I suppose this tests the scope of this forum but please bear with me.
I was walking to the local shop the other night and I saw a crappy 10w practice amp in a skip. So I thought I could use this for some parts: chassis, transformer, pots, speaker, etc. I didn't know what, but I could definitely use it for something. I didn't expect it to work but when I got it home, I plugged it in and it did. It sounded awful but it worked. The pots were really flaky and cut in and out as you dialled in.
Coincidentally, I was building a Run Off Groove Britannia, so when I soldered the last piece of that, late at night I thought I would test it. Not to wake my two boys I decided to use the crappy 10w. It sounded amazing... low volume. So, in the morning I tried it again and it still sounded good.
Here's the amp
(http://dirtmonkey.org/foxx/crapamp.jpg)
My six year old, already a Jedi master of rock has just started to ask for guitar lessons from me. He can almost play a Whole Lotta Rosie, so his training is nearing competition.
I'm now thinking that this could be a great amp for my lad. My plan is to replace the existing amp pots with trimmers and then add the ROG Britannia to the input stage of the amp and expose the pots from the Britannia.
Is this the way to go? Am I missing something? Is there a better approach?
Just a foot note: I've only ever made a few pedals (badly) and have never done anything with amplifiers.
Hey Nick...yes, you could do what you're thinking of (trim pot, no controls on the amp, only on the Brittania), but you'd sort of "lose" something, i think. Just my opinion.
The Tyke would not be able to experiment with different settings to get wacky new sounds, and would be limited to only the Brittania. Not that it's a bad thing by any means ;) I also think it would be more work for you to install trims on a crappy amp than it would ever be worth. And you might disturb the mojo!!
You could just mark "The Perfect Setting" with some white paint, on the dials...
I love when putting a couple of simple things together results in what you described - sonic harmony! And for a 'noob' builder, the Brittania is pretty ambitious.
Hello. IMHO, if you have almost none experince with guitar related electronics, I don't think it's a good idea if you want all this working in a near future.
You already had set up as a the cheap amp as your PA+speaker cab, and ROG britannai as your rack preamp.
If you want to go, might conisder completly strip out the amp pream or turn it into a FX loop snd ret. I'm guessing there's already an active baxandall and a low power TDA chip.
BTW, most these generic cheap amps come with very bad speakers. Don't ask me why but I had a friend that once plug one into a twin reverb cab and it sounded lots better. Not saying you should do such a thing haha.
Sounds like it might be worth looking in at changing the pots in the amp.
At a later point you might think about changing either the speaker and/or the actual amp circuit. If there's a working power supply in there you have both a cab and power supply for your own amp build. Makes it a whole lot easier to build an amp. Build a Tiny Giant and stick a decent speaker in there (and perhaps a pre-amp). Would probably make it a great practice amp.
Quote from: Perrow on May 15, 2015, 07:40:10 PM
Sounds like it might be worth looking in at changing the pots in the amp.
Maybe open it up first and try cleaning the pots to get rid of the scratchiness instead of going full-bore and putting new pots in...De-Ox-It....
Four pots from Tayda is about two dollars, make sure you don't spend more trying to rescue the old ones.
Those amps are low-cost but not utter crap. Fairly straight-forward. Pots are a major cost item so of course they use the very cheapest pots on the market (unless they can get cheaper ones).
I'd start with a pot-cleaning, then go on to replace them. You will probably end up cutting the PCB legs, mounting a normal pot on the panel, and running wire jumpers pot to PCB, since the stock pots will be some odd PCB-mount and lug-space you can't readily find. Plan on replacing the main rectifiers and filter caps in another decade, and some fancier grille cloth when you have leftover from some larger amp re-covering. I'm sure the speaker is pretty crap, but good 5s and 6s are hard to find and not cheap; I'd install an external speaker jack so you can plug it to a Full Stack for larger venues.
Doesn't matter if the kid discovers girls-- you always need a handy-amp around the shop.
Quote from: PRR on May 15, 2015, 08:50:56 PM
Doesn't matter if the kid discovers girls-- you always need a handy-amp around the shop.
BBOMN! Good one, Paul.
Quote from: Perrow on May 15, 2015, 08:42:35 PM
Four pots from Tayda is about two dollars, make sure you don't spend more trying to rescue the old ones.
Time is worth money...for someone who doesn't understand how amps are set up inside, could be a LOT more time that it's worth. Get the iron in there, you might wreck the whole deal.
Not to discount your opinion, cuz I hear ya - but cleaning pots is just maintenance. 1 min. with some pot cleaner, almost always you're on your way and happy.
Oh one more thing,
You might expect not many discreet stuff if it's recent production.
Which means... no components to work as in your average DIY fuzz. In case you don't already know what discreet about.
Was that amp used on the Nina, Pinta, or Santa Maria? ;)
No, didn't they use it on one of Cortez' ships? As a PA, calling for gold...
Thanks for all the suggestions guys. Ok. I'll go with cleaning the pots and I'll put the Britannia in an enclosure for my lad. He'll probably be more excited about having his own pedal anyway.
Thanks again
talking of finding amps, a friend of mine said he found a tiny battery amp, and said do you want it...
of course i said, he brought it round and turnef out to be a mint roland micro cube..
someone had threw it in a bin....tried it, works perfectly...whohhhoooo.hooo...i now have 2 for camping.. 8)
as you were...
If the cleaning of the pots doesn't help then I might just go for it and take it apart.
I'll also go for changing the speaker as suggested.
i came across a complete POS Squier practice amp a month or so ago, and i loved it! i tried looking up a schematic for the preamp section, and it seemed utterly unremarkable. i figured i didn't have a great enough need to try and build it to see what made it tick, when the magic might've been in the power amp stage (or just a result of something failing) anyway. but i agree, there are some real diamonds in the rough.
yup.....de-oxit. dont use crappy "eloctronic cleaner" from radio shack or a hardware store. they are probably fine! unless it has 900 million miles on it or something.
i'll tell ya another half decent "crap amp" you can find cheap.....guys from the 80's will prolly remember these little combo's..... Gorilla. they have some crunch!