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Author Topic: GU-50 power amp  (Read 13552 times)
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wavebourn
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« on: May 16, 2007, 01:42:49 PM »

Hi guys,

do you like this layout?



http://wavebourn.com/images/audio/gu50_amp_layout.gif

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WA1GFZ
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« Reply #1 on: May 16, 2007, 01:51:54 PM »

I would move the small tubes back an inch or so. This will allow more room the wire them.
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wavebourn
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« Reply #2 on: May 16, 2007, 02:07:48 PM »

Thanks, interesting idea!

What if to move phase splitter tubes back one inch leaving indicators on the edge?

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WA1GFZ
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« Reply #3 on: May 16, 2007, 02:41:50 PM »

I would move the phase splitter tubes back between the input amp and output. This will allow more room to wire each socket.
I don't like stacking components around tube sockets. Too hard to work on. I like all the parts on one plane.
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wavebourn
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« Reply #4 on: May 16, 2007, 02:56:07 PM »

I will order PCBs for each channel of a phase splitter.

Here is the schemo:





http://wavebourn.com/images/audio/gu50amp-phsp.gif

Correction: 6N1P will be loaded on 27K resistors instead of 56K and powered from unregulated 375V, 6N6P will be used instead of 6N1P

Almost all stages are directly coupled for better stability on low frequency end.




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W1GFH
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« Reply #5 on: May 16, 2007, 03:25:55 PM »



Is this for hifi/guitar consumers?

If so, I'd leave the small tubes where they are, and mount them on a series of platforms made from L-brackets, arraged with the tallest in the middle (like an Olympic Gold Medal ceremony). I'd paint the chassis fire-engine red except for a bare strip of aluminum shaped like a "V".  Also I'd add a few jeweled pilot lights.
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"A perfect 1:1 SWR is for sissies" - Joe W1GFH
wavebourn
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« Reply #6 on: May 16, 2007, 03:32:40 PM »



Is this for hifi/guitar consumers?

If so, I'd leave the small tubes where they are, and mount them on a series of platforms made from L-brackets, arraged with the tallest in the middle (like an Olympic Gold Medal ceremony). I'd paint the chassis fire-engine red except for a bare strip of aluminum shaped like a "V".  Also I'd add a few jeweled pilot lights.

Thank you!

It is actually a vocal amp for concerts, 2X100W output. Also, I am going to target them as studio monitoring amps. Front panel will be made of Lexan. It will be fitted into a grilled 4U enclosure so all internals will be visible.

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Rick K5IAR
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« Reply #7 on: May 16, 2007, 03:37:22 PM »

I'd be interested in hearing more about the studio monitoring aspects when it's complete.  She's gonna be a beaut!
Rick
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k7yoo
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« Reply #8 on: May 16, 2007, 03:51:41 PM »

Leave the tubes out near the edge so you have enough room for the tank circuit components
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wavebourn
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« Reply #9 on: May 16, 2007, 04:01:46 PM »

I'd be interested in hearing more about the studio monitoring aspects when it's complete.  She's gonna be a beaut!
Rick

I can tell you now: unlike solid state amps it is immune to cellphones near speaker wires, it is the most significant advantage except warm tube sound.

Thank you!

I am going to order also perforated 4U enclosures for them, like Collins transmitters. The enclosure will be black, the chassis will be bright red.

Front panel made of lexan, with pair of volume knobs, power switch, and safety "ignition" key, like on this my breadboard:



http://wavebourn.com/images/audio/gu50ampbg.gif

Input and output sockets will be on rear panel

(2 for in, 2 for 4 Ohm, 2 for 8 Ohm, 2 for 16 Ohm) -- all TRS.

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wavebourn
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« Reply #10 on: May 16, 2007, 04:03:53 PM »

Leave the tubes out near the edge so you have enough room for the tank circuit components


Tank circuits will be flat to fit inside of 1U chassis, here are breadboards:



http://wavebourn.com/images/audio/ps_bb.gif

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wavebourn
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« Reply #11 on: May 16, 2007, 04:20:27 PM »

Here is schemo of power supply (screen grids' and preamp regulator)



http://wavebourn.com/images/audio/pyramidps.gif

However I could use  Zener diode, but 0A2 looks cool and visually indicates presence of a voltage

Also, it looks nice in darkness...



http://wavebourn.com/images/audio/wavebourntubepp.gif

I will have another version: 4x 6L6GC per channel in relaxed mode, for 50W only per channel, with smaller output transformers for better clarity of details.

