Sunday 29 January 2017

Electro-Harmonix Deluxe Memory Boy

Another quick one. This is the high-end version of the Memory Boy that I've looked at before. The Deluxe adds an extra gain control, tap tempo, tap divide, a rate control for modulation, an effects loop and the ability to control rate, depth, feedback or delay time with an expression pedal.
I got this used with a fault, the seller said the delay signal was very quiet compared to the dry. I plugged it in, and sure enough the delay was kind of weak. The manual for this one says that the added Gain control goes from -6 dB to +20 dB. When I put it straight up at 12 o'clock the delay seems to match the dry signal in terms of volume. I can't find anything wrong with it so I'm just taking a look inside.



Both PCBs.

The guts are similar to the Memory Boy, 4558/LM324/TL072 opamps, SA571 opamps and of course the 4 BL3208A BBDs. There is an ATMega16 microcontroller doing the tap-tempo and probably modulation waveforms as well. There is a JTAG port but I don't know how to dump the ATMega through JTAG, and I'm fairly certain it will be read-protected anyway.

BBD board, front
BBD board, backside

The BBDs are on a daughterboard, as per the Boy. This time they are connected with header pins and sockets and held down with screws into brass inserts instead of soldered to the main board. On the backside is the same 4011 IC used as an oscillator for the BBD clocks.


Main board uncovered

Underneath the BBD board we can see an LM13700, most likely modulating the clock frequency in the same way that the Memory Boy worked. I was a little surprised as I thought the ATMega would generate all the clock signals, it must just generate control voltages to the LM13700 to adjust the clock rate.

One nice feature is that the full IC part numbers are on the silkscreen, which should make life easier for anyone attempting to repair one.

The tap-tempo features are nice, but the rest of the pedal is essentially the same core delay as the Memory Boy. The tap-tempo does seem to allow longer delay times than the knob, around 1 second (by ear).

I'm not the biggest fan of this series, I prefer the Ibanez ES-2 for analog delays. This version is definitely an upgrade over the original if you can afford the real estate.

1 comment:

  1. Hi, I have encountered the same problem with my Deluxe Memory Box as the seller of your DMB mentioned.Very weak delayed signal vs. the dry one. Was not like this from the beginning, it started after about 5 months of use. Visually, I can not find any flaw or defect. All the functions seem to be working, they are just very quiet...And of course, there is no way to force the effect into oscillation, even with the repeats knob maxed. Do you have any hint please? What can happen to the circuit to start behaving like this? It couldn't suffer from aby abuse, I am a "weekend warrior". It used to be "unity gain" when blend and gain knobs were at 12 o'clock. Now I have to go far to the wet side of blend and almost max the gain to maintain the level od bypassed signal. I am lost. The effect is still under warranty, so I must make a claim ASAP, but in case of being it some stupid little thing i'd prefer to fix it DIY. Thanks, Jan

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