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Apollo Booster help!

Started by martyfriedman86, October 08, 2006, 12:35:18 PM

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martyfriedman86

Hi
I'm trying to build the apollo treble/bass booster.
I've already put all the part together as the schematics from rg green suggest, but i can't get it to work

Has anyone ever tried to build this?
is there anything I should add to get it working?

Sorry if my questions sound too stupid, it's my first electronic project ever.

Thank you very much

joecool85

Can we see a schematic?  I've never done an apollo booster.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

martyfriedman86

http://www.geofex.com/FX_images/apolobst.gif

there's a think from geofx

this may sound really stupid but I think i might have messed up with the transistor. I'm not sure if I have put it the correct way

when I put the transistor with the soldering wires upside i can see this
  *
*
  * 

and i've solded

*collector
*base
*emitter

is that right?

martyfriedman86

pd: sorry for my english
I'm from argentina and i'm used to speaking spanish

thank you very much

Stompin_Tom

try socketing the transistor... then you can try putting it in there anyway you want (hopefully you'll find the right way!). In any case, when I'm putting together a pedal and it doesn't work it's usually because I either 1) miswired a pot, jack, or switch, or 2) managed to make a very small solder bridge somewhere on the board (vero, perf, whatever). You can just take a hobby knife or exacto knife and make sure there's no unintended connections.

You probably know about this, but diystompboxes.com has a lot of great info for beginners (check out the faq, wiki, debugging thread, beginners project, search function, etc.), and a lot of extremely helpful and knowledgable people.

I've made the apollo before. I liked it and used it for a while, but decided that either a rangemaster or mosfet booster did what I needed better (depending on amp and guitar).



martyfriedman86

did you use the exact schematic or did you add something particular?
about the 5uf electrolytic capacitor... it doesn't have a '+' symbol in the diagram, so I just wired the thick line as negative and thin line as positive.
is that ok?

Stompin_Tom

You know what, I actually made the orange treble and bass booster! I forgot... but they're basically the same thing with slightly different values. I didn't add or change anything on the schematic. I think I used this veroboard layout and schematic:

http://aronnelson.com/gallery/album18/orange_tb_boost

I believe you have the 5uf electrolytic cap right.  If you look at the schematic I linked to above, it just has a nonpolarized .1uf cap instead. Also, you might have to bias the circuit to get the Ge trannie to work... did you read the article on the rangemaster over there at Geo, too? RG tells you how to select a good transistor and bias it, etc. in that article. Although if you bought 'preselected' Ge it should work even if the bias is off (but might not sound as good as it could).

What layout did you use? Did you make your own?

martyfriedman86

i'll probably be kicked for this question but well
what does bias mean?
I went to an electronic shop and asked for a 2SB175 germanium transistor and I used that

Stompin_Tom

I see... go here: http://www.geofex.com/ and look for the rangemaster in the 'schematics and more' section. There's a 'technical discription and how to build one' link... under that download the how to build one pdf. You should read the whole thing (the apollo is basically a rangemaster with a 'tone' pot on the front end, instead of a volume pot at the end), but in particular the 'turn on, tune in' section talks about biasing the transistor. Germanium transistors vary a lot in their qualities (gain, leakage)... I'm actually surprised you were able to buy one from an electronics store. I ordered a butt load of Ge transistors from eastern europe and, although all of them 'worked' in the rangemaster and the orange t/b booster I made, only a few sounded really good.

but back to the biasing at hand, you can also use 100k trim pot instead of the fixed 80k resistor to bias the transistor... it'll be a bit noisier in the end, but I did that on my rangemaster and it doesn't bother me (of course other people really want it to be very quiet... i'm not that picky). Actually, I've never noticed it being particularly noisey at all... granted it amplifies treble, so it will be a bit hissy no matter what...

But let's not get ahead of ourselves... as I've tried to hint at, if you're using the stock resistor values and your transistor isn't totally fried, then you should probably be getting something out of your circuit.

Are you using a bypass switch? Does it pass the guitar signal when you have the effect 'off'? If not, it's wired wrong. Try retracing your layout against the schematic to make sure there isn't anything shorting or connected wrong. Also make sure you have the battery hooked up properly. Most effects are negative ground, this one's positive.

martyfriedman86


Stompin_Tom

Trimpot!: http://www.smallbearelec.com/Detail.bok?no=160

Yeah, it's a small pot that you can put on your circuit board... for infrequent adjustments (set and forget).

martyfriedman86

thanks everyone
anyway I got frustrated of not being able to make apollo work
and started another booster from DIY
i think it's called gus minibooster or something similar
I'll post results as soon as I finish it
and if I can't I'll definitely should give up electronics

martyfriedman86

i kinda got the apollo to work
but pretty bad :S
you can hear a low and distorted output when battery is disconnected and an even lower output when I connect it
anybody knows what this could be?

Stompin_Tom

I don't think you should hear anything when there's no power! It sounds like something's connected that shouldn't be... (extra solder blob or something). The apollo should have LOTS of boost and I imagine it'll be fairly clean until you really crank it up so yours is not working right.