suggestions how I could proceed with this one?

Thanks,

-Ile

 

[jrfred453]

Need some help with my dual 1176 build. One channel is working fine but I have not calibrated it yet. The second channel, I mis-connected the wires that go to the 20 and 18 spots on the mnats board. I got the wires switched back to the correct way but the meter doesn't work. Zero adjust and tracking move the needle but audio to the meter shows no movement. Voltages around the meter are a little off but I can't track the problem down yet. I already changed the fet. Any ideas?

 

[SIXTYNINER]

FOUND 1176 BOMLIST FOR REV
G
H
AND
D
BUT NOT FOR REV J
ANY HELP ABOUT ARE WELLCOME
THANKS IN ADVANCE

ALL THE BEST
6TNR

 

[Echo North]

http://www.geocities.com/m_natsume/1176_bom.html

Mike

 

[guitarguy12387]

Hey Guys,

I could use a little help debugging my 1176! I have one that works great. One that doesn't pass any signal. I have triple checked the wiring and its exactly the same as the working one. I have done continuity checks on all the wires and they all check out. So i turn to the board. I would like to follow the signal and see where i lose it, however, being a noob, i am having some trouble following the schematic. That is, i'm not entirely sure of what the path is where the signal is supposed to go exactly.

Another thing i'm wondering about is: i can follow the signal fine to the input transformer. But then i cannot get ANY signal on the other side of the tranny. I find that curious. And it's a brand new lundahl so i'd like to avoid trying to replace it if that's not the problem...

Any advice/help following the signal would be great! Thanks.