[Amps] SB-201 conversion to GI-7B?

[Manuel R. Alonso]

Hello

Looking at those numbers you could drive ONE GI-7B. Power output will be about the same as the pair of 572's

I have not done any of these conversions yet, but I am in the process of converting an MLA-2500 to a pair of GI-7b's and a Henry 2K-4 to a GI-35b.

You have to add a new fillament transformer and bias circuit, as well as a timer to allow the tube to heat up before HV is applied.  Chassis should also be modified for a pressurized chimmeny type cooling, however for SSB use you may get away with a fan.

Since 572b's are available and are not to expensive, I don't think its worth the effort in converting to the GI-7b, unless you just enjoy these kind of projects. You will NOT get any more power output due to the limitations of the HV supply.

However with the conversion you will have a more durable tube with a replacement cost of $20.00

You can find alot of info on russian tubes and conversions at this site.

http://www.nd2x.net/base-1.html

Enjoy

Manny, KC4MNE

  ----- Original Message ----- 
  From: Mike, K8LH 
  To: Manuel R. Alonso 
  Sent: Thursday, October 21, 2004 12:36 PM
  Subject: Re: [Amps] SB-201 conversion to GI-7B?


  Greetings Manny...  I trust you and family are well Sir?

  The SB-200 and SB-201 use a pair of 572B tubes...  The no load plate voltage is around 2300 volts dc...  When "loaded" for 800 to 1000 watts dc input, the plate voltage is around 1950 to 2000 volts and the plate current is between 400 and 500 milliamps...

  Have you done any GI-7B conversions Manny?

  Very 73 for now, Mike - K8LH (Westland, MI)...

  Manuel R. Alonso wrote: 
Hello

What tubes does the SB-200 have?

What is the no load plate voltage of the SB-200?

What is the Plate amperage capacity of the SB-200 power supply?

Let me know and I will give you my opinion.


Manny, KC4MNE
----- Original Message ----- 
From: "Mike, K8LH" <k8lh at arrl.net>
Cc: <amps at contesting.com>
Sent: Thursday, October 21, 2004 9:57 AM
Subject: [Amps] SB-201 conversion to GI-7B?


  Has anyone documented an SB-200/SB-201 conversion to a single GI-7B
    please?
  Thanks...  Mike - K8LH (Westland, MI)...
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