DFAM attack/EG inconsistencies???

Mother-32, DFAM, Subharmonicon, Grandmother, Matriarch
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Doherty
Posts: 2
Joined: Sat Sep 11, 2021 6:37 am

DFAM attack/EG inconsistencies???

Post by Doherty » Sat Sep 11, 2021 7:19 am

Hey everybody,

I have just bought Moog studio bundle 2.

I am questioning whether I need to send the items back for the reasons I'll state below.

With the DFAM set up as shown on 'Exploring the DFAM' patch (DFAM User manual page 8 -see attached picture) I am experiencing some anomalies/variations which I do not believe I should be.

The attack/punch of the notes audibly changes as the sequencer runs through its cycle.

Audio file can be heard here:
https://soundcloud.com/davedohertymusic ... v07jrb4GOm
*At 29 seconds I manually lower/shorten the VCA Decay time to demonstrate the same issue with a different setting

These changes are random in nature and mean it is impossible to create a 'set' sculpted sound for use in composition - because the sound changes.

To remove the change of micro differences in sequencer pitch/velocity knobs, I have set all velocity knobs to their maximum value position (fully clockwise) and all pitch knobs to minimum value position (fully anti-clockwise). I realise with the 'seq pitch mod' switch set to 'off' the pitch knobs shouldn't be a factor, but I wanted to rule that out. (See Soundcloud picture)

I am loving the DFAM as a module but this bugs me both as I can't rely on the sound I set to behave as I feel it should, and, I'm wondering if I have a faulty unit.

Also, on the Subharmonicon, one of the 'white dots' is missing from the top of the knob - which makes a harder to set values while composing/performing.
Is this considered within normal QC tolerance for Moog products, or would this be considered something that is not accepted by QC.
(See attached picture - VCO 2 Sub 2 freq knob)

Any assistance you can provide will be greatly appreciated - I have media composition to complete and I need to make a decision on this asap.

Best,

Dave
Attachments
Subharmonicon knob.jpeg

synthpeter
Posts: 28
Joined: Tue Sep 07, 2021 8:41 am

Re: DFAM attack/EG inconsistencies???

Post by synthpeter » Mon Sep 13, 2021 2:37 am

The DFAM does not sync the VCO1 and VCO2 waveform cycles to the sequencer, this means that when a step hits, VCO1 and VCO2 can be anywhere in their triangle or square waveform. When a VCO is at the top of its waveform, the attack will sound harsher, sometimes up to almost a click, and when the VCO is at the lowest volume of its waveform, the attach will sound softer. This is common for analog synths without digital VCO control. The lower the VCO frequency, the more pronounced this effect is.

Also be aware that even if you set all the pots to either max or minimum, there are still manufacturing tolerances that make for slight differences in their resistance. Temperature changes also play a role here, so things may sound different from day to day, or even over the course of a session.

In other words, with a fully analog synth, you will never get 100% identical attacks over time.

But on the plus side, some slight variation in attack does prevent longer sequences from becoming stale.

Doherty
Posts: 2
Joined: Sat Sep 11, 2021 6:37 am

Re: DFAM attack/EG inconsistencies???

Post by Doherty » Tue Sep 14, 2021 7:51 am

Dear Synthpeter,

Thank you very much for your response 🙏🏻

While I have a knowledgeable person around... I’m experiencing issues with DFAM volume pot. Every now and then -5 or 6 times in 7 days and many hours of use - when turning the master volume pot up or down, the volume drops right down, and with it, all the low end (this could seem exaggerated due to amplitude level dropping)
It will remain this way for a minute or two until, or, until I’ve sufficiently moved the volume knob up and down, then it returns to normal functionality.
Another normal analogue quirk, or reason to return? My concern is it will fail altogether eventually. Sending back to be safe is obviously smart, but I’m loving the synth so much I’m reticent to be without it for a week + only to discover it’s a normal variable.

Thanks so much for your help.

Dave

synthpeter
Posts: 28
Joined: Tue Sep 07, 2021 8:41 am

Re: DFAM attack/EG inconsistencies???

Post by synthpeter » Thu Sep 16, 2021 2:21 am

The volume drops are strange, especially if the volume doesn't sound scratchy when turning the master volume control.

I can think of a couple of things to check first though.

Are you patching the VCA output into something else? If so, a volume change may affect another setting with unpredictable results. Then there may be other patches possible that lead to strange results, for instance self generative sounds are sensitive to any change. On top of that, open patch cables into inputs may also be a source of unexpected behaviour.

Have you connected the audio-out/headphone to either a head phone or proper mixer/audio-interface input, and not shorted to some other device, like with a reversed splitter? That may lead to grounding problems.

Also make sure you're using the proper cables and don't run the audio-out with a TRS cable into a balanced input.

Is the power supply connected properly, both on the DFAM side and the power socket side. My DFAM's power supply came with interchangeable sockets for different countries; slide in the proper one until it securely clicks in place. A bad power connection can make the synth choke when it's demanding more current. Also check that the supply doesn't overheat.

And finally, could you have been in a situation that led to condensation of moist inside the device?

Kind regards,
Peter

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