• 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.

$200 6V6 Amp

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I was going to enter this amp in a $200 6V6 listening competition but they do not allow Ebay parts source.

So, I thought I would post the schematic here for your amusement. I have not built it yet.


2006V6AMPSCHEMATIC.png
 
I have not built it yet.

That's a good thing. The Walton-Cockroft is a bad choice for a voltage doubler. The W-C is half wave circuit, which means DC through the secondary. This is highly likely to cause core saturation. The W-C is useful when the current demand is much lower, and when you can use it with a gapped core xfmr (think CRT flyback xfmrs here). That should be replaced with a full wave doubler.
 
That's a good thing. The Walton-Cockroft is a bad choice for a voltage doubler. The W-C is half wave circuit, which means DC through the secondary. This is highly likely to cause core saturation. The W-C is useful when the current demand is much lower, and when you can use it with a gapped core xfmr (think CRT flyback xfmrs here). That should be replaced with a full wave doubler.

I don't understand it. To me the original schematic is based on a full wave doubler, at least it is exactly like this schema (last schema on the page)

but, if it is not, I can explain it by the fact that it is almost two in the morning :)
 
Could be, but I don't think so. It's nearly a cut and paste from PSUDII... Notice the ground connection, I don't see DC. But if Mr. Prower says its there it must be... please explain! The only place that DC could be dawn is off ground, not through the tranny, no? This is Greinacher topology not WC.

Picture2-4.png
 
Last edited:
Could be, but I don't think so. It's nearly a cut and paste from PSUDII... Notice the ground connection, I don't see DC. But if Mr. Prower says its there it must be... please explain!

A full wave doubler should look like this

An externally hosted image should be here but it was not working when we last tested it.


If that's how it works, then it'll be just fine. Don't use PSUD-II, as I do designs the old fashioned way: with a scientific calculator, and so am not familiar with the effffffffffffffff-up ways PSUD presents schemos.

That thing still looks like a W-C, and is very confuzzling.
 
Sorry Miles, I'm self taught and sometimes my schematics are from Mars ;) I get that all the time! Your inquiry is very much appreciated! I'm glad there is no smoke (yet).

And happily, I have been able to source all the parts from NON-Ebay vendors, so its a go! And here is the updated schematic, still under $200!


Take a guess how it'll sound, I haven't a clue! I'm thinking maybe a little distortion cancellation of 6V6 driving 6V6 and stunning detail. If microphonics is a issue I'll adjust the driver circuit for a lower loading of 6K.

BATES2006V6AMPSCHEMATIC.png


http://greenvalve.wordpress.com/files/2009/11/bates-200-6v6-amp-schematic.jpg?w=560
 
Last edited:
Great idea. I'm going to sim the Triad chokes. How much ripple do you think 5K loaded 6V6 finals can take and still be silent? The Input tube is dead silent already.

Going from 10H (144mv) to 6H is 244mv.

What about 2 dare I say Triad C-40X ? But that would up the cost again and need another cap. Nope, at this current the low DCR supply has over 1V of ripple.
 
Last edited:
The multiplier is half wave. I dont see it as being a problem. If you could find a center tapped tranny, much like a site transformer or an industrial one where the CT is grounded you could build a full wave Coockroft-Walton type doubler but it would need two stages and be worse for it. Its fine as it is.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.