Poll! What do you use in your X-BOSOZ or BOSOZ for Volume Control and Input Selector?

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Pole! What do you use in your X-BOSOZ or BOSOZ for Volume Control and Input Selector?

Hi everybody!
I am kinda puzzled with what I should use for volume control and input selection.
I would like to have a balanced volume control so that doesnt allow the use of normal pots.
I dont like chip volume controls so that leaves me to a relay attenuator.
I dont have a clue how to programm a microcontroller so it kinda hard to find a solution.
does anybody have an idea?
or what are you using in your preamp?

Would really like to hear from you guys?
 
I'm still thinking (and hoping for some advice).

I dont really need a remote, but I do want 2 balanced and 3 single ended inputs (and top quality).

My options:

- Go DACT all the way and pay the price (230 euro for a 4-deck volumecontrol only)

- Thel CP-2500 pot - 85 euro for 2 deck (of 109 met motor). I don't know if they sell a 4 deck pot for balanced control. Onky volume control, so you haved to add a input selector.

- use a relay based kit, such as :
Dantimax RelVol3 - 48 euro (only volume) + input2 - 75 euro (2 balanced, 3 single endend)? PS (30 euro) en remote control (24 euro) or so. According to the pictures this includes XLR and RCA inputs.

Or some of the stuff from Diyclub biz
V3310 balanced - $68
V03 - $160 NS V03 - $260 with Holco resistors (actually don't know whats the difference).

- Look at what Russ White is designing. probably the best option if there will be some sort of kit. I understand its just volume control.

What I would like to know, soundwise is a DACT still the best??
 
Promitheus,

I´m using a simple balanced, stepped output attenuator made out of an old Elma switched attenuator.

It is simple (only two decks), you have only 1 resistor in the signal path and can make this as high quality as you want. And, it is always perfectly balanced by design.

Mine uses two 1k2 resistors as series elements and 22 1% metalfilm resistors as shunting elements. (plus one open and one closed position for mute and very loud)

I´ve got an excel sheet somewhere to calculate the attenuation in dB and the output impedance of each step.

William
 
wow! that must be balanced right? How many positions?

No, it's not. This is ladder type attenuator which means one resistor in signal path and one to ground in each position.

The switch is regular Elma 4 deck 24 position one.

For balanced one would need 8 deck switch and twice the resistors.

You can build balanced attenuator using 4 deck switch , but that would have to be series type, quite inferior to ladder , but still better than many pots.

Bartek
 
volume control - front

An externally hosted image should be here but it was not working when we last tested it.


volume control - back - ALPs

I find that these blue ALPs need to be used every so often or they oxidize,
you get little clicks when you change the settings. Not bad unless you let it sit for a
month or so.

Input selection- NAIS D4S 4 pole latching relays.
These are very nice but very expensive...if you can find them.

An externally hosted image should be here but it was not working when we last tested it.
 
going it alone

I have the same problem so I'm building my own switcher
and volume control.

I'm using the attenuator circuits from the Pass Labs manuals,
the switching is by relays also. I'm also adding some nice
trickery to have output level displays using 7-segment LEDs
BLUE of course.

I use a PIC for control and a daisy chain of shift registers
to make it look like the PIC has 64 outputs.

I am doing the board now using PCB123 - actually got the first
full layout last nite. It's not as easy as it sounds, there are
almost 600 nets on the board. The board is 6" x 8" and it
has all the circuitry on it plus areas to cut out so the PIC and
the displays can be remotely mounted. I use headers for
and terminal blocks for all the IO.

I could make it avialable to known DIY'ers.

I'll post when it's done.
 
Here's a balanced 6 channel, relay-based volume control that uses a micro-controller for my BOSOZ. It's not done yet, so don't start thinking that it actually works!
 

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