Question about Swan 1200x amp

Discussion in 'General Technical Questions and Answers' started by K8DLM, Nov 7, 2008.

Thread Status:
Not open for further replies.
ad: L-HROutlet
ad: l-rl
ad: Subscribe
ad: K3QNTad-1
ad: L-rfparts
ad: l-gcopper
  1. K8DLM

    K8DLM Ham Member QRZ Page

    I just bought a swan 1200x amp off of ebay and was just wondering if anyone has used this amp and how they like it. Also I have been doing some checking and I have a kenwood ts 140s and need to make a cable to go from the radio to the amp so it keys it. I have the manual and it seems pretty simple, is there anything I need to be aware of when doing this. Thanks for the help.
  2. K9STH

    K9STH Ham Member QRZ Page

    You need to make sure that the keying voltage/current can be handled by the TS-140S. To be safe you probably should build a simple relay circuit using a 12 VDC coil relay to "key" the linear. The manual is not on BAMA so I could not verify the keying voltage / current.

    Attached is a schematic of a control relay that you can make for around $15. I originally drew it for a similar question involving a Heath SB-200 linear and another transceiver. But, substitute Swan 1200X for SB-200 and your transceiver for the one listed and you can build the circuit.

    Glen, K9STH
  3. K8DLM

    K8DLM Ham Member QRZ Page

    More information

    Thanks for the help. One the diagram for the pin outputs in the manual they are as follows (see attached file) Can you help me to which the amp would connect to. Also attached is the file for the amp and how it connects to the radio. Thanks
  4. K9STH

    K9STH Ham Member QRZ Page

    The resolution of your scan of the 1200X connection is very bad (you need to rescan at a much higher resolution). From what I can "make out" there is a cable labeled "relay control". This cable needs to connect to the normally open relay connections on the circuit that I gave you.

    Next you need to see if pin 2 of your remote connector goes to ground. If so, then you need to connect the wire from the relay coil (of the circuit I gave you). Of course the 12 volt source for the relay coil has to have the negative side connected to the chassis of your TS-140S. If you supply the 12 VDC to the relay circuit from the same power supply as the TS-140S then you won't have any problems.

    If pin 2 does not go to ground (chassis of the transceiver) then let me know to what it is connected.

    Glen, K9STH
  5. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Be really careful with the 1200X. It used sweep tubes that were cheap in the early 70s and are very expensive today. Longer tune up periods (and "long" is anything more than 10-15 seconds with sweep tubes) can destroy the tubes faster than lickety-split.

    Hope you didn't pay a lot for the 1200X; they go at the local swap meets here for about $150 in very good condition.

    Glen's right, you probably need to use a keying interface such as he suggested. Other than that, you should be good to go.

  6. W9GB

    W9GB Ham Member QRZ Page

  7. N8BHL

    N8BHL Ham Member QRZ Page

    1200 homebrew

    Doug, I agree with everybody- the relay circuit is 'different' on the 1200- in its undisturbed state, it expected to see 12 volts from the accompanying Swan radio. Almost any schematic you download for this will contain an anternate connection scheme, with a simple open/closed connection to a relay that keys the amp. It's no problem. In fact, you might want to check to see if that hasn't already been done. I built an amp copying the 1200 using the 4 sweep tubes and it performed very well- you should like this amp. I'd be careful not to over-drive it to save the tubes, but it should handle pretty much anything you give it. Good old basic amp!
Thread Status:
Not open for further replies.

Share This Page