DIY: Summer Projects

[captain paranoia]

What is your filter design supposed to do? Where did you get the design from? A schematic would help.

https://en.wikipedia.org/wiki/RLC_circuit

 

[Silou]

What is your filter design supposed to do? Where did you get the design from? A schematic would help.

https://en.wikipedia.org/wiki/RLC_circuit

These are the passive filters designed by solderdude to reduce peaks. The parts in the picture apply to the Amiron Filter.

 

[solderdude]

Exactly... that goes in series with the 'hot' wire.

As you mentioned I could change the volume of the DAC, but I do not know if my future DAC will be able to do that
I have got some IEMs, but there is no need to use them with the new amplifier since I have the Atom as a "backup"

Parts List:
- 2x PCB
- 2x Parts only Kit (I know that I do not need two full kits, but I guess it might be good to have some backup parts)
- Input and Output sockets (2x 3-Pin-XLR female, 1x 4-Pin-XLR female)
- power supply
- parts for the modification of the negative board

Did I forget something?

enclosure... It can't hurt to have a spare volume control. Some of them start to become scratchy quite quickly.

 

[Silou]

I guess enclosure is optional until everything is built and I figured out if I want to build the filters inside. Are the volpots fine or should I get a "proper" one?

 

[solderdude]

volpots work fine ... they have some imbalance in the bottom part of the range.
Some a bit less than others ... a lottery really.

 

[Silou]

What are the differences/pros/cons of stepped attenuaters compared to a normal potentiometer?

 

[solderdude]

stepped attenuators have less imbalance but a stepped range where normal pots are gradual (stepless).
It really only is an issue when a normal volpot is below 8 o-clock position.
There are great 'normal' volpots though. The Alps Blue velvet series never failed me.
I have some still in use for over 30 years.. work as new till today.

Stepped attenuators can have a really nice feel to it and you could customize the 'curve' if one so desires by replacing resistors.

Instead I would recommend to use software volume control. No more imbalance and as good as stepless.

 

[Silou]

I do not really want to give up on a physical volume control unless it makes things really complicated. I saw some stepped attenuators on Aliexpress. These cost roughly the same as the Alps Blue Velvet you mentioned. 23 steps seems a bit low tough

 

[solderdude]

You could try one, they won't break the bank. Ali also sold Blue Velvet for about half the price of the stepper. No idea if they are the real ones though.

 

[Silou]

You could try one, they won't break the bank. Ali also sold Blue Velvet for about half the price of the stepper. No idea if they are the real ones though.

Which resistance would be required?

 

[solderdude]

10k will be fine

 

[Silou]

The Amiron Filters are done. What do I have to measure to assure they work how they are supposed to work?

 

[solderdude]

listen to it with it and when bypassed (just short it to bypass it)
If you want a little less filtering lower the resistor value. If you want a little more remove the resistor.

Check if the capacitor is 220nF or 0.22uF.
The inductor looks like the 1.5mH (1500uH) I use as well so is probably O.K.

Bye, bye sibilance/sharpish 'edge' should be the result.

 

[Silou]

These are the parts I mailed you to check if they are correct and you told me they will be fine. The K712 Filter is finished aswell. The capacitor for the HD58X was not in stock sadly. I will solder them to some connectors and report back. Lets say I screwed it and got cold solder joints. Can it damage the headphones or amplifier in this case?

 

[solderdude]

Nope... besides the solder-joints look fine.

My experience with parts suppliers (especially Conrad) is that sometimes they send the wrong components despite the description and order code being correct. Have had this happen a few time already.

The resistor and inductor are fine. Just read the capacitance value on the caps.
All I can verify is that the vendor has the right description not what they actually send.
The resistor is the correct one for sure and the inductor the same as I order.

In the filters I supply I use SMD capacitors and resistors so I can fit all of it in a small tube. I would not even wish my enemies to solder those tiny parts (1206 is not extremely small).
The selected values for caps and resistors are selected so they can be soldered quite easily and technically are superior.

I can select another 1.5uF cap if you don't want to wait for it.

 

[Silou]

The Amiron capacitors say 22K63 and the K712 capacitors say 2u2K63. This is the Amiron test setup

Edit: It works

 

[solderdude]

The 22k should have said 220k..
That might be the wrong one.
Perhaps that one is 22nF (22kpF) instead of 220nF but it could also be that the cap says .22k (the point before 22k is essential here) in which case it is the correct one after all.
The order code is for the 220nF
Kemet R82DC3220AA60K+ 1 St. Polyester-Kondensator radial bedrahtet 220 nF 63 V 10 % 5 mm (L x B x H) 7.2 x 2.5 mm x 6.

IF the peak is not reduced (significantly) the capacitor is not the correct one.

 

[Silou]

There is a point. Did not know that the point is important.

 

[solderdude]

Ah yessss.
The filter is correct it seems.
Plug it in and have a thorough listen.
Check if L and R are correct. The data sheets of the socket should give the clues as to what is tip (left channel) and Ring (Right channel)

There are times where I thought a headphone sounded vastly different while all I did was swap the L and R channel.

 

[Silou]

Check if L and R are correct.

There are times where I thought a headphone sounded vastly different while all I did was swap the L and R channel.

That is actually the first thing I do everytime, because I usually screw it up
The Amiron filter works. I will try the K712 now.
The HD58X capacitors will probably arrive until I am back from my vacation so no need to look for other ones since I already paid them.