[TenTec] Centaur Tubes odd ones in parallel

[Mike Schatzberg]

I never use tetrodes myself and that is what QRO uses. 

Commander may have one of the best RF decks in the business. But their control board is in need of help generally particularly their switching. I have modified many units over the years. 

73,

Mike
W2AJI 

Sent from my iPhone

> On Apr 2, 2015, at 2:06 PM, Rick - DJ0IP / NJ0IP <Rick at DJ0IP.de> wrote:
> 
> Mike, I agree with you.
> Far too many people talk only theory here, without actually "doing".
> I generally only write about things I have done myself.
> 
> I was surprised to hear you had to modify the Commander.
> I thought they were pretty good amps by design.
> Very similar to my old QRO Technologies amps.
> 
> 73 - Rick, DJ0IP
> (Nr. Frankfurt am Main)
> 
> 
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Mike
> Schatzberg
> Sent: Thursday, April 02, 2015 6:13 PM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] Centaur Tubes odd ones in parallel
> 
> Actually, I tested many of his concepts on my SB 220 which I built around
> 1967 or so. I do not ascribe to them all. His theory on VHF parasitic
> oscillation has remained a topic which is still controversial and debated to
> this day. 
> 
> I did discovered something of interest to perhaps only myself when I read
> last night his circuit improvements compendium on the SB 220. He had changed
> the wattage of his grid equalization resisters to 1/2 watt and added some
> dissipation protection as well. 
> 
> I wrote to Mr. Measures years ago, regarding his grid fuse concept, which he
> advocates for additional tube protection. I told him that the original
> wattage he used, 1/4 watt I think, was really too low. I also told him that
> I generally thought that resisters make poor fuses even if they are
> flameproof. 
> 
> I recommended that the value be changed to a 1/2 watt, and forget the grid
> fuse concept and just go with RF negative feedback and grid equalization
> which I had decided to use. 
> 
> Well, last night that is what I found in his circuit description. While he
> still talks about grid fuses, they will not open without being seriously
> over driven. 
> 
> My SB 220 was a great test bed for lots of experiments. Many of the concepts
> were so easy to apply and evaluate. My own QSK systems that I use today on
> many ceramic triode conversions were adopted from my Heathkit test bed. I
> have modified many models of Alpha and Commander amplifiers which are in use
> in many places today. 
> 
> As they say, one well designed experiment is worth a hundred expert
> opinions. I generally don't offer opinion but rather test results. 
> 
> Sorry for the bandwidth. I know the moderator will be tolerate however.
> 
> 73 and Happy DXing,
> 
> Mike
> W2AJI
> Owner Ten Tec Reflector
> Owner Orion 565/566 Reflector
> Owner 1000MP Reflector 
> 
> 
> Sent from my iPhone
> 
>> On Apr 2, 2015, at 9:07 AM, Rick - DJ0IP / NJ0IP <Rick at DJ0IP.de> wrote:
>> 
>> Hi Tony,
>> 
>> It's W2AJI.
>> He pointed out work that Rich Measures had done on this topic.
>> Specifically it was, "High Speed Switching / QSK for the TL-922 and 
>> SB-220 With Circuit Improvements for the TL-922"
>> Here: http://www.somis.org/QSK922.html
>> 
>> The topic was using non-matched tubes in a multi-tube linear amp.
>> Scroll down a ways until the paragraph on ANODE AND GRID GLITCH
> PROTECTION.
>> 
>> 73 - Rick, DJ0IP
>> (Nr. Frankfurt am Main)
>> 
>> 
>> -----Original Message-----
>> From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Tony
>> Sent: Thursday, April 02, 2015 4:51 PM
>> To: Rick - DJ0IP / NJ0IP
>> Subject: Re: [TenTec] Centaur Tubes odd ones in parallel
>> 
>> Rick ,
>> Who's this Mike? Does he have a website?
>> 73, Tony VE3DWI.
>> 
>> Sent from my BlackBerry 10 smartphone on the Bell network.
>>  Original Message
>> From: Rick - DJ0IP / NJ0IP
>> Sent: Thursday, April 2, 2015 04:08
>> To: 'Discussion of Ten-Tec Equipment'
>> Reply To: Discussion of Ten-Tec Equipment
>> Subject: Re: [TenTec] Centaur Tubes odd ones in parallel
>> 
>> Well done, Wade!
>> As Mike showed us, it indeed can be done that way.
>> 
>> 73 - Rick, DJ0IP
>> (Nr. Frankfurt am Main)
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