We actually had one of those Tokyo amps here in the club.
It is Tokyo High power HL-1K
Very nice little thing. We sold it together with a THP HL-2K
to invest in a OM Power amp...
The 1K had acceptable IMD.
Peter
----- Original Message -----
From: "Carl" <km1h@jeremy.mv.com>
To: "LA7SL Nils Petter" <la7sl@norgespost.no>; <amps@contesting.com>
Sent: Friday, April 01, 2011 8:41 PM
Subject: Re: [Amps] 813 Amplifier Article
> Tokyo High Power had a nice compact 2x 4X150/250 amp that was Super
> Cathode driven. Ive repaired a few but didnt have the equipment at home
> then to run IMD tests.
>
> The NCL-2000 may have been the first commercial linear (1963) to use a 50
> Ohm swamped grid input. In that tap position it would do 1200W out key
> down with 15-20W drive.
>
> Carl
> KM1H
>
>
>
> ----- Original Message -----
> From: "LA7SL Nils Petter" <la7sl@norgespost.no>
> To: <amps@contesting.com>
> Sent: Friday, April 01, 2011 2:16 PM
> Subject: Re: [Amps] 813 Amplifier Article
>
>
>>I ran 2x 4cx250B grid driven with passive grid in AB2.
>> Grids loaded by 50ohms dummy load and bias feed on
>> "inside" of grid coupling C via RFC (could have coupled
>> bias to ground side of dummy R but then I would have
>> needed a real RF bypass cap there to handle the drive power.
>> I got away with a regular 200V disc :-)
>> G2 fed with normal voltage and bypassed to ground. I got into trouble
>> with my first screen supply as those tubes draw negative G2 current
>> over part of operating range. That solved ,-this little amp performed
>> flawlessly more than three years. The driver was a FT901 (tuned output)
>> so the IMD was not too bad. Pwr out was in the range 650 watts. The amp
>> was a monoband 75 meters job. Worked a lot of good DX phone on it !!
>> Telling this just to show that it does not take much to get a respectable
>> signal, not much work or professional skill either really.
>> My next project was a very similar thing, just BIGGER :-) using
>> QBL5-3500's
>> Those are 3KW plate diss jobs... and tuned grids this time,- but that is
>> a
>> different
>> story...nearly burned down my barn on the farm here.... too tight
>> coupling
>> to
>> something apparently :-) Did not work much more DX on that one, I just
>> did
>> not
>> have to spend the same amount of time in the pileups....
>> Now I am 61 and have become an appliance operator...
>> Peter
>> ----- Original Message -----
>> From: "Fuqua, Bill L" <wlfuqu00@uky.edu>
>> To: "Rob Atkinson" <ranchorobbo@gmail.com>; "Carl" <km1h@jeremy.mv.com>
>> Cc: <amps@contesting.com>
>> Sent: Friday, April 01, 2011 7:28 PM
>> Subject: Re: [Amps] 813 Amplifier Article
>>
>>
>>>I once knew a guy in Nashville, John Brown, who loved building amplifiers
>>>in the 1960's.
>>> He made a RF deck that he drove with his TR3 or TR4 which he could
>>> change
>>> sockets and
>>> try different tubes that most people would not try or had be advised not
>>> to try.
>>> One setup was four 4-65As in grounded grid. Talk about hot plates when
>>> he
>>> pushed up the plate input power. They were a bright yellow
>>> Another set up was 4x 4CX250bs or were they 4X150A/7034? No difference
>>> really.
>>> He tried direct grounded grid, they were toasted. Then connected the g1
>>> to k and low
>>> power gain but worked well and lastly he tried g1 to ground via a
>>> resistor
>>> to limit grid dissipation.
>>> None worked out to his satisfaction.
>>> 73
>>> Bill wa4lav
>>>
>> _______________________________________________
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>
>
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