3D "AIR" EQ - "Night EQ" PCB's Complete!

[frazzman]

You already excluded a broken right side XLR input or output connection ?
With input signal present, compare right side with left side channel to see where signal get lost might be the easiest approach, following from input to output, IE compare AC voltages at U4-pin1,...., U5-pin6, U4-pin7.

Yeah checked the XLR wiring, those molex crimp pins have sent me on a wild goose chase before. I'll follow your lead and see where I get. It's strange as you can hear the eq working even though it's barely audible. I'm cross eyed from putting all these trimmers in, we will see what the new day brings. Thanks again

 

[Autophase]

Unfortunately I don't have the time to finish my Nite EQ, if anyone is after a pair of stereo boards I've got a post in the Black Market
http://groupdiy.com/index.php?topic=55086.0

 

[frazzman]

You already excluded a broken right side XLR input or output connection ?
With input signal present, compare right side with left side channel to see where signal get lost might be the easiest approach, following from input to output, IE compare AC voltages at U4-pin1,...., U5-pin6, U4-pin7.

Hi Harpo,

I've followed your recommendation, with a 1khz sine WAVE. I found a few deviations between the working and non working channels.

U5 - Pin 6 on working channel measures 0.868VAC. On the non working channel I have a negligible AC reading here.

Pin 7 on U6 is showing 0VAC on the non working channel.
On working channel this measures at +1.732VAC for the given input signal, which is the same reading when measuring at the output XLR pins.

Bear in mind this channel use to work fine, the issue has only arisen in the process of swapping out a heap of resistors with trimmers (R21,R23,R18,R20,R15,R17,R12,R14,R9 & R45,R43,R41,R39,R37).

I've already removed all of the IC's and checked that the trimmers are at their correct calculated resistance and they all checked out OK

No doubt I have introduced a fault during this process as the left channel is working fine with the same configuration. I am just having trouble finding where...

Thanks a lot

 

[Harpo]

U5 - Pin 6 on working channel measures 0.868VAC. On the non working channel I have a negligible AC reading here.

So either the opamp is broken or signal doesn't arrive at its non-inverting input (this is a virtual ground node, so current not voltage).
L/R voltages are the same at U4-pin1 (output of input debalancing stage) ?
L/R voltages are the same at U2-pin1 (output of 640Hz gain stage) ?
Does last measurement voltage or slightly lower arrive at the non working channel U5-pin2 with the U5 opamp out of its socket (broken trace check) ?

Pin 7 on U6 is showing 0VAC on the non working channel.
On working channel this measures at +1.732VAC for the given input signal, which is the same reading when measuring at the output XLR pins.

U4-pin7 on working channel (unsigned)1.732VAC with jumper set for unbalanced out config. On non working channel this is only a followup from U5-pin6 (inverting 2* nothing is still nothing).

 

[Harpo]

[quote author=Bonsaimaster]
Ok here is what I got. As I plug the module in my rack the power LED lights up and the Peak LED lights up. No signal passes thru. When I hook it up with my Classic API extension card non of the LED's light up. Voltage checks are all over with U1 and U4 showing varying voltages. TP4 TP5 show about .1mV.Any thoughts?

Thanks in advance
Bonsaimaster[/quote]
Took me a while to figure out what project your PM might be related to.
Did you place the 4 jumpers at the J9 connector, IE 'Link 1&3, 2&4, 7&9, 8&10 for Rear panel I/O', as explained at the left side of 'Prodigy Nite500 EQ schematic.pdf', so your input signal across XLR-pins2/3 arrives at TP4/TP5 ?

 

[frazzman]

Hi Harpo, and anyone else still interested in this thread...

So this is how I finished up with my unit. (I did find a dry joint on my right channel which was causing a loss of signal).

With 14 trimmers fitted on each channel to compensate for parts tolerances, my frequency response is better, but I think its as close as its going to get.

So far, i'd say that EQ sounds "good", not excellent but I am thinking this is due to some dips in low end frequencies. Attached is how my frequency response ended up.

I feel that the signal through the EQ (all pots centered) kind of sounds like its loosing a bit of 'balls' (subjective term... maybe = loss of some low end??

Drum sample: No EQ - https://dl.dropboxusercontent.com/u/108741277/niteeq/drumloop-noEQ.mp3
Drum sample: Nite EQ (all pots centered) - https://dl.dropboxusercontent.com/u/108741277/niteeq/drumloop-niteEQ.mp3

It becomes a bit of an interesting exercise - am I percieving some low end loss because I can see it on a graph, or can actually hear it? I *think* my -0.35db~ dip @ 350hz-ish is this perceived loss of low end (or "balls")

There is a pretty small volume drop with the EQ engaged due to tweaks of feedback resistor...

