Turtlerock Forum

Hi guys,

I've been stalking the DIY pages here and prodigy for a while and I've even built my first distortion pedal (including pot, power and switch mods - woo hoo - I know) from a Jaycar kit.... I've also read the first few chapters of "Electronics Projects for Musicians" by Craig Anderton (as recommended by Rick) and I'm loving it... now it's time to start building some projects from scratch.

BUT... parts... where are you guys getting them? Jaycar seem to have tonnes of caps and resisters, a fairly decent selection of pots, switches and boxes, but for stuff like the op amps, do I need to look somewhere more specialised? Where?

I've been cruising ebay a bit, but I'm not really sure what can be substituted for what on some of these projects so I'm a bit in the dark... but I'm learning.

Ta.

Dave.

Hi Dave

Jaycar is my first port of call, but they do tend to have only the more common things. They do have most of the common amps like the 5534 (single) and 5532 (dual) 8 pin ICs, and the TL072 and 074 FET opamps.

I find Futurlec a good source of IC's (www.futuerlec.com.au) as well as some more specialised beasties like inductors. I buy my Burr Brown opamps from them, and have upgraded some of the 5534 opamps in the Gyraf SSL compressor to AD843s.

Still, some parts I have just had to buy from overseas. The Prodigy boards generally point you in the right direction.

Are you looking for something specific? I should add

Try these two-

rsaustralia.com

www.farnellinone.com.au

just a quick tip if you are buying from Jaycar - they have a wholesale division which if you are a registered business you can purchase from them at wholesale prices - most items are around the 40-50% off RRP mark and they have large discounts for multiple purchases of the same item.
It goes under the name Electus and they sell everything that Jaycar sells in their store. There is usually around a minimum $100 per order but once you throw in a couple of rolls of Nashua Gaffa etc it adds up! Get a catalog sent out and away you go!

http://www.electusdistribution.com.au/

cheers
Geoff.

Thanks for the input guys.

The projects book uses the RC4739 and XR4739 IC's a lot... I can't seem to find them listed anywhere... I'm assuming that since the book is starting to get a bit dated, so are these opamps... any suitable substitutes?

Dave

Chris P,

That site you listed can't be opened (Futuerlec - yes, I tried Futurelec as well).

Dave

The RC4739 is an obselete part. It is a dual opamp in a 14 pin package with the following pinout:

1. Amplifier A output
2. NC
3. NC
4. NC
5. Amplifier A in (-)
6. Amplifier A In (+)
7. V (-)
8. Amplifier B In (-)
9. Amplifier B In (+)
10. NC
11. NC
12. NC
13. Amplifier B Output
14. V (+)

There are many 8 pin DIL opamps that are functionally equivalent, bowever you'd need to get a wirewrap 8 pin socket and bend the legs around so that the 8 pin opamp I/O meets up with the 14 pin I/O of your circuit board. Best to use a socket on the pcb instead of soldering direct to the board.

The pinout for a standard dual opamp in 8 pin DIL such as the NE5532 is as follows:

1. Amplifier A output
2. Amplifier A in (-)
3. Amplifier A in (+)
4. V (-)
5. Amplifier B In (-)
6. Amplifier B In (+)
7. Amplifier B output
8. V (+)

good luck!

Thanks Otto,

There are many 8 pin DIL opamps that are functionally equivalent, bowever you'd need to get a wirewrap 8 pin socket and bend the legs around so that the 8 pin opamp I/O meets up with the 14 pin I/O of your circuit board. Best to use a socket on the pcb instead of soldering direct to the board.

I'm not exactly sure what you mean by this, but I'm assuming I can should get hold of a substitute opamp (like the NE5532) and "make it fit" the existing PCB or any PCB I'm making. Assume complete beginner status as far as this goes...

It's going to take me a little bit of time to get my head around everything... I have to work out how I'm going to source/make the PCB's for these little projects first.

