Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Heathkit SB-101 Finals  (Read 1496 times)
N0XAX
Member

Posts: 49




Ignore
« on: December 14, 2018, 11:25:00 PM »

I am restoring a Heathkit SB-101 transceiver with bad 6146A tubes. My question to you elmers is, can I put 6146W tubes in this radio, or does it have to have 6146A tubes? I know I have to neutralize the new tubes after I install them in he radio. I know some radios like the Kenwood hybrids had to have certain tubes. I was going to put 6293 tubes in it, but I found (2) 6146W NOS tubes at a really good price. I'm quite sure that there are some operators on here that are familiar with the SB-101. Any input greatly appreciated!
Logged
W5RKL
Member

Posts: 1107




Ignore
« Reply #1 on: December 15, 2018, 05:47:14 AM »

I  recommend 6146As. You can find them at

http://vacuumtubes.net/

for $22.

The final amplifier is the same in the HW-100/101, SB-400/401, and the SB-100/101/102 set of transceivers/transmitters.
They all operate in Class AB1.

The 6146As will last a long time providing the operator does not abuse them by trying to push for higher power output.
When properly tuned, the above transmitters will produce approximately 100 watts output into a 50 ohm load.
Switching to a "B or "W" or pulse version of 6146 Beam Power tube will not result in an increase in power output.

73
Mike W5RKL
www.w5rkl.com
RMC(SW) USN RET

Logged
KC1BMD
Member

Posts: 943




Ignore
« Reply #2 on: December 15, 2018, 08:21:39 AM »

See this well-respected reference:

The 6146 Family of Tubes
by Glen E. Zook, K9STH Copyright 2002 by author

Logged
KD0REQ
Member

Posts: 2364




Ignore
« Reply #3 on: December 15, 2018, 08:31:15 AM »

best conclusion I've come to is, depends. most Heathkits should have enough latitude in the neutralization to make them work. a few folks have had trouble.  since you have the tubes on hand, give it a try. all you've got to lose is a few hours of fooling around if they don't stay stable.
Logged
WA5VGO
Member

Posts: 69




Ignore
« Reply #4 on: December 15, 2018, 11:25:52 AM »

Used them all in my HW-10 and SB-100. No problem with any of them.
Logged
KX4OM
Member

Posts: 353




Ignore
« Reply #5 on: December 15, 2018, 03:11:42 PM »

GE 6146Ws did not neutralize in my HW-101. The rig came to me several years ago with one 6146 and one 6146A. After the 6146W trial, I put GE 6146B tubes from RF Parts in it, and it still works fine. The 6146W tubes were NOS new from the FAA directly to me in 1979. I used them briefly, about 3 months in my SB-100 before I sold it (sans the 6146W finals.) I suppose I could try the 6146Ws in my Tempo 2020, which has the original Toshiba 6146B tubes in it. The 6146x tubes and Heathkit continue to be a mystery to me. Glen's article on the family provides insight, especially Heathkit's stock of relabeled tubes from the vendor after the 6146A stock ran out.

Ted, KX4OM
« Last Edit: December 15, 2018, 03:22:44 PM by KX4OM » Logged
N0XAX
Member

Posts: 49




Ignore
« Reply #6 on: December 15, 2018, 04:52:07 PM »

Thank you all for your replies. I'm going to try the 6146W tubes and see what happens. If they won't neutralize correctly, then I will put 6146A tubes back in it. FYI: The RCA tubes in this have a date code of 9-67! These are probably the original tubes in this radio? The grids are bad in both tubes. Also, the operator that had this radio knew tubes! 75% of the tubes are original Mullard tubes and they all check better than 90% or better! I have a Sencore Continental tube checker that also checks mutual conductance as well on certain tubes. Thank you again, and I will also check out those links. I'll let you all now how it turns out. Oh, also, I have to find an rf probe for my heathkit vtvm! I saw where this is needed in the neutralization procedure! So it's off to find an rf probe. 73
Logged
KD0REQ
Member

Posts: 2364




Ignore
« Reply #7 on: December 15, 2018, 06:17:16 PM »

Make the probe, diagrams clutter the web.
Logged
KB2WVO
Member

Posts: 443




Ignore
« Reply #8 on: December 16, 2018, 11:58:45 AM »

Thank you all for your replies. I'm going to try the 6146W tubes and see what happens. If they won't neutralize correctly, then I will put 6146A tubes back in it. FYI: The RCA tubes in this have a date code of 9-67! These are probably the original tubes in this radio? The grids are bad in both tubes. Also, the operator that had this radio knew tubes! 75% of the tubes are original Mullard tubes and they all check better than 90% or better! I have a Sencore Continental tube checker that also checks mutual conductance as well on certain tubes. Thank you again, and I will also check out those links. I'll let you all now how it turns out. Oh, also, I have to find an rf probe for my heathkit vtvm! I saw where this is needed in the neutralization procedure! So it's off to find an rf probe. 73

if u have a Oscope. there is a video on neutralization with a Oscope.. YOU MUST REMOVE THE HV FROM TUBES...
its on utubers. i did it on the sb110 i have worked great. check for sb110 on utubers. iam guessing bein same tubes and probley same final section probley close..

found vid for ya..

https://youtu.be/5n-BdFx2HT8
« Last Edit: December 16, 2018, 12:01:22 PM by KB2WVO » Logged
AD4U
Member

Posts: 2537




Ignore
« Reply #9 on: December 16, 2018, 04:34:42 PM »

Why not just buy a new pair of 6146A tubes and be done with it. I built a SB 101 in 1970. This was my first "real" rig. I used it daily until around 1985 when I bought a Drake station. I still have and still use my SB 101 and it still uses the original 6146A tubes that came with the rig and they still give 100+ watts in 2018. The purpose of my post is to say a pair of NOS 6146A tubes should run DECADES if operated properly.

Dick AD4U
Logged
G3RZP
Member

Posts: 1165




Ignore
« Reply #10 on: December 19, 2018, 03:06:49 AM »

NEVER remove the plate supply to tetrodes WITHOUT removing the screen grid supply. If you do, all the current goes to the screen and over-dissipates it.
Logged
K1DA
Member

Posts: 744




Ignore
« Reply #11 on: December 30, 2018, 11:46:20 AM »

Read Glen Zook's work as previously mentioned.   6146w tubes could be EITHER a standard 6146 OR a 6146B which requires different neutralization. 
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!