suggestions for a parallel feed 45 amp?

[Sylver300B]

Hi from Quebec!

I have a set of parallel feed outputs and chokes (Magnequest) that I got from a friend in a trade. Most schematics I find on the net do use transistors in the first stage.

I am looking simple and neat, direct coupled, parallel feed, no transistors anywhere. Just because I'm not confortable working with them anyway.

So, if someone has a link to suggest, a schematic, or a great idea. I'm opened to persuasion.

My first thought was to build an adaptation of the Shishido 2A3 (wich I built and loved) but for 45. But since I do own these parallel feed trannies, I guess I should give it a try.

Thanks!

[Seta45]

http://www.bottlehead.com/VALVEarchi...7/va101997.pdf

Enjoy!

[vconsumer]

Originally Posted by Seta45

http://www.bottlehead.com/VALVEarchi...7/va101997.pdf

Enjoy!

This was my first thought, but Seta45 doesn't want ransistors anywhere, and the Bottlehead design uses a CCS.

[Sylver300B]

Thanks for the suggestion, but that's exactly the design I had found.. and this one uses transistors.
Can Parallel Feed be built only with tubes ?

When it comes to building tube amps, I am a novice. Have built 3 of them.. they all worked, but I did follow the diagram, I admit. ;-) Then, I can do a few adjustments, but I'm no engineer. It's easier to tune pianos. ;-)

[regal]

Originally Posted by Sylver300B

Thanks for the suggestion, but that's exactly the design I had found.. and this one uses transistors.
Can Parallel Feed be built only with tubes ?

When it comes to building tube amps, I am a novice. Have built 3 of them.. they all worked, but I did follow the diagram, I admit. ;-) Then, I can do a few adjustments, but I'm no engineer. It's easier to tune pianos. ;-)

It can you just need to use an inductor or resistor of the right value in place of the transistor shown in the link above.

[smbrown]

You can't just sub in an inductor, the plate voltage on the driver will be messed up. A resistor will work, figure the current (I'm thinking it was 10ma, but didn't re-read the article, got stuck at the t-shirt ad). And the needed voltage drop (IIRC plate is 150v).

[regal]

Originally Posted by smbrown

You can't just sub in an inductor, the plate voltage on the driver will be messed up. A resistor will work, figure the current (I'm thinking it was 10ma, but didn't re-read the article, got stuck at the t-shirt ad). And the needed voltage drop (IIRC plate is 150v).

Obviously you would add a CRC filter to drop the voltage then sub the ccs with an appropriate inductor. A resistor would be OK depending on how sensitive the speakers are (hiss.)

[mach1]

Or even better just put a resistor in series with the plate choke to match voltages and get an even higher plate load.

[Nick F]

I don't remember for sure but I think Gordan Rankin shared this design.

[Sylver300B]

Originally Posted by mach1

Or even better just put a resistor in series with the plate choke to match voltages and get an even higher plate load.

Nice compromise I think. Now, I must dust off some of my past knowledge and calculate how it should be built. I'll make a try and post it here.

Thanks friends.