avc questions

discussion of magnetic volume control design for both line and speaker levels.

Post Reply
oceanobsession
Posts: 4
Joined: Mon Aug 26, 2019 3:11 pm

avc questions

Post by oceanobsession »

Hi dave my first post im interested in the avc some questions please

1. 0 to 42db of attenuation is 0 full volume and 42 no volume
2. 14 pins on your avc what 2 are joined via a switch for lowest volume
3. what size are the pins could you use a connector instead of soldering
4 I would need a 2 pole switch with at least 14 steps if you use a 24 step would
you just not use the 10 5 at the start and 5 at the end
5. would you keep the attenuator as close as poss to the avc either side
that's all for now. phil.
dave slagle
Posts: 2085
Joined: Sat Jan 22, 2005 3:54 am
Location: NYC
Contact:

Re: avc questions

Post by dave slagle »

oceanobsession wrote:Hi dave my first post im interested in the avc some questions please

1. 0 to 42db of attenuation is 0 full volume and 42 no volume
-42dB is the lowest setting with sound. you can wire the ground tap to the switch which will provide a mute or off setting.
2. 14 pins on your avc what 2 are joined via a switch for lowest volume
the signal input wire is attached to the source and ground is attached to signal ground then the last pin and ground are used for the lowest volume setting. (-42dB)
3. what size are the pins could you use a connector instead of soldering
pins are 0.028" square and a connector could be used but any noise from a bad or intermittent connection could be problematic.
4 I would need a 2 pole switch with at least 14 steps if you use a 24 step would
you just not use the 10 5 at the start and 5 at the end
16 positions on the swithc allow for full volume and mut. If there are more than 24 positions and no adjustable stop you can pick any of the switch taps you want. I would put ground all the way counter clockwise and once you reach full volume (0dB) I would connect the remaining switch positions to the full volume setting. This will prevent an open setting and you will simply not hear it get louder once you past the last tap. A 12 position switch could be used and then you can just select the taps that represent the volume range you would need. I do offer several options prewired to switches which make installation much easier.
5. would you keep the attenuator as close as poss to the avc either side
since the autoformer has a lower output impedance I like to place it as close to the source as possible and since it is a magnetic device keeping it away from power sources is also a good idea. The switch should be wired as close to the autoformer as possible.

a general FAQ that explains most of this in more detail can be found here
Get Your Fix
www.hifiheroin.com
Post Reply