It's all simple stuff I'm planning to make between now and christmas... a basic preamp, a basic EQ (passive tone control), a couple of "fuzz" pedals, and we'll see where it goes from there. Once I've got a handle on what everything does, I'll be heading on to the higher-end stuff... really keen on the Baby Animals, Neve Clones and alike... but want a thorough understanding first.

Thanks again. Let me know if I'm getting annoying, and if there's a "beginner" forum anywhere... I couldn't really find anything that I understood 100% clearly on the Prodigy site.

Dave

If you are making your own boards then you should modify the layout before you make them them to use a current type of 8 pin IC using the information I gave before. Good Dual Opamp ICs of this type for audio are Burr Brown OPA2134 or Signetics (or other brand) NE5532.
If you have a pre-made circuit board that is laid out to use a 14 pin dual opamp IC, you can substitute an 8 pin IC by using the 8 pin wirewrap socket (it has long pins/legs ~2 cm long, so you can bend them around to meet up with the appropriate pin on the pcb) as follows:

8 pin -> 14 pin
------------------
1 Amplifier A output -> 1 Amplifier A output
2 Amplifier A in (-) -> 5 Amplifier A in (-)
3 Amplifier A in (+) -> 6 Amplifier A In (+)
4 Voltage (-) -> 7 Voltage (-)
5 Amplifier B In (-) -> 8 Amplifier B In (-)
6 Amplifier B In (+) -> 9 Amplifier B In (+)
7 Amplifier B output -> 13 Amplifier B Output
8 Voltage (+) -> 14 Voltage (+)

If you have trouble finding the sockets then I'm sure you can get them from Joe Malone.

Dave

(1) The site is http://www.futurlec.com/. Sorry about the misspelling.

(2) Otto's comments are great, but yes, they do apply to the situation where you have a PCB with holes for a 14-pin IC (2 rows of 7) and need to fit the more modern 8-pin IC form factor into it.

If you are sketching out your own PCB, or if you are simply using point to point wiring, you can do it using Otto's pin mapping to work out what connects to where.

The general point he makes about IC sockets should be taken to heart, though - always use IC sockets rather than soldering a chip to the board. There are just sooooo many reasons for doing this its not funny.

Where in Sydney are you Dave? I'm happy to get together sometime to go through a project if you're nervous about getting started. PM me if interested.

http://www.altronics.com.au has a lot of stuff

some of the big US players can be good, especially for stuff that is either hard to get or expensive here (e.g Panasonic and Nichicon electrolytic caps, some FETs and opamps etc). I've found ordering using US mail option where available is reasonably cheap and not so slow as to be objectionable (I prefer to buy local where possible, but it isn't always the way):

http://www.mouser.com

http://www.digikey.com

Also have a look at

http://www.smallbearelec.com for some slightly different stuff as well.

Thanks Chris,

I'm out at Quaker's Hill... let's play sometime!

I'm not really nervous about getting started on something, like I said, I've soldered before, and onto PCB's... and the pedal I made and modded went together perfectly, worked first time, and is sitting in the studio adding an extra stage of dirt to my marshall... BUT... understanding what I'm doing, that's a completely different ball game... and going from a schematic to a blank circuit board and making the two into something I can put my bits and pieces into is a little daunting...

IC sockets... yes... my pedal could have done with an IC socket... as soon as I heard it (and it sounds ok!!!) I wanted to go get a few different opamps and play around with the possibilities!!! (although there's more than one advantage I'm assuming).

Dave.

[quote="OzDrum"]
It goes under the name Electus
http://www.electusdistribution.com.au/

cheers
Geoff.[/quote]

yep thats jaycars supplier... if you don't want to wait for the delivereis and dont want to spend over $100 and buying in smaller quantities (or have an ABN or business etc) you can apply for a trade discount at jaycar too..

its made out like this is trade only but they'll give it to just about anyone who isn't buying a solar powered pool torch or some plastic crap

most of the guys at jaycar like it when sound tech guys come in and buy up parts, they'll spend all day talking to you about it if you have the time

how do i know? worked there until 3 days from now!