I need some help!
I did something stupid. I decided to mod my CMoy, eliminating the rail splitter, and since it runs off 2x 9V in series, I'd just use the middle lead as the ground. I made this decision in some haste, and didn't really think it through. I am using one of the switched Alps pots, how can I work that switch in so that one switch will break both circuits?
 
I'm probably going to have to move it to a new board, but I really can't figure out how to do it. If I don't figure it out soon, I may just use a BUF634 that I have lying around as a replacement for the rail splitter, my goal was just to up the current a bit.
 
Thanks in advance, guys!

Unfortunatly you can't if you want to use two batteries that way it'll need a DPDT (double pole double throw) switch
 
cheers

Quote:

fred_fred2004 said:

Unfortunatly you can't if you want to use two batteries that way it'll need a DPDT (double pole double throw) switch
 
cheers

Click to expand...

I was sorta hoping for a transistor or relay based solution. Else maybe some reason not to go with a transistor or relay solution.
 
Maybe something like this: http://www.radioshack.com/product/index.jsp?productId=2062481&filterName=Brand&filterValue=RadioShack
or: http://www.radioshack.com/product/index.jsp?productId=2062483&filterName=Brand&filterValue=RadioShack
 
Also, what about this?
http://www.diyaudio.com/forums/construction-tips/200131-switching-dual-supply-rails-single-switch.html

Quote:

scootsit said:

I was sorta hoping for a transistor or relay based solution. Else maybe some reason not to go with a transistor or relay solution.
 
Maybe something like this: http://www.radioshack.com/product/index.jsp?productId=2062481&filterName=Brand&filterValue=RadioShack
or: http://www.radioshack.com/product/index.jsp?productId=2062483&filterName=Brand&filterValue=RadioShack
 
Also, what about this?
http://www.diyaudio.com/forums/construction-tips/200131-switching-dual-supply-rails-single-switch.html

Click to expand...

I would recommend using 2 Reed-Relays instead of 1 Mini-DPDT (or DPST) Relay because the coil current of Reed-Relays are Significantly Lower (around 6mA each).
 
Otherwise, You can use 1 P-MOSFET and 1 N-MOSFET to switch both rails.

Quote:

akiroz said:

I would recommend using 2 Reed-Relays instead of 1 Mini-DPDT (or DPST) Relay because the coil current of Reed-Relays are Significantly Lower (around 6mA each).
 
Otherwise, You can use 1 P-MOSFET and 1 N-MOSFET to switch both rails.

Click to expand...

Thanks for the suggestions!
 
What are the drawbacks of using relays?

Can someone check this circuit for me?
It should work in theory.
 

 
EDIT:
Someone just pointed out to me that I connected the S / D terminals on the P-MOSFET the WRONG WAY AROUND.

Quote:

scootsit said:

Thanks for the suggestions!
 
What are the drawbacks of using relays?

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They use an electro-magnet to hold the contacts in place, This requires a large current (relative) and will shorten battery life.
On the other hand, MOSFETs do not because they operate using an electric field.
 
Comparison:
 
EDIT:

MOSFET	RELAY
Small Voltage Drop (< 1V per rail)	No Voltage Drop

 
Voltage Drop depends on MOSFET used.

Quote:

akiroz said:

They use an electro-magnet to hold the contacts in place, This requires a large current (relative) and will shorten battery life.
On the other hand, MOSFETs do not because they operate using an electric field.
 
Comparison:

MOSFET	RELAY
Solid State	Mechanical
Small	Large
Low Power	High Power
Silent	Clicking
High cost	Low cost
Vulnerable to ESD	Electrically Robust
Long life	Short life

 
EDIT:

MOSFET	RELAY
Small Voltage Drop (< 1V per rail)	No Voltage Drop

 
Voltage Drop depends on MOSFET used.

Click to expand...

I'm thinking that bridging the switch in the pot and simply adding a DPST switch will likely effect the sound least.

Quote:

scootsit said:

I'm thinking that bridging the switch in the pot and simply adding a DPST switch will likely effect the sound least.

Click to expand...

Not sure what you mean by bridging the pot. switch....
 
But none of the above methods would affect SQ. 

Someone from DIYAudio suggested this circuit which also works in simulation.
 
 

Quote:

akiroz said:

Quote:

scootsit said:

I'm thinking that bridging the switch in the pot and simply adding a DPST switch will likely effect the sound least.

Click to expand...

Not sure what you mean by bridging the pot. switch....
 
But none of the above methods would affect SQ. 

Click to expand...

The pot I have is switched, and acts as the main power switch, I was going to jumper it and just do that. But, that last one you posted, I like, very simple.The only problem is that my switch is set into the pot and onto the board. The switch has to be between the power supply and the first transistor, or after it, on the V+ side, it cannot be on the base. Again, unless I jumper the switch in the pot, and add a second switch, which could just be a dpst switch to begin with.
 
The more I think about the circuit on the board, the more I think that if I want to use the stock switch, it will have to be relay based, because the switch is between the battery V+ and the opamp V+, directly, there is no way to move the switch, so the switch has to be a part of the V+ circuit, and the V- simply controlled by whether or not the V+ is powered. A relay may work, but I don't know how well. Is there any way to have the transistors in parallel with the opamp, basically, or have the switch come before the transistors? Not sure if that makes any sense... Sorry.
 
Ultimately, would it work if the switch was between the battery and the collector of the PNP, with the remainder of the circuit also coming on the collector side of the PNP?
 
I stole this picture from wikipedia, wouldn't it work if the emitter from this circuit went to the base of another transistor? http://en.wikipedia.org/wiki/File:Transistor_as_switch.svg
The circle "X-ed" out is a load.

Quote:

akiroz said:

Someone from DIYAudio suggested this circuit which also works in simulation.
 
 

Click to expand...

If you eliminated the transistor at the top, and moved the switch to just after the supply. Such that the base had a resistor coming from V+, wouldn't that saturate the base and act as a switch if the red were V-?

Quote:

scootsit said:

If you eliminated the transistor at the top, and moved the switch to just after the supply. Such that the base had a resistor coming from V+, wouldn't that saturate the base and act as a switch if the red were V-?

Click to expand...

That would work id the circuit isn't connected to a load.
In which case, when the switch is open, both rails would be at -ve voltage.
But it IS connected to a load it'll try to make both rails at 0V will just automatically open the transistor 
Since 0V is positive relative to -Ve.

Quote:

akiroz said:

Quote:

scootsit said:

If you eliminated the transistor at the top, and moved the switch to just after the supply. Such that the base had a resistor coming from V+, wouldn't that saturate the base and act as a switch if the red were V-?

Click to expand...

That would work id the circuit isn't connected to a load.
In which case, when the switch is open, both rails would be at -ve voltage.
But it IS connected to a load it'll try to make both rails at 0V will just automatically open the transistor 
Since 0V is positive relative to -Ve.

Click to expand...

Darn. Shorting the switch in the pot and putting a new switch in is sounding more and more appealing.

Quote:

scootsit said:

Darn. Shorting the switch in the pot and putting a new switch in is sounding more and more appealing.

Click to expand...

Yes, you can either do that or use something like this:
the extra MOSFET is an inverter.