The EQ sounds pretty nice if you disregard any empirical info/precision and just crank the knobs until it sounds good, more like an effect in a way, and probably the way this was designed to be used...

Interested to hear any thoughts?

 

[dmnieto]

Hi Harpo, and anyone else still interested in this thread...

So this is how I finished up with my unit. (I did find a dry joint on my right channel which was causing a loss of signal).

With 14 trimmers fitted on each channel to compensate for parts tolerances, my frequency response is better, but I think its as close as its going to get.

So far, i'd say that EQ sounds "good", not excellent but I am thinking this is due to some dips in low end frequencies. Attached is how my frequency response ended up.

I feel that the signal through the EQ (all pots centered) kind of sounds like its loosing a bit of 'balls' (subjective term... maybe = loss of some low end??

Drum sample: No EQ - https://dl.dropboxusercontent.com/u/108741277/niteeq/drumloop-noEQ.mp3
Drum sample: Nite EQ (all pots centered) - https://dl.dropboxusercontent.com/u/108741277/niteeq/drumloop-niteEQ.mp3

It becomes a bit of an interesting exercise - am I percieving some low end loss because I can see it on a graph, or can actually hear it? I *think* my -0.35db~ dip @ 350hz-ish is this perceived loss of low end (or "balls")

There is a pretty small volume drop with the EQ engaged due to tweaks of feedback resistor...

The EQ sounds pretty nice if you disregard any empirical info/precision and just crank the knobs until it sounds good, more like an effect in a way, and probably the way this was designed to be used...

Interested to hear any thoughts?

No, i can hear it too, but it might be more related with the fact that the tracks are massively in anti-phase... Just mono it and you will see.

In any case, hearing it only one channel at a time, it does not seem like it has lost punch for me... It is a tad brighter though.

 

[frazzman]

Hi Harpo, and anyone else still interested in this thread...

So this is how I finished up with my unit. (I did find a dry joint on my right channel which was causing a loss of signal).

With 14 trimmers fitted on each channel to compensate for parts tolerances, my frequency response is better, but I think its as close as its going to get.

So far, i'd say that EQ sounds "good", not excellent but I am thinking this is due to some dips in low end frequencies. Attached is how my frequency response ended up.

I feel that the signal through the EQ (all pots centered) kind of sounds like its loosing a bit of 'balls' (subjective term... maybe = loss of some low end??

Drum sample: No EQ - https://dl.dropboxusercontent.com/u/108741277/niteeq/drumloop-noEQ.mp3
Drum sample: Nite EQ (all pots centered) - https://dl.dropboxusercontent.com/u/108741277/niteeq/drumloop-niteEQ.mp3

It becomes a bit of an interesting exercise - am I percieving some low end loss because I can see it on a graph, or can actually hear it? I *think* my -0.35db~ dip @ 350hz-ish is this perceived loss of low end (or "balls")

There is a pretty small volume drop with the EQ engaged due to tweaks of feedback resistor...

The EQ sounds pretty nice if you disregard any empirical info/precision and just crank the knobs until it sounds good, more like an effect in a way, and probably the way this was designed to be used...

Interested to hear any thoughts?

No, i can hear it too, but it might be more related with the fact that the tracks are massively in anti-phase... Just mono it and you will see.

In any case, hearing it only one channel at a time, it does not seem like it has lost punch for me... It is a tad brighter though.

Hey there, thanks for the feedback... I didn't check that actually. When you say anti phase ... You mean the eq-d track L and R channels are out of phase with each other ? I wonder what could cause that... Xlr wiring pins reversed ?
I'll have another listen... The slight brightness/boost +0.5db~ in the highs could be attributed by the wide high end freq boost

 

[frazzman]

EDIT: Looking at the waveforms I can see exactly what you mean, completely out of phase...

 

[dmnieto]

Hey there, thanks for the feedback... I didn't check that actually. When you say anti phase ... You mean the eq-d track L and R channels are out of phase with each other ? I wonder what could cause that... Xlr wiring pins reversed ?
I'll have another listen... The slight brightness/boost +0.5db~ in the highs could be attributed by the wide high end freq boost

I'd say that you have the hot an cold pins in one of the channels reversed, or some kind of wiring issue. It was quite fenomenal on a first listen because it felt like the sound was bouncing from one side to another in my room when i moved the head a little bit.

