Ruby/Noisy Cricket practice and headphones amp

[JRM]

Hi, I'm planing to build a Ruby/Noisy Cricket practice amp based on the LM386 chip.
I wanted to add a Biig Muff Pi style tone control instead of the simple tone control of the Noisy Cricket (the Ruby doesn't have any tone control). Actualy, the main reason for this is because I can't understand how the tone control of the Noisy Cricket works! It's neither a typical LPF nor HPF nor a mix of the two. Is there any inconvenience in adding this tone control? I'll do it before the LM386 in order to overcome the loss expected from the tone control.
On the output side I want to use it with either my headphones and a small speaker (I'm thinking of building a small travelling cab using this http://www.hotroxuk.com/ch-6-15-jensen-speaker-8604-0.html 6 inch speaker). Should I use different outputs or can I use the same? I was planning to use the same output jack (stereo because of the headphones) and then make a specific cable to connect the speaker cab to the amp.
A wall-wart in is a must have in order to drive the speaker and save money in batteries, but this is quite simple.
Schematics:
http://www.runoffgroove.com/ruby.html
http://www.beavisaudio.com/projects/NoisyCricket/
http://www.beavisaudio.com/techpages/BigMuffToneControl/

[ayayay!]

It is a LPF.  This is very close to the SWTC, http://hammer.ampage.org/files/SWTC.gif

It's not wired quite the same way, as Beavis's is after the volume and has no inline resistor, but I can attest it works very well.  You're simply feeding a cap to ground, thereby rolling off some of the highs. 

[JRM]

Thanks! Now I understand how the tone works. And that makes me think if I realy need to get it more complex than that.

[ayayay!]

I gotta admit, it's a neat little circuit.  One of the first I build some years back.  More of a novelty, but I liked having it to have a battery powered way to test speaker cabs, and it was fun to build and fiddle with.  Kinda miss it, but not enough to build another one.  Hehe. 

[JRM]

Do you think I'll have any trouble if I hook the speaker and headphones the way I've described in my first post?

[ayayay!]

Oh I think if you keep the volume super low you could probably use headphones, but keep it depends on how your headphones handle it.  That half watt can be deceiving.   

[jefe]

runoffgroove has info on adding a headphone out to the ruby, here in the FAQ section:

http://www.runoffgroove.com/faq.html

[JRM]

Thanks Jefe, I've missed that one!

[JRM]

Hi guys,
Why should one use linear pots to both gain and volume controls on this build? Wouldn't be more reasonable to have log ones? At least for the volume. Or is there something that I'm missing?

[twabelljr]

I used a stereo jack for the output of mine and just jumpered the left and right lugs at the jack. Then you can use headphones without having to make a special speaker cable. I have one breadboarded now with an "Easy Drive" in front that can be switched in and out. Adds a nice gritty overdrive and a huge volume boost. I plan on experimenting with the "SWTC" and Dano's "Noisey Cricket" tone controls also. Keep us posted how the tone controls work out for you. It seems the "SWTC" would be the easiest to tack on the end. As for why use linear pots, maybe it helps make the volume and gain more interactive with each other. Just a guess.

[JRM]

Pots are still a mistery then.
I don't know when I have the time to breadboard this. I might try the noisy cricket and the BMP style tone controls.

[RickS]

I am very pleased with my Noisy Cricket--it's become my default play at home amp, because usually the Bandmaster is just too much!

I'm driving an 8 ohm 12 inch speaker with no problem--more than ample volume for home practice, or jammin with others in home setting.   Based on how it does with speakers, I'd definitely recommend you check out the circuits for adaptation to earphones. Truly, that "1/2 watt" specification can be really misleading in terms of volume!

If I had it to do over again, I'd forget the "Grit" switch, doesn't do much, or much that I like anyway.  Turning up the gain pot gives me the overdrive that is all I need for a small amp.  I have not tried any pedals with it--just a tube reverb unit I have.  Not sure if it will sound even close to the Bandmaster with a Big Muff Pi, for instance.  Most stuff I play is clean, or with just a little o-drive from the gain pot.

Don't really need a wall-wart, unless you just want to--9V Duracell has lasted over 8 months now, with no degradation of the sound. 

I bought one of Small Bear's "slightly defective" BB enclosures to house it, which makes it very portable--I built it on veroboard (Dan Haught/jpm83's layout) which fits well in the case along with pots, battery, etc., and the whole thing fits in a gig-bag pocket nicely.  I recommend it!