Rob Flinn
Well-known member
Anyone got a source for the 2n3391 in the UK, or know of a suitable substitute that is obtainable ??
[BUILD] 1176LN Rev D DIY
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Rob Flinn
Well-known member
Gor them here in the end http://www.bardwells.co.uk/.
Also very cheap for polystyrene caps
Also very cheap for polystyrene caps
trancedental
Well-known member
:
The latest in a long line of cretinous updates from the biggest numpty on the forum is that I have decided to start a new board & so ordered parts from Mouser & Mnats ??? ???
Just as I was contemplating taking a hammer to the existing board I decided to have one last go at getting it working properly. I then ripped a trimmer out, R44 which didn't click at either end of it's turning cycle, replaced a dodgy alpha attack pot & bingo I seem to have a almost working build
Done the first 2 calibration steps without problems, all the meter function settings work, compression sounds fine, no distortion or noise. I'll do the 3rd calibration when I get some new output & attack / spdt pots ;D
One last slight problem is that using my 20:1 ratio push button setting just makes a bubbling noise without much audio getting through (sounds like a tremelo guitar pedal!!!!!!) The 12:1, 8:1, 4:1 push button settings all work & sound fine
So I'm, perhaps / probably assuming that one of the four FET's Q7-Q10, in the Gain Reduction section is faulty or / & some nearby parts, I don't think it is the Ratio PCB as I have a spare to swap over that results in the same issues!!!
Anyone know the part of the circuit that the 20:1 setting uses? Am I on the right track with this?
Thanks & Cheers JK ;D ;D
The latest in a long line of cretinous updates from the biggest numpty on the forum is that I have decided to start a new board & so ordered parts from Mouser & Mnats ??? ???Just as I was contemplating taking a hammer to the existing board I decided to have one last go at getting it working properly.
I then ripped a trimmer out, R44 which didn't click at either end of it's turning cycle, replaced a dodgy alpha attack pot & bingo I seem to have a almost working build Done the first 2 calibration steps without problems, all the meter function settings work, compression sounds fine, no distortion or noise. I'll do the 3rd calibration when I get some new output & attack / spdt pots ;D
One last slight problem is that using my 20:1 ratio push button setting just makes a bubbling noise without much audio getting through (sounds like a tremelo guitar pedal!!!!!!) The 12:1, 8:1, 4:1 push button settings all work & sound fine
So I'm, perhaps / probably assuming that one of the four FET's Q7-Q10, in the Gain Reduction section is faulty or / & some nearby parts, I don't think it is the Ratio PCB as I have a spare to swap over that results in the same issues!!!
Anyone know the part of the circuit that the 20:1 setting uses? Am I on the right track with this?
Thanks & Cheers JK ;D ;D
dmp
Well-known member
I'd triple check the wiring and resistor values on the ratio pcbs. If the other ratios are working it seems like it must be at the buttons.
ChrioN
Well-known member
Just to make sure: If you stereo link, you solder a wire to point 7 and solder the other end to the other units point 7?
dmp
Well-known member
I used the stereo link kit from Hairball. It buffers the connection with opamps the same way the Purple Audio version did a stereo link. I think if your FETs are perfectly matched though, point 7 can just be connected.
ChrioN
Well-known member
Hello everyone,
I have just finished my Rev D using Mike's amazing kit and everything seems to be working correctly except my ratios are too high.
4:1 is 5.5:1, 8:1 is 9:1, 12:1 is 14:1 and 20:1 is 24:1. The other thing I have noticed is that the release knob effects the level of the signal when I pass a continuous test tone through the unit and GR is enabled. I have checked my wiring against Skylar's diagram and have also triple checked the resistors on the ratio board as well as going back over the calibration procedure 5 or 6 times.
Any help with this would be greatly appreciated.
Thanks
-Simon
I have just finished my Rev D using Mike's amazing kit and everything seems to be working correctly except my ratios are too high.
4:1 is 5.5:1, 8:1 is 9:1, 12:1 is 14:1 and 20:1 is 24:1. The other thing I have noticed is that the release knob effects the level of the signal when I pass a continuous test tone through the unit and GR is enabled. I have checked my wiring against Skylar's diagram and have also triple checked the resistors on the ratio board as well as going back over the calibration procedure 5 or 6 times.
Any help with this would be greatly appreciated.
Thanks
-Simon
Echo North
Well-known member
simonlef said:
This is normal. It's a discrete circuit so nothing will be spot on. These ratio's looks good to me.
