What is a Drake L4B worth that has no power supply?

Discussion in 'Amateur Radio Amplifiers' started by K8CCA, Apr 9, 2021.

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  1. AG5CK

    AG5CK Premium Subscriber QRZ Page

    The prices people ask for a Heap(can I say that here) SB220 is crazy. They're fine for SSB but a light weight transformer and poor cooling system doesn't appeal to me. I feel like they should have only used a single 3-500 for that dinky transformer.
     
  2. W1BR

    W1BR Premium Subscriber QRZ Page

    A power supply could be built around an AnTek power transformer-they are an inexpensive option. The filament winding might be possible by adding a few turns on the AnTek, which are toroids. If the RF deck could be had for a reasonable price it would be a fun project for an avid homebrewer who has some experience.
     
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The L-4B has its filament transformer in the RF deck section. The L-4PS is only a B+ supply, but still a challenge for anyone who hasn't built stuff before and maybe scary for those who never worked around high voltage.

    An issue in this case is that without the supply (where'd it go?), the seller likely has no way to test the deck so it could have bad tubes, which would reduce its value by about $450 (!) if the buyer has to obtain new ones.
     
  4. W9JSW

    W9JSW Ham Member QRZ Page

    I bought mine sans PS for $200. Two tubes were present that the seller reported to be OK. Later found that one was defective. I built a PS for it (see QRZ page) using an antek trans and a harbach board. Wired for 220 only but uses the correct multi-conductor cord with jones plug. Later on found another Eimac tube for $125. So, have around $600 in it.

    Works well. Looking back I think the $200 I paid was over-priced given the unknowns and what it takes to build a PS.

    My 2 cents...
    John
     
  5. G3YRO

    G3YRO Ham Member QRZ Page

    Personally, if it was here in Britain, I would certainly pay $500 for this.

    Even if both 3-500s were duff, it would still be well worth the money. Given that the Amp has its own Filament Transformer inside, it wouldn't be that expensive or hard to knock up an HT supply.

    A working L7 or TL-922 would normally sell for the equivalent of $1,400 to $1,700 over here.

    When you consider that a new AL-82 costs over $3,500, that's pretty cheap. (and they're not nearly as well engineered)

    Roger G3YRO
     
    Last edited: Apr 12, 2021
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page



    Usually not here. Too many in circulation.
    AL-82 new here is $3100 but there are a lot of them in circulation also, so the used prices are under $2K, and for years were in the $1500 range (probably up higher now because the "new" price has increased). AL-82 runs more power than an L-4, L-7 or TL-922, although in the U.K. with the 400W power limit that probably doesn't mean anything. But the higher power comes from higher anode voltage in the '82. And it has a much more robust power transformer than the other amps; no thermal limit switches or anything needed, the transformer can deliver 1A CCS forever.

    I do like the L-4B and L-7 in that they have a separate HV power supply, which makes the RF deck lighter and much easier to carry around. AL-82 is very heavy.

     
  7. K8CCA

    K8CCA Ham Member QRZ Page

    Thanks for the insight guys. I am going to look at this gear this evening.
     
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Ask "what happened to the power supply?" and "is there any way to demonstrate this so I know the tubes are good?"

    Remember 3-500Zs today cost $225 each or so.
     
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Quick search finds the typ selling price for a complete L-4B with the power supply and claimed working tubes with full output power is about $875. Like this one:
    l-4b.PNG
     

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