[AMRadio] Modulator design needed


Brett gazdzinski brett.gazdzinski at verizonbusiness.com
Sun Mar 26 20:09:12 EST 2006


I never had much luck getting 6146's sounding good as modulators,
I think it takes a fair amount of effort.


The KT88 or KT90 on the other hand works great in AB1.

The KT90 is reasonable in price, and can run up to 800 volts or more,
170 watts out I think in AB1 at low distortion.

Brett
N2DTS


 

> -----Original Message-----
> From: amradio-bounces at mailman.qth.net 
> [mailto:amradio-bounces at mailman.qth.net] On Behalf Of Mike 
> Dorworth, K4XM
> Sent: Sunday, March 26, 2006 5:05 PM
> To: Discussion of AM Radio
> Subject: Re: [AMRadio] Modulator design needed
> 
> 6146.... AB-1, 500 volts, 75 watts, 600 Volts, 95 watts, 750 
> Volts, 120
> watts..
> 
> I thought the original question was to modulate a Johnson 6N2 
> which uses a
> 5894. Usually one uses the same Plate supply for the final as 
> the modulator.
> The 6146 gives way too much power for the voltage rating the 
> 6N2 would use,
> 450-600 Volts. The AB-1 807 or some of the hotter 6L6 
> versions such as 6L6GC
> seem more in the same voltage line to give the power needed.
> 
> The Viking II could do the whole job with a Ceramic 4 pole, 2 position
> switch as shown in Bill Orr's 14 Edition Handbook (his First) 
> It was mounted
> on the rear apron along with a 3 lug terminal strip.
> 
> In the older 12th Edition (Editors and Engineers) there is 
> shown a phase
> inverter driving 6V6's and also one driving pair 813. A 6C4 
> in the former
> and a pair of 6SJ7's in the later case. On the AM Forum 
> Archives there is a
> pair of 4-400's driven in AB-1 by a pair of 2E26. Google 
> N9FOY and click on
> modulator. Circuits from 6AQ5, 6V6, 807, 6146, 813, 4-400 all 
> published and
> none using driver transformers shows this is an OK way to go 
> for most any
> power level.
> 
> Mike
> 
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