I've never been able to get them much closer.
Mike
Echo North
Well-known member
Not to mention as you get closer to the "knee" the ratio will skew.
dmp
Well-known member
Either describing or posting a graph of how you measured the ratio would be interesting.
I recall in the UA manual there is a graph of the compression curves. The compression ratio is the slope of the output signal vs the input signal. I took data to make this type of graph to look at the ratios. The dotted lines are the exact ratios. Notice there is a soft knee at the threshold point and that the lines waver a bit. If you are calculating a ratio from just two points, the points must be after the threshold is into the full compression region.
I recall in the UA manual there is a graph of the compression curves. The compression ratio is the slope of the output signal vs the input signal. I took data to make this type of graph to look at the ratios. The dotted lines are the exact ratios. Notice there is a soft knee at the threshold point and that the lines waver a bit. If you are calculating a ratio from just two points, the points must be after the threshold is into the full compression region.
Attachments
crisotop
Well-known member
Another one is born:
UTC P12 input (octal o12) / ed anderson output. 20dB (1dB Steps) switched Elma T-Pad, switched Elma output, attack/release are pots, but will be replaced by switches once I find a cheaper alternative to the elmas
Many thanks to Jakob, Mnats, Mike & Ed for this wonderful build. Haven't compared it to my stereo Rev J yet, but wiring is the same pita
Christoph
UTC P12 input (octal o12) / ed anderson output. 20dB (1dB Steps) switched Elma T-Pad, switched Elma output, attack/release are pots, but will be replaced by switches once I find a cheaper alternative to the elmas
Many thanks to Jakob, Mnats, Mike & Ed for this wonderful build. Haven't compared it to my stereo Rev J yet, but wiring is the same pita
Christoph
Echo North said:
Thanks Mike,
I just wasn't sure whether I had made an error or if this was normal for the circuit.
dmp said:
There is a method described in the 1176LN manual on the JBL website for testing ratios (as well as testing attack and release times) but the method I used to check my ratios was roughly the one outlined here http://www.axtsystems.com/index.php?option=com_content&view=article&id=54:1176lnratios&catid=34:1176ln&Itemid=62. I did a number of different varations on this test to ensure that I wasn't getting confused by the 'knee'. The first test I did was to input a 0db tone at 1k and then set the input so that I had 10db of compression on 20:1. I then left all the controls as they were and moved through the ratios measuring the level at 0db, -3db, -6db, -9db, -12db and -15db. I then plotted the information on the spreadsheet. I also repeated the test but adjusting the input for each ratio so that I started with 15db of compression and then repeating the measurments. The results for each test showed that the ratios were a little higher than I expected.
pearldrum944
Active member
- Joined
- Dec 25, 2009
- Messages
- 41
Today I successfully got my mnats (with hairball kit) 1176 rev d to pass audio...hooray! ....unfortunately I am having a few issues:
When I shorted r44 with my shorting block my fuse blew. I do have this right, correct? Not shorted are the two pins closest to the rear panel, and shorting r44 are the 2 pins toward the front panel? (this is how it appears in the mnats video). Any idea what would cause the fuse to pop?
When I shorted r44 with my shorting block my fuse blew. I do have this right, correct? Not shorted are the two pins closest to the rear panel, and shorting r44 are the 2 pins toward the front panel? (this is how it appears in the mnats video). Any idea what would cause the fuse to pop?
I'm building a Rev D using the Hairball kit, with the GR switch on the attack pot.
I've looked through the forum, and puzzled over the schematic a little, and still have questions about the wiring of the switch.
I looked at Skylar's wiring diagram and CanIdoit's photo clipped below.
As I understand it, if using the pot switch, nothing from main board 22 and G or Ratio board BLK and GRN goes to the meter board at all. These connections all go to the switch on the pot.
I have wired this using two single connector (plus shield wires).
One wire goes from the ratio board GRN (shield connected to ratio board BLK) and then connects to the pot switch with the shield on the upper connector and the main wire (GRN) on the lower connector. The shield on this wire is carrying the signal from BLK on the ratio board to the switch.
The second wire goes from main board 22 and the G pad beside it. The shield connects to the G pad. At the switch, the main wire connects to the common terminal on the switch; the shield connects to the upper terminal of the switch (which also connects to the shield of the other wire, which is connected to BLK on the ration board).
Is this correct? Should I be using a two conductor wire to connect from the switch to the ratio board GRN and BLK?
