Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Balance on amp (Nigel...?)

Status
Not open for further replies.

grrr_arrghh

New Member
Hi

i'm trying to add a balance function to an amp (u've prob seen the posts). Nigel told me to add this to the output of the amps, so that the pot would control balance (shown below, but without all the extra bits around the op-amp). it looks good on paper, but doesn't work in real life...

why not? (i can't see any faults in my circuit)

Tim
 

Nigel Goodwin

Super Moderator
Most Helpful Member
grrr_arrghh said:
Hi

i'm trying to add a balance function to an amp (u've prob seen the posts). Nigel told me to add this to the output of the amps, so that the pot would control balance (shown below, but without all the extra bits around the op-amp). it looks good on paper, but doesn't work in real life...

why not? (i can't see any faults in my circuit)

Neither can I - because it's not there :lol:

When you say you've added it to the output of your amps, what exactly do you mean? - from what I remember, this was to do with a simple mixer.
 

grrr_arrghh

New Member
lol

very funny

sorry, here is it

by amps, i meant op-amps
 

Attachments

  • balance.JPG
    balance.JPG
    10.3 KB · Views: 218

Nigel Goodwin

Super Moderator
Most Helpful Member
grrr_arrghh said:
lol

very funny

sorry, here is it

by amps, i meant op-amps

These are for the individual input channels to the mixer aren't they?, the output resistors cound be the mixing resistors into the mixer op-amps.

What doesn't work about the circuit?.

One possibility I've just thought of - are you using a split supply?, if not you will probably require DC blocking capacitors.
 

grrr_arrghh

New Member
hi

what doesn't work - the circuit works in general - it mixes, amplifies, and the volume control pots work, but when I tried to add your balance control, it did something a bit strange. instead of making one speaker louder and the other quieter (when the pot was turned) it just made BOTH speakers quiter... which is a bit strange

as for the split supply - i'm using a single 9v PP3, and a a 'Midpoint HT Rail' (diagram below - I hope)
 

Attachments

  • mix_134.jpg
    mix_134.jpg
    27.2 KB · Views: 218

Nigel Goodwin

Super Moderator
Most Helpful Member
You need to make sure that there's no DC fed to the balance control, otherwise it will upset the DC conditions. On the circuit above, where exactly are you connecting the balance circuit?.
 

grrr_arrghh

New Member
ah, well

you see the first circuit I posted - where the resistors are connected to the op-amps, there is actually a capacitor between them. Soooooo... on the circuit above - the balance circuit is simply inserted between the cap, and the pot (the pot with 'output' written next to it)

Does that make any sense?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
grrr_arrghh said:
ah, well

you see the first circuit I posted - where the resistors are connected to the op-amps, there is actually a capacitor between them. Soooooo... on the circuit above - the balance circuit is simply inserted between the cap, and the pot (the pot with 'output' written next to it)

Does that make any sense?

The values you have chosen are too low to go there. You could try your existing values on the input to the pots, depending what it's been fed from. Or use higher values.
 
Status
Not open for further replies.

Latest threads

Top