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Blenders - suggestions

Started by madbean, October 28, 2021, 12:28:16 AM

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Aentons

#15
Quote from: jkokura on October 28, 2021, 03:29:47 PM
As a guy whose primary PCB sales are driven by a Test Rig and Parallel PCB tools - the key is found in an old RG-Keen article on blending. Most blend circuits I've seen don't actually blend. The good ones find a way to ground the circuit you blend out, to actually mix the two circuits accurately. That's the first thing I'd be reading if I were you Brian.

http://www.geofex.com/Article_Folders/panner.pdf

Jacob
Very useful... Thanks for pointing that out!

I'd bet that is how the Boss LS2 A+B mix is done. It doesn't have the volume drop that some others have. One thing I like about the LS2 is that it has independent volumes on the returns, which the geofex circuit seems like it could easily accommodate without compromise.

I've always thought it would be great to have a sort of modular utility board with a single buffered send/return loop. That way you can parallel/chain them together to create a splitter/mixer with as many channels as you'd like. If you only need 1 to add a buffered effects loop, then great, if you want to try and recreate the Klien bottle with 3 of them... great, if you want to create an 12 channel mini mixer, it can do that too

Aentons

Quote from: madbean on October 28, 2021, 03:11:35 PM
maybe there is a simple version that would be useful.
It occurred to me that if use the single channel board idea, you could sell them individually or as breakable panels of 10 or whatever

Zerro

Only one little note - that Swamp Compressor schematic:
C17 has wrong polarity. There will be negative voltage at gate of j-fet. Proper detail is attached.

Some comments around attack-decay details are edited here.
"Nudíte se? Kupte si našeho cvičeného ježka! Pobaví vás svými veselýmí kousky!"

midwayfair

Quote from: Zerro on October 28, 2021, 08:02:05 PM
Only one little note - that Swamp Compressor schematic:
C17 has wrong polarity. There will be negative voltage at gate of j-fet. Proper detail is attached.

Some comments around attack-decay details are edited here.

Thanks

To be honest I'm not even totally sure it was the version of the schematic I made the board from. I thought I had done something different with the threshold in this but I've reused that envelope detector so many times that it's hard to know.

madbean

Quote from: jkokura on October 28, 2021, 03:29:47 PM
As a guy whose primary PCB sales are driven by a Test Rig and Parallel PCB tools - the key is found in an old RG-Keen article on blending. Most blend circuits I've seen don't actually blend. The good ones find a way to ground the circuit you blend out, to actually mix the two circuits accurately. That's the first thing I'd be reading if I were you Brian.

http://www.geofex.com/Article_Folders/panner.pdf

Jacob

Thanks, Jacob. I'll take a close look at that tomorrow.

Glad to see there's some interest in this topic. I drew up a bare bones AB scheme on how I think it could be accomplished with minimal components. This is what I came up with so far. Insofar as I can tell, including stereo outputs for all three options (A+B, B+A, A||B) using analog switching is not possible. Or, at least working through the logic of that escapes me so far. But, this schematic is a pretty straight-forward solution for the mono in and out implementation. The extra op-amp could be used to buffer Vb. Or, maybe use it on RTN2 and use a pot to blend its output from 0 to 180 phase. That might be cool.

Last note, maybe make R4 1M instead of 100k. That would ensure it has no influence on A+B and B+A modes.






benny_profane

The simple circuit is looking good. Series (AB / BA) with active parallel (A||B) (i.e., from Jacob's post above) would be a great utility box. Have you considered a CMOS switching solution?

Aentons

Quote from: benny_profane on October 29, 2021, 03:37:51 PM
The simple circuit is looking good. Series (AB / BA) with active parallel (A||B) (i.e., from Jacob's post above) would be a great utility box. Have you considered a CMOS switching solution?
I don't think the parallel mode is active. Wouldn't it need a buffer before the split and some gain after the mix?

madbean

Quote from: Aentons on October 29, 2021, 04:11:54 PM
I don't think the parallel mode is active. Wouldn't it need a buffer before the split and some gain after the mix?

