Frequency dependent phase inversion - 80's delay nerdiness

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Inspired
Hi all!

I recently grabbed an Effectron II (ADM 1024). It's an 80's delay and I'm quite enchanted by it. The delay sound is percussive and it fits into the mix perfectly - plus the modulation is weird enough to really capture your ear. I like it enough that I've searched up 2 more because I'm betting that this 80's gear has a limited lifespan. I use the Axe Ins and outs to let me fake a line mixer.

The Axe ADM style delays are awesome - but the Effectron sounds more like a poorly tuned 2290. It's an ADM delay - but the sampling freqs are FAR lower. At the 2x delay settings I can hear some digital weirdness that just fits perfectly with a bit of modulation. As a certified delay nerd I just can't turn it off.

Another part of what makes this device so cool is the pseudo-stereo output. It has the typical 80's "invert the right channel" setup to make a mono delay sound "stereo-ish" but this one sounds different. The inversion circuit is a simple opamp but to my admittedly non-expert eyes it looks like a frequency dependent inversion. I sounds like lower frequencies are not effected at all. I found a schematic of the inverter - the C26 cap would seem to support this.

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Is there a way to do smooth frequency dependent phase inversion in the AFIII? I've tried a pair of opposing filters at about 300Hz with a phase inverter after one of them but it frankly sounds pretty different than the Effectron. Maybe that opamp inverter has a few more tricks up its little analog sleeve? Has anyone built anything like this in the AXE and can offer some advice?
 
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Hi all!

I recently grabbed an Effectron II (ADM 1024). It's an 80's delay and I'm quite enchanted by it. The delay sound is percussive and it fits into the mix perfectly - plus the modulation is weird enough to really capture your ear. I like it enough that I've searched up 2 more because I'm betting that this 80's gear has a limited lifespan. I use the Axe Ins and outs to let me fake a line mixer.

The Axe ADM style delays are awesome - but the Effectron sounds more like a poorly tuned 2290. It's an ADM delay - but the sampling freqs are FAR lower. At the 2x delay settings I can hear some digital weirdness that just fits perfectly with a bit of modulation. As a certified delay nerd I just can't turn it off.

Another part of what makes this device so cool is the pseudo-stereo output. It has the typical 80's "invert the right channel" setup to make a mono delay sound "stereo-ish" but this one sounds different. The inversion circuit is a simple opamp but to my admittedly non-expert eyes it looks like a frequency dependent inversion. I sounds like lower frequencies are not effected at all. I found a schematic of the inverter - the C26 cap would seem to support this.

View attachment 92662

Is there a way to do smooth frequency dependent phase inversion in the AFIII? I've tried a pair of opposing filters at about 300Hz with a phase inverter after one of them but it frankly sounds pretty different than the Effectron. Maybe that opamp inverter has a few more tricks up its little analog sleeve? Has anyone built anything like this in the AXE and can offer some advice?
Yes, that's an allpass filter. Building block of a phaser. This particular circuit has zero degrees phase shift at low frequencies, increasing to 180 degrees at high frequencies.

You can probably use the Allpass type in the Filter block to recreate this.
 
Yes, that's an allpass filter. Building block of a phaser. This particular circuit has zero degrees phase shift at low frequencies, increasing to 180 degrees at high frequencies.

You can probably use the Allpass type in the Filter block to recreate this.

Ahhhh . . . I never thought of that. That means we can build DIY phasers in the Axe! I'm going to have to try that . . .

Thank you sir! I'll try it as soon as I get back to my studio.

The Effectron also uses a companding scheme as well. I'm going to try to digitally build the Effectron in the Ax to see how close I can get.

What would the best way be to simulate the sound of an undersampled ADM AD convertor? I don't think that bit depth would cover it really.
 
Ahhhh . . . I never thought of that. That means we can build DIY phasers in the Axe! I'm going to have to try that . . .

Thank you sir! I'll try it as soon as I get back to my studio.

The Effectron also uses a companding scheme as well. I'm going to try to digitally build the Effectron in the Ax to see how close I can get.

What would the best way be to simulate the sound of an undersampled ADM AD convertor? I don't think that bit depth would cover it really.
The Drive block has a sample rate param.
 
Super interested to hear your results. Would you be willing to upload a sound sample of the unit? I’m intrigued.
 
I had one of those back in the day. No idea what I'd think of it now, but then, I thought it was "cost effective", euphemism for "not great but what I could afford".

I'd listen to samples if you post em though, and try your Axe version too. Maybe I'm de-romanticizing the past maybe?
 
Would a simple stand-alone sampling reducer / bit reducer block be on the table (outside of the blocks that have it embedded)?

Probably cake for you to implement!
Maybe a drive, set as transparent as possible, then add bit reduction?
 
For pseudo stereo, I don't think I've heard anything better than the Stereoizer in the Axe. And it's mono compatible. For me, it's indispensable for recorded solos. I absolutely love it.
 
An allpass filter is a crude approach and will create comb filtering when collapsing to mono. The Stereoizer is expressly designed to prevent this.
The Stereoizer sounds like it disappears when collapsed to mono, which is far preferable to comb filtering. It's perfect for a mono guitar in the center of a mix, especially with headphones or IEM. It does what a simple delay or chorus can't. Would it be possible to add modulation to it? I'm trying to imagine what that would sound like.
 
On the III, the "Bit Crusher" drive type just takes 3.6%.
And if you turn the clip type to null , it cuts it down further.
Ah, thanks guys, forgot about Bit Crusher and about the NULL option. It's about 3.0% then and probably sound-wise equivalent to a pure bit/sample reducer block but with some EQ.

I can get some gnarly/farty low-bit game sounds especially turning down sampling rate.
 
Here's a quick snip . . . it's a compressed AC20 and the straight delay in stereo with a tiny smidge of reverb. The delay is cranked a bit and the feedback is set a bit higher than I like but I’m trying to make the sound of the delay more clear.

The guitar is a Jackson SL4X with a mix of EMG S and SA pickups. Active singles with a Floyd . . . ahh the 80s. I did a few quick pops in the beginning so you can hear the delay trails and then noodled a bit afterwards. Out of time U2 licks required for a ADM delay right?

EDIT - This is actually the external delay . . . I'm working on matching it with the Axe.

 
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