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The "$250" Amp? - 6LU8 Compactron SE, UL

Not a solid state supply guy for my tube stuff, I updated the first page (my first post).
(but SS will work just fine, not drawing lot a current so voltage should be close there)
It now has links to both the solid state supply later in the thread an the tubed version.

I prefer the slow warm-up of indirectly heated tube rectifiers, plus I feel they do sound
better, as long as you don't push the rectifiers hard and use rectifiers that have a "low"
voltage drop you shouldn't have any sag or compression issues either.
 
Kegger, could you explain in terms of the electrical characteristics of SS and tube rectification why they sound different or one sounds better?
 
(I will try) :)
Well there probably is no 100% way to explain or say why 1 might prefer 1 or the other.

But technically wise there is noise/hash with solid state diodes that is not there with a
tube rectifier some claim you can't hear it others claim you can, for me "anything" done
on a SE amp has a very good chance of influencing the sound with the low parts count
and simple circuit, I feel the SS supply is not as clean and as smooth sounding as tube,
for me the tube just has a more pleasing presentation to it. (a very subjective feeling)
 
Getting closer, have the tubes, sockets, power tranny, radiodaze chokes, and caps and resistors, IEC jack, power cord, rca jacks and binding posts

I worked off the list posted by Jimbofish


Working out the layout, and chassis ideas.


Still need the output tranny, from Edcor.

Question for somebody who has a operating one with the antek tranny, how warm does it get?

I want to put it and the chokes down under and need to know if they need much room for ventilation.
 
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Can't answer for certain Clifwst, but I've always heard that the turtle type trannies don't get that warm.
 
I know this is probably a dumb question, but I have no shame.

What is a good wire to use for the point to point connections?
 
clifwst said:
Getting closer, have the tubes, sockets, power tranny, radiodaze chokes, and caps and resistors, IEC jack, power cord, rca jacks and binding posts

I worked off the list posted by Jimbofish


Working out the layout, and chassis ideas.


Still need the output tranny, from Edcor.

Question for somebody who has a operating one with the antek tranny, how warm does it get?

I want to put it and the chokes down under and need to know if they need much room for ventilation.
Click to expand...

The anteks we are using are rated for higher duty than we are putting on them with this amp. I don't expect that you'll have serious heat issues, but it's never a bad idea to provide good ventilation.
 
rage said:
I know this is probably a dumb question, but I have no shame.

What is a good wire to use for the point to point connections?
Click to expand...

I used stranded 600V 22 gauge hookup wire from Radio Daze. You could go with silver plated wire if you desire but pretty much anything rated for high enough voltage will do nicely.

BTW, my Antek tranny has never seemed hot at all to me.
 
Thanks for the answer about the antek, I was having an idea of mounting it on top and creating a wooden cover over it, but didn't know how much heat it needed to dissipate.

However in rereading the thread again, I realized that building the amp based on a design like this;

Integrated compactron would make a good little amp in the end,

I plan on building the original design, first and when I have that one accomplished to my satisfaction, then try to find a suitable pre I could add to the chassis to make it a integrated amp.

I know big plans for a noobie, but then again that is how things really get done sometimes around here, (my 2 car garage plans grew into a 34'x64' workshop with a 30x20 attached three car garage on the front. It makes a real good "playplace" for grown-up dads, I tell my daughter.)

Oooh, that's brave! I gave up on this project because wasn't sure what parts to order.
Click to expand...

Well Kegger did check it.

BOM

Last edited by Kegger; 08-31-2009 at 04:46 PM. Reason: corrected quantities and descriptions (Kegger)
Click to expand...

So hopefully it is close.

I'll let you know when I get to build it.

I do have one question, the 7uf 400V cap;

Is there any real difference in the sound or operational reliability between the motor run oil cap and the poly cap for use one for the first cap in the power supply?

Is the motor run oil cap a better choice or just a preference some use?
 
"Is the motor run oil cap a better choice or just a preference some use?"

I would say that is a pretty good assessment, either will work fine there.

--------------

Also yes the "bom" you posted the link to is upto date an correct for the build.

I wish we could of had a bit better instructions an help then what we have but
it just hasn't come to fruition, I did update my post on the first page with links.

Thanks to everyone else who helps out others with there choices an questions.
 
Have you tested your wall voltage?
Click to expand...

Yes I have, 123.5 volts AC, I am the only house on the transformer since I am on a very small branch line and another plus, less then 1/2 mile to the substation in a rural area. No heavy industry or large suburban loads out here.


Thanks again for everyone who replied, it did help this neophyte, tube jockey out a lot. I am learning from you all.

As an aside exactly how is the secondary of the antek wired,

The antek page shows two, to my eye, separate 275 volt circuits and the schematic shows three connections with 275 volts on each side of a center tap ground.

How are the four wires, two yellow, two white connected?

Are two of them combined for the "center tap" ground, with the other tow connected to the sides of the rectifier tube?

Are the primary side red and black wires connected together by color to the hot and neutral 120VAC line inputs?
 
Yes, combine the two whites.

It may be hard to see but the two whites are connected to my ground bar here:

6LU804.jpg
 
Thanks, a question like that stops people because the schematic shows three wires out of the transformer, and the antek has four. I was guessing, but when playing with 275 volts guessing ain't really a good idea.
 
Well finding this nice piece of aluminum diamond plate, at a local scrap yard, helped me decide what I wanted the amp to look like,

It was very cheap less then $1, and already had the nice fold I am going to use for the front edge.

That is a 6LU8 compactron tube in front of it for reference.

The plate is 9 1/2 by 14 inches.

Now I need to do a layout based on it and a wooden frame, with a removable aluminum bottom plate.

My basic idea for now, Edcors on top in back, Antek and Radiodaze chokes hidden underneath, tubes up front.
 

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Be sure to keep in mind that your Edcor OPTs will have exposed high voltage connections. You might want to consider a cage or cover of some kind.
 
someone beat me to the diamond plate chasis!

my tubes and sockets are here! just waiting for outputs and building a couple metal boxes.....
 
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