Adding attenuator network from AC4TV to other amps

[SDS]

Hey folks,

I've got an AC4TV mini (the 6.5 speaker combo) and I love the selectable attenuation on it. I get that it has an affect on tone at the lower settings but it means I can plug in and overdrive the pre after my kid has gone to sleep... 2 things that I can't do with any of my other amps so it's a very valuable feature for me.

Here's my question:
- Can the attenuator network from the AC4TV be added to any amp? (...matching for expected ohms for the head and speaker of course.)

Actually, couldn't you add this network to a speaker cab?

Here's the schematic for the non-mini version of the AC4TV. (Note the mini has selection options of 4 watts, 1 watt, or 1/10 watt.)
[img718]http://harmony.demont.net/myharmonies/J ... ematic.jpg[/img]

Is there any reason I can't add this to all my low watt amps? In particular an Airline 62-9023a, a Sivertone 1472, or a Harmony 400?
There must be a reason that every amp doesn't have this.

[SDS]

Bueller... Bueller...

... Frye ...

Anyone? Anyone?

[SDS]

Mic check 1, mic check 1...

Is this thing on?

[Zippy]

Check the Trainwreck files "Air Brake" for a similar concept.

[printer2]

There must be a reason that every amp doesn't have this.

At one time manufacturers put a volume control on amps to control volume.

[SDS]

Thanks, Zippy!

At one time manufacturers put a volume control on amps to control volume.

And at one time amp manufacturers saw overdrive as a defect so they kept making amps with more and more headroom until they were unusable and musicians kept having to crank it louder and louder just to get overdrive. People do lots of stupid things.

'Volume' and output are 2 very different things. I'm looking for some drive for the preamp, without a master section that sucks all the tone away, at a reasonable (read: low) 'volume'. Not a tall order.

[hans-jörg]

Hi,
isn`t it worth to think aubaout an extern attenuator, which you can use at any amp you want play.
On the other hand - shure it is not a bad idea to have his own att. in every amp (better than a master).
But manufactor usualy wants keep the costs low and to sell you an additional attenuator.
A amp with all the nice and usefull features would cost a lot and you could order anything by a custom amp builder.

Its def. a good idea to have his implemented attenuator in his own build amp.
But I´m not so good to know the right sizes of Rs.
therefore:
I use a extern att. (home brewed) when I want to bring the power down.

Not shure if this helps ...


Best
Hans-Jörg

[rock_mumbles]

The 1 watt setting is just a slightly modified (added caps) fixed L-pad ...

I've seen a calculator that has speaker impedance amp, wattage etc. desired attenuation that calculates the resistor values and necessary wattage for L-pads ...

I'll see if I can find it and post a link ...


What kind of wattage amps are you wanting to attenuate?

[ampdoc1]

I've been touting a design I first used in 2005. I wanted lower volume with the same sound from my Express build, and was thinking about using a variac. But they are heavy and turn down all the voltages. So, I considered what it would take to just turn down the power to the output tubes.

I ended up using a 25W, 3 ohm variable resistor in the AC line connected to only the power tubes. It worked like a charm! (and still does) All the other voltages in the amp are unchanged, so the signal is not affected until it reaches the output stage, where fewer electrons are boiled off to make their way to the plates. I'm able to get fairly unchanged sound down to 1 watt or less.

Now days this can be more elegantly done by using a VVR with DC voltage only to the power tubes. (Both methods do take a second or two for the voltage/volume to "settle".)

I'd suggest a power supply modeled from the Peavey Classic 20 to power the tubes from your 6.3 heater windings. This gives a pretty robust and clean 6VDC supply to the output tubes.

a'doc1




a'doc1