z3d
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Post by z3d on Jun 22, 2015 20:43:36 GMT
Wired the DC/DC and the 3 last caps (electrolitic ones); I placed a bit of blu-tack under the converter to avoid vibrations and movements:  I'm waiting for the 4x female rca panel connectors and the isolated supply connector to arrive so I can finish the job and start testing the board to see if all is working fine, before putting it in the system. For the eclosure I gave a look to the Hammond 1457C1201 and I like that the filter board can be fitted in without any screws. What I'd prefer is a larger enclosure (something like 120x80-90mm H35-40mm) in order to fit the 4x rca connectors in a single row. I will check this, I noticed Hammond offers many different measures and so other manufactures so it will not be a big problem. |
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z3d
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Post by z3d on Jun 24, 2015 13:35:23 GMT
That's a franken-filter, lol!
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solderdude
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Post by solderdude on Jun 24, 2015 15:37:32 GMT
You can do some pré-checking already.
Connect the 48V and check (without op-amps) that the '8' pins all have +15V (or 12V depending on converter) on it and the '4' pins all have -15V (or -12V) on it.
Don't worry if the voltages are slightly off.
Then insert the opamps (if all is well) and check all pins again.
Aside from the power pins (4 and 8) all other pins should be very close to 0V
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z3d
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Post by z3d on Jun 24, 2015 19:36:28 GMT
I have to wait till the power supply connector arrives but then I will make these tests, thanks Frans.
About the 10KOhm potentiometer, all CCW what exactly does and all CW what it does? I used a couple of Bourns series 3362P.
I gave a look to the datasheet of the DPDT rocker switch I bought (http://www.digikey.com/product-search/en?KeyWords=432-1252-ND&WT.z_header=search_go) but they don't tell much about the pinout; have you any clue about how I should wire it or it's better to directly contact Carling Tecnologies for these informations?
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solderdude
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Post by solderdude on Jun 24, 2015 19:54:04 GMT
CW = Clockwise (like a turning up the volume)
CCW = counter clockwise (like turning down the volume)
The potmeter (in this case) controls the 3kHz 'dip'.
Fully clockwise it doesn't filter 3kHz at all, fully counter-clockwise it filters the most (-3dB).
The potmeter range is not 'linear' to the hearing so it will do the most near one of the 'ends' of the potmeter.
So in the middle setting it just filters -0.5dB or so not - 1.5dB as one may expect.
The filter works as designed when it is set almost turned fully to the left (CCW) set it to around 10% (when 100% is fully clockwise).
Of course you should experiment and may find it better in another position.
Adjust L and R potmeters at the same time and set them in the exact same position.
If you want even more 3kHz filtering (a larger range on the potmeter) a resistor value needs to be changed.
For most switches the middle pin is the 'common' and the other are the contacts.
I would say measure the contacts with your multimetermeter (Ohm or 'beep' setting) as often the contacts on the opposite side toi where the swicth rocker points to is made.
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z3d
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Post by z3d on Jun 25, 2015 17:03:25 GMT
Thank you for the explanation. To change the subbass lift a couple of resistors should be changed? I checked the rocker, connection questions solved. I'm taking my time to choose the enclosure; I'd like to stack the filter under Ember because the former will be quite lightweight and with the cables connected I think it will lean toward the side without connections and that's not nice. If you think stacking both together will give too much hum/emi problems I will check for a bigger and heavier enclosure for the filter so I can put it alone on the table without any problem. Anyway I think I will fit the board into the enclosure by the longer side so I have more room for the rca+power connector plugs and I can make short wirings (braided couples).  |
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solderdude
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Post by solderdude on Jun 25, 2015 20:40:36 GMT
Listen to the filter first.
You can change the whole filter action by changing resistors and capacitors.
Just use the filter PCB without an enclosure.
If it doesn't pick up hum etc you can make it open frame.
Personally I like all my equipment screened.
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z3d
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Post by z3d on Jun 27, 2015 14:40:39 GMT
Yesterday the power connector arrived and today I checked the board on 48Vdc.
Without op amps I have a stable +-15,02-15,03V on all sockets, with the 4x opamps inserted I have a stable +-14,94V on all operationals.
The small drop should be cause of the little current draw of the 4x op-amps and I assume all is working fine.
Also all the pins 1,2,3,5,6,7 measures near 0V.
Are there any other checks which I could do?
About the two solder points on the board labelled as "gnd", do I have to solder a 2x1 strip in those and bridge them together?
I'm using power option 4, isolated power connector and isolated rca connectors.
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solderdude
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Post by solderdude on Jun 27, 2015 15:47:48 GMT
All connections marked 'gnd or ground' are connected.
You can connect the ground (screen) of the left channel to the left side and the ground of the right side to the ground on that side.
Just connect the audio connectors and give it a go.
Just connect the input voltage to the appropriate connections.
The 48V is separated (electrically) from the ground.
So when you use it with the Ember you can also 'split' the power supply of the Ember and use this power supply to fed both the Ember and the filter at the same time.
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z3d
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Post by z3d on Jun 27, 2015 17:13:04 GMT
About the gnd I mean this, give a look to the red circled marking "GND":  I checked with the multimeter the pin on the left side of this "GND" and it's connected to the 0V (input, on the center left of the image) and to all the ground on the board (for example on the right pin of R214 near IC202 and so on..). The pin on the right side of "GND", however, isn't connected to those points but only to the adjacent hole for the screw. This hole for the screw isn't connected to the other 3x holes for the screws. Should I solder a 2x1 strip on this "GND" and put a little jumper (or well, just solder together the 2 plated holes) and screw the adjacent hole to the chassis to improve emi/rfi rejection or it's not useful? And if for the moment I only use the filter board without an inclosure, it's better to just leave those GND points as they are? At the moment I'm only waiting the 4x rca sockets to arrive from HK, that's something like 20days of waiting now...uff! |
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solderdude
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Post by solderdude on Jun 28, 2015 7:14:49 GMT
That jumper indeed connects the ground plane to the mounting hole right next to it.
If you have a metal enclosure and mount the PCB with screws to that metal enclosure you can put a solder-drop between those pads which connects the chassis to ground.
It's optional and can save you a wire.
The screw used should have spring washers when using it.
When you want to ground the PCB to the enclosure while sliding in the PCB you can connect a wire connected to the chassis (under one of the rear panel screws ?) and connect it to the '0V' pin or connect it to the left GND pad.
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z3d
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Post by z3d on Jul 5, 2015 21:38:58 GMT
I'm working on the enclosure :<
Frans, is it possible to "play" with the potentiometers when the filter is powered and a signal is processed through it (music ON) or this is something unsafe to do?
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solderdude
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Post by solderdude on Jul 6, 2015 9:18:37 GMT
Yes you can play with the potmeters while using it.
Remember to adjust BOTH pots at the same time in the same way.
Also not that the potmeters are linear and their range is limited.
For instance the potmeter can have a range of 0dB to -3dB over the entire range.
It doesn't work like a standard graphic EQ with +/-12dB.
Also only near the 'end' of the potmeter range you will hear the effect.
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solderdude
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Post by solderdude on Aug 11, 2015 17:47:12 GMT
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oldson
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Post by oldson on Aug 31, 2015 18:04:28 GMT
Frans,
just wanted to ask a (probably stupid) question.
how different are the lcd2 and hd650 filters?
reason i ask is i am buying an hd650 from Ian and wondered if my lcd2 filter could be adjusted to get close to the requirements of the senn.
cheers
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