Since you are sending one signal to two separate devices (which we would assume are both active) I don't think input buffers are needed. But, you make a good point on the outputs. If both devices have volume controls directly mixing them means one could load down the other. So, that could be fixed by adding buffers on each output and then have one of those outputs select its phase (in case it's needed). Or, cover all the bases and have either output be able to select its output phase. Two ICs are all you plus two switches.

Aentons

Quote from: madbean on October 29, 2021, 04:38:20 PM
Quote from: Aentons on October 29, 2021, 04:11:54 PM
I don't think the parallel mode is active. Wouldn't it need a buffer before the split and some gain after the mix?

Since you are sending one signal to two separate devices (which we would assume are both active) I don't think input buffers are needed. But, you make a good point on the outputs. If both devices have volume controls directly mixing them means one could load down the other. So, that could be fixed by adding buffers on each output and then have one of those outputs select its phase (in case it's needed). Or, cover all the bases and have either output be able to select its output phase. Two ICs are all you plus two switches.
If you are using the sends as a stereo splitter and have long cable runs to each amp you may want it buffered

benny_profane

Quote from: Aentons on October 29, 2021, 04:11:54 PM
Quote from: benny_profane on October 29, 2021, 03:37:51 PM
The simple circuit is looking good. Series (AB / BA) with active parallel (A||B) (i.e., from Jacob's post above) would be a great utility box. Have you considered a CMOS switching solution?
I don't think the parallel mode is active. Wouldn't it need a buffer before the split and some gain after the mix?
Sorry for the confusion. I meant to make a distinction between the posted 'simple' schematic and one with an active mixer for parallel circuits.

Aentons

Quote from: Aentons on October 29, 2021, 04:59:06 PM
Quote from: madbean on October 29, 2021, 04:38:20 PM
Quote from: Aentons on October 29, 2021, 04:11:54 PM
I don't think the parallel mode is active. Wouldn't it need a buffer before the split and some gain after the mix?

Since you are sending one signal to two separate devices (which we would assume are both active) I don't think input buffers are needed. But, you make a good point on the outputs. If both devices have volume controls directly mixing them means one could load down the other. So, that could be fixed by adding buffers on each output and then have one of those outputs select its phase (in case it's needed). Or, cover all the bases and have either output be able to select its output phase. Two ICs are all you plus two switches.
If you are using the sends as a stereo splitter and have long cable runs to each amp you may want it buffered
I'd put that extra buffer right here so as not to interfere with order switching options. You could always jumper it if you wanted to build without it

Aentons

#26
Quote from: madbean on October 28, 2021, 12:28:16 AM
Not what the title leads you to believe. With the release of the VFE DragonHound coming this week I started thinking a bit about blended circuits. The DragonHound puts the AlphaDog and PaleHorse in one box and lets you blend them in parallel (with the tone and level being shared by both). I've thought about this concept on and off for a few years but never really went anywhere with it. But, the DragonHound sounds great so I want to start tackling some other possibilities.

The two that I've already started drawing up are pretty solid ideas: An OCD and Zendrive (both using mosfet clipping, one hard one soft) and two of my favorite boosters - the AMZ MiniBoost and Mosfet boost. The boost one goes further in that it lets you run them in series (both ways) AND parallel.

Any suggestions on other blender circuits you might like? This could be another category of offerings at mbp.
The DOD FX76 Punkifier is two blended circuits. The FX13 Gonkulator is too

LaceSensor

sounds like the Boss OS-2
maybe worth checking that out?

jimilee

Nice, I'd like to see more. I've asked around, and the OS2 was not very popular, but I'd like to judge for myself.


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Pedal building is like the opposite of sex.  All the fun stuff happens before you get in the box.

LaceSensor

Quote from: jimilee on November 15, 2021, 10:45:04 PM
Nice, I'd like to see more. I've asked around, and the OS2 was not very popular, but I'd like to judge for myself.


Sent from my iPhone using Tapatalk

The OS-2 is amazing