28 vs 14 pin autoformers

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

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androxylo
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Joined: Sun Feb 21, 2021 4:01 pm

28 vs 14 pin autoformers

Post by androxylo »

Hi Dave and folks,

I want to start my autoformer soldering project in a week but please help me to decide. Now you have this new $400 variant with 2 DB steps instead of 3 DB, but I'm a bit scared that it could be a lot more tricky to solder. My questions:

1. can you please post the 28 steps autoformer picture next to a coin? Next to the 14 steps one? I want to visually assess how hard it could be. I am beginner solder, I definitely can do simple projects but I am not sure about this one.

2. Folks who already tried the 28 step variant - did it work for you? Are you happy with sound? Do you think 2 DB is much better than 3 DB?

3. I see the already wired 23 step solution. But why it still has 3 DB steps? I think 23 steps would be enough for me, but I am not sure 3 DB is right.

I will use for my desktop system, from Schiit Modius DAC to Aegir amp, the gain is far too huge, I am using Sys volume pot at 9 am dial. I am not sure how much is say -20 DB, but my working range will be quite far on the suppression scale.
dave slagle
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Re: 28 vs 14 pin autoformers

Post by dave slagle »

replies..

1) I don't have a picture handy but the 28 step is simply the 14 step with pins on both sides. It is no more or less difficult to solder but keeping track of the wires becomes the main issue.

3) the prewired modules have 3dB steps at the beginning and end and 2dB steps in the middle.

dave
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androxylo
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Joined: Sun Feb 21, 2021 4:01 pm

Re: 28 vs 14 pin autoformers

Post by androxylo »

Oh, thanks - indeed now I see that the prewired version has 2 DB steps in the 12-36 interval. Perhaps the page should make it more explicit. It looks like a deal maker to me, I hope I won't need the range beyond 36 much with desktop listening. I'll have funds in a week, thanks a lot David!
androxylo
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Joined: Sun Feb 21, 2021 4:01 pm

Re: 28 vs 14 pin autoformers

Post by androxylo »

Hi Dave,

I've received my prewired 23 steps order, looks super cool, thanks!

However there is no schematics attached. There are 4 pins, what they are?

Thanks!
-A
androxylo
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Re: 28 vs 14 pin autoformers

Post by androxylo »

Ok, sorry, I found - instead of wiring to the pins there are actually 3 holes marked as Gnd, In, Out. I was confused because I thought the connector will have the form of a pin, not a hole.
androxylo
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Joined: Sun Feb 21, 2021 4:01 pm

Re: 28 vs 14 pin autoformers

Post by androxylo »

I wired it and very pleased with result. Just the basic copper autoformer is clearly superior to Schiit Sys pot I used. Great job Dave, thank you!
androxylo
Posts: 7
Joined: Sun Feb 21, 2021 4:01 pm

Re: 28 vs 14 pin autoformers

Post by androxylo »

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