Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Regards Speakers.
 Years ago i read an article in a El magazine, I can't recall details now of course but the writer made the observation that it is better to design from the speaker back to amplifier.
He was referring to hifi but over the years I've come to understand why he made that observation.

The reality of this Amp/speaker thing is complex.
FWIW,
Many pages on guitar forums are filled with Spk debates and observations.
I can tell you that even though many amp circuits might look similar one only has to alter a 20cent passive in a circuit and it can have big impact on the outcome.

Much like Valve shootouts, they always give me a giggle.
Someone swaps a whole lot of valves in a particular amp circuit and gives an observation of which one is best.
Even some educated folks entertain this stuff.
Yes in one particular amp circuit Valve X might work better than Valve Y.
But that does not mean that valve X is better for every circuit. In another circuit design the opposite might be the case.
Same goes for speakers.
I may have told this little story before but years back a mate brought me his Trademark 60 combo.
He said do whatever you can but if it does not work I'll dump it. It's way wrong, too harsh, brittle. Dist ch is not usable.
After a few days of pondering what could be done I decided to try a few old speakers I had laying around.
OK the Hot rod Eminence special design speaker that was in the trademark might have higher SPL and make the amp sound a lot louder than another similar 50 watt chip amp design but those big name fancy pants drivers that promise so much will often peak at higher freq and hence sound Louder. (they know the kids will often buy the loudest unit)
Problem with that is they are excessively bright when using heavy distortion, All sweetness is lost when you do that.
To overcome that issue one would have to dig deep into the circuit and change a lot of stuff.
As Trademark goop all the circuitry that I would need to change,, well it's just not worth all the fuss when all that was needed was a more balanced (Flatter SPL freq response driver)
My mate could not believe the huge difference.
the speaker was a $10 junk sale purchase.

Just my observations,, Phil.

Thanks for posting that. Looks cool, might try it.

Which diode is the LED and which is the 4148?

Can two general purpose NPN transistors be configured as the darlington, or does the sound depend on the characteristics of that particular transistor?

Phil in gorgeous Young Harris, Georgia, USA

It doesn't matter which diode is which as long as you have them facing opposing directions.  I haven't built it with general NPNs as a darlington, but others have on diystompboxes, and it seems that it works fine.  That said, I had another person build it and try a bunch of trannies and couldn't get the exact same sound as MPSA13 with anything else - close enough to work, but not quite the same.  Take that for what it's worth!

Thanks for the welcome and speaker vote!  Duly noted.

 

Ok, the reverb coil winding has started.... 

First pic is the bobbin mounted to the winder with the old wire still on it.

Second pic is the new wind started.

Wow this thing is tiny!

Winding going really sloooow cuz I don't want to break the wire and hafta start over...

The new wire is thicker than the old, so I'll over-wind it somewhat.

Old wire measures .015"
New is .025"

I was able to find the end wrap and paid attention to the direction of wind.

New wind is going on the same direction, don't know if it would matter (phase issue, maybe?).

Or any other way to get acoustic instruments talking to a computer.

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