Question about a Slow Loris (madbeanpedals) Build

[jfrabat]

I am about to start building a Madbean Pedals Slow Loris (BOM and schematics are here), but I am having a hard time finding the LM308 locally (I live in CR, so ordering online can get expensive quickly!  Especially for small items like this, where I pay standard shipping fees!).  So I was thinking about using a TL071 and omitting the 30 pF cap (C3) that joins PIN 1 and PIN 8 (the TL071 is internally compensated, so it should not need it).  Will this work?  If it does, do you think that the sound will be too harshly affected by this change?  Is it worth doing like this?

[287m]

you can try it man.
or while waiting for 308, you can try NE5534 or OP07, but dont expect too much

[reddesert]

Yes, it will work.  It may sound somewhat different, but probably less than all the hype about the LM308. Be cautious with ordering an LM308 because they are obsolete and chips with prices that are too good to be true might be faked. You could try a 741, which is almost as old as the LM308. I tried swapping between a 741 and an OP08 in a Rat-derivative build and didn't hear a noticeable difference.

[jfrabat]

You could try a 741, which is almost as old as the LM308. I tried swapping between a 741 and an OP08 in a Rat-derivative build and didn't hear a noticeable difference.

Excellent, I got 3 of those laying around, so I will start with these...

[duck_arse]

you could also try an LM301, which is uncompensated, like the LM308, but has none of the mojo precision of the 308.

[vigilante397]

I know this isn't always the case, but I've had some damn good sounding results with a batch of fake LM308's I picked up from China a while back.

[jfrabat]

I will try the 741.  If I do not like the sound, I will order some 308's online, but for now, the 741 is going in, as I have a few of those.  If I do switch to the 308, I will just solder the cap in its place (in the meantime, it will stay with no cap).

[bloxstompboxes]

The OP07 is a drop in replacement for the LM308, has the same magical slew rate that supposedly is responsible for the rat sound, and is currently used in Rats now in production. They are also very much available and lower in price than the LM308.

[jfrabat]

Another quick question; I could not find any 2N5457 locally, but I do have a NTE451 laying around (links go to spec sheets).  They are both JFETS, and pinout is the same, but the specs are somewhat different (of course, I have NO CLUE as to what it all means!); wonder if it is too much difference?  I also ran out of sockets, so I do not want to solder the NTE in if it will not work (will try to get some sockets tomorrow, but they are not always available).

[thermionix]

I think the ProCo Rat actually uses a 2N5458.  Since it's a buffer, it probably doesn't matter too much what type N-channel JFET you use.  It's a good idea to socket, because you want to find one that biases up well in the circuit.  Look for >1VDC from source to ground.

This thread reminds me, I got four metal can LM308AHs from Ebay about six months ago, and I still don't know if they're real.  I need to mock up a Rat on the breadboard and test them.

[thehoj]

Is shipping from Small bear expensive for you?
Maybe order a few other things at the same time to make it worth it..
They've got these http://www.smallbear-electronics.mybigcommerce.com/ic-ua308hc/

[jfrabat]

Is shipping from Small bear expensive for you?
Maybe order a few other things at the same time to make it worth it..
They've got these http://www.smallbear-electronics.mybigcommerce.com/ic-ua308hc/

That's where I get my stuff, but I have to make purchases that make sense.  Shipping to CR means you need a company to act as a PO Box who ships it to you, and then pay taxes.  So for anything under $10, I end up paying about $35 in shipping and taxes.  If I order $100, then I pay about $50 in shipping and taxes...

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[thehoj]

Is shipping from Small bear expensive for you?
Maybe order a few other things at the same time to make it worth it..
They've got these http://www.smallbear-electronics.mybigcommerce.com/ic-ua308hc/

That's where I get my stuff, but I have to make purchases that make sense.  Shipping to CR means you need a company to act as a PO Box who ships it to you, and then pay taxes.  So for anything under $10, I end up paying about $35 in shipping and taxes.  If I order $100, then I pay about $50 in shipping and taxes...

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Damn.. And here I thought I had it rough in Canada.. Is CR Costa Rica? Are there any places that will ship directly to you?

[jfrabat]

Is shipping from Small bear expensive for you?
Maybe order a few other things at the same time to make it worth it..
They've got these http://www.smallbear-electronics.mybigcommerce.com/ic-ua308hc/

That's where I get my stuff, but I have to make purchases that make sense.  Shipping to CR means you need a company to act as a PO Box who ships it to you, and then pay taxes.  So for anything under $10, I end up paying about $35 in shipping and taxes.  If I order $100, then I pay about $50 in shipping and taxes...

Sent from my SM-G950F using Tapatalk

Damn.. And here I thought I had it rough in Canada.. Is CR Costa Rica? Are there any places that will ship directly to you?

You could, but then it takes FOREVER to get here, you STILL need to pay taxes (about 35% including sales tax), and then you need to pick it up at 5he central mail because you have to pay the taxes before they give you the package (which is a real PITA).

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