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Re: [Amps] Tubes vs. Solid State (was) Expert Amps 2K-FA: Any Opinions ?

Subject: Re: [Amps] Tubes vs. Solid State (was) Expert Amps 2K-FA: Any Opinions ?
From: Rob Atkinson <>
Date: Sun, 29 Apr 2012 15:56:36 -0500
List-post: <">>
On Sun, Apr 29, 2012 at 2:31 PM, W2XJ <> wrote:
> Well, not as flawed as one might think. SS is now less expensive than
> the almost impossible to find tube TXs. I don't think anyone makes a
> tube BC TX below 10 KW and you have to go to Eastern Europe to find a
> new tube TX below 50 KW. Manufacturing processes and better solid state
> devices like LDMOS have been a real game changer.  Other things such as
> eliminating power transformers along with most cable harnesses also help
> lower prices. A 50 KW AM transmitter is now less than 2 racks wide. A
> new LDMOS 40Kw FM TX is 19 inches wide by about 6 feet high.

You are fixated on 10, 40, 50 KW broadcast gear as some sort of
barometer or defining standard for ham radio.  I love AM medium wave
broadcasting and the people in it to death but there is little overlap
between it and ham radio in terms of RF, even on 160 m., albeit there
a lot can be learned from observing transmitter sites.   Broadcasters
only have to worry about the gear, plant, everything working on one
frequency with a flat vswr curve 20 to 30 kc wide (that's the hard
part); they don't have to worry about receiving (except to monitor
their own sig).

> Old amps have the problem of deteriorated wire harness and deteriorating
> insulation.

Replace them.

They have other components other than tubes that are
> unobtainium as well. I had to scrap an old Kenwood for just that reason.

What was unobtainium?

> The THP 2.5K that replaced it was much more capable. Personally I would
> not invest in a new tube amp only to use old or poorly quality
> controlled new tubes. An Alpha manually tuned AMP and a THP 2.5K Solid
> state automatically band switched amp cost about the same new.  The
> Alpha uses a pair of 4cx1000s which are still stocked new.

Run your THP whatever it is at 1500 w. into a dummy load for 30
minutes and let me know how it does.

> To each their own (and this hobby is a different experience for each of
> us), but the forward looking path is solid state.

Not if you build your own.

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