Author Topic: A/B box to both series and parallel?  (Read 5438 times)

PaxWorks

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A/B box to both series and parallel?
« on: May 06, 2011, 01:44:09 PM »
I'm still new to efffects building so please be patient with me. I plan on purchasing the POG2. I like the way it sounds in parallel as well in series with other pedal. I don't want to have to buy two,(one connected in parallel the other in series on my pedal board).

I was wondering if it would be at all possible to build some kind of A/B box that would let me switch the effect from parallel to series in realtime? This way I could get those "shimmering" underneath my tone and when I want to play the guitar like a synth pad.

Myramyd

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Re: A/B box to both series and parallel?
« Reply #1 on: May 06, 2011, 02:47:55 PM »
Well, you might have to use a 4PDT switch, because you have to switch both the input and output at the same time. But it could be done.

I just did a similar thing with my POG and Whammy so I could run them in parallel to each other for multiple harmonies.

J
« Last Edit: May 06, 2011, 02:51:30 PM by Myramyd »

Myramyd

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Re: A/B box to both series and parallel?
« Reply #2 on: May 06, 2011, 02:49:29 PM »
One thing to note however, is there is a gain difference when running in parallel. You might want to build in a pot to balance it out. Otherwise it adds some gain and a bit of noise when running in parallel full out.

J

Myramyd

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Re: A/B box to both series and parallel?
« Reply #3 on: May 06, 2011, 02:55:05 PM »
I wonder if you could just build a looper pedal and have the input and output jumpered in some particular fashion.

Hmmm....maybe somebody else can debate this.

J
« Last Edit: May 06, 2011, 02:56:57 PM by Myramyd »

JakeFuzz

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Re: A/B box to both series and parallel?
« Reply #4 on: May 06, 2011, 03:03:53 PM »
Yeah I think your best bet would be a Paramix with a series bypass switch.

jkokura

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Re: A/B box to both series and parallel?
« Reply #5 on: May 06, 2011, 03:45:56 PM »
I have a splitter/buffer layout for you, which will give you a buffered parallel signal. From there, you need a mixer at the output, and you can use a true bypass loop to activate the parallel effect. I'll post some more details for you later tonight on how I would do it.

Jacob
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PaxWorks

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Re: A/B box to both series and parallel?
« Reply #6 on: May 06, 2011, 04:51:11 PM »
I have a splitter/buffer layout for you, which will give you a buffered parallel signal. From there, you need a mixer at the output, and you can use a true bypass loop to activate the parallel effect. I'll post some more details for you later tonight on how I would do it.

Jacob

That sounds great. Can't wait to check it out.

jkokura

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Re: A/B box to both series and parallel?
« Reply #7 on: May 07, 2011, 12:19:02 AM »
K, didn't get to this tonight. Will post more details. Suffice it to say, it's probably more simple than you'd imagine, but it might require some experimentation.

Jacob
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jkokura

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Re: A/B box to both series and parallel?
« Reply #8 on: May 07, 2011, 10:21:00 AM »
Ok, on further review, I agree with Jake Fuzz that the Paramix is an excellent suggestion. You can find details on that here: http://www.buildyourownclone.com/board/viewtopic.php?f=41&t=20555 and I will likely be working up a layout based on that schem soon.

An alternate way with a much lower parts count, and the way that I was going to suggest, would be to use a simple buffer-splitter (see attached layout, not yet verified, available soon) to split your signal into 'dry' and wet'. Then you'd use a passive mixer at the other end, which essentially a volume pot rigged up to share an output. This could be rigged up to be an active mixer with very little effort, simply using another pair of gain stages to drive the volume pots. In between, the dry would simply run through one side and be continuously available at the output. The wet however would go first to a bypass switch, and then through a send and return jack.

That is essentially what the paramix circuit does, however it also accounts for the phase relationship of the circuits. Helpful if you need that sort of thing, but it's a much higher parts count than you 'need' persay. Still a good solution in this case.

Jacob
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bigmufffuzzwizz

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Re: A/B box to both series and parallel?
« Reply #9 on: May 07, 2011, 11:36:16 AM »
Just grabbed a paramix from guitarpcb.com which i'm very excited to build. 2nd one is definitely going to be done with tonmann's vero!
Owner and operator of Magic Pedals

JakeFuzz

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Re: A/B box to both series and parallel?
« Reply #10 on: May 07, 2011, 12:14:53 PM »
I am building one on vero right now for a guy. The only additional modification he wants is a Baxandall eq on the wet return signal, easy (I lifted it out of the AC booster).

I think it should be said about the paramix that if you only build a one channel version you can only mix your clean (or dry) signal with the wet loop. If you want to mix two or more wet effects in parallel you will need a two channel mixer which you could do by duplicating the return loop circuitry (adding a dual opamp).

A bypass switch could easily be wired to make the pedal just run in series and skip all the mixing electronics. I think the video demo on guitarpcb shows a paramix with a series bypass footswitch. 

PaxWorks

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Re: A/B box to both series and parallel?
« Reply #11 on: May 08, 2011, 10:59:19 PM »
All these examples sound great. I'm gonna try each suggestion to see what will work best. Thanks for the help. :)