Quote from: ShadowSpectrum on December 21, 2006, 03:46:33 PM
Yeah, the 10k is a resistor, you had already told me and I completely forgot. Alright, thanks alot for the help 

<edit>Forgot to ask you this before, but do the pots, input jacks, etc. from smallbear come with the nuts to secure them in place? How are the LEDs secured in place? I'm pretty sure they use some kind of ring. Also, do you have any sound clips of your 5th Gear? Thanks.

Yeah, they come with the mounting hardware.  LEDs can be glued in placed, or you can buy LED holders.  I have sound clips of the 5th Gear OD here on the wiki: http://wiki.ssguitar.com/index.php?title=5th_Gear_Overdrive

- For the 0.047uf caps, which should I buy? Or does it matter? These are all the .047 caps I could find.

I would run the cheapo $0.25 panasonic ones, supposedly more expensive caps can bring better tone, but I haven't seen such results, at least not in an application like this.


- For the pots, does it matter if it's single or double gang?

Single gang


The pots come in 16mm and 24mm. Does it matter which size I get?

24mm is fine, 16mm is good if you are jamming it into a small enclosure, but either one works the same.


For the 10k pot, which type should I get?

The 10k is a resistor not a pot, any 10k resistor will do fine.


- For the 9v battery snap, does it matter if I get #22 or #24 leads?

Either one will be fine, but I find #24 harder to work with, so if it was me, I would get the #22 just to make it easy.  (The bigger gauge number, the smaller the wire...#24 is damn small)


- What kind of wire should I get?

Technically any wire is fine, I'm not sure exactly what smallbear has, but anything from #20-#26 will work real well.


Sorry for all of the questions, I just want to be sure I'm getting all the right things when I order.

No problem, I'd rather have you ask questions now, than ask questions later and have to place another order.

The LM1875 amps sound great!  Trust me, I have two :-)  The LM3886 is good as well, but more powerful.  If you want one based off transistors as opposed to ICs, I would have you check out Joe Davidson's guitar amp (its more than 10-20 watts though), but his schematic isn't online anymore and I don't have it on my computer :-(

You could look into the schematics at deanmarkley.com, some of their legacy amps used transistors instead of ICs.

http://www.deanmarkley.com/Info/LegacyAmps/Docs.shtml

Like the K-20B (uses an IC for the preamp, but you could change that to something else): http://www.deanmarkley.com/Info/LegacyAmps/Schematics/D1513.pdf

The K-20B is technically a bass amp, but its a great little amp.  If you built something else for a preamp and just used the K-20B poweramp circuit, you'd be good to go for guitar.

I have this for an LM1875 setup:

http://cordova.asap.um.maine.edu/~raymondj/imagehost/lm1875.pdf

Regardless of what they put in (if any) you can always change them out for larger ones/add some.  Like I said, something in the order of a 1000uF cap should do it.

I didn't know it was battery powered lol.  I don't know a ton about pignose amps, but I did know some where battery and some are not.  Well, there is a good chance you could run it at 12volts with no problem, I wouldn't do it without looking at a schematic first and making sure it would work.  The other thing would be to run it on some size C or D batteries, keep the same voltage but up the mAH at your dispossal, not only should this help clean it up a bit, but also it will play longer on the same set of batteries.  Not sure if they'd fit though.  Also you might consider putting in larger power supply caps, or if it has none, put some in lol.  I would say something like a 1,000uF cap would do the trick, should help keep it clean when you're hitting the low notes.

**edit**
Just noticed this is a one knob amp, there is a good chance that you could mod your gain stages to keep it clean better.  It is SUPPOSE to get dirty when loud the way it comes out of the box.  Regardless of messing with gain stages or not, the mods I mentioned (caps, possible raising of voltage, and larger batteries) along with the speaker you are getting, WILL help.  It's hard to tell how much though.

The speaker is the first real good mod to get better clean volume out of the amp, after that I'm not 100% sure.  One thing you might be able to do is raise the voltage to the opamps, we'd need to see a schematic to see if that's possible.

Well, you have a few options, but unfortunetly the only full out kits offered are tube, and expensive.  To get the kind of wattage you want it would be rediculous expensive doing tube, I would go with solid state.  So thats the bad news, no SS kit for you.  The good news is that it is really easy to build a 50w RMS solid state power amp, and relatively easy building a good preamp (its harder deciding what one to build than it is actually building it.)  A simple LM3886 circuit will give you a solid 50w RMS. 

You can buy a kit to do that from brian at chipamp.com normally, right now he is out of boards.  I would shoot him an email if you are interested though because if he gets enough people interested it will get him to order boards sooner.  There is another website to buy kits, http://audiosector.com but I haven't dealt with him.  His kits are LM3875 (very similar to the LM3886).  And he sells stereo and dual mono (essentially the same thing), you would want to order a dual mono (then you'd have enough for two guitar amps) or email him and ask if you can special order a single mono.

The other good news is that you can build a poweramp, then use a small amp's lineout as a preamp, or buy a preamp.  Musicians friend has a mic preamp that would work (tube driven no less) for like...$30 or so.

Technically you could have either jack be the stereo, but it makes more sense to be the input.  That way you can leave the pedal plugged into your amp and it won't be on as long as you unplug the guitar. 

And for the offboard wiring: http://www.tonepad.com/getFile.asp?id=76

While I agree with teemuk for the most part, I will say that all of that isn't necessary (for instance knowing how to measure a transistor), these things are important:

- You need to know how to be safe working with 110v AC
- You need to know how to measure resistance and voltage and own a DMM (digital multimeter)
- You need to know how to solder, and have the equipment (a basic soldering iron and solder is fine)
- You need a basic understanding of how electronics work

With these things you should have a good chance at fixing your amp, not being an amp tech.  If you can't fix your amp by resoldering some joints and checking that your voltages are good, odds are it will need to see a professional.

Could be a bad solder on one of the jacks, but I'm guessing more than likely its a bad solder elsewhere.  What I would do is go through and resolder all the pots and jacks, its easy to do and then you don't have to worry about that.

Yup, you should buy your parts from steve at smallbearelec.com, he's the man.  The parts are decent priced, and he's the best guy to work with for buying specialty stuff like this.  If you are going to make it a pedal, keep in mind you will want one mono 1/4 jack and one stereo, that way you can wire the pedal so it's only on when you are plugged in.  Also you will want a DPDT stomp switch and an enclosure to put it all in. 

If you are just doing it for the learning experience, you don't really need an enclosure or the stomp switch, and you could just use two regular mono 1/4 jacks and unplug the battery when you are done using it.

Yup, thats right, except the 10k is a resistor, not a pot (a pot would work if you turn it all the way to one side though.)  For voltage on the caps, anything more than 9volts is good.  I think 16volt is what I used, but it really doesn't matter as long as it is more than 9volts. 

That brings up a good point, caps should always be rated for higher voltage than they are getting put into them, if you have a 16volt cap in a system where it is recieving 30volts, it could explode.

Thats really good progress!  Transistors are what power a lot of pedals, they provide the gain. 

Here is a good sheet to study:



Capacitors can also be two straight lines (like how they are in my schematic).

I don't know about this specific circuit, but I know that the TL071 itself can take substantially higher voltage.  Something like 30volts (normally used as +/-15v).