Drake L4B

[Mr Clean]

Anyone ever use one? Have been reading they are built very well. Power supply sounds like it could be bigger but if it will do 1200 pep it would be enough for me.

 

[W5LZ]

They are nice amplifiers. The 'L4-B' is a typical two tube 3-500 amplifier. Does about like any other 3-500 amplifier of the same period. Output depends more on the tubes than anything else, new/used/how used, sort of thingy.
That '1200w Pep' is with SSB, expect something about half that or less for AM/FM. Typical drive was something around 75-100 watts.
All amplifiers have their own particular qwerks. Not necessarily good or bad, just different. It's a good thing to talk to a few users (I've used one but not for very long, and that was a long time ago), find out what they thought was the amplifier's worst fault or characteristic. (Summer time, no air conditioning, expect to sweat! )
- 'Doc

 

[Beetle]

Remember, it's rated 1KW on AM/CW/RTTY and 2KW SSB. And that's DC power INput. Class B. Figure around 60% efficiency.

Also don't expect the output at 11 meters to be quite as high as on 20 meters, even with new "Graphites".

 

[W5LZ]

"Power supply sounds like it could be bigger"
--
Yes, it could be. But then, it wouldn't fit inside that box anymore, or maybe on the desk. Both of which were considerations when it was designed something like 30 years ago to compete with the 'other' similar amplifiers on the market. None of those 'old' amplifiers were designed to be the "end-all" of power makers. They were designed to give a sort of moderate, but long-lived service, which they have (they'er still around, ain't they?).
- 'Doc


PS - One little known fact that isn't spread around much is that any thingy that produces much power tends to drop the stray electron now and then (usually fall to the bottom of the thingy's case). Those electrons do have mass. After heavy use, the desk/table it sits on tends to creak a bit. Now you know why...

 

[Toll_Free]

"Power supply sounds like it could be bigger"
--
Yes, it could be. But then, it wouldn't fit inside that box anymore, or maybe on the desk. Both of which were considerations when it was designed something like 30 years ago to compete with the 'other' similar amplifiers on the market. None of those 'old' amplifiers were designed to be the "end-all" of power makers. They were designed to give a sort of moderate, but long-lived service, which they have (they'er still around, ain't they?).
- 'Doc


PS - One little known fact that isn't spread around much is that any thingy that produces much power tends to drop the stray electron now and then (usually fall to the bottom of the thingy's case). Those electrons do have mass. After heavy use, the desk/table it sits on tends to creak a bit. Now you know why...

Heres a tip for everyone using an L4B. Pull those goddammed equalizing resistors out of the thing and cap it with newer low ESR caps.

That thing burns up hundreds of watts in the already flaky power supply by equalizing resistors. You can see > 250 pep watts, for free, by doing this. Some report even more pep output increase.

--Toll_Free

 

[gc505]

Here's my Drake L-4B, I love it. I use it primarily on 80, 40 and 20 meter SSB, but it performs well on AM.

The power supply was rebuilt (with a heavy dose of Viagra) and does 3300v instead of the stock 2800v, with a 100 watt drive I see 1800 PEP on 80m SSB, 1700 PEP on 40m SSB and 1600 PEP on 20m SSB. 10-11m AM sees 1300 avg with 1600 peaks, but I don't drive it that hard very often... that's what the X-Force 2x10 is for.

 

[gc505]

double post...

 

[SteveG]

I've used one at Field Days in years gone by. Drake made this amp to standards few dual 3-500Z makers ever matched, with a few exceptions. A couple of others produced dual 3-500Z amps that were of equal or better quality. Henry made several versions back then that competed.

Even today, QROTEC makes one that is built better, and with new technology and components. Even Ten-Tec makes a nice dual 3-500Z amp today, but with an equal or slightly less-capable internal power supply. Both are highly rated, and well designed.

Back to the L4Basher...

Because of their old age, the electrolytics and equalizing resistors will need to be replaced in the power supply. A highly recommended and complete HV power supply upgrade kit is available from the Heathkit Shop, URL: http://www.theheathkitshop.com/page10/page10.html . Check this site out.

If the amp is in great condition, was used by those with their heads screwed on straight, and taken care of... I would not hesitate. It's a great amp, and easy to work on.

Oh... I wouldn't run the amp much, if at all, until the electrolytics are replaced... unless you like hearing firecrackers going off and nasty, noxious smoke being released -- a general mess on your hands.

Good Luck!

Anyone ever use one? Have been reading they are built very well. Power supply sounds like it could be bigger but if it will do 1200 pep it would be enough for me.