First i wanna thank you for your capacity to share that kind of knowledge.
I MUST SAY that is incredibly rare and precious...
i have been reading and researching those kind of stuff for years (i mean
- ideas about tube amps made with SS)...
but it´s very sad that we cannot find very much ideas to apply..
when the thing is good it is always protected..
I personally agree that tone shaping (equalization) can make the sound you want..
but sounds to me that a good circuit for tone shapping
in general gets very expensive...
in many ways it is very hard to me to get the sound of tubes in my country.
the problem is entirely mine, but i like the distortion produced
by tube amps...
thanks again hope you be happy with your research.
Hi Rodriki,
Very kind words so I thank you and I'm glad that you find my observations useful.
Re cost of good tone;
try this,
http://www.ssguitar.com/index.php?topic=1136.0That is the circuit I designed and built and is the tone control used in these clips.

The tonal possibilities here are very broard and I can't imagine you could not get something close to ACDC sound.
Not counting the Reverb unit all the preamp gear here is cheap enough to build.
The *PhAbbtone* parts cost me about $30 Aus.
*DDC* is similar cost but more complex,, all doable for anyone with resonable pedal building experience. So in a box complete I can't see it costing over $150.
Oh and the *Graphic EQ* cost me $8 at S/hand shop.

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Re thoughts on tone:
A big *arh huh! Now I get it moment* for me was once I discovered that tone response is much like a garden hose laying on the ground,, where when you lift one point (the Q point) off the ground you also lift a fair part of the rest of the hose. Passive tone shaping does the same thing. (so tone is all just a big rubbery thing)
A bigger moment was understanding that tone is constantly altering as it passes through each passive and sometimes active components,, Not just the tone stack.
For want of a better explaination;
Tone is just one tone shape (response curve) imposed onto (or into) another element with a different shape.
What I think makes it difficult to grasp is that we all tend to go hunting for that *One magic circuit* that delivers the major component of a specific tone.
Truth is it's a culmination of many circuit topographries and tricks all working together that makes the final result.
Adding to that already complex situation

is the simple truth that there may be many ways that effect the same end result.
For a novice, this is much like walking through a 3D mine field with so many twists and turns that getting it right first go is impossible.

The magic of the classic Marshall amps that are now famous actually have a unique Flaw.
""It is in fact the design Flaw that makes it so great.""
if you ever find yourself with a *Genuine* older model all valve Marshall,, try this out.
At low *level volume* turn the tone controls up and down and note how they affect the freq response.
Now crank the volume way past halfway and play a few rifts/power chords,,, while you are doing that start playing with the tone controls again ?
You will now realise they don't work very well and depending what guitar and how far you crank some tone controls may no longer seem to function AT ALL

The compressing output stage renders the tone stack almost non existant?? Hum??
Early Marshalls tend to develop a huge wall of midrangey honk that suits the rock compressed sound. below 100hZ just falls like a brick and the combination of dramatically altering impeadences and output transformer limitations of high freq kill off above 4khZ. choise of speakers helps too.
It more complex than that but I won't get into pointless detail.
Now take a Peavy Bandit, All SS (only cause I've been fiddling with these recently)
Try cranking up the drive and notice how the tone controls still work as effectivly as they did with no gain/distortion.
technically it could be argued that the Peavy tone works better than an old Marshall?,,
No argument from me,,, but which Amp would you rather use?

You see the Peavy uses *Active* Tone shaping,, not passive.
It also suffers from WAY to much bandwidth,, way to much low freq content below 100hZ and the treble is extreme even by comparison to some other SS Amps.
Yet some players love those Bandit Amps? and that's kool,,Everyone want's something different but if you wish for a Bandit to sound like my clips you will be tweaking it for a very long time.

What I've found is that passive *Before* the distorting device and Active *After* seems to work very well together. There are probably other ways but I do actually play guitar and I've only got one life.
What is most interesting is that my setup seems to have the very same tone control flaw as the Marshall.

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Try googling *Ed Rembold Marshall cab sim* or grab a schematic of
a Marshall JTM 30 or 60 Valve Amp where you will find the *Built in Cab sim* which is an add on SS circuit which does a respectable job of the sound required. (No distortion though just tone shaping).
The marshall cab sim is a little less complex than my DDC but delivers similar results. I've built 5 of them so I know they work.
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You mentioned Vox, I'll assume here you are reffering to Brian May Sound?
Consider this,, Brian May used the *** Normal** Channel,,not the *Bright* channel (as most assume) to get his particular sound.
So simulating the tone stack seems rather pointless because the normal channel on a Vox AC 30 *Has No Tone stack*. The signal passes through a 500k volume pot and the only other tone altering device is a *Top cut pot* mounted across the PI section.
Simply by implimentaion of a rather basic treble boosting transistor circuit in front of the Normal input will deliver that particular tone.
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Re the circuit you give seems to do nothing in my simulation but I may have missed something?
Have fun with it all, Cheers, Phil.