buschfsu

1176LN Rev D DIY
« Reply #500 on: March 03, 2008, 02:47:15 PM »
also interested in a run...

just finished a rev g and would like to start a rev d

thanks
PRR said...
OHM'S LAW. Not as an abstract thing: you should be able to glance at a small circuit and "instantly" know I and V, the way a soccer player glances at the ball and knows the angle and kick


mnats

1176LN Rev D DIY
« Reply #501 on: March 03, 2008, 03:00:11 PM »
I've been busy with other things lately, but I intend to do another batch.

While I was building mine I made the following list of changes I intend to make on the original Rev D files:

Fix ground plane shorts on Q7 - Q10
Make C2 and C11 0.2" pitch
C18 Pitch narrower
More room for Q6
Ground near Pad 7 to aid proper wiring
Larger holes/pads for power in
Place for shorting pins for R44 to assist calibration
Correct value of emitter resistor Q3

If there are any other suggestions please post them here, particularly if you have built one and had any issues not covered by the above.

radiance

1176LN Rev D DIY
« Reply #502 on: March 03, 2008, 03:08:26 PM »
Quote from: "mnats"
I
Larger holes/pads for power in
.


Maybe larger holes for all screw terminals...

I drilled mine larger and thus disconnected the lower groundplane from the upper one. Easy to fix but still...
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan

Nele

1176LN Rev D DIY
« Reply #503 on: March 03, 2008, 03:53:06 PM »
Quote from: "mnats"
I've been busy with other things lately, but I intend to do another batch.


Ok, cool!
Looking forward to building a stereo unit.

Skylar

1176LN Rev D DIY
« Reply #504 on: March 04, 2008, 01:17:38 AM »
Quote from: "mnats"
Correct value of emitter resistor Q3


Hmmm, what's wrong with this? The Q3 emitter resistor (R11) should be 82ohms according to the schematic, which is also what your boards say.

mnats

1176LN Rev D DIY
« Reply #505 on: March 04, 2008, 10:26:45 AM »
Just finished all the modifications I outlined above plus radiance's request - all the pads for external wiring are now 50 mil (1.2mm) rather than 40. Also gave the last stage of the line amp its own ground path. Checked each net - all lookin' good though it's nearly 2AM and I'd better get some rest before getting up at 6 to head to work :evil:

radiance

1176LN Rev D DIY
« Reply #506 on: March 04, 2008, 10:36:59 AM »
:thumb:
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan

Nele

1176LN Rev D DIY
« Reply #507 on: March 04, 2008, 10:47:04 AM »
excellent!

 :guinness:  :guinness:

nielsk

RevD
« Reply #508 on: March 07, 2008, 10:16:31 PM »
I am just finnishing stuffing my boards (finaly) and would greatly appreciate some steering on the problem fixes that you mention, how do I fix the ground plane short on Q7-10? with the black boards, it is very difficult to see (please save me from reading 30 pages to find this!) I also can find no problem with the resistor mentioned....
BTW, count me in for some more bords when you make them!

Thanks

kazper

1176LN Rev D DIY
« Reply #509 on: March 08, 2008, 02:05:37 AM »
Page 9 there nielsk...
Intentionally left blank


nielsk

1176LN Rev D DIY
« Reply #510 on: March 08, 2008, 06:52:39 PM »
got it, thanks

nielsk

Board layout improvements
« Reply #511 on: March 09, 2008, 09:27:32 AM »
How about adding the extra pad for the use of 2n5088s on Q5, 12 & 13?

mnats

Re: Board layout improvements
« Reply #512 on: March 10, 2008, 04:34:10 PM »
Quote from: "nielsk"
How about adding the extra pad for the use of 2n5088s on Q5, 12 & 13?

Nice one. Done.

BTW the ground plane short fix post is linked directly from my Rev D site as always.

Regarding the resistor value correction think series resistance. Never mentioned R11 myself...

At some point I'll stop fiddling with it and send the files off, but I might wait a week to see if there are any more ideas for improving the original Rev D boards that haven't been covered yet. Thanks for the ideas so far.

Skylar

1176LN Rev D DIY
« Reply #513 on: March 11, 2008, 03:00:55 PM »
doh!
Series resistance on the Q3 emitter...

Rev D has 992R (82R + 910R) whereas Rev F has 1.882K (82R + 1.8K) resistance at this point in the circuit.

Thank you.

mnats

1176LN Rev D DIY
« Reply #514 on: March 17, 2008, 07:20:01 AM »
I'm going to send off the files to the fab before I go on a short break. Here are the things I've changed from the original PCB...

