The Amp Garage

My guess is that the real speaker is:
Jazz version A
Over the Rainbow version B
Georgia version A

I also agree that in a live context with no direct comparison, non-guitarist audience members won't know.

It's already been said that it's in the vacuum between the plate and cathode, and is a function of the operating point of the valve. I just wanted to add - the fact that it changes with operating point is a hint that it's not just the plate material resistance (which doesn't change, and is relativel...

I too only found out the joy of cobalt drill bits a few months ago. What a difference!

Wanted to add an experience post to back up the theory. A lot of datasheets say heaters are +/-10% which means up to 7V. Years ago I used to live in a house where the wall voltage was right at or sometimes above the allowable supply spec. House was full of dimmers and back then the only dimmable hig...

I made up a model of the full Express amp years ago. Don't think I've got the file anymore. Express or Liverpool, you'll need to model the full amp including the power supply to see everything that's happening inside the amp. The clipping character of most Spice valve models will also show inaccurac...

I think of it in this way.... You know how if you plug your lead into an amp with the volume up, but no guitar connected on the other end you get a heap of hum and noise pickup? Then if you do have a guitar connected, it's acting as a (relatively) low impedance source and isn't as susceptible. This ...

I built an amp heavily based on a Gibson GA-75 a while ago and was having major problems that ended up being due to cross-talk in the dual triode. My mistake was making it single channel and using the same valve for the first two stages. The GA-75 has an uncommon set up where the volume pot is befor...

Great work! I love submini builds and this has turned out really nice.

I use and really like Ardour. It's free and open source, but runs on Linux.

I haven't had direct experience with them, but Reaper and Audacity as already recommended are both pretty popular for good reason.

The push-pull 6112 & 5902 based amp I made years ago, I had a B+ of 170V to stay within the published valve limits. Sorry I don't have any experience running them any higher to share.

I've never fully understood why Dana included that diode. It protects the mosfet from reverse bias across drain to source during power off, when the filter caps are all discharging at different rates. But the mosfets that are used all have an internal protection diode (albeit parallel instead of se...

Like Tillydog's post here on TAG, it's just the standard VVR circuit, reversed polarity and smaller mosfet. People get hung up on mosfet selection and if you know how to spec it, there are many to choose from. I picked the model shown in the diagram below because it was one of the cheapest options f...

With the bias coming off a 1M pot wiper, it's possible that the grid leak impedance could be quite high. Any concerns about that? Absolutely! I assume you are referring to the Power_Sliding pdf? I made comments on the Wattkins thread about why I thought that was a bad idea, how the mosfet in the bi...

I was going to post my opinions on the Powersliding circuit, but see that I've already done so in the thread that Martin linked.

Just as a postscript on this thread...I was able to play and turn this amp up in a band situation over the holidays. It sounded really good on both channels. I played through it as did another guy and we both used Les Pauls. It was very smooth and the high end had great clarity and detail with no h...