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Author Topic: The definitve Push Pull 211 Amp  (Read 13880 times)
Wardsweb
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« on: January 19, 2009, 07:03:46 PM »

Lee just completed "THE" amp to have. A very serious 211 stereo amplifier. Just look it - WOW!

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nickh
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« Reply #1 on: February 02, 2009, 07:44:11 PM »

How much does that bad boy weight?
 Grin

Nick


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Audio_Builder
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« Reply #2 on: February 03, 2009, 10:23:49 PM »

140 pounds
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nickh
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« Reply #3 on: February 04, 2009, 12:40:55 PM »

Nice, I want one LOL

Can we see a schematic?


Nick
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Audio_Builder
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« Reply #4 on: February 04, 2009, 09:53:44 PM »

I donít like giving out schematics, but if you are interested in building one I can help you.

Lee
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Wardsweb
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« Reply #5 on: February 06, 2009, 10:51:37 PM »

Any particular reason for going stereo in place of mono blocks or is it more of a personal preference thing?
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Audio_Builder
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« Reply #6 on: February 08, 2009, 08:37:19 PM »

Mono blocks are fine, but I donít build them because:

1.   the time and material costs are higher
a.   you spend more time machining two mirror image chassis with additional power supply component holes
b.   you end up doubling the power supply components
2.   the voltages will be slightly different between amps
3.   you can create ground loops and pick up noise if you plug them into different outlets

At the moment, I seem to have hit my personal practical limit for a stereo amp at 140 pounds.  If I build a bigger amp, I may go to mono blocks or separate chassis for the power and audio section. 

Lee
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nickh
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« Reply #7 on: February 13, 2009, 05:26:16 PM »

I agree with you Lee, But I do like to have the amp and the chassis separate, thats about it.

I would like to build a 211 or 845 push pull amp but by what I hear they aren't in production by anyone anymore.

After I finally finish my first amp I'll start building my se 833 amp, I know that one will tip the scales pretty high as I want to use a tube voltage regulator on the b+. It will be heavy make no mistake about that. I just haven't figured what I can use as a pass tube or two.

No particular reason why I asked to see a schematic, jut like to see who different people do thing I guess, Kind of how I learn new things.

Nick
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Audio_Builder
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« Reply #8 on: February 15, 2009, 10:25:39 AM »

Once you hear large transmitting triodes it is hard to go back to anything else.  While American made 211 and 845 are no longer produced, Chinese versions still are.  You can pick up a Chinese 211 for $30 and a NOS GE 211 for $150.  All and all not bad compared to a pair of Western Electric 300B at around $800.  845 are a little more expensive.  Another alternative is a GM70 which is around $50 each.  I got my tubes from Penta Labs.  They tested them and Matched them and the price was better than Ebay.

I have though a lot about a SE833.  I actually have one tube that I stare at and think of the possibilities.   If you are planning on running a 2K to 5K B+, you might consider an 813 as a pass tube.  The other option would be to use another 833 as the pass tube.  No mater what you do, it will be a big monster.  I have shied away from using 866 because they would add another 20 pounds and 12Ē to the chassis. 

For the ultimate triode, look up a GM100.  The filaments alone are over 200 watts!

Let me know if you need any help with your SE833 amp.  We both may learn something.

Lee
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nickh
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« Reply #9 on: February 15, 2009, 08:15:41 PM »

Hi Lee,

I was only planning on 1 to 1.5kv on the p[late of the 833, as going higher then that you have trouble finding someone to make the output transformer unless you got the parafeed route.
I don't think a 813 would cut it as a pass tube since each 833 will be pulling 250 to 300 ma on the plate, I'm using a 4-1000a for the pass tube.

When did you buy the 211's for penta labs? My friend is building a 211 amp but Shuguang has stopped producing the 211's and 845's.

The Gm100 is a nice tube except for the socket issue, that thing is bright when the filament is energized, have you seen it. It's weird the russian tube all seem to use high filament voltage, some where over 20 volts, which can make hum some what of an issue if your supply isn't WELL filtered.  Doesn't mean I wouldn't try it though just like if I had 2 hf3000's I would build an amp with them in a heart beat, that things a real monster, almost 2 feet long.
Here check it out.
http://www.mif.pg.gda.pl/homepages/frank/sheets/111/h/HF3000.pdf

I would love to have 1 of them for my collection, if not 2  Grin

It will be a while before I'm starting on the 833 amp though, I will probably will have moved back to Houston by the time I start building it. My Friend who is an Analog engineer and he also Was the owner of Kennedy Tube audio and is well know in the tube hifi crowd for his 300b amps. He's my guru LOL. He gave me a idea for a driver for the 833, kind of a cascode on steroids running with 1kv on the plate of it.

But I will keep you guess in mind since I probably won't be living in Massachusetts at that time so I will probably be needing a nearer support group by then LOL.

Do they have any vacuum tubes anonymous down there. LOL.


Nick 
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