The Source noise source

[sinewave1kHz]

Dear moog users,
this is my first post here. Sorry if my question is too simple, but I am wondering is it expected that the noise source on analog synthesizer sounds "looped"? On my Moog the Source, I can hear the "cut" every (approximately) 0.7 seconds when listening to the noise only.
Thank you for the answer!

[thealien666]

Hello and welcome.

The white noise on the Moog The Source is digital, not analog. It is generated by a badly designed chip (well known to have issues with audible short loop) the infamous MM5837 (used in many synthesizer of the eighties such as Prophet 5, Oberheim OB-x, early Korg Mono/Poly, the Moog MG-1, The Source, and a few others).

[sinewave1kHz]

Thank you thealien666 for the detailed explanation! Although I love the sound of The Source, it's digital side is weak and sometimes useless, apart from 16 memory slots. For example, I found out that the arpeggio has a very bad latency (around 27 ms), when synced via SYNC IN.

[MC]

Factory service bulletin for Memorymoog but also applies to Source

http://www.interlogic.jpn.org/memorymoog/842-1.jpg

[torinkrell]

Sinewave1kHz welcome to the forum! I have recently added an early version Moog The Source to my studio and it exhibits exactly the same cyclic "rhythm" in its noise source - which is most noticeable in the lower noise frequencies. My 1973 Minimoog and the new Minimoog reissues in contrast have a very smooth, nonrhythmic, (and analog) noise source. Does anyone here have service notes specific to The Source on reducing this issue? Thanks thealien666 and MC as always for your info!

[thealien666]

Sinewave1kHz welcome to the forum! I have recently added an early version Moog The Source to my studio and it exhibits exactly the same cyclic "rhythm" in its noise source - which is most noticeable in the lower noise frequencies. My 1973 Minimoog and the new Minimoog reissues in contrast have a very smooth, nonrhythmic, (and analog) noise source. Does anyone here have service notes specific to The Source on reducing this issue? Thanks thealien666 and MC as always for your info!

Read MC's reply just above yours... It includes a PDF of a service bulletin (for the Memorymoog but also applies to The Source) which shows how to replace the MM5837 by the much improved MM5437, with minimal modifications because they're not pin for pin compatible unfortunately.

Thanks MC !