EHX - Deluxe Memory Baby

Dirk_Hendrik · Post by **Dirk_Hendrik** » 13 Apr 2011, 16:58

Where to put this thread? There's no showoff category.... (nor should there be)

Anyways,
When EHX started off with the nano series a couple of years back this picture howed up.:

Nice! But a photoshop. As I understood that caused some tears at TGP. Fine. Harden up a little. However I did expect EHX to show up with the DMM in a Nano style and they did. The DMM, the (Horrible) DMM with Hazarai, and the much more back to basics Memory Boy. But they did not do it in a 1590B style case.

This left me wondering wether the concept, DMM in a 1590B, could be done. Not the same as that photoshop for sure. Technically impossible and it lacks a control. But still... can I get that to fit.

Which made me thinking what to do to make it fit.
Change 1: Change over to MN3205 BBD's, ensuring it is possible to build one without having to hunt for 3005's. I never design with scarce components of which I do not have a shitload at hand.
Change 2: Easy. Adapt to 9volts negative center supply power.
Deliverable 1: The DMM is not battery powered! Neither does the project have to be, giving a load of extra boardspace.
Change 3: 2 LED's (power and overload)? Make that 1 duo led.

Can it be done? Yes it can:

I'll post some guts tomorrow. Don't ask for a schematic, the DMM schem is on the web. The only difference is the BBD's and the BBD's supply voltage control (Ibbie AD9). This is a case of engineering to get the parts to fit, not to get the circuit to sound.

Then,
I am aware this IS a serious infringement of the EH/New Sensor trade dress. Let em be assured this is in no way expected to be a production pedal and should be considered a parody.

ps,
Boris,
This is the one I promised you.

Lachlan C. · Post by **Lachlan C.** » 13 Apr 2011, 21:44

Most impressive, Dirk!

Looking forward to seeing the guts

madbean · Post by **madbean** » 13 Apr 2011, 23:22

Well, son of a bitch....

Hides-His-Eyes · Post by **Hides-His-Eyes** » 14 Apr 2011, 00:14

Very impressive!

Also, the SMMw/H is a fantastic pedal. My favourite digital delay in that price range. Haters gonna hate...

culturejam · Post by **culturejam** » 14 Apr 2011, 00:17

Sonofabitch.

Post by **azrael** » 14 Apr 2011, 00:57

Oh my. Quite a squeeze, I would imagine?
Sound just like the real thing?

coldcraft · Post by **coldcraft** » 14 Apr 2011, 01:33

don't hate on the hazarai! It works great at my feet, but I digress.

Great effort! It looks epic!

earthtonesaudio · Post by **earthtonesaudio** » 14 Apr 2011, 03:48

Okay so if you can shoehorn one into a 1590A

...Memory Fetus?

coldcraft · Post by **coldcraft** » 14 Apr 2011, 04:20

that made my day, e.t.a.

quarara · Post by **quarara** » 14 Apr 2011, 09:27

Dirk_Hendrik · Post by **Dirk_Hendrik** » 14 Apr 2011, 10:31

Thanks for the compliments!

OK, some more details and I promised guts.
For the controls I chose 9mm Alpha's. These are all 5 mounted on 2 little PCB's standing upright on the main PCB. The left of these contains the Chorus/Vibrato pot and the input level control and the preamp circuitry that belongs to that gain control. The other, right, PCB, contains the blend control, the feedback cotrol and the delaytime control. For that delay control the circuitry that comes along with it, that is the 4047 plus caps and resistors, is on that board as well. All in SMD. As said these are mounted upright amd make the pots float just above the components on the main board. On the main board all non-electrolit caps, resistors and semiconductors (other than the BBD's) are SMT. When using more tough hole components things would not fit.

Further,
The board is single sided. This means there is 61 centimeters of jumper wire used in 107 jumpers. Compared to the bottom/trace side that has a total trace length of 23 meters (nerdy details these are).

Deviations from the original DMM circuit:

The original DMM uses a 15 volts voltage regulator. This means that the supply voltage for all circuitry is always stable. In this case supply voltage is dependent of the adaptor used (as it may state 9 volts but not be 9 volts) . Therefore I borrowed the 100Ohm, 8.2 volt zener "trick" frim the Ibanez AD9 to provide a stable supply for the BBD's and their biasing trimmers. Also the use of 9 volts MN3205 type BBD's means that the DC biasing of all amplification stages is more critical since there is only plus and minus 4.5 volts available (totalling 9 volts supply voltage). Too much deviation from this 4.5 volts would sacrifice headroom. The SA571 compander was recalculated for a DC output of 4.5 volts. All other amplification stages were retuned to have an output DC level of 4.5 volts. More? All opamps are TL072, except for the LFO opamp that is still a 4558.

that's about all ...

Oh!
Gutshot!

theehman · Post by **theehman** » 14 Apr 2011, 10:44

That is some beautiful work, Dirk. Will you have PCBs available?

KindaFuzzy · Post by **KindaFuzzy** » 14 Apr 2011, 10:52

Son of a bitch (I don't think enough people have said that yet), that's kick ass.

jb351 · Post by **jb351** » 14 Apr 2011, 11:21

That is one sweet pedal. Very nice job Dirk.

hewie · Post by **hewie** » 15 Apr 2011, 18:45

Impressive work

willc1968 · Post by **willc1968** » 15 Apr 2011, 20:42

Excellent looking work there Dirk. It is quite the cute pedal.

nightraven · Post by **nightraven** » 15 Apr 2011, 21:07

that is crazy!!!

rocklander · Post by **rocklander** » 15 Apr 2011, 21:22

bitching sons of bitches! that's damn cool

madbean · Post by **madbean** » 15 Apr 2011, 22:25

Dirk, could you expand a little bit on the relationship between the compander and DC output a bit more? My thoughts have always been "just run it at the highest voltage it will tolerate". How did you go about changing it in relation to the different biasing voltage?

RnFR · Post by **RnFR** » 16 Apr 2011, 02:45

well, as if anybody didn't know yet, Mr. Hendrik- you are indeed THE MAN.