Quote
Rev D Version 2 changes:

Fixed ground plane shorts on Q7 - Q10

Added alternate pads for Q5, Q12, and Q13 so 2N5088s can be used in these positions too (like the Purple MC76)

Made C2 and C11 0.2" pitch rather than 0.1"

C18 Pitch narrower for better fit

More room for Q6 + heat sink

Ground pad near Pad 7 to aid proper wiring

All pads for external wiring changed to 50 mil holes

AC IN pads larger

Place for shorting pins for R44 to assist calibration and room for three pin header to hold shorting plug

Correct value of resistor R12

Power supply has its own ground plane

Final stage of line amp has its own ground path

Should have boards in a couple of weeks, then a few more weeks to test one before offering them at the Black Market and posting self-etch files.

David Kulka

1176LN Rev D DIY
« Reply #515 on: March 25, 2008, 10:25:38 PM »
I was working on some 1176LN Rev D's with meter issues and a web search led me to this thread.  (Actually, the thread helped me to work out my procedure.)  Regarding R44 and the meter calibration steps, here's how I align this circuit on Rev D's.  I don't add trimpots to original units but you can bypass the last step by using a 10k trimpot for R44.  The FET is critical.

Let the unit warm up for at least a half hour.  After setting the Q1 bias and verifying that audio limiting is working ok, measure the output level with an external meter, select GR metering, and select 20:1 ratio.  Connect a 10K pot or a resistor sub box, set to 3K, to the Q12 and Q13 emitters (R44 pads, with no R44 connected yet).  Apply a 1K sine wave to the input (+4 is fine but input level is not critical) and adjust the input and output controls so that when you turn the attack on, output level decreases by 10 db.

Turn attack off.  Connect a DVM (range of 2-5 VDC is good) to R74.  Adjust R75 (Null) for zero volts.  Adjust R71 (GR zero) for zero on the VU meter.  The adjustments interact so you might have to repeat them 2 or 3 times.

After that is done, turn the attack switch back on.  The GR meter reading should go down.  Change the setting on the test pot or sub box to achieve a reading of -10 on the VU meter.  Double check your external meter to be sure you still have a 10 db change.  Toggle the attack switch on/off a few times to verify zero and -10 on the meter.  (With attack and release set to fast this part will be quicker.)

Turn off the attack, and re-check the voltage across R75.  If it's not zero, re tune the trimmers as needed.  Check R44 again, you may have to adjust it one more time for an exact 10 db change.

Disconnect the pot or sub box and check the resistance.  If using a test pot, you'll use your DVM to carefully measure it's resistance at that setting.  Choose a resistor or (if you don't have a Wall Of Resistance like the one on our web site http://studioelectronics.biz/MeetTheShop8-13.html) combine resistors to match the value that you measured.  Temp in the resistor(s) and if you still have -10 on the meter, solder it in and you are done.

Quote from: "ap123"
Upon actually following the calibration procedures outlined in the urei docs I encountered a never-ending circle of confusion.  For instance, the more I tinker I realize that the procedure outlined in 5.3.2 is sort of dependent on that of 5.3.3 and so on.

Does the procedure to adjust the null and tracking require the complete removal of R44?  On page 60 of the urei pdf, there is a document entitled "Meter Calibration" the relationship between R75, R71, and R44...that is a sensitive dynamic that one there, especially when you throw the R44 as a trim pot into the mix.

Also, I read in the G thread that shorting terminal 22 to ground is the same as placing attack in the off position (as mentioned numerous times in the docs).  Does this apply to the rev D board?

Can the bias adjustment be made with the meter trim pots whacked out (or centered, say)?  

I need to finish reading the rev G thread one of these days...sorry.

mnats

1176LN Rev D DIY
« Reply #516 on: March 29, 2008, 06:02:31 AM »
Wow, thanks for the post, David!

A small error cropped up on my new PCBs so they'll be delayed. I'll post @ the Black Market when they are ready.

nielsk

rev d's
« Reply #517 on: March 29, 2008, 08:58:28 AM »
please plan on at least 4 for me!

thanks

buschfsu

1176LN Rev D DIY
« Reply #518 on: April 06, 2008, 12:43:56 AM »
im in for at least one any idea when a batch would be run?
PRR said...
OHM'S LAW. Not as an abstract thing: you should be able to glance at a small circuit and "instantly" know I and V, the way a soccer player glances at the ball and knows the angle and kick

mnats

1176LN Rev D DIY
« Reply #519 on: April 07, 2008, 03:51:28 AM »
Quote from: "buschfsu"
im in for at least one any idea when a batch would be run?

Well, like I wrote four posts ago I sent off files on the 17th of March. I posted again on the 29th saying there was a small error. The corrections were made on the 2nd of April so the boards should be finished in 7 working days and in my hands the following week.