looking for ultralinear push-pull project

[mnewport]

I've been trying to find schematics for an ultralinear pushpull
amplifier that puts out roughly 30-40 watts in class A...I haven't had much luck finding one. Any suggestions?
Also, any recommendations for simulation software for tube circuits?

TIA

Matt

[Thatch_Ear]

Take a look at Allen Organ amplifiers. They used those types of OPTs, though not sure about the circuits.

[TG]

Hello mnewport,

maybe this will suit you:

http://www.svetlana.com/docs/TechBul...hnoteNo60.html

This amp uses Svetlana tubes, but equivalents from another manufacturers exist.

Good luck!

[TJ]

Hi, designing a 30- 40w class A tube amplifier is not a good idea ! wasting ur tube life ! most tube amplifier working on class AB . Class A doesn't meant good sound ! i don't think u can find a GOOD tube simulation software ..... b'coz tube design is not complicated like transistor !

[mnewport]

The Svetlana looks interesting in theory...except I can't get a good look at that schematic, it's too tiny (and it's not a link, unfortunately ).
As far as software goes...I recently ordered a copy of TubeCad--
it seems like it may be nice to work with on PP designs. Anyone have any experience with this?
TJ, your point about 30-40W in Class A is interesting. I hadn't really thought about it from that aspect. I may just have to look into going AB instead of A...or at least compare them head to head.

Thanks for the replies

Matt

[TG]

>>I can't get a good look at that schematic, it's too tiny...

To do this, you can right-click on that image, choose "Save Picture As..." and save it to your disc. Then open this file with virtually any GIF viewer... Picture will be much bigger

[Tube Addict]

Look at www.amplimo.nl (dutch site) for the UL40-S2 designed by Menno Vanderveen, or look at www.plitron.com
The UL40-S2 has an ultralnineair schematic. standard with svetlana 6n1p/EL34. I build it with Svetlana KT88's.
It has a lot of class A power and sounds great. A lot better than the Audio Innovations series 500 i had before...
If you need the schematic, let me know..

Greetings,
Tube Addict

[Aud_Mot]

I have a copy of the TubeCAD software. It is very educational and interesting. There are some very nice features and the interface is very intuative. It has interactive plate curves for lots of tubes types. It calculates things like output impedence. It evaluates your circuit for exceeding the tubes ratings, makes suggestions, and will even fix up your circuit automatically.

It is different from traditional SPICE programs. In SPICE you draw the schematic. Define paramters, component values, power supply values etc. Then you run the simulation and get the different results.

TubeCAD comes with about 48 pre-drawn schematics. You cannot change the schematic. This is fine because there is such a wide range of schematics to choose from.

The problem I do have with the program is, there are too many user defined variables. You have to define resistor values, power supply voltages and (idle?) current. The current is what throws me off.

I have never been able to get my head around that. With Ohm's and Watt's laws, once you have established any 2 of the four parameters, (voltage, resistance, current and power) the other 2 can be calculated.

Maybe some out on the forum can explain this to me?

What would work best for me: Specify resistor values and power supplies and then let the program calculate the currents and power dissipated.

Then I can tweek the values to get the power and current levels where I want them. I have contacted John at TubeCAD to get an explaination on how to deal with this. Never got a response that addressed my confusion. The answer may be obvious some one who understands tubes (and math) more than myself.

They also have a very interesting on-line magazine.

http://www.tubecad.com/

It is still a very good deal, I am never sorry I purchased it. John, the guy who writes the software and the magazine deserves your support.

Aud_Mot

[Thatch_Ear]

I blew up the schematic for the Svstlana and took a look. Check out the Dynaco MarkIII(3). Looks to be very close. The smallest Allen Organ amps use a PP UL 6L6 with a 12AY7 for low harmonics and high gain. I understand that the larger amps built for the tone cabinets used 4 6550s per channel/amp getting you up into the 100 watt range and I am presuming using the UL style of circuit. The Allen Organ people will gladly send you a hard copy of their amp schematics. That is how I got the one for the 20 watt 6L6.

[PassFan]

David:
How did you find anything about tubes on their web site? I am researching a P-P 6L6 to build and would love to see their scams. Especially the 20 watt one you got. Thanks