RobbieZ
Gearhead and I were discussing valve amplifiers and their design the other day. That got me thinking :-\ and I would like to know what you guys think of it. The design I am fine with and we, Gearhead and me, will still discuss this aspect further.
What I was thinking of is the output of the amplifier. I have an 18W in mind with a variable voltage regulator, or as I like to think if it, a “master volume” setting on it because as I was told a pure 18W valve is “insanely load”. ?
Now, I do not think I will ever play in any venue larger than our church. It is about the size of an average school hall. Does that mean that I will be wasting my time and money building a 18W and should rather settle for a 5W?
Here are my reasons for thinking I should rather go for the 18W.
1. If I understand it correctly, the first 75% of a valve amplifier’s range is clean and the last 25% it is in overdrive. Am I correct? If I am, I can turn down the VVR to get to the over drive quicker, or I can have a decent clean channel by turning it up. I see it the same as a powerful car. You can only drive 120km, but that extra “oemf” that it gives you if it can go to 220, can be very useful. Does this make sense?
2. If one day, I do play outside or a bigger venue, or just to irritate the neighbours :?, I will be okay.
On a serious note, what do you think?
Robbie
ezietsman
If you are talking about the Marshall 18 watt style amps then yes. That all seems correct. Without VVR it will be much too loud to drive at home or church but will give you beautiful cleans. With VVR you get to drive it basically anywhere any time.
Of course I will get the 18 watt + VVR over the 5 ? ?
One thing, the VVR does not work like a Master Volume. You can install master volume in the 18 watt but that will not get you drive at low volumes, it'll just dictate the amount of drive, more like a gain knob than anything else. But in a sense the VVR knob becomes the Absolute Volume Control (Tm) yes ?
Keira-WitherKay
If you already in talks with gearhead about your amp you in fabulous hands , he's someone i would trust about valve amp design and components . So you already have an expert on hand ? btw 15 to 18 w is cool for a tube amp for medium gigs and just mic it up if you play huge venue's
MikeM
VVR can be better explained as a wattage control.
Master volume can be better explained as an overdrive control.
Channel volume can be better explained as a gain control.
The point you raise in #1 is a bit complicated.. But basically as you've pointed out, you turn the VVR down to more or less what volume you want, then proceed to tweak it from there. So that means you can have ultra saturated tone at 1watt, or super clean at 18watt (with the 3 controls outlined above).
But yea, as Keira says, Gearhead is a genius and one of the most helpful guys on the forum, he'll sort you out (as long as you do try pull your own weight heheheh).
RobbieZ
Yes, you right, Gearhead has a vast knoladge of valve amps and guitars. Once I am ready, we will sit down and get down to the technical detail.
Gearhead
Enough about Gearhead already ☹
The main thing to figure out, as I said to Robbie (but would like to point out to all interested forumites), is whether you like single ended or push-pull tone. Wattage is just volume and, as has been posted, can be tamed. You could theoretically make any wattage in either push-pull or in single ended, but they will always be different. You can get drive at any volume if you figure out how much power you need, but single ended will drive differently from push-pull.
bottledtone
And to choose valve type, and phase inverter type, not just thinking about volume, but its character. Certain valves, driven by certain phaseinverters (or lack of for single ended). eg. EL84's pushed by longtailed PI will break up much quicker than say 6V6 by concertina PI
