freestompboxes.org

neoflox wrote:Well, the title says it all. I was only able to find old threads where people said the Octabass was do-able on PCB or even Stripboard.

Also, I would be happy for recommendations for good sounding bass compressors (maybe even including a layout? )

Thanks in advace!

I am using THAT4301 compressor and I am very happy with sound on bass,best for me of all I have tried.

I separated this from a request and found no better place to put this than here: complete build documents. Do let me know if there a more appropriate place to put it.

thanks

This is a project from the german musikding forum. It is a clone of the carl martin comp.
I built one and it sounds absolutely fantastic (just like the original). My favorite comp for bass guitar.
Btw mesa boogie was using that same chip in a similar config (just with less user adjustable controls) in their m-pulse heads.

cheers,
lohstah

The problem is where buy it.

That Corp. will ship you "samples" at low prices. I got several that way!

Vicus wrote:The problem is where buy it.

If your in Europe musikding.de have them. They even sell a kit IIRC.

I've often wondered: how important is the AC transformer to the overall design? Would it lose anything by replacing the transformer section with an external bipolar supply like the MAX1044 based circuits? What about a buffered virtual ground, like with a TLE2426?

THAT are very nice about samples and you can buy them from profusionplc otherwise

Any advantage to using a high grade opamp for A1, and if so which one?

I wouldn't stress about it too much, but it's an always on buffer so don't use anything 741 based or equivalently worthless

This would be a cool project to redo using a MAX1044.

derevaun wrote:I've often wondered: how important is the AC transformer to the overall design? Would it lose anything by replacing the transformer section with an external bipolar supply like the MAX1044 based circuits? What about a buffered virtual ground, like with a TLE2426?

The only problems with voltage doubler circuits are firstly that they can be electrically noisy (especially as the compressor is a fairly high gain circuit) and the output isn't too stable - particularly where you're trying to draw a variable amount of current. If you're determined to use battery power, use a pair of 9V batteries, to get +/-9V.

The simplest way to power a bipolar supply circuit is to use a wall wart with an AC output. You can then use two half wave rectifiers and two smoothing capacitors to develop the two DC rails. You can then use two three-terminal regulator ICs to stabilise the supplies.

Just to counterpoint, having a mains transformer inside your pedal is just as capable of producing noise, and at 60Hz, which is much worse than the 60kHz you can manage with a 1044.

I agree that using external AC is a better solution overall though. Do you need 9VAC to get +-9, or 18VAC? or is it 9VAC for halfwave and 18VAC for fullwave?

askwho69 wrote:can i?? ?? ^

What do you need to know about it?

A simple PSU for this circuit would use a 15V AC transformer (could be an AC output wall wart), two diodes (as half-wave rectifiers) two smoothing capacitors (I used 1000µF at 35V) and two three-terminal voltage regulators - I used 78L12 and 79L12. Remember the 100nF capacitors from each live leg of the regulators to ground (keeps the rails clear of regulator noise).

I used a small toroidal transformer rated at 15 VA (15 Volts at 1 Amp maximum) which was overkill for the load, but didn't introduce hum and noise of its own.

Hi everybody, here I have done a small verified pcb for that4301 compressor by carl martin compressor schematic or that which is uploaded by me in the top of topic. to make it small I used smd resistors and ceramic capacitors size 0805. for power i used DC-DC 2W converter NMH0515SC which runs from 5V so there will be 5V regulator for it attached directly to enclosure. that saying pedal will easy run from standard 9V supply. PCB I've done in Sprint-Layout so including it to downloads and few my build pictures. pedal is not finished because I do not have enclosure for it at the moment. feel free to ask if anything is unclear. I'm not very good on creating whole project file in pdf so if there is anybody that can do it is welcome.

askwho69 wrote:i need to now about using Max1044 and make it to +/- 12v or more... can u advice doing that? thanks

A 1044 won't deliver enough current, use a LT1054. This is the power supply of the "THAT Jam" version, as it's sold as a kit at musikding.de:

Complete project: http://www.musiker-board.de/faq-worksho ... ost4699621

why I can't download it?

My latest build to 1590A using stock circuit and dual 15V DCDC inverter with input from 5V to13V, all resistors and some capacitors are at the bottom on PCB, added polarity protection fet BS250.
Sprint Layout files for pcb:
https://www.dropbox.com/sh/s9l2nr1kwqi6 ... 4Hoza?dl=0

WOW!

Wow do you sell some pcb?

askwho69 wrote:Wow do you sell some pcb?

You can order pcb from https://oshpark.com (you can use zip file (I added) from dropbox link) . It's not that expensive for 3 of them ( $15.90 ). actually on my first order pcb I had error which is fixed in the files provided.
Here is the link for dcdc:
http://www.ebay.co.uk/itm/3W-DC-DC-Boos ... 33d71d0590