#1
Alright, this amp is great and all. However, I'd like to make it more Hiwatt-ish. I've fallen in love with the Hiwatt tone and my Rocker 30 already does a fantastic Marshall tone...

So I thought, well why not mod my 18watter? I need some help though.

The first thing I will do is of course to post the schematic for my amp:


And here's the post-phase inverter master volume mod I'm doing:
]

Secondly, time to start with looking at the Hiwatt preamps:
CP103 (Pete Townshend model, probably what I will do)
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DR103 (used by David Gilmour, also a good one)
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The Marwatt: 18watter with a Hiwatt style channel, however it's for a tremolo or TMB model with 3 preamp tubes...
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Also here's a 2 tone tonestack for an 18W Lite IIb. If it would be possible to change it to more Hiwatt style values?
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I could maybe fit a 3 way tonestack, but being a HUGE fan of The Wo, I'm more tempted about a CP103 which has a 2-way tonestack (treble and bass)

The ones who helps me will be GREATLY thanked and so on!
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18watter video demo

My band

Recognised by the Official EG/GG&A Who To Listen To List 2009
Last edited by Gabel at Jul 3, 2008,
#2
Cant you just buy a hiwatt? y'know probably be cheper and more time saving or am i missing the point
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#3
^You are missing the point, they are terribly expensive, plus my amp is possible to do more Hiwatt like!
Quote by stratman_13
It's okay Gabel. You kick ass.



18watter video demo

My band

Recognised by the Official EG/GG&A Who To Listen To List 2009
#4
If you add a tonestack you would definitely need at least one triode for recovery. That means drilling the chassis... Maybe you could replace the tone control with a tone stack. Even so you might need a recovery stage.

Also Hiwatt uses the same gain stage setup as tweeds and early Marshalls (JTM45). It has two gain stages, a tone section and recovery. 18Ws have a gain stage and a recovery stage.

From my experience with Hiwatts they are brighter and more punchy than Marshalls with less gain. Lots of easy little mods you can do for those things.

I might start with the pre-amps cathodes. Lots can be done there to alter the sound... Look at a bunch of Hiwatt schems for ideas.
#5
^Yes, I would replace the tone control with a tone stack, here's one I found
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Exactly, Hiwatts are much brighter and "clearer" in tone. Something like Pete Townshend's tone in 1969/1970:
http://www.youtube.com/watch?v=dV2X_Ek2bms
http://www.youtube.com/watch?v=fU9OC1ySvXY

Something along those lines. And yes as you said, they have adifferent kind of cathodes in them. Also I heard a 20W Hiwatt with El84s and they sounded great. Not as clean, but punchier. Like Townshend's tone in those clips. Punchy and dynamic, but not very distorted.
Quote by stratman_13
It's okay Gabel. You kick ass.



18watter video demo

My band

Recognised by the Official EG/GG&A Who To Listen To List 2009
#6
as far as the tonestack goes,
the one on CP103 is far different from anything i have ever worked with.
i can't even set up a sim on the TSC, because the configuration
is too different from anything it has.

these pics are ridiculously large.
you need to change that.
use a photobucket account and make two copies of each.
one full-size, and one no more than 640 pixels.
you can set it up so clicking on any of the normal width pics displayed in your post,
will open a full-sized version.
that gives you the best of both worlds.
detail, when you need it,
the ability to compare the overall of one to another at a glance.

cba to be scrolling all over the place to try to compare these.
this is frustrating.
Meadows
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#8
Having checked up, it seems the best thing to do is to "adapt" the Hiwatt channel of the Marwatt for my 18W Lite. Also I listened to some soundclips and the Marwatt sounds just like I want! If somebody could help me out with this, I will greatly appreiciate it! Also would it be best with a 3tone or 2 tone tonestack?
Quote by stratman_13
It's okay Gabel. You kick ass.



18watter video demo

My band

Recognised by the Official EG/GG&A Who To Listen To List 2009
Last edited by Gabel at Jul 4, 2008,
#9
Nobody who could help me on this one?

Also I checked, I can probably fit in a three tone tonestack in there!
Quote by stratman_13
It's okay Gabel. You kick ass.



18watter video demo

My band

Recognised by the Official EG/GG&A Who To Listen To List 2009
#10
Some ideas...

If you want a solid tone that doesnt have "loose" bass I would look at adding some negative feed back. An easy mod but very useful. I don't think Hiwatts usually have it but I think it would help with the sound your trying to get. Clear and defined...

When I think Hiwatt distortion I think of power tube distortion...you don't want it coming from your pre amp or phase inverter. Again I might rebias those pre amps to lower gain in the pre amp....

What kind of phase inverter does your amp have? If it is a paraphase or cathodyne I would really suggest going to a long-tail PI. They are very high quality and don't distort like the later... They were used in a lot of hi-fi amps back in the day. The paraphase and cathodyne are also well liked but for the distortion flavour they add... They can be found in tweed Fenders and some Marshalls, they give those amps their classic sound. For a Hiwatt though I would use a long tail.

Also Hiwatts use the classic gain stage setup of two triodes for gain stages followed up a volume control and tone stack then followed by two gain stages... The tone stack is a cathode follower btw, another Hiwatt special.

Also maybe bias your tubes a bit "hot". This way you can push the tubes to their maximum wattage capability while also pushing the headroom level to the max. Though sometimes biasing hot can make your amp sound cold/sterile I think it is worth a try for the Hiwatt sound.
#11
^Allright, I need two triodes for that Hiwatt tone... However as I said, I just need it to sound more Hiwatt-ish. You have some good suggestions there kurtlives91! If you feel like it, would you mind possibly doing a layout or so? This wold make things a lot easier for me when I do the actual mod...

Also Hiwatts are loaded with ECC81s, thinking that it might be a hood idea to put in a pair? The ECC83s already in can go in the Rocker 30 instead anyway.

Oh and for the help!
Quote by stratman_13
It's okay Gabel. You kick ass.



18watter video demo

My band

Recognised by the Official EG/GG&A Who To Listen To List 2009
#12
I think playing with tubes would be a good start. I would start by trying the EC81s in the PI then move them around.

I would also try some 6072/12AY7 again in the PI then move them around. I know SRV used these (actually a nicer version but I forget the name) on his Fenders. Its really supposed to tame them and make them smoother....worth a try imo. I bought a bunch of tubes for testing in my Deluxe Reverb...you never know what you'll find.

Ill try to make a layout (up to the PI)...