B Blender help. Noob alert.

[Cubes_Mahone]

I'm really new to all this so I apoligise in advance. I know this subject has come up before but I'm really stuck here.

I started my own pedal based on a little kit I got from maplins (robot voice changer), I thought it's sound like a weird robot fuzz but it sounds bloody awful. It's my first pedal though so I'd like to be able to use it at least a few times. I'm thinking I might blend a small amount under my regular guitar signal to make it at least bearable... I also think I might put the blend into it's own enclosure, then when I'm bored of the sound of a ridiculously crackly; spasming robot I'll still be able to use the blend for something else.

I've been looking at the scematic for the Mini B. Blender (http://seanm.ca/stomp/minblend.html), and I think that looks the easiest to build.

I think I could understand it, but the problem I have is I'm not sure what a FET Transitor is. I've researched it online but it's all too advanced for me to understand at the moment.

Would this be what I need to buy: http://www.maplin.co.uk/p/2n7000-mos-fet-transistor-to92-case-uf89w?

Thanks for any help!

[GibsonGM]

Hi Cubes...you're close, but not *ANY* FET will do.    Didn't find this in Maplin, so hopefully you have another supplier...2N5457 (or 58, 59) will do fine in this blender.   http://www.fairchildsemi.com/ds/2N/2N5457.pdf    Watch the pinout when you build this!  Make sure each pin goes to the correct place, IOW...

Try Mouser, Tayda, etc.     Get a few of them in case you ruin one or more.  5 is a good number    I buy them in lots of 10, myself....

Good project, hope it works but if not, come back and ask here! 

[duck_arse]

... I haven't even started typing yet ....

^ what gibson says. depending where you are, you might be more local to types mpf102 or bf245A or bf245B. there are many many fet numbers, find something and we'll be able to say good or bad. even if they are wrong for this project, you'll have 'em for the next. you probably want to avoid the surface mount types.

about your robot voice, does it have any tone controls? have you tried adding some at the output, like a big muff or a swtc?

[Cubes_Mahone]

Ah thanks for your help GGM, but I wonder, would the B. Blender be as easy and could I find the parts in maplins?
http://seanm.ca/stomp/bblender.html
I live 5 minutes away from one and I'd like to start today as I'm off work!

The 4 op amps in the schematic, are they 4 seperate op amps? Sorry for my confusion. I can understand resistors and caps (just about) but my knowledge ends there! I've always wanted to be able to understand this stuff so I just thought I'd throw myself in and see what happens!

duck arse: No tone controls, you might have to explain a little more. All I have are the stock controls. Pitch up/down, robot and vibrato. There's a 'volume' pot as well. I am thinking of trying to add some more control though. Would a tone knob be similat to a tone knob on a guitar? i.e. a pot with a cap wired to ground ?

Thanks

[duck_arse]

really? I just searched maplins, and they don't seem to know what a "jfet" is. you might be best to just give them the swerve. as for tone controls, if you follow the links at the page top and look over at AMZ, there is a dissection of both the big muff tone and the stupidly wonderful tone control.

the four op-amps can be 4xsingles, 2x duals or a single quad opamp. maplin does have some of them. get yerself some tl072's and some tl074's. if you can wait a few days, you could get these and others sent from TI as free samples. look their site.

you've some reading to do.

[Cubes_Mahone]

Haha yeah I know.

Well actually I am going to do a quick mod on my cry baby today actually. Just put an LED in it and make it true bypass (don't know if i'll hear the difference but I have some 9 pin switches so what the hey).

I might just think about the blender for a little while longer before I rush into anything..

Thanks again!

[duck_arse]

while you're at amz, have a look at the "mosfet booster". it is as simple as the jfet (nearly), and we know you can get the parts nearby .....

[anchovie]

I just searched maplins, and they don't seem to know what a "jfet" is.

Probably because all through-hole JFETs are now end-of-life or obsolete. I think they only used to carry the 2N5485 and they've been scaling down their discrete component offerings so I guess they're not in a hurry to buy any remaining stock from manufacturers.

[Cubes_Mahone]

Hi again,

I've been reading up and I am starting to understand electronics a bit more. I now see components where I once saw chinese. I have another question though... Could I use these op amps: http://www.maplin.co.uk/p/lm358n-uj34m with this perfboard layout: http://gaussmarkov.net/wordpress/circuits/b-blender/?

Here's a strange question as well. I was watching a video and the guy said he was about to get some op amps out of an xbox. I have an old xbox 360 here that broke a while back. Could I reappropriate the op amps into this project (or another)?

Thanks in advance!

[Buzz]

If the op-amps have been soldered in it's very hard to de-solder them without cooking them and/or ripping the legs off.

It's much easier to buy them. They're pretty cheap.

[Buzz]

It can be good to use sockets for your op-amps, too.

http://www.maplin.co.uk/p/dual-in-line-socket-8-pin-bl17t

The benefits are that you won't cook your op-amps soldering them in, You can quickly swap op-amps to compare and experiment, and down the track you can re-use your ops in new projects.

[duck_arse]

I've said it before ...... maplins: really?

the lm358 is usable, yes. but, you would be better to save it for those apps where it's particular properties are called for (it's not the best audio choice). you'd be better off buying 2 off TL082 (I couldn't see tl072, nice one maplins) for only 15 of your p more.