[BUILD] 1176 Rev A - Back to the beginning...

[acoustix]

Here somes "hand-free" picts with some missing caps.
Better comes asap

http://imageshack.us/photo/my-images/685/dsc6111p.jpg/

http://imageshack.us/photo/my-images/412/dsc6106z.jpg/

 

[atticmike]

Here somes "hand-free" picts with some missing caps.
Better comes asap

http://imageshack.us/photo/my-images/685/dsc6111p.jpg/

http://imageshack.us/photo/my-images/412/dsc6106z.jpg/

that's very generous of you sir, greatly appreciated

 

[Lucin Niega]

Hi Guys,

I'm wiring up the Avel Lindberg transformer. Pictured on hairballs site it shows orange and red together tied to make the center tap. The written instructions say to wire the 0V leads together to make the center tap, which are orange and black. I wired orange and red first, which didn't work. Then I wired orange and black, which also didn't work. Would the first wiring be capable of damaging the transformer after power up?

 

[Lucin Niega]

tko,

Are you in the states? If so, did you wire your primary in parallel? Are you using the Avel Lindberg transformer? If so, how did you wire your secondary center tap (what colors did you tie together)? It would be a big help. I can't get mine powered up. thanks.

 

[tko]

No I'm not in the States, so I followed Mnats link to wire for 240v. Have you seen it? http://mnats.net/1176_reva-d_hairball_wiring_power_avel-lindberg.html TKO

 

[justinvm]

Hi Guys,

I've spent the last 2 days looking over the forum and service manual trying to work out these issues. Thought i'd try posting here.

Issue 1:

Revision A finished, but Meter is pinned hard left in GR mode. Swapped R71 2kohm for a 10k pot, but does nothing to change the meter position.

- Meter seems to work okay in +4 and +8
- Trims appear to be working.
- Checked all resistor values in Meter section.
- 3707s in the Meter section (Matched HFE to 2%) . Tried swapping them with 5088s but no luck.

Issue 2: When the output pot is set to max (full clockwise) output level jumps significantly, and the meter pins hard right. Is this normal behaviour?

Input and output is working fine. Compressor appears to be working correctly in all ratio modes.
Voltages at power supply test correctly.

Any ideas?

Thanka.

 

[spase]

can i use toroidal transformers with this spec (2x24V, 50VA) for this project ? Thank you.

 

[Volume11]

Hey guys, I can really use some help here. I have been messing with this thing for over a month now with no progress. I have the V1.2.5. I have been blowing fuses off and on since day one and burnt R32. I have wired the PT for what I believe is the correct way for US. After reading this entire thread and going back through it a great deal of times I have managed to correct a few errors. I started off using 2n5088s, inserted incorrectly. I replaced those with the 2n3708s from the bom. Then I realized that the two leftover wires (orange and yellow) on the OT needed to be tied together, so I did that. I haven't burnt r32 at all since. The main problem I have been having lately and since the beginning, is that I can't get my q-bias to do anything at all. I have switched out the trim pot a few times, tried different orientation as well as a higher resistance, 5k. When I had the last 2k mounted, I measured it for only a total of 1.38 in the circuit. When I pulled it out, it measured the full 2k. I know this is normal in a lot of cases, but there is nothing going to one of the legs of this VR. Should it still give me the incorrect reading?

If it matters, I am using an old Heathkit signal generator for the sine wave. The guy I bought it from showed me that it worked perfectly on his oscilloscope. I have also tried the sine wave plug in from PT, no dice.

Over the past three years I have built several effects pedals and a few amps. I built two SCA N72s a couple months ago, but those were so easy with the step by step instructions. I honestly didn't think that I would have so much trouble with this project. If someone is willing to give me some pointers, I would really appreciate it. I would hate to have to take this somewhere to get worked on, as it defeats the whole purpose of DIY, and the learning process is completely out the window for me. Unfortunately my frustration is pushing me in that direction, as I actually need this compressor for my home studio.

 

[Lucin Niega]

Hey Guys,

I noticed in your pictures that c8 and c2 look a lot different than the caps I used. Are they the ones on the mouser cart  link?

 

[tko]

Hey Guys,

I noticed in your pictures that c8 and c2 look a lot different than the caps I used. Are they the ones on the mouser cart  link?

