Tube Amp Archive

What do you mean by clippers?

As you've just discovered, a treble peaker in your mixer was a big part of the missing magic. Betcha didn't think you needed more high end content before, eh? hehe Yes. And now I need to add third gain stage. I would really like the Friedman Brown Eye mod ;) But I think it would ruin the "plexi" ch...

It may be unpopular advice, but stop using the calculators. I've personally found that site and its calculators to be useless. Not that the calculations are wrong, but a lot of the supporting information is so incomplete as to be totally misleading. Sure, they may give you some idea of what's going...

Thanks Matt. I will just play around with the values.

For the tweed, yes, you'll want to change the 820 to a 1.5k, you may even prefer a 2.7k (which is yet another doubling in value, notice a trend?) for the first stage for the more "plexi" crunch you're looking to hear. Did you include the "treble-peaker"? The Marshall I actually build and really lik...

Ok. I changed the first channel complety to a plexi (or 5f6) circuit now. I also use an AX7 PI and the feedback with a presence control. The only thing I did not change yet is the tail resistor. I still have the original blackface channel. When the amp is not turned up I have to say the channels sou...

I changed the whole preamp to CF now and it sounds much better. Warmer and not agressive at all. I can't make out the value of the bias resistor, it appears to be 270ohm? I am using 470 at the moment. The 500pF "entrance" cap to the PI from the preamp input side would also do some icky things to a m...

This is what I am having right now. Looks pretty similar expect for the "fizz cap"

http://thevintagesound.com/ffg/schem/ba ... _schem.gif

If you want to switch to a 12ax7 PI, it's not that difficult.

Did not even know I have to switch something. I though just swapping out tubes would be OK? Maybe I could change the tail resistor from 22k to 10k. But i am not sure if this will have a huge effect.

Great post Matt! Thanks alot. I am thinking about why a Marshall sounds like a Marshall thing right now. Would you think the cathode follower also has a major impact? Or is it more the position of the tone controls in the signal chain? I currently modded my BF Bassman first channel to sound more lik...

So now that we have the RCA 35 circuit analyzed. Here comes another one. http://ivanrichards.com.au/2013/01/16/service-centre-for-morgan-amplifiers-in-australia/ I am not too familiar with dumble circuits. It is supposed to be based on one. It seems to have 3 gain stages and a MV. The gutshots are r...

OK. I modded this to the trainwreck schematic and added a La Mar MV. It makes the amp more versatile for sure. I don't know what a Trainwreck sounds like in "real live" but to me the amp still sounds like the same amp with more gain and a little more grit on tap. Slightly different voicing. I though...

If you are combining youbarent getting the best of what each channel has to offer.
It is subtractive.

Of course you are right. But I will not combine the channels. I will use either the blackface or the Trainwreck channel.

What did this big tube amp actually sound like? He desribes is as an american (so Fender) amp with great cleans. Is this what it actually sounds like ? The regular 18W Marshalls do not sound like this at all. Is it just the power section that makes such a huge difference? I also know somebody who de...

The shorting jacks on the input of the bass channel should stop all sound and noise if nothing is plugged into them. Check to see that they are indeed shorting the signal to ground at the input. Should be no need to remove the tubes from the bass channel. Mhh. There is no difference when i remove t...