It's pretty much the same circuit that Matt Taylor posted up with the exception of the 220K resistor between the treble control and the P.I. input that was omitted.
I'm a big fan of AC-30's though I have felt in the past that they don't break up enough (with my Strat.) I did play a AC-30 reissue amp with Celestion Blue speakers some time ago and I thought the amp sounded too stiff. I did try playing a few different guitars through the amp but I still didn't like it.
I do really like the prototype amp. it has a good range of clean tones and the distorted tones are what I like most about the amp. My Strat that is equipt with Kinmans (purely to inform, not to plug ) sounded really good through this amp, the back pickup sounded balanced and in no thin.
Anyway, I hope to record the prototype and let you guys hear it for yourselves.
Sounds awesome and I can't wait to hear some clips! What'd you end up doing for the first stage coupling cap and did you decide to bypass the second stage cathode? What about B+1 capacitance? I've got so many questions...
The amp is a prototype, so it's not a pretty thing to look at.
Regarding the build, I put all the amp components on a second version of the Rocket layout that I have yet to post, it's pretty much the same layout minus the 33K input resistor which I mounted directly on the valve socket, I also left out the 220K resistor that is between the treble control wiper and the P.I. stage.
As far as the amp goes it is only a 15 watt version due to the iron I have.
The power supply is typical Trainwreck with the exception of the first two filter caps which is a LCR 50/50uF can cap, the choke is a New Sensor twin reverb one, the output transformer is a New Sensor 022913 (I think)12 watt output transformer the primary impedance is 8.5K which is pretty much ideal.
The power transformer is the massive one I got wound for my Liverpool project.
As far as component choice goes I stuck with all the standard AC-30 values, that being the 500pF coupling cap, and I didn't bypass the second stages 1.5K cathode resistor, I was certain that I would have to do this to get a decent amount of gain. I shall experiment with this later though.
I have experimented with the use of a 1.5K resistor and a 3.3K resistor for the cathode of the first stage. I have found the 1.5K to be a tiny bit warmer than the 3.3K resistor, I put this down to the fact that the 500pF cap would roll off a lot of the extra warmth and gain provided by the 1.5K resistor value. That said, I shall put a signal in and see what the scope says.
I've probably said quite a bit previously about this amp. I do beleive that we shouldn't overlook this amp, particularly if your an AC-30 fan as I am.
I'll try and get onto recording the amp as soon as I can, and let you all hear what it sounds like, it is quite a bit different to the Express, and that is when using the same output transformer.
Any further question feel free to send me an email.
Mark, I am curious to hear how your Rocket prototype has progressed since the last post a couple of weeks ago. Any soundclips yet?
I must say, I have always been intrigued by the Rocket idea (a 'Wrecked AC-30) and have been even more intrigued since I saw your posting about the prototype.
) sounded really good through this amp, the back pickup sounded balanced and in no thin.
