BAJA Wet Cat analog delay (mini version)

bajaman · Post by **bajaman** » 05 Feb 2009, 02:32

Hello folks
After reverse engineering the Way Huge Aqua Puss analog delay (https://www.freestompboxes.org/viewtopic.php?f=7&t=4216 )
and noticing a more than casual similarity to the infamous BOSS DM-2, I decided to present this new DIY project.
I called it the Wet Cat - not very original I know

Anyway, some notes:
Like the WHAP this delay is true bypass - it does NOT use the Boss fet silent switching circuit.
I have provided two versions - one with the original MN3005 and MN3101 chipset, the other with the MN3205 and MN3102 chipset, which is more readily available.
Like the WHAP both these layouts use the slightly changed capacitors and resistors, and additional 100n filter caps on the clock driver and delay line chips, but you could quite easily build the stock DM-2 version without too many parts changes.
In fact the board layout is based on the original DM-2 layout but adjusted to suit the Hammond 1590B or equivalent NSC enclosures. It may be a tight squeeze but you should be able to get a 9 volt battery in it too.
The more observant members may spot two additional 25k resistors on the board by the compander chip. These can be left out if you want the DM-2 or AP to be "original". The NE570,NE571 or SA570 /1 compandors have two inverting op amp gain stages within - these are biased using a low voltage precision internal voltage source to 3v dc on their output terminals.
We are running our delay from a 9v dc source and a far better bias voltage would allow the op amps to have 4.5 volts dc on their outputs - less distortion due to assymetrical clipping in these gain stages. This is the purpose of the additional resistors - to increase the half rail voltage closer to the theoretical best value of half the supply voltage. For further information, the reader is advised to consult the data sheet PDF file, which is readily available (google NE571).
Okay - enough talk - here are the project files.
members/bajaman/Baja/Baja%20Wet%20Cat%20mini%20version/
enjoy

bajaman

ps: all drawings are 1200 dpi

rocklander · Post by **rocklander** » 05 Feb 2009, 02:53

yay bajaman again!
any hints on where you source your ICs from (in NZ?)

am keen to get into one of these after a few other projects are cleared off my table.

KHELSTROM · Post by **KHELSTROM** » 05 Feb 2009, 03:24

Thanks Bajaman!!! Have you put together one with the MN3205 yet? If so how does it sound?

moltenmetalburn · Post by **moltenmetalburn** » 05 Feb 2009, 04:49

Thank you!

borislavgajic · Post by **borislavgajic** » 05 Feb 2009, 11:26

http://www.mgelectronic.co.yu/components/8-dip.jpg

is this IC same as MN3005( with longer body???).....it is MOS,NF-SIGNAL-4096-STAGE DELAY
Kućište: 8-DIP
Tip: MOS-IC...............could it be used here???

analogguru · Post by **analogguru** » 05 Feb 2009, 16:53

I called it the Wet Cat - not very original I know

Is this derived from Aqua Puss ?
My English is not so god, but how about "Wet Pussy" ?

analogguru

Fuzzer · Post by **Fuzzer** » 05 Feb 2009, 17:28

The Wet pussy,

suggested Usage: With a Super Hard On before it.

Post by **audioguy** » 05 Feb 2009, 19:48

dumb question... but what is the 1meg clock?

Fuzzer · Post by **Fuzzer** » 05 Feb 2009, 20:21

It is a trimpot. 1 Megaohms resistance.

Post by **audioguy** » 05 Feb 2009, 21:17

Thats kinda what I thought, I just wanted to be sure before I place my parts order

puppiesonacid · Post by **puppiesonacid** » 06 Feb 2009, 01:45

Fuzzer wrote:The Wet pussy,

suggested Usage: With a Super Hard On before it.

nice stompbox use of stompbox innuendo...

what about the muff pi... you've gotta throw that one in there too, or the butt probe...

talk amongst yourselves...im all vishclempt

bajaman · Post by **bajaman** » 06 Feb 2009, 06:48

Build report:
I just completed my prototype and had a few small problems but all sorted out and it works fine

BUT, it is not an easy task to fit the board with components over the sockets and the footswitch. I used the plastic PCB mount sockets that Aron sells over at "the other forum" , but I had to chop off the little plastic lugs and bend the legs over at 90 degrees to clear the components. I also placed a thin sheet of plastic mylar overhead transparency film over the footswitch and sockets to avoid any shorts. I had to chop and file off the footswitch contacts to clear the board assembly as well - this is a very tight fit and the cancel preset is directly below the footswitch. When I mounted the 3PDT footswitch I had to slightly enlarge (bevel at 45 degrees) the mounting hole on the enclosure, so that I could push the footswitch up against the inside of the top as much as possible. I did not have a 330uf capacitor small enough to fit the board so I used 3 low profile 100u 25v capacitors in parallel (drilled 4 more holes between the +9v and ground traces). I had to lay one of the 10uf electros on it's side and use a very low profile 1uf 16v as well in one place as well.
Finally I had to grind the galley on the bottom plate of the enclosure by about 1.5 mm and fit a piece of mylar overhead transparency film in the middle of the lid to avoid the solder contacts shorting out on the enclosure case lid.
I used the setup instructions in the Boss DM-2 service manual to adjust the three presets correctly and boxed it up and had a play with it - it sounds like a BOSS DM-2 - never heard an Aqua Puss so cannot comment any further.
I used metal film resistors, an OP275G dual op amp, an NE571 compandor, a NOS Panasonic MN3005 and MN3101 (been saving them since the 80s

) and 2N5089 transistors.
Pictures will follow shortly.
I am going to redesign this project in the near future, because it is NOT easy fitting everything in a Hammond 1590B enclosure. The new design will be for the Hammond 1590BB and will most probably incorporate board mounted sockets and footswitch etc., similar to my Baja Real Tube Overdrive design perhaps.
In the meantime, please do not attempt this project unless you have a lot of patience, it is not one for beginners

cheers
bajaman

soulsonic · Post by **soulsonic** » 06 Feb 2009, 07:33

What about the "125" size enclosure that Small Bear and PedalPartsPlus sells? It's still small-ish, but it has considerably more elbow-room than the 1590B.

bajaman · Post by **bajaman** » 06 Feb 2009, 07:43

what are the internal dimensions

soulsonic · Post by **soulsonic** » 06 Feb 2009, 07:58

Approximately 2.5" x 4.75 x 1.5" deep

bajaman · Post by **bajaman** » 06 Feb 2009, 08:31

pictures up now - sorry for the shaky hands

bajaman
members/bajaman/Baja/Baja%20Wet%20Cat%20mini%20version/

bajaman · Post by **bajaman** » 06 Feb 2009, 09:23

Notice how high up the sides the jack sockets are

and the mylar insulating film on the enclosure lid and inside the case

cheers
bajaman

bajaman · Post by **bajaman** » 06 Feb 2009, 09:30

Just checked the 1590BB vs the 1590B enclosures - the 1590BB has 0.12 inches extra height (3.05mm) which should make things a whole lot easier to fit ( especially if I move that trim pot away from directly under the footswitch

cheers
bajaman

puppiesonacid · Post by **puppiesonacid** » 06 Feb 2009, 11:46

thank you very much for this great work ( as usual bajaman) It is very much appreciated!

Post by **abfackeln** » 06 Feb 2009, 12:06

Once again, great work. It always amazes me how you cram all that stuff into the small enclosures.....