[Boatanchors] Replacing 866s with 3B28s

[w4awm at aol.com]

 For the most part, MV rectifiers are fine tubes and will do the job adequately. Most problems are caused by failure to give adequate warmup time. Regardless of specs, MV rectifiers should have a minimum 3 minute warmup time before applying plate voltage. If that is adhered to, there are very few problems with these tubes. Soft start on the plate tranny after the warmup helps, too.

73,

John,  W4AWM

 


 

 

-----Original Message-----
From: Jim <jbrannig at verizon.net>
To: The Pollacks <rinkies at att.net>; 'bill kipping' <ke7kk at earthlink.net>; boatanchors at mailman.qth.net
Sent: Wed, Dec 29, 2010 6:29 pm
Subject: Re: [Boatanchors] Replacing 866s with 3B28s




My homebrew 572B amplifier sat in the top rack.  The power supply sat in the 

open on the bottom of the rack....

where I could watch the 866's do their pretty thing...........



One nite I'm having a really gud CW QSO....watching the 866's....



The family cat came down and became intrigued with the 866's...I don't know 

if it was the lights or the slight buzz.....



So (compressed time expanded).....The cat is stretching her neck towards the 

plate caps of the 866's......I like the cat....I don't like 2500VDC.....

more CW sending.......the cat is getting closer......decision time.......I 

turn it over to the other station and give the cat a swift kick...get a 

hurt, dirty look in return.......(feel bad)...

Cat saved, CW QSO continued, make amends with the cat later.......



Jim







> Amen.  I made that sub in my Valiant several years ago.  One of the 3B28s

> went bad recently, but in a manner that did no other damage.  The 866s 

> might

> have taken other things with it.

>

> I also have a Warrior which originally came with 866s.  I had a pair of 

> plug

> in solid state replacements, and when I rebuilt the Warrior I used those.

> It had come with the 866s replaced with 3B28s.  When I got the Valiant,

> those are the 3B28s that I put in.  Since I use the Valiant all the time,

> and the Warrior seldom, I really should put the SS ones in the Valiant, 

> but

> the thought of taking both of them out of the cabinets makes my back hurt!

>

> -----Original Message-----

> From: boatanchors-bounces at mailman.qth.net

> [mailto:boatanchors-bounces at mailman.qth.net] On Behalf Of bill kipping

> Sent: Wednesday, December 29, 2010 12:22 PM

> To: boatanchors at mailman.qth.net

> Subject: [Boatanchors] Replacing 866s with 3B28s

>

> Hi to the group.  I want to replace the 866 rectifiers in the Johnson

> Valiant with 3B28s (blue tubes are scary!). Any thoughts or experiences 

> pro

> or con. TNX Bill

>

>

>

>

>

>

> New Years wish to all, may Washington DC stay out your lives and wallets 

> in

> the new year.

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