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W1GFH
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« Reply #12 on: May 16, 2007, 04:32:21 PM »

Tolly, you do EXCELLENT fabrication work. I can't WAIT to see your version of a 100 watt AM phone transmitter.
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"A perfect 1:1 SWR is for sissies" - Joe W1GFH
wavebourn
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« Reply #13 on: May 16, 2007, 04:43:53 PM »

Tolly, you do EXCELLENT fabrication work. I can't WAIT to see your version of a 100 watt AM phone transmitter.

Thank you Joe!

I have an idea about screen modulated couple of GU-50 toobs, with AF feedback from antenna output. I'll try it later when my audio business is up and running.

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W1GFH
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« Reply #14 on: May 16, 2007, 06:15:52 PM »

GU-50 is an interesting toob. Can you tell me what this guy is doing?

http://news.cqham.ru/articles/detail.phtml?id=558
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"A perfect 1:1 SWR is for sissies" - Joe W1GFH
wavebourn
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« Reply #15 on: May 16, 2007, 07:04:00 PM »

GU-50 is an interesting toob. Can you tell me what this guy is doing?

http://news.cqham.ru/articles/detail.phtml?id=558

Yeah! LS-50 was developed by Telefunken for Hitler. Russian engineers took it from enemy and made own version GU-50.
It is very linear ray pentode and excellent both for audio and radio.

The guy on your link builds linear amplifiers using GU-50 tubes.

On his page he is standing near his Uragan-1 gear that had not been finished because authorities thought the he can't use GU-43 tube that may give 2 KW of output power so it could be technically possible to break the rules despite the power tranny is up to 1 KW only!

Uragan-2 is an amp made of mobile military transceiver R-140

Cube is amplifier with GU-74 output

The rest is amplifiers with GU-50 outputs.

Polew 4GU50 - 150-200W output FM, 650W SSB

3GU50 "Hi-End" - up to 450W SSB

2GU50 - 250W peak SSB



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wavebourn
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« Reply #16 on: May 17, 2007, 01:46:37 AM »

Is it better?



http://wavebourn.com/images/audio/gu50red.gif
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wavebourn
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« Reply #17 on: May 18, 2007, 12:45:01 PM »

Here is it with a mirror between hot toobs and transformers.



http://wavebourn.com/images/audio/gu50red_2.gif

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WA1GFZ
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« Reply #18 on: May 18, 2007, 12:54:07 PM »

Chassis reminds me of a small block chevy.......from the '60s
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wavebourn
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« Reply #19 on: May 18, 2007, 01:37:39 PM »

Was it red?

It is Joe's idea about red color.  Grin
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W1GFH
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« Reply #20 on: May 18, 2007, 02:01:05 PM »

I'm sure you were planning to paint it red all along.

I like the "muscle car engine look" too. The "ignition key" is a great idea. Maybe you can find an excuse to run some heavy cable on top of the chassis (suggestive of ignition wires). Also maybe think about bringing some caps up top next time.

And how about a meter set up to suggest a tachometer, chrome trim ring, a red line, etc.
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"A perfect 1:1 SWR is for sissies" - Joe W1GFH
wavebourn
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« Reply #21 on: May 18, 2007, 02:10:48 PM »

4X807 instead of 2xGU50 would defenitely need ignition cables.  Grin
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The Slab Bacon
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« Reply #22 on: May 18, 2007, 02:36:16 PM »

I really like the thumbnail indicator tube avatar!!
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wavebourn
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« Reply #23 on: May 18, 2007, 03:58:58 PM »

I really like the thumbnail indicator tube avatar!!

Thank you!  Wink
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wavebourn
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« Reply #24 on: May 18, 2007, 05:31:23 PM »

Here is it with a front panel with ignition key:



http://wavebourn.com/images/audio/gu50red_frontpanel.gif

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