I quote Mr Fahey;
"Start by building a classic amp, you'll have a lot of fun doing it, *later* you start experimenting.
Otherwise you do not have a reference sound in your head.
You will never know what any mod is doing."
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What is written above is the BEST Advice you will ever get.
Sadly few will take note of such wisdom.
FWIW, I built my first Valve Amp and quickly built far more complex valve circuits *Assuming* I was improving things,,,,, well 20 Years later all the fancy stuff went and I found that one of the very first simple Valve Amps I built was the best. I still use it today.
A lot of Valve circuits/mods are over rated and often don't reap the rewards that are often claimed by forum blabs.
As to bypassing coupling caps,,, DON"T.
You have DC and AC inside these circuits as the cap *Decouples the AC signal from the DC operating points on the Valve. **a Capacitor in that configuration Blocks DCV but allows the ACV signal to pass onto the next stage.**
Most Valve circuits are AC coupled, you can have DC coupled circuits with Valves but not often used.
Go look at the guts of a simple 741 opamp or similar and you will see that all the transistors Are in fact Directly coupled.
Remember that Amplification is AC voltage (the signal you hear) floating on a DC voltage.
So there are two things happening at the same time when you look at the schematic.
You have to set the DC parameters so that you get the best transfer of the AC signal.
**Think of a schematic as 2 separate circuits drawn as one**
Tiss not very hard to see the AC signal path through a Valve amp but some learning is required to see the more complex DC parameters.
Some reading and experimenting with simple BJT transistor circuits will soon reveal biasing procedures and help you get a handle on DC biasing. (setting the Q or quiescent point)
This will also reveal that transistor and valve circuitry is not so different.
The beauty of transistor circuits is that you can mess with them LIVE and not kill yourself.
(at low voltage they are a very safe learning tool)
It takes forever to rewire valve circuits and AB test stuff.
Learning on transistors is good as It will speed up the Valve understanding.
Blowing up small transistors is way way cheaper than blowing valves or worse melting transformer winding which is an extremely expensive way to learn.
Phil.
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