alternative parts

[suckerformimi]

They just showed up. I got the 100-pack from MATCH-A-KNOB on eBay.

The numbers on them are:
C945
P92C

What sort of beta values am I looking for? Should I just look for the ones wiht the highest beta? I have plenty to spare

[bcbox]

I'm using some very nice 4-turn trimmers for my x0xi0 mod for VCO Tune and Width adjustements. I'm using them because it has two VCO's and it's more critical to have fine adjustments but I have also found it can be hard to get an exact setting with the single turn trimmers in the stock x0xb0x (or TB-303 for that matter). The part is also a standard drop-in replacement. They're not cheap but well worth it....

Digikey Part #'s
3339P-503LF-ND
3339P-502LF-ND

Mouser Part #'s
652-3339P-1-503LF
652-3339P-1-502LF

(they're significantly cheaper at Digikey)

[eil]

ladyada says the LM358 might work as a substitute for the AN6562. I have an LM358N in my parts bin and was wondering if someone can tell me if the two are at least going to be electrically compatible. There seem to be at least a large number of LM358 variations and I'm not yet good enough at reading data sheets to be able to tell how the N model differs from the others.

If it is compatible, I'm willing to test it once I have my b0x put together.

[did concombre]

I have quickly red the datasheet and the "n" seems to be the type of package. Thow this is a lm358.

[guest]

the lm358 is essentially the same thing as the an6562
just a different part number

i read through the datasheets and compared them
and it is a really crappy amplifier
im suprised it stays in tune at all

[eil]

Once my box is a little closer to done, I'll socket the AN6562 and try swapping the LM358N to see what the result is. If there's no significant difference between the two, that'll make it a little easier on people sourcing their own parts. (Except for those who need as many original 303 parts in their b0x as possible. Me, I just want the sound.)

[jerwin]

Hi,

For the 2SK30 rare parts, can the 2SK30ATM-Y be used as an alternative?

Is 2SK30ATM-Y going to effect the sound in anyway? Or are the two parts identical?

[phono]

Hi,

For the 2SK30 rare parts, can the 2SK30ATM-Y be used as an alternative?

Is 2SK30ATM-Y going to effect the sound in anyway? Or are the two parts identical?

you'll need the datasheet to know if they are pin compatable. As for sound, it will most likely make a difference, and probably not in a good way.

[guest]

i compared the datasheets
and they might as well have just made
a photocopy of the one and pasted it into the other
i couldnt tell the difference between them on paper
give them a listen and decide if you can tell the difference

[bcbox]

the LM358 works just as well as the AN6562. you can use it as a direct replacement.

[Gaetano]

Just be careful to test the transistors you get, to make sure you get the correct ones.

I recently bought some 2SC945's to try, and all of them were marked C945, and sold as 2SC945, but are in fact KSC945's.

The same goes for some 2SA733P's I ordered, i got some KSA733's Marked A733 instead.

(No-one got any of these from me BTW, so don't panic!)

How do you tell which ones you have?

Hold the transistor with the Flat Side Up and the legs facing you.

2SA733, 2SC536 and 2SC945: Legs are . . . E C B <= Will work in x0xb0x

KSA733 and KSC945: Legs are . . . E B C <= Will not work, even Emily Post says that, crossing your (transistor) legs is not recommended!

If you don't know how to check these, you have two simple options:

1. Use a multimeter with a transistor tester.

2. Use a normal multimeter, there are lots of tutorials around.

[mome rath]

Just be careful to test the transistors you get, to make sure you get the correct ones.

I recently bought some 2SC945's to try, and all of them were marked C945, and sold as 2SC945, but are in fact KSC945's.

The same goes for some 2SA733P's I ordered, i got some KSA733's Marked A733 instead.

2SA733, 2SC536 and 2SC945: Legs are . . . E C B <= Will work in x0xb0x

KSA733 and KSC945: Legs are . . . E B C <= Will not work, even Emily Post says that, crossing your (transistor) legs is not recommended!

would shielding a component leg not work in that case?


(courtesy subatomic)

[Gaetano]

'Will not work' applies to just using them straight in a x0x. I was pointing out if someone self sourced the transistors, they actually needed to check out what they had been sold (I thought I got 2SC945's, - and 2SA733's previously).

Lucky I checked to make sure before I used them.

It would be interesting experiment to see if a x0x actually made any weird sounds with the wrong transistors, or just weird smells.

BTW, I have crossed legs like that if you can't get a direct replacement, the Emily Post joke only works for non-insulated legs though.

I would however rather get 24 x 2SC945's than cross the legs of 24 x KSC945's, and/or 2SA733's instead of cross the legs of 10 x KSC733's.

But as a last (last) resort you could even glue one upside down using the 'dead bug' method, and just connect the legs with wires if necessary, although I would rather cross the legs.

[westfw]

So what happens if you make a x0xb0x with "generic" parts instead of all the "hard-to-find" versions? (Assuming you fix pinouts as appropriate.) Does it just not sound like the original device that you're trying to clone, or does it not work at all?

[Gaetano]

You should in theory be able to get any similar part to 'work', but whether or not it sounds as good or even similar, would depend on whether the parts have similar characteristics. The consensus seems to be no though, the right parts for the right job, as one of the defining characteristics of the x0xb0x over other 303 clones is the attention to the original detail.

You could probably also get virtually any transistor (within reason, bi-polar pnp for bi-polar pnp etc.) to work also, but whether it would work well is debatable. An example of a similar substitute seems to be the simple case of not using a correct 2SK30A in the correct place, i.e., any generic 2SK30A, instead of a 2SK30A(O) for the VCO to get a good 303 sounding square wave (I don't want to get into a debate about this though). I'm sure you could get any OTA for example to work in place of the BA6110 (a 3080 or LM13700 for example), but you would probably have to change things around quite a lot, and adjust all the other components around it. Just like in the case of the BA6110, which needs four other transistors to fit where the BA662A did in a 303.

I mentioned the transistors below, as I was surprised to find that I was not sent the correct ones, as the markings were the same as the others I had. Transistors do not like to be put in the wrong way around, so if you soldered in a KSA733 were a 2SA733 was supposed to go without crossing and insulating the legs, (as mome rath pointed out), would at best just not work.