Moog 104M Analog Delay

Trey added the Moog 104M Analog Delay to his rig in Summer 2017, bumping the Way Huge Supa-Puss from atop his effects rack.  Like the Supa Puss, the 104M is a bucket brigade-based analog delay (BBD) pedal.  These were only made in limited runs from Moog, and they remain very difficult to find and quite expensive because the Panasonic chips used to power the BBD system are out of production and exceedingly rare.  From Moog:

Originally designed by Bob Moog and released in 2000, the Classic MF-104 Analog Delay was manufactured as a limited edition release of 1000 units. A special “Bucket Brigade” delay chip was employed allowing the effect to remain completely analog. Unfortunately, the supply of these chips was limited and the final MF-104 sold in 2001.

There were a few reissues, including the 104Z and the 104SD (even more rare!).  But the 104M is the closest thing to the original run of any of the others.  It features 800ms of delay time and, most importantly, is controllable with tap tempo, a feature that very few analog delays can boast (the Supa Puss has a tap feature, as well).

The voice of the 104M, like the 104 and 104SD before it, is absolutely beautiful, with rich analog tone and a pronounced “bucket decay” or “bucket loss” when the delay time is turned up that you’d never get from a digital device.  Strymon has a great white paper on delays that explains how bucket loss works, starting with an explanation of digital vs. analog delays:

Analog delay chips move a signal along a chain of analog storage elements (capacitors) in a fashion that is similar to the way water gets transferred in an old-time firefighting bucket brigade. Hence the name of these Bucket Brigade Delay (BBD) devices. The total time of the delay is determined by the number of storage capacitors (buckets) and the time it takes (controlled by a clock chip) to move from one bucket to the next.

Digital ICs use a fundamentally different approach to delay a signal. The signal is converted to digital and stored in a memory bank where it is read out at a later point in time and converted back to analog. The total delay time is determined by the size of the memory bank.

The paper goes on to explain the concept of bucket loss as follows:

In the BBD chip, there is signal ‘loss’ at each bucket transfer, similar to water being spilled when pouring from bucket to bucket. The loss degrades the fidelity of the delayed signal by introducing noise and distortion. To achieve long delay times, more buckets are required, which results in yet more loss.

Alternatively, a slower clock signal from the clock chip can be used to increase the delay time. But extra filtering is required to prevent excessive artifacts that arise due to the slow clock, and this also reduces the fidelity of the delayed signal. Therefore there are practical limitations on the maximum delay times achievable with an analog BBD delay, as delay time is increased at the expense of fidelity.

In contrast, digital delays experience no loss of fidelity after the conversion process, and can have arbitrarily long delay times without adverse consequences. While extended delay times are a good thing, the high fidelity of the digital delays can sound ‘cold’ and ‘sterile’ compared to the ‘warm’ and ‘organic’ sounds of the analog delay.

The sound of bucket loss has become a sought-after “deficiency” in analog delays, and none does it better than the 104M.  Here’s an example of bucket loss when Trey uses a relatively longer delay time during the Baker’s Dozen Lawn Boy: