Mozz, you may be right. I pulled a lot of that from Fender and Marshall circuits, so what Fender called "bright" Marshall could have called "Normal" and vise-versa.
I'm working on getting more done on the actual uke before I start this project. I have been digging out my box of tube amp tools though, and getting ready.
Two sets of EI66 thin (0.35mm) laminations, with bobbins for a 35mm tall stack
Plenty of magnet wire in about 20 different sizes
Found 3 NOS Cinch Loctal sockets in the sockets box, there's probably another one here somewhere.
A whole 2lb bag of 4-40 threaded ceramic terminal studs, why do I have these??
9 colors of 1kV rated cloth-over-plastic jacket wire
I've LOTS of power transformers...I'll just pick out whatever gives me the appropriate voltages from the stack.
There's plenty here to get the job done. I even have the option of winding the output transformer too-It's been a while since I wound one and I already have to wind the pickup coils so the winding machine will be setup again.
As for the uke, I had a bit of a mishap the other day and haven't figured out how I'll fix it yet. Bandsaw kicked back and proceeded to gnaw on one of the finished faces.
It does fall under the fingerboard and will be completely hidden when the neck is fitted to the body, though.
I'm working on getting more done on the actual uke before I start this project. I have been digging out my box of tube amp tools though, and getting ready.
Two sets of EI66 thin (0.35mm) laminations, with bobbins for a 35mm tall stack
Plenty of magnet wire in about 20 different sizes
Found 3 NOS Cinch Loctal sockets in the sockets box, there's probably another one here somewhere.
A whole 2lb bag of 4-40 threaded ceramic terminal studs, why do I have these??
9 colors of 1kV rated cloth-over-plastic jacket wire
I've LOTS of power transformers...I'll just pick out whatever gives me the appropriate voltages from the stack.
There's plenty here to get the job done. I even have the option of winding the output transformer too-It's been a while since I wound one and I already have to wind the pickup coils so the winding machine will be setup again.
As for the uke, I had a bit of a mishap the other day and haven't figured out how I'll fix it yet. Bandsaw kicked back and proceeded to gnaw on one of the finished faces.
It does fall under the fingerboard and will be completely hidden when the neck is fitted to the body, though.
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Sorry to hear about the uke-related accident. Uck. It's never as much fun having to do the same somewhat tedious task over again a second time...at least, not for me.
But if it has to be done, it has to be done. I'm sure you'll have your 'uke back on track soon enough.
There is a bit more to it, too, which I'll discuss at the end of this post.
Look at C13 and C15. C13 is 25 uF, way oversized for its job (Leo copied a Hi-Fi amp with response down to 10 Hz), meaning lots of beefy bass from the guitar. C15 has a value of 100nF (same as 0.1uF), again big enough to allow lots of bass through.
Not look at C12 and C14 in the other channel. C12 is only 0.68uF (a full 37 times smaller than C13!), which is a "Marshally" value that will cut deep bass from the guitar signal, allowing for crisper overdrive without muddiness and blubbering. And C14 is only 4.7nF (twenty-one times smaller than C15!), and will strip out some more deep bass from the guitar signal.
So it's pretty clear - the channel with C12 and C14 in it is designed to produce crisper overdrive, and lots of bass will be stripped out of the signal to help achieve this. The other channel, with C13/C15, is the "full-fat" channel with full bass response, which will sound deep and full for clean tones, but may become muddy and "blubbery" (i.e. suffer from blocking distortion) if overdriven too much.
Now, in some Marshall amplifiers, there is an additional "bright" capacitor that boosts treble in the bright channel. In other words, not only is the bass cut, but the treble is also boosted.
That bright capacitor doesn't exist in either channel of your design. So technically you don't so much have a bright and a normal channel - rather, you have a less-bass and a more-bass channel. 🙂
Not everyone likes or wants the bright cap, and if you decide that you do want it, you can always add it to the "less-bass" channel.
-Gnobuddy
But if it has to be done, it has to be done. I'm sure you'll have your 'uke back on track soon enough.
Mozz is right, the labels on the two channels are switched. The clue is in the capacitor values.Switch said:
There is a bit more to it, too, which I'll discuss at the end of this post.
Look at C13 and C15. C13 is 25 uF, way oversized for its job (Leo copied a Hi-Fi amp with response down to 10 Hz), meaning lots of beefy bass from the guitar. C15 has a value of 100nF (same as 0.1uF), again big enough to allow lots of bass through.
Not look at C12 and C14 in the other channel. C12 is only 0.68uF (a full 37 times smaller than C13!), which is a "Marshally" value that will cut deep bass from the guitar signal, allowing for crisper overdrive without muddiness and blubbering. And C14 is only 4.7nF (twenty-one times smaller than C15!), and will strip out some more deep bass from the guitar signal.
So it's pretty clear - the channel with C12 and C14 in it is designed to produce crisper overdrive, and lots of bass will be stripped out of the signal to help achieve this. The other channel, with C13/C15, is the "full-fat" channel with full bass response, which will sound deep and full for clean tones, but may become muddy and "blubbery" (i.e. suffer from blocking distortion) if overdriven too much.
Now, in some Marshall amplifiers, there is an additional "bright" capacitor that boosts treble in the bright channel. In other words, not only is the bass cut, but the treble is also boosted.
That bright capacitor doesn't exist in either channel of your design. So technically you don't so much have a bright and a normal channel - rather, you have a less-bass and a more-bass channel. 🙂
Not everyone likes or wants the bright cap, and if you decide that you do want it, you can always add it to the "less-bass" channel.
-Gnobuddy
The original C13 was 250uF, which I thought was absurd, so I cut it down to something that's equally invisible.
I'll annotate the schematic accordingly.
250uFd additionally shunts some cases of heater leakage hum. It's not wrong, not a mistake.
There were a few multiple mixed input stage amps with, say, four jacks and triodes but one shared cathode network. This can cause odd leaks and nulls unless bypassed with a boulder.
There were a few multiple mixed input stage amps with, say, four jacks and triodes but one shared cathode network. This can cause odd leaks and nulls unless bypassed with a boulder.
Interesting about the heater leakage hum.PRR said:
I would say attempting to share one cathode bypass cap between several triodes was the mistake.😀
Done for cost-cutting reasons, one presumes.
-Gnobuddy
Haven't folded up the chassis yet, still working on the source.
Got both pickups wound, just need to finish the pole pieces for the 4-string P90's that are going in the J-body.
Once the pickups are finished the body will get routed and it'll be time to finish the fretboard and neck-then glue up the assembly.
Got both pickups wound, just need to finish the pole pieces for the 4-string P90's that are going in the J-body.
Once the pickups are finished the body will get routed and it'll be time to finish the fretboard and neck-then glue up the assembly.