Any advice gratefully appreciated!
Philo
I've looked through the forum, and puzzled over the schematic a little, and still have questions about the wiring of the switch.
I looked at Skylar's wiring diagram and CanIdoit's photo clipped below.
As I understand it, if using the pot switch, nothing from main board 22 and G or Ratio board BLK and GRN goes to the meter board at all. These connections all go to the switch on the pot.
I have wired this using two single connector (plus shield wires).
One wire goes from the ratio board GRN (shield connected to ratio board BLK) and then connects to the pot switch with the shield on the upper connector and the main wire (GRN) on the lower connector. The shield on this wire is carrying the signal from BLK on the ratio board to the switch.
The second wire goes from main board 22 and the G pad beside it. The shield connects to the G pad. At the switch, the main wire connects to the common terminal on the switch; the shield connects to the upper terminal of the switch (which also connects to the shield of the other wire, which is connected to BLK on the ration board).
Is this correct? Should I be using a two conductor wire to connect from the switch to the ratio board GRN and BLK?
Any advice gratefully appreciated!
Philo
canidoit said:I wired that section like this, which is correct from what I recall.bdubya said:
pearldrum944
Active member
- Joined
- Dec 25, 2009
- Messages
- 41
Philo, that is how I wired mine....but...I have 2 non working units.
I figured out my fuse issue (fast acting instead of slow blow)
On one of my units, I only get the GR meter (...and I think GR in general) to work when in SLAM mode. On the other unit I get no GR meter on any ratio. +4 and +8 seem to work fine on both. Any ideas?
EDIT: by GR meter won't work I mean that it won't even go to 0, just sits on the left.
I figured out my fuse issue (fast acting instead of slow blow)
On one of my units, I only get the GR meter (...and I think GR in general) to work when in SLAM mode. On the other unit I get no GR meter on any ratio. +4 and +8 seem to work fine on both. Any ideas?
EDIT: by GR meter won't work I mean that it won't even go to 0, just sits on the left.
As I understand it, if using the pot switch, nothing from main board 22 and G or Ratio board BLK and GRN goes to the meter board at all. These connections all go to the switch on the pot.
I have wired this using two single connector (plus shield wires).
Do you mean two core cable with shield?
One wire goes from the ratio board GRN (shield connected to ratio board BLK) and then connects to the pot switch with the shield on the upper connector and the main wire (GRN) on the lower connector.
From my pic, the pot solder tabs looks like this.
A B
C
See how A and B have red wires in the pic. Green writing is for the green arrow lines.
Meter GRN -> A (red wire)
Meter BLK -> C (shield)
The shield on this wire is carrying the signal from BLK on the ratio board to the switch.
The shield runs from Ratio BLK -> Meter BLK -> Pot C
The second wire (single core cable with shield) goes from main board 22 and the G pad beside it.
Yes
The shield connects to the G pad.
At the switch, the main wire connects to the common terminal on the switch; the shield connects to the upper terminal of the switch (which also connects to the shield of the other wire, which is connected to BLK on the ration board).
Is this correct? Should I be using a two conductor wire to connect from the switch to the ratio board GRN and BLK? Explain this bit a little further please, what do you mean by switch? Are you talking about the solder tabs at the back of the pot - A B C as I mentioned above?
I have wired this using two single connector (plus shield wires).
Do you mean two core cable with shield?
One wire goes from the ratio board GRN (shield connected to ratio board BLK) and then connects to the pot switch with the shield on the upper connector and the main wire (GRN) on the lower connector.
From my pic, the pot solder tabs looks like this.
A B
C
See how A and B have red wires in the pic. Green writing is for the green arrow lines.
Meter GRN -> A (red wire)
Meter BLK -> C (shield)
The shield on this wire is carrying the signal from BLK on the ratio board to the switch.
The shield runs from Ratio BLK -> Meter BLK -> Pot C
The second wire (single core cable with shield) goes from main board 22 and the G pad beside it.
Yes
The shield connects to the G pad.
At the switch, the main wire connects to the common terminal on the switch; the shield connects to the upper terminal of the switch (which also connects to the shield of the other wire, which is connected to BLK on the ration board).
Is this correct? Should I be using a two conductor wire to connect from the switch to the ratio board GRN and BLK? Explain this bit a little further please, what do you mean by switch? Are you talking about the solder tabs at the back of the pot - A B C as I mentioned above?
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