synthetic

Los Angeles-area G1176: success + pics!
« on: November 13, 2005, 05:51:46 PM »
I've hit quite the snag with my G1176 and I'm not sure where to go from here. I have it passing signal, but the gain reduction meter doesn't work and I can't set the bias. I've checked the votage plot backwards and forwards and looked at the GR section pretty closely, but I can't make it happen.

Is there anyone in the LA area who could have a look at it? I'm not in any terrible rush, so it could just reside on your bench for a while until you had the chase to look it over. I might also be able to compensate you, if necessary.

This is actually the second G1176 I've attempted. The first was a complete wreck and I ended up selling it for parts. This second one looks much better, except for the non-working thing.

PM me if you're interested/available. Thanks for your help, -jl


mnats

Los Angeles-area G1176: success + pics!
« Reply #1 on: November 14, 2005, 03:26:04 PM »
More than once I've accidentally put a dualie in the meter driver circuit rather than the single opamp package it requires e.g. a TL072 instead of an '071.

But you probably didn't make such a dumb mistake :oops:

synthetic

Los Angeles-area G1176: success + pics!
« Reply #2 on: November 14, 2005, 04:54:03 PM »
It works fine in VU mode. It's a problem with the GR circuit, I think.

nwsoundman

Los Angeles-area G1176: success + pics!
« Reply #3 on: November 14, 2005, 08:24:03 PM »
I can take a look for you / with you.


PM me for info.



Kirk
Tech Talk Take Two, Rollin'

cannikin

Los Angeles-area G1176: success + pics!
« Reply #4 on: December 04, 2005, 11:45:04 PM »
Hey NwSoundMan

You want to look at mine?  I'll pay you
Tube limiters..yum!

synthetic

Los Angeles-area G1176: success + pics!
« Reply #5 on: December 05, 2005, 06:15:21 PM »
Thanks to nwsoundman, my G1176 is complete.



http://www.jefflaity.com/gallery/g1176

Click on the link for more photos.

The G1176 has been an ongoing saga for me. My first G1176 was a total disaster. I made my own boards (mistake #1...), printed the transparency at 91% scale (doh!!!) and so my board was a complete mess. I had extra holes and shorts everywhere. I eventually sold that board for parts and started this one from scratch, using mnats board. I got it 99% of the way there, but I couldn't set the Q bias and the GR meter stopped at -16dB. nwsoundman figured out that there are two jumper holes marked 18: you use the one according to the trim pot you've installed.

I'm very happy with the results. Thanks again to Gyraf, mnats, nwsoundman and everyone else that helped me out. :guinness:  :guinness:

Next up: a GSSL comp. Hopefully this one will be slightly easier...

pucho812

Los Angeles-area G1176: success + pics!
« Reply #6 on: December 05, 2005, 06:30:18 PM »
:thumb:
You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is.

laitue5

Los Angeles-area G1176: success + pics!
« Reply #7 on: December 05, 2005, 07:34:56 PM »
Great! I?m happy for you.
Thanks for the pics, it will help me.  :wink:

Do you think your API/Forsell Preamp was easier to build?
In fact, I guess it?s easier but I?m a little afraid building things on this type of board only with a schematic reference.

And what about the sound of your 1176?   :grin:
metal film 1/4W is ok

Greg

Los Angeles-area G1176: success + pics!
« Reply #8 on: December 05, 2005, 07:42:22 PM »
She's a beaut !!!  :thumb:

Happy squishing.
Greg Stein
New Orleans, LA

synthetic

Los Angeles-area G1176: success + pics!
« Reply #9 on: December 05, 2005, 07:59:14 PM »
I had an easier time with the Forsell project. I was making it up as I went along, with help from the lads on The Lab. Even if you start with a project with a board designed for you, you're still on your own. You can get help from the board, but there's no step-by-step instructions unless you get a kit from someone like Seventh Circle. Here's the discussion thread for my mic pre:

http://www.groupdiy.com/index.php?topic=3408

Of course, I had an espeically hard time with the G1176, so maybe I'm not the best one to ask. :roll:

Here's a tip for other people rescuing VU meters from an old tape machine. Go to a hardware store and grab some of the paint sample cards. Find the one that matches your meter the closest and tape that to the back of the meter, covering the little holes for Clip and Input LEDs. I found that Navajo White was a close match for my TEAC meter.   :wink:


asm

Los Angeles-area G1176: success + pics!
« Reply #10 on: December 05, 2005, 11:04:23 PM »
props to nwsound man.

he hooked me up with an old 9 DIN mac cable that was un-findable.

cool guy. :thumb:  :thumb:  :thumb:
...has a 'gold sputtered capsule for vintage sound'...

dissonantstring

Los Angeles-area G1176: success + pics!
« Reply #11 on: December 06, 2005, 10:42:04 AM »
a job well done synthetic!! :thumb:

Quote
nwsoundman figured out that there are two jumper holes marked 18: you use the one according to the trim pot you've installed.


 :? i never knew there was a jumper option on pad 18!  are you refering to the  ratio board or main board pad 18?  could you explain in more detail the purpose of the jumper?  i can't tell on the layout (sorry i haven't referenced the schematic, i shouldn't be so lazy).

again, nice work synthetic!  the G1176 build didn't break you, it only made you stronger (or better) :wink:
regeards,
grant

synthetic

Los Angeles-area G1176: success + pics!
« Reply #12 on: December 06, 2005, 10:52:28 AM »
On mnats board, there are two holes for pad 18 on the main board. Pad 18  jumpers from the Q bias trimmer to the ratio board. I just checked Gyraf's board and it doesn't have this problem.

dissonantstring

Los Angeles-area G1176: success + pics!
« Reply #13 on: December 06, 2005, 11:25:44 AM »
thanks synthetic!
i think i know what you are saying now.  i'm working on zero caffine at the momment.  you're saying that the mnats boards have options for the different trim pot legs and depending on which trim pot you use will depend on which pad 18 hole you connect to.  is that right?
regards,
-grant

synthetic

Los Angeles-area G1176: success + pics!
« Reply #14 on: December 06, 2005, 12:13:05 PM »
That is correct. You can sorta see this on my photo of the board, though there's a wire in the way:

http://www.jefflaity.com/gallery/g1176/cat1205_227?full=1

To the left of the the R81 trimpot is an orange wire in pad 18. You can see two holes above that for a longer trimpot and its corresponding pad 18 hole.

dissonantstring

Los Angeles-area G1176: success + pics!
« Reply #15 on: December 06, 2005, 12:26:18 PM »
thanks for clearing that up synthetic.
i also noticed in that photo that you had opted for what looks like a standoff or huge nut instead of a heatsink on the v-reg.  i know that the heatsink is difficult to fit in that area (i opted for a small one which just fit and is only supported by the legs of the v-reg which can't be good).  how's that working for you?  any heating problems?
cheers.
grant


 

Related Topics

  Subject / Started by Replies Last post
2 Replies
1321 Views
Last post October 11, 2011, 03:52:45 PM
by hagybear
0 Replies
811 Views
Last post February 06, 2012, 10:36:25 PM
by ChrisTownsend
0 Replies
284 Views
Last post January 30, 2019, 10:56:06 PM
by john12ax7
2 Replies
1395 Views
Last post August 20, 2019, 07:03:58 PM
by john12ax7