Lucin,

If your talking about my pictures yip they are from Mouser.

TKO

 

[justinvm]

Issue 1:

Revision A finished, but Meter is pinned hard left in GR mode. Swapped R71 2kohm for a 10k pot, but does nothing to change the meter position.

- Meter seems to work okay in +4 and +8
- Trims appear to be working.
- Checked all resistor values in Meter section.
- 3707s in the Meter section (Matched HFE to 2%) . Tried swapping them with 5088s but no luck.


Input and output is working fine. Compressor appears to be working correctly in all ratio modes.
Voltages at power supply test correctly.

Resolved:

Seems like this issue was caused by loose wiring on the Meter Board. I was able to give these wires a bit of a jiggle and watch the meter swing into action. I decided to remove the 6pin header and solder directly to the board. Couldn't exactly work out what was causing the issue, I think the header itself may have been making poor contacts with the pins. 

I'm able to zero the meter now.

Unresolved: 

Still having this issue: When the output pot is set to max (full clockwise) output level jumps significantly, and the meter pins hard right. Is this normal behaviour?

 

[MicDaddy]

Unresolved: 

Still having this issue: When the output pot is set to max (full clockwise) output level jumps significantly, and the meter pins hard right. Is this normal behaviour?

Totally normal, to expect something else would be like expecting your car to not accelerate with gas pedal to the floor.

 

[marshman]

Justinvm - I had some noise (showed on the meter) when the output went past about 3 o'clock with no input signal.

I re-routed the blue and red wires that run from the meter board to the output XLR away from the shielded wire on the output pot and that seemed to fix it.

mm

 

[justinvm]

Unresolved: 

Still having this issue: When the output pot is set to max (full clockwise) output level jumps significantly, and the meter pins hard right. Is this normal behaviour?

Totally normal, to expect something else would be like expecting your car to not accelerate with gas pedal to the floor.

I should have clarified. When the Output pot is turned past 90% counter clockwise, the signal suddenly jumps in volume and the meter pins hard right in +4 or +8 Input mode. Prior to this this point the output volume and meter level increases smoothly without jumping.when rotating the pot.

Faulty pot? It seems to test okay with a multimeter.

 

[atticmike]

do I have to pay attention to anything in particular when powering both power sections of a stereo unit through a single transformer?

I'm skipping the separate psu and stuffed both power sections of the pcb.

 

[Randyman...]

do I have to pay attention to anything in particular when powering both power sections of a stereo unit through a single transformer?

I'm skipping the separate psu and stuffed both power sections of the pcb.

That's what I did on my 2-1176 Rev D.  The power section works fine in that configuration, and I believe having local on-board regulators actually decreases cross-talk vs. sharing common regulators.  I really didn't want to add a 5th PCB in my chassis anyways (2x 1176, 2x Stereo Link PCB's, AND a PSU PCB).

8)

 

[ChrioN]

I picked up where I left off the last time:
compressor is working, but only when running unbalanced, and I have a high pass filter starting at 1k. -20dB @ 100hz...

when trying to hook it up with balanced cables, the signal dissappears after the input transformer I think. I've quadrouple checked all the resistors, capacitors, transistors..

Hooked up as per Mnats guide. Such fury.

 

[Biasrocks]

when trying to hook it up with balanced cables, the signal dissappears after the input transformer I think. I've quadrouple checked all the resistors, capacitors, transistors..

You sure it's disappearing after the transformer?

The balanced input control is before the transformer, check the wiring of that first.

Make yourself a signal tracer and trace the signal and find out where it disappears.

Mark

 

[ChrioN]

Make yourself a signal tracer and trace the signal and find out where it disappears.

Mark

Thats how I traced it. Wired exactly as per mnats guide.

I can trace through the whole unit with from [after the input transformer] to [before the output transformer] and get excellent results. But as soon as I go through one of the transformers things gets ugly.

 

[Biasrocks]

Make yourself a signal tracer and trace the signal and find out where it disappears.

Mark

I can trace through the whole unit with from [after the input transformer] to [before the output transformer] and get excellent results. But as soon as I go through one of the transformers things gets ugly.

So it's getting lost in the output transformer.

How about a photo of the output transformer wiring from the board to the XLR out.

Mark