• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

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Hello group. Great forum you have here. Lots of expertise, information and interesting projects.

I enjoy playing with my hotrod and stereo system (not home theater). I'm a retro kind of guy who makes a living working with state of the art technology (IT) and plays with vintage technology. Can't say I'm an expert in either, but I get by.

I'm currently building a pair of tube monoblocks. Hope to have them running next week. They're based on Dynaco Mark III trannys and all of the electronics are from Curcio Audio Engineering (Premium Upgrade driver board, power supply, and cap board). They have aftermarket chassises that I had powdercoated. The tranny bells are gold plated. And, I've spent weeks building the bases.

I've enjoyed reading the posts. However, most are way over my head.

Don

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That's some seriously pretty stuff.

Curcio has done some excellent circuits; I have one of his ST-70s running the system in my garage. Understanding this stuff isn't too hard- read some basic books (I find myself continually recommending Morgan Jones's "Valve Amplifiers"), get some basic tools (voltmeters, signal generator, oscilloscope), and start experimenting. Expect some smoke, expect to hit some dead ends, expect to ask for help now and again. That's OK, that's what we're all here for.
 
Hey there Hipo!

Nice looking Mark IIIs. I went with the VTA boards, which I like very much. Your examples look much better than mine in a stock case. Putting the pcb on risers is a nice touch too.

I see you went SS rectification, I stayed tube. Retro is as retro does.

What is that cap can doing there besides hiding the tubes. I hope you are not really using it. I was thinking of putting an eye tube in that hole or just cover it up. With all that precious extra space underneath, you could put some oilers in there. I ran some ASC oil caps outboard to good effect, but the contruction is not so safe. Currently using the triode board, which was a tough fit since the VTA boards are bigger than stock.
 
Thanks guys, for the warm welcome!

I use the Mark IIIs to drive JBL L100s. I have a pair of Phase Linear 400s that power the subs I built. The preamp is a Phase Linear 4000 Series II and the crossover is a Paradigm X-30. It's a lot of old gear, but it rocks! The subs vibrate the walls and floors and some songs you can feel in your gut. For the most part I listen to music from the 60's - 70's.

I had the tranny bells gold plated at the shop that has done all the chorme on my car. Like all plating shops they are slow, but I've always been happy with the results. Gold plating is more expensive than chrome. The plating cost $400, but it's permanent and will look good forever.

I agree, the factory Mark III is a bit on the ugly side. I don't think the chrome plated chassis was a good idea. It was bright and sparkley, while every other aspect of the amp was dull and flat. Wasn't a good combination. The new powder coated chassis reflects like a black mirror. It really highlights the gold trannys.

I kept the cap can for looks as it helps fill out the chassis. It isn't connected electronically. I buffed them out and will spend some more time with them on the bench grinder. When done I'll clear coat them and they'll look like chrome.

The CAE driver board is elevated to provide room for the larger power supply board that is under the chassis. With the three CAE board set there isn't much room underneath. I may cut the standoff in half and drop the driver board down a bit. It think it would look better.

I spent five weeks designing and building the bases. I agonized over the design, type of wood, color, finish, etc. I wanted a 1930s kind of look, whick is why I made finger joints and rounded the corners. In each box is an Antec computer fan for cooling. The fans have neon blue lights that shine out from beneath and around the chassis. Will look very cool with the glow of the tubes.

Sy, I have a scope, signal generator, variac, DVM, etc. I've got the basics down, but that's about it. As time permits I read up on the theory. I'll take your recommendation and read Morgan Jones book.

Don
 
HipoFutura said:

Gold plating is more expensive than chrome. The plating cost $400, but it's permanent and will look good forever.

Don


!!!! A single guy, eh?

I hear what you are saying about it being tight underneath. I was close to abandoning the chassis all together. My VTA board would have to sit way high, but maybe I'll give that a thought. I had to jerry rig in my power supply board, and I am not happy with the the job. Not mechanically sound.
 
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