Amp Kits with variable wattage

[ehdwuld]

So I was wanting to build an amp kit

A small 1x12 combo probably a 20-30 watt would be what i want

I would also like the option of choking it down to 1 watt for bedroom playing

So is there a way to tap the transformer for a lower wattage ?

I guess that would depend on which kit I get.

Also I have an eight ohm 100 watt L-pad attenuater

Can I use this to choke a 20 wat amp ?

 

[jeremy]

i dont know of any kits with power scaling. the lpad would work fine, though as with any attenuator the more you dial the volume down, the more the tone changes

 

[donaldr]

Maybe your can do what James Brown is doing with the 5150 Iconic amps:

No, the way it works is that we cut the high voltage rail in half......half voltage gives you 1/4 power. And of course we tweak the bias at the same time, and we also drop the gain a little bit so it's easier to get lower volume settings on the pots.

Exactly.....with one important caveat: We leave the voltage high for the preamp, so it's not all squished and mushy sounding and stays tight. That way when you DO hit the power amp at 1/4 power, it hits just as hard as when at full power.....just not as loud. You get the same dynamics, and the guitar cleans up just as nicely.

 

[ehdwuld]

i dont know of any kits with power scaling. the lpad would work fine, though as with any attenuator the more you dial the volume down, the more the tone changes

I should be able to tweak the preamp EQ to correct for the L-Pad and still get a good sound

maybe a "Treble Bleed" of some sort

 

[jeremy]

sure, theres lots of mods you could do. even just a bright switch, which is basically what you are talking about, can make a big difference

 

[ehdwuld]

Maybe your can do what James Brown is doing with the 5150 Iconic amps:

No, the way it works is that we cut the high voltage rail in half......half voltage gives you 1/4 power. And of course we tweak the bias at the same time, and we also drop the gain a little bit so it's easier to get lower volume settings on the pots.

Exactly.....with one important caveat: We leave the voltage high for the preamp, so it's not all squished and mushy sounding and stays tight. That way when you DO hit the power amp at 1/4 power, it hits just as hard as when at full power.....just not as loud. You get the same dynamics, and the guitar cleans up just as nicely.​

Not sure i understand what this means

 

[ehdwuld]

sure, theres lots of mods you could do. even just a bright switch, which is basically what you are talking about, can make a big difference

so if I get an 18 watt marshall kit
add an L-Pad and a presence knob to roll in some treble bleed
it should be awesome

 

[jeremy]

a presence control is different than a bright switch or treble bypass, but it should work fine. if you find you need a brighter tone at higher levels of attenuation, then you can always add a bright switch later

 

[donaldr]

Not sure i understand what this means

Don't know either LOL
Instead of using an attenuator in the 5150 Iconic amps, James used half of the high voltage rail. Maybe an on-on switch where one position is using one half (for 1/4 of output) and the second position is using the other half (for full output). Maybe send a message to @amptweaker on thegearpage.net.

 

[ehdwuld]

I have seen some smaller amps ( the Stage Right clone of the Laney Cub) have a 15 watt main amp with a 1 watt switch
maybe something like that

a toggle choke and cap

 

[ehdwuld]

when Looking at this thread on the main page
it says "0 responses"

but clearly it has has responses

weird

 

[jeremy]

no idea about the zero responses thing... odd. but theres plenty of odd forum behavior.

i understand what james brown is saying. dropping the voltage to the power section will lower the output. so instead of running a 6l6gc power tube at 450v, you run it at 225v which will significantly reduce output. at the same time, the bias is adjusted so things are in balance between voltage and current for the tube. i dont know the mechanics of how to do that, but i get the concept.

 

[ehdwuld]

dang it I will look into that

but yall can see the 0 responses thing too right?

my NFL app on my Cell Phone wont give me scores of week 5
but the same app on my work phone does

weird

 

[jeremy]

i see 12 responses and 48 views

i assume a lot of the "studio" type tube amps that are running big tubes but have 15w-25w output are doing what james brown is talking about. if you run a el34 at 450v youll get 50w out of a pair, but drop that down and you can get the 20w of the studio series marshalls. im sure there are other things going on with the transformers and other aspects of the amp, but to get that output from a tube capable of 25w-30w, you need to run it at lower voltage

 

[ehdwuld]

ah i see the change in responses now

some of the Carvins back in the day had a 50/25 watt switch
some Mesa's have it now

my H&K has a 20/5/1/0 switch which has a dummy load for the 0

the Tonemaster Amps have an LPad built in
which is probably what I will do as well

 

[ErikH]

no idea about the zero responses thing... odd. but theres plenty of odd forum behavior.

i understand what james brown is saying. dropping the voltage to the power section will lower the output. so instead of running a 6l6gc power tube at 450v, you run it at 225v which will significantly reduce output. at the same time, the bias is adjusted so things are in balance between voltage and current for the tube. i dont know the mechanics of how to do that, but i get the concept.

Right, and the preamp section voltage remains the same. The voltage drop is strictly in the power amp section. That's a brilliant way of doing it actually. Where as using a Variac to drop the voltage actually does it for the entire amp.

 

[jeremy]

using a variac can also be cool, but it does change a lot of things. i find a lowering things from 122v down to 110v makes a big difference and i like the way it feels and sounds. i dont play metal though

 

[ehdwuld]

maybe a variac and an Lpad

be a heavy combo

 

[jeremy]

my variac is old as hell and it is heavy, its been modified to use three prong plugs now

 

[ehdwuld]

I see several on Amazon from China