But yeah, I did feel a slight less punch and detail in the sound, it could be because the original was a bit louder and that somehow the mp3 compression added more artifacts. It is also that the 350Hz is right in the middle of where the fundamentals of the kit/snare are so the 0.5dB difference can actually be heard. Dunno.

Do you mind printing the wav files and inverting the phase of one of the channels?

 

[frazzman]

Hey there, thanks for the feedback... I didn't check that actually. When you say anti phase ... You mean the eq-d track L and R channels are out of phase with each other ? I wonder what could cause that... Xlr wiring pins reversed ?
I'll have another listen... The slight brightness/boost +0.5db~ in the highs could be attributed by the wide high end freq boost

I'd say that you have the hot an cold pins in one of the channels reversed, or some kind of wiring issue. It was quite fenomenal on a first listen because it felt like the sound was bouncing from one side to another in my room when i moved the head a little bit.

But yeah, I did feel a slight less punch and detail in the sound, it could be because the original was a bit louder and that somehow the mp3 compression added more artifacts. It is also that the 350Hz is right in the middle of where the fundamentals of the kit/snare are so the 0.5dB difference can actually be heard. Dunno.

Do you mind printing the wav files and inverting the phase of one of the channels?

Hey dmnieto,

You're a legend ! I can now see I have reversed the hot and cold pins on the left channel XLR in. What an idiot I am!!! Because these boards are self etched , there's no silk screen so I stupidly wired the input wrong on this channel! I'm pretty certain it will work properly now. The dip at 350hz is only about -0.3, it's wide as well so I don't think it should be too catastrophic...
But having the polarity totally flipped on one channel is diabolical!
I really was scratching my head wondering why it sounded so "odd", interestingly as you tweak some of the knobs, it kind of started to sound better (phase shift due to boosting certain bands..?)
Anyhow I'll report back soon once I've fixed it. Such a simple oversight that I embarrassingly have probably spent hours working on - I'm glad I posted the sound clips and that you took the time to listen to them. Thanks again...

 

[dmnieto]

You're a legend ! I can now see I have reversed the hot and cold pins on the left channel XLR in. What an idiot I am!!!

You are not an idiot, I made the same mistake on one of my 1176. I chased that one for a full weekend. In my case it manifested as oscillation at low levels... This was due because I was measuring on a single ended equipment and reversing the phase was actually creating a positive feedback instability when I was using the passive attenuator so the signal was very close to ground.

On the other hand, it was a cool LFO.

 

[frazzman]

You're a legend ! I can now see I have reversed the hot and cold pins on the left channel XLR in. What an idiot I am!!!

You are not an idiot, I made the same mistake on one of my 1176. I chased that one for a full weekend. In my case it manifested as oscillation at low levels... This was due because I was measuring on a single ended equipment and reversing the phase was actually creating a positive feedback instability when I was using the passive attenuator so the signal was very close to ground.

On the other hand, it was a cool LFO.

This is perfect .... All fixed! Such a minor oversight with major implications. The sound was so strange before, it makes perfect sense now ... And more importantly it sounds awesome, the way I thought it always should have sounded.
I'm glad you found your bug on your 1176 build. I loved building my 1176s , the last one worked perfectly on first power up... As opposed to this build, I would hate to see how many hours I spent tweaking this unit and chasing this bizarre issue. I'll be happy never taking the lid off this thing again

 

[Jordan]

Salut,
Je découvre cet EQ aujourd'hui. Peut être un peu tard ... Est il possible d'acheter les PCB? Merci pour votre aide !
Amicalement.

Jordan

 

[steves.mastering]

Hi,

Is anyone still making these PCBs? or does anyone have the etch files so i can make myself some?

thank you very much

Ste

 

[snaper]

Hi,

Is anyone still making these PCBs? or does anyone have the etch files so i can make myself some?

thank you very much

Ste

Interested in etch layout too

 

[Whoops]

Hi,

Is anyone still making these PCBs? or does anyone have the etch files so i can make myself some?

thank you very much

Ste

Schematic:

https://dl.dropboxusercontent.com/u/12176165/Night%20EQ%20Docs/Nite_3D_EQ.JPG

BOM:

https://dl.dropboxusercontent.com/u/12176165/Night%20EQ%20Docs/NIGHT_EQ_Parts.doc

https://dl.dropboxusercontent.com/u/12176165/Night%20EQ%20Docs/Nite_EQ_Parts_-_fIXED.xls

 

[peterc]

Hi Whoops

PM sent regarding these files.

Peter

 

[Whoops]

Hi Whoops

PM sent regarding these files.

Peter

Links removed

 

[mrscary]

Does anybody still have PCBs available for this, or perhaps the etching files so I can